- Email: [email protected]
The worldwide epidemic of female obesity
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The worldwide epidemic of obesity Q6 Q1
Sheona Mitchell, MD, MPH, FRCSC a, 1, Dorothy Shaw, MB, ChB, FRCSC a, b, * a
University of British Columbia, Northern Medical Program, 3333 University Way, Prince George, BC V2N 4Z9, Canada b British Columbia Women's Hospital and Health Center, B242, 4500 Oak Street, Vancouver, BC V6H 3N1, Canada
Keywords: obesity reproductive health LMIC
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The rapidly rising number of individuals who are overweight and obese has been called a worldwide epidemic of obesity with >35% of adults today considered to be overweight or obese. Women are more likely to be overweight and obese than their male counterparts, which has far-reaching effects on reproductive health and specifically pregnancy, with obese women facing an increased risk of gestational diabetes, preeclampsia, operative delivery, fetal macrosomia, and neonatal morbidity. The etiology of obesity is highly complex encompassing genetic, environmental, physiologic, cultural, political, and socioeconomic factors, making it challenging to develop effective interventions on both a local and global scale. This article describes the extent and the cost of the obesity epidemic, which, although historically seen as a disease of high-income countries, is now clearly a global epidemic that impacts low- and middle-income countries and indigenous groups who bear an ever-increasing burden of this disease. © 2014 Elsevier Ltd. All rights reserved.
* Corresponding author. British Columbia Women's Hospital and Health Center, B242, 4500 Oak Street, Vancouver, BC V6H 3N1, Canada. Tel.: þ1 604 875 3536. E-mail addresses: [email protected] (S. Mitchell), [email protected] (D. Shaw). 1 Tel.: þ1 250 960 5430.
http://dx.doi.org/10.1016/j.bpobgyn.2014.10.002 1521-6934/© 2014 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Mitchell S, Shaw D, The worldwide epidemic of obesity, Best Practice & Research Clinical Obstetrics and Gynaecology (2014), http://dx.doi.org/10.1016/j.bpobgyn.2014.10.002
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Definition Obesity was first recognized as a disease by the World Health Organization (WHO) in 1948 at the time of its formation [1], and since then multiple measures have been trialed to accurately measure body fat percentage, the most accepted of which is body mass index (BMI) measured in kilograms of weight per meter squared of height [2]. Although, historically, obesity has been considered a disease primarily of industrialized countries, there are now growing data on the rising prevalence of obesity across the world as it becomes a leading cause of morbidity and mortality globally [3,4]. Much controversy exists over the use of BMI as an indicator of body fat mass because the percentage of body fat differs by sex, age, and ethnicity making it an imperfect tool for categorizing individuals who are overweight and obese [5]. Two individuals with the same BMI may have markedly differing percentages of total body fat. Other guidelines suggest the use of waist circumference as an assessment of visceral fat as this is a better correlate with insulin resistance and metabolic dysfunction [6]. Despite its limitations, BMI is a general reflection of body fat mass and is widely used globally [2,5,7]; it also correlates with the risk of morbidity and mortality associated with obesity [8,9] as well as all-cause mortality. Adults with a BMI of 25e30 kg/m2 are considered overweight and those with a BMI of >30 kg/m2 are defined as obese [2]. Scope of the epidemic An estimated 1.1 billion adults were considered overweight in 2005 [9], and this is predicted to increase to 1.5 billion by 2015, 300 million of whom are classified as obese [10] (see Fig. 1). A staggering 35.8 million disability-adjusted life years (DALYs) are lost due to overweight and obesity accounting for 2.3% of global DALYs with 35% of adults globally considered overweight or obese [10]. Global obesity has doubled in the period between 1980 and 2008 with 2.8 million deaths attributable to this disease. Significant challenges present themselves in measuring the scope of obesity globally with additional barriers in low- and middle-income countries (LMICs). BMI is often calculated based on self-reported height and weight with inherent limitations of underestimating weight [1]. In LMICs, the country reporting is skewed by disparate accessing of health-care systems, with those of higher socioeconomic
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Fig. 1. Global prevalence of overweight and obesity in females aged 15 years and older, 2010. Reproduced, with permission of the publisher from “WHO Global Comparable Estimates”, 2010. (https://apps.who.int/infobase/Comparisons.aspx, accessed 22 August, 2014).
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status (SES) having more encounters with medical care and therefore passive surveillance of BMI rates disproportionately representing segments of society of higher SES [3,11]. According to the most recent data published in 2011 from the WHO, there is significant variation across the globe with the estimated overweight and obesity prevalence for women aged 15 years globally ranging from a low of 3.7% in Ethiopia to a high of 93% in Nauru [12] (see Table 1). The WHO region for the Americas represents the highest prevalence rates with 62% of both men and women Q7
Table 1 Prevalence of obesity by country and WHO world region. Reproduced with permission of publisher from “WHO Global Comparable Estimates,” 2010. (https://apps.who.int/infobase/Comparisons.aspx, accessed 22 August 2014). AFR
Ethiopia
AFR SEAR SEAR SEAR WPR WPR AFR
3.7 EUR 6.3 6.7 7.9 9.9 12.2 13.8 15.8
SEAR EUR EUR AFR AFR EUR WPR
Kazakhstan
38.9 AFR
Thailand Italy Romania Comoros Senegal Denmark Malaysia
Equatorial Guinea 52.3 WPR Brunei Darussalam 39.9 EUR Albania 52.5 EMR Jordan 40 AMR Honduras 52.5 EUR Slovenia 40.6 EUR Armenia 52.8 EUR Turkey 40.7 WPR Solomon Islands 52.9 AMR Bahamas 41 AFR Botswana 53.5 EMR Qatar 41.4 EMR Iraq 53.6 EMR Saudi Arabia 42.2 EUR Georgia 53.8 WPR Australia
65.4 65.7 65.7 65.9 65.9 65.9 66.5
67.2 67.2 67.3
Eritrea Bangladesh Sri Lanka Nepal Viet Nam Cambodia Democratic Republic of the Congo WPR Japan SEAR India AFR Burkina Faso
16.2 EUR 18.1 AFR 19.4 EUR
Belgium Benin Lithuania
42.9 EUR Finland 43.8 WPR Marshall Islands 43.9 EUR Austria
AFR
20
EUR
Kyrgyzstan
43.9 AMR Ecuador
AFR EMR AFR AFR AFR AFR AFR EMR AFR AFR
Central African Republic Zambia Afghanistan Burundi Rwanda Chad Kenya Uganda Somalia Madagascar Guinea-Bissau
54.5 AMR Cuba 54.7 WPR Vanuatu 55.2 AMR Venezuela (Bolivarian Republic of) 55.5 EUR San Marino
20 20.8 21.1 21.7 22.9 23.3 23.9 24 24.1 25.1
EUR EUR EUR AFR EUR EUR AFR EUR EUR SEAR
Ireland Poland Latvia Liberia Turkmenistan Bulgaria Cameroon Norway Netherlands Myanmar
43.9 44.3 44.7 45.4 45.5 45.5 45.8 45.8 46.1 47
55.8 56 56.1 56.2 56.7 56.8 56.8 56.8 57.1 57.4
AFR AFR
Niger Malawi
25.1 EUR 25.2 EUR
Sweden Hungary
Guyana Paraguay Suriname Luxembourg Lebanon Azerbaijan El Salvador Mauritius Germany The former Yugoslav Republic of Macedonia 47.2 EMR Morocco 47.4 AMR Belize
WPR Singapore
26.7 EUR
Tajikistan
47.4 AMR Haiti
AFR
Congo
26.8 AFR
Cape Verde
48
AFR Mozambique AFR Gambia SEAR Indonesia
26.9 EUR 27 EUR 27.1 EUR
Croatia Ukraine Serbia and Montenegro Sierra Leone
AFR
United Republic 28.7 AFR of Tanzania EMR Pakistan 29.5 WPR Lao People's Democratic Republic AFR Sao Tome 30.5 EUR Czech Republic and Principe WPR China 32 AFR Algeria
65.2
67.4
Malta Monaco South Africa Andorra Fiji Bahrain Belarus Peru Lesotho Guatemala
67.6 67.6 68.5 68.7 69.5 69.5 69.9 70.1 70.8 70.9
71.2 71.6
AMR Saint Vincent and the Grenadines 48.3 AFR Mauritania 48.5 EUR Switzerland 48.5 AMR Panama
57.5 AMR Argentina 57.6 EMR United Arab Emirates 57.7 AMR Dominican Republic 58.3 AMR Mexico
58.6 AMR Nicaragua 58.9 AMR Bolivia 58.9 AMR Chile
73.1 73.2 73.3
49.1 EUR
59.3 AFR
Seychelles
73.8
49.2 AMR Canada
59.5 AMR Saint Lucia
74.1
49.3 EMR Syrian Arab Republic 49.4 EMR Libyan Arab Jamahiriya
59.6 WPR New Zealand 74.2
AMR AMR AMR EUR EMR EUR AMR AFR EUR EUR
Israel
EUR EUR AFR EUR WPR EMR EUR AMR AFR AMR
59.8 WPR Mongolia
71.7 73
74.4
(continued on next page)
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Table 1 (continued)
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EMR
Yemen
32.2 SEAR Bhutan
AFR
Ghana
EMR WPR EUR WPR AFR
Sudan Philippines Estonia Papua New Guinea Namibia
32.5 SEAR Democratic People's Republic of Korea 32.5 EUR Spain 33.6 EUR Uzbekistan 33.8 AFR Zimbabwe 34 EUR Republic of Moldova 34.4 EMR Oman
EMR AFR
Djibouti Guinea
AFR
Togo
AFR
Cote d'Ivoire
AFR EUR
AFR AFR
49.6 EMR Iran (Islamic Republic of) 49.7 AMR Brazil
60.3 AMR United States 76.7
49.8 49.9 50.6 50.7
Grenada Colombia Tunisia Antigua and Barbuda 50.8 AMR Saint Kitts and Nevis 50.8 WPR Tuvalu 51 EUR Slovakia
60.4 61.1 61.4 62.1
51
AMR AMR EMR AMR
Nigeria France
34.5 SEAR Maldives 34.9 WPR Republic of Korea 35.5 EUR Bosnia and Herzegovina 36 SEAR Democratic Republic of Timor-Leste 36.8 EUR Portugal 36.9 EUR Russian Federation
Angola Mali
37.2 AFR 38.4 AFR
51.9 AMR Costa Rica 52.2 AMR Uruguay
Swaziland Gabon
60.2 EMR Egypt
WPR AMR EMR AMR
76
Kiribati Jamaica Kuwait Trinidad and Tobago 62.6 AMR Dominica
77.1 79 80.4 80.8
62.9 AMR Barbados 62.9 WPR Samoa
83.3 84.1 84.5
WPR Palau
80.8
EUR
Cyprus
63
51.1 EUR
Greece
63.2 WPR Niue
86.7
51.2 EUR 51.7 EUR
Iceland United Kingdom
63.7 WPR Cook Islands 63.8 WPR Micronesia, Federated States of 63.8 WPR Tonga 64.4 WPR Nauru
90.3 91.1
92.1 93
*AFR: African Region, AMR: Region of the Americas, SEAR: South-East Asia Region, EUR; European Region, EMR: Eastern Mediterranean Region, WPR: Western Pacific Region.
overweight and 26% obese compared to the WHO region for Southeast Asia, with only 14% of men and women considered overweight and 3% obese [10] as shown in Fig. 1. Overall, the Americas, Europe, and the Eastern Mediterranean report the highest rates of overweight and obese individuals. Women are more likely to be obese than their male counterparts matched for ethnicity and age [5]. Of the 193 countries for which data are available, 107 (55.4%) have reported overweight/obesity rates of >50% for women over the age of 15 (see Table 2). Any discussion of the global epidemic of obesity would be remiss if childhood obesity was not mentioned as this encompasses present and future challenges. As in adults, childhood obesity has drastically increased in high-income countries starting in the 1980s [13]. Instead of using BMI measurements, childhood overweight and obesity is measured by percentiles of height and weight for age with >85th percentile defined as overweight and children >95th percentile considered obese [14]. Not only are obese children more likely to become obese adults, but the children of obese parents also have a two to three times increased risk of becoming obese adults [15]. Estimates from both North America and European countries show that the prevalence of overweight and obesity have increased between 60% and 70% in the past two decades [14]. To a greater degree than overweight and obese adults, these children have drastically increased risks of developing diabetes, hypertension, dyslipidemia, and heart disease during their lifetime. Table 2 Prevalence of overweight and obesity in 193 countries. Source: “WHO Global Comparable Estimates,” 2010. (https://apps.who.int/infobase/Comparisons.aspx, accessed 22 August, 2014). Prevalence of overweight/obesity: ranges (%)
No. of countries total 193
3.7e19.9 20e34.9 35e49.9 50e64.9 65e79.9 80e93
12 31 43 59 37 11
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A neglected health issue Although obesity was always recognized as a disease by the WHO, it was primarily seen as a health problem of the developed world with the WHO focusing its efforts on low-income countries where undernutrition and infectious diseases were their priority. Despite reports in the 1970s and 1980s by both the American and British governments warning of the growing public health impacts of obesity on a global level, the WHO, with many competing priorities, did not identify it as a global priority [1]. A panel of experts from the United Nations, the WHO, and the Food and Agriculture Organization (FAO) in 1981 was formed to examine protein and energy requirements but obesity was still not seen as a leading health issue [16]. It is only more recently that the WHO has described obesity as a global disease that has been largely neglected; this change was catalyzed by many factors including a report in 1988 by the European region of the WHO calling the WHO on a global level to bring attention to obesity and significant work by the International Obesity Task Force (IOTF) [2,17]. It was not until an interim report published in 1998 on the prevention of the global epidemic of obesity after much lobbying by the IOTF that the WHO officially addressed the issue and distributed its recommendations to health ministries in all member states [2]. Cost of the epidemic Much of the cost of overweight and obesity comes from the related comorbidities associated with this disease. Obesity is the third most significant risk factor contributing to burden of disease in highincome countries [11]. It is estimated that nearly 45% of the health costs of diabetes are associated with obesity and nearly 25% of the burden of cardiovascular disease, specifically ischemic heart disease, is related to overweight and obesity [10]. The burden associated with several cancers can also be attributed to obesity, with an estimated 10% of cancer correlated with obesity [9]. Obesity increases the risk of hypertension, diabetes, venous thromboembolism (VTE), dyslipidemia, coronary artery disease, ischemic strokes, and arthritis, and has significant implications for reproductive health throughout the life course. With increasing awareness of the impact of overweight and obesity on health economics in the past decade, many high-income countries have estimated both the direct and indirect costs of obesity. Direct costs are those associated with medical treatment including medication, admission to hospital, rehabilitation, and cost of health-care workers, whereas indirect costs are often much larger encompassing costs that result from loss of work and decreased productivity due to disease or disability [18]. A 2010 prediction for the United Kingdom (UK) showed that treating obesity costs £9.4 million annually with comorbidities caused by obesity costing an additional £470 million each year [6]. Further indirect impact on the economy of the UK was estimated at £2 billion a year. The United States (US) total healthcare costs that are due to overweight and obesity have been predicted to double each decade and reach as much as $956 billion by 2030, which represents 18% of total health expenditures [19]. In the European Union, examination of the obesity trends of the 15 member states prior to 2004 estimated the direct and indirect costs of obesity to be nearly V33 billion [20]. A meta-analysis in Canada found that the total cost of obesity by 2004 estimates was $4.3 billion yearly with obesity representing 2.2% of total health-care costs and an additional 2.5% of health-care costs attributed to physical inactivity [21]. These amounts had more than doubled in the previous decade. Etiology The etiology of obesity is multifactorial, and there is much about the pathophysiology, genetics, and epigenetics of obesity that are not fully understood. There is evidence that the in utero environment plays a role in future obesity [22]; the most well-known study was done on a cohort of men whose mothers were pregnant during the Dutch famine in the mid-1940s. Those whose mothers had very poor nutrition during the first half of their pregnancy were more likely to be obese as adults suggesting the impact on hypothalamic centers in the brain during pregnancy [23]. Such findings raise questions about the impact of poor nutrition due to poverty and conflict in developing countries and fragile states as well as marginalized populations. The etiology is further compounded by cultural, political, Please cite this article in press as: Mitchell S, Shaw D, The worldwide epidemic of obesity, Best Practice & Research Clinical Obstetrics and Gynaecology (2014), http://dx.doi.org/10.1016/j.bpobgyn.2014.10.002
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socioeconomic, ethnic, and geographic differences. The global market has been flooded with caloriedense foods including those with high-fructose corn syrup and much higher contents of refined fats contributing to changing patterns of food consumption and the rise of fast food in higher-income countries [7]. Additionally, the built environment, particularly in high-income countries, is designed to decrease the distance that individuals need to walk during their daily activities and this decreased energy expenditure is also postulated to exacerbate the obesity epidemic [24]. The etiology of obesity is complex and encompasses deeply held cultural beliefs, societal structure, genetic predisposition, socioeconomic issues, physiological changes to the endocrine system of the body, and potentially epigenetic contributions over the course of generations [22]. Global efforts to limit the intake of highly refined sugars have also been limited by powerful lobbying from the food industry who have attempted to draw attention to the economic impact that recommendations to restrict sugar intake may have [5]. The Expert Technical Consensus on Diet, Nutrition and the Prevention of Chronic Diseases produced by the WHO in the late 1980s recommended a sugar intake of 0e10%; the evidence base for this was immediately questioned by several large players in the food industry representing the larger sugar lobby despite its logical public health implications [1]. These recommendations around carbohydrate intake were later removed from WHO publications as a result of this controversy and do not appear in the interim report published in 1988 [2]. The increasing availability of low-cost highly refined oils and the increasing contribution of carbohydrates to traditional diets in LMICs contribute to the growing number of overweight and obese people [4]. Drastic changes in physical activity with a preference for sedentary activities such as video games and television in high-income countries and changing lifestyles in LMICs, with migration from rural to urban settings, are further exacerbating the epidemic across the globe. Globalization has been central to the changing availability of affordable high-caloric-density foods across the world, and the resulting cultural changes are challenging to quantify as populations shift away from traditional lifestyles to ones that involve less physical activity. All of these factors contribute to the complex nature of the obesity epidemic. Low- and middle-income countries Unique challenges and trends present themselves in LMICs. Despite a recent worldwide economic recession and a growing global food crisis, the number of overweight individuals is growing across LMICs and the number of those underweight, historically seen as the main population of concern in LMICs, is decreasing [25]. Surprisingly, approximately two-thirds of women in the Middle East and North Africa are overweight or obese and half of the women in Central and South America and the Caribbean are in this category. In response to the growing number of overweight and obese populations across Latin America, the Pan America Health Organization (PAHO) has specifically targeted obesity and recognized its association with poverty at an organizational level. However, much of the impact of their recommendations relies on individual governments where investment to address obesity has thus far been lacking [26]. The greatest impact of the epidemic has thus far been in primarily urban areas in these low-resource setting but is having a growing presence in more rural environments [11]. Obesity is more prevalent in women of higher socioeconomic classes in LMICs; however, as these countries have developed economically and national gross domestic product (GDP) rises, obesity disproportionately affects women of lower SES [4]. Although we have seen that higher levels of education are associated with lower rates of obesity in high-income countries, this is not the case in LMICs and, in fact, higher rates of obesity may be seen in more educated populations in LMICs. Globalization with its spread of fast-food chains and traditionally “western” foods that are often calorie dense, high fat, and more likely to contain high-fructose corn syrup in beverages has been postulated as contributing to growing levels of obesity in LMICs [4,7]. This is reflected in the increasing consumption of fast food in developing countries, which are initially mostly consumed by higher-SES groups but later affect lower socioeconomic groups over time as fast food becomes more economical and affordable. Additionally, cultural norms in certain countries associated overweight and obesity with wealth, power, and higher education for both men and women, however more markedly affecting women as appearing healthy for childbearing [5,27]. In sub-Saharan Africa specifically, where human immunodeficiency virus (HIV)/ Please cite this article in press as: Mitchell S, Shaw D, The worldwide epidemic of obesity, Best Practice & Research Clinical Obstetrics and Gynaecology (2014), http://dx.doi.org/10.1016/j.bpobgyn.2014.10.002
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acquired immunodeficiency syndrome (AIDS) is associated with malnutrition, wasting, and thinness, being overweight is associated with health instead of illness [4]. It is estimated that over one in five pregnant women are overweight and obese putting them at a risk of preeclampsia, gestational diabetes, fetal macrosomia, and cesarean delivery [6]. A recent study from Iraq demonstrates the health-care systems level implications of the increased need for cesarean sections in overweight and obese pregnant women stressing health systems that are already stretched to their limits [28]. If overweight and obese populations in LMICs continue to increase as predicted, there are significant implications for increased maternal and neonatal morbidity and mortality as access to timely cesarean sections is already a challenge in many LMICs. Prentice has described the added cost of obesity in low-income countries as a “double burden,” adding to the already overwhelming burden of infectious diseases such as malaria, HIV/AIDS, and tuberculosis [4]. Obesity, diabetes, and a long list of comorbidities associated with these will continue to complicate delivery of reproductive care in many resource-poor settings. Although more women than men across high- and low-income countries are overweight and obese, the gender divide is most stark in some of the poorest countries; a study from Gambia reported that 17 times as many women than men were obese and this is reflected in several African countries [4]. Cultural and ethnic differences Culture is the single most powerful factor that influences how, when, and why people eat and the amount of physical activity that they engage in recreationally or as part of their daily activities [24]. Culture varies over time and with migration as people from diverse areas of the world move and resettle. Sociologic studies have attempted to look at perceptions of weight across cultures and have found that 80% of over 60 cultures that were examined preferred fatter body types [29] noting that the preference for slim body types seems to be isolated to postindustrial societies [24]. Trends in obesity show much variation between ethnicities. In the US, significant differences are seen among Mexican American, non-Hispanic black, and non-Hispanic white women with the lowest rates of obesity in nonHispanic whites, but these disparities are not present for men across ethnicities [5]. Women are more likely to be obese than men, and in the US the rates of obesity overall are higher in African American women than in white and Hispanic women [30]. Similarly, in the UK, obesity is more prevalent in people of Black Caribbean or Black African ancestry or in those of Irish descent relative to the rest of the population [7]. In Canada, the lowest rates of obesity occur in their Southeast Asian population and is markedly lower than other ethnic groups [31]. Interestingly, the gendered differences in obesity despite ethnicity are attributed to both physiological and cultural differences. Predictions from the US for the year 2030 based on current trends in obesity are that >50% of the population will be obese with >85% overweight, and those most significantly affected by obesity will be black women and Mexican American men with >90% of both of these groups predicted to be overweight [19]. Indigenous populations Overweight and obesity disproportionately impact indigenous populations from as disparate areas of the world as the Canadian Arctic to South Pacific islanders [31,32]. Maori populations in the South Pacific have the highest prevalence of obesity in the world with >90% of the population classified as overweight and obese [10]. Historically, much of this has been attributed to the positive light that an overweight body habitus is seen in as representing health, wealth, and potential evolutionary benefits [32]. This draws attention to the powerful influence of culture on the rates of obesity and sheds light on how diverse cultures have differing views of obesity and may not see being overweight as a disease state, but instead a sign of health. Canada's aboriginal population, which makes up an estimated 3.4% of the total population, have a much higher prevalence of obesity than their non-aboriginal counterparts for both childhood and adult obesity, a trend that is most marked for on-reserve aboriginals [31]. Explanations for this are varied but, in a large part, are attributed to transitioning away from traditional lifestyles that in the past involved manual labor and a hunter-gatherer culture to more sedentary lifestyles and drastic dietary changes [33]. A higher prevalence of type 2 diabetes and cardiovascular disease has also been described for the aboriginal population than for non-aboriginals across Canada Please cite this article in press as: Mitchell S, Shaw D, The worldwide epidemic of obesity, Best Practice & Research Clinical Obstetrics and Gynaecology (2014), http://dx.doi.org/10.1016/j.bpobgyn.2014.10.002
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[34]. Specific challenges present themselves during pregnancy due to the high rates of gestational diabetes and preexisting diabetes in pregnant Canadian aboriginal women with implications for the provision of clinical services for those who do not dwell in urban centers and populate geographically disparate regions that are located far from centers able to provide caesarean sections if required. Higher rates of overweight and obesity are also seen in indigenous populations in Australia. McDermott et al. have described aboriginal and Torres Strait Islander (TSI) women in rural and remote populations in Northern Queensland with an obesity prevalence of 40% for aboriginal women and nearly 70% for TSI women [35]. High rates of micronutrient deficiency, alcohol, and tobacco use were also reported, and nutritional intake was poor in a population with overall very low socioeconomic indicators and an incidence of diabetes between three and six times the national average. Obesity in these populations along with its significant comorbidities are impossible to separate from SES, food insecurity, and a history of colonialism, which has historically pushed them to the margins of society. Latin America has undergone an enormous economic transformation over the past two decades with a widening gap between the richest and poorest in many Latin American nations as we see a growing prevalence of overweight and obesity. Indigenous populations have also been impacted by this economic growth; studies of the Mapuche in Chile and Aymara in Bolivia have described increases in obesity as a result of changing lifestyles to adapt to the industrialization that has occurred in those countries [36]. Urban indigenous populations are particularly affected by these changes compared to their rural counterparts who retain more of their traditional diets and physically active lifestyles. Indigenous populations around the world are diverse and generalizations should not be made on a global level, yet repeatedly in many countries we see that aboriginal and indigenous peoples have been disproportionately hit by the epidemic of obesity and the role that poverty and SES play in this cannot be discounted. Reproductive health Several comorbidities associated with obesity relate specifically to women's reproductive health and also have implications for female cancers. Obesity is associated with abnormal uterine bleeding, polycystic ovarian syndrome (PCOS), earlier age of puberty, infertility, and subsequently higher rates of spontaneous abortion if pregnancy is achieved [30]. Stress urinary incontinence is more common due to increased intra-abdominal pressure in overweight and obese women, and any surgery that they may require for gynecological or obstetrical indications are associated with an increased risk of VTE, larger blood loss, and a higher incidence of wound infections [37,38]. From an oncological perspective, obesity is a risk factor for postmenopausal breast cancer, endometrial cancer, and ovarian cancer. Infertility is more common in overweight and obese women due to ovulatory disorders; however, interestingly, decreased efficacy of several types of contraception leads to more unplanned pregnancies [39]. The only contraceptive option that does not have altered efficacy, including tubal ligation, in overweight and obese women is the intrauterine device [40]. The risk of hormonal contraception is also higher due to the increased risk of VTE. Issues around contraception in the growing number of overweight and obese women in LMICs will be of increasing importance as lesser options for contraception are available in these resource-limited settings. The obstetrical comorbidities contribute significantly to the cost of the obesity epidemic with prolonged hospital visits for both maternal and neonatal indications. These include higher rates of congenital anomalies, specifically neural tube and abdominal wall defects, VTE, hypertension, gestational diabetes, postpartum hemorrhage, and a higher chance of requiring an operative vaginal delivery or a cesarean section [6,38]. Neonatal outcomes are worse in obese mothers with higher rates of macrosomia, stillbirth, and admission to the neonatal intensive care unit. Future challenges The global epidemic of overweight and obesity poses a significant public health and clinical crisis, as it is a complex medical, epidemiological, social, and political issue. Stigmatization of obese women in many high-income countries, where thinness is currently portrayed as the ideal, though clearly not the norm, adds further complication and creates needless barriers to engaging in care. Little is acknowledged about the challenges of losing weight for those who are obese, even when they are motivated. Please cite this article in press as: Mitchell S, Shaw D, The worldwide epidemic of obesity, Best Practice & Research Clinical Obstetrics and Gynaecology (2014), http://dx.doi.org/10.1016/j.bpobgyn.2014.10.002
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Food addiction has not been well studied, but may be a contributing factor [41]. Although structured weight loss programs show impressive results in short-term weight loss, the long-term maintenance of a lower weight is much more difficult to achieve [42]. Developing health policy to effect change has thus far been limited by the complexity of the factors involved and ultimately by poor quality of data on a global level regarding effective interventions as well as the sheer cost due to the number of individuals affected [7]. Due to the diverse geographic and ethnic populations affected by obesity, targeted interventions for these different settings are critical, with an emphasis on indigenous and lowerSES individuals in both high- and low-income countries. Earlier interventions and sustained approaches that are population based and supportive are required. The WHO has introduced a population-based childhood obesity prevention strategy that requires policies and interventions at the government level, population-wide policies, and initiatives as well as community-based interventions [43]. This illustrates the complexity of addressing the obesity epidemic. There are also other interesting approaches including workplace obesity prevention programs such as the one developed by the Centre for Disease Control [44]. It is unclear how effective or sustainable such programs may be. From a clinical obstetrical perspective, adjustments need to be made to provide high levels of care for overweight and obese women who are at the risk for several complications in pregnancy. Care providers should avoid judgmental attitudes and be encouraged to see pregnancy in overweight and obese women as an opportunity for engaging in lifestyle and dietary changes that will benefit both the women and their children in the long term at a time when they may have additional motivation. The growing epidemic in LMICs that is now being recognized will require significant resources and political will to implement changes to health-care delivery and health interventions to address overweight and obesity at early stages and prevent childhood obesity. Summary Obesity in obstetrics is a timely and critical public health issue that has growing implications for an ever-increasing global obesity epidemic. Many limitations exist in the epidemiology of obesity worldwide, not the least of which is getting accurate surveillance in LMICs where there are many competing health needs. Although there is no question of the magnitude of the problem of obesity in high-income countries, there is also an urgent need to prevent the rising rates of obesity in LMICs and in so doing avoid a much larger catastrophe. Appreciation of the role of culture is lacking in suggested interventions to date, including cultures where overweight and obesity are identified as positive attributes, especially for women. Little is acknowledged about the challenges of losing weight for those who are obese. More research is needed regarding epigenetic factors and how they can be influenced as well as the role of food addiction. Economic drivers of the food industry are serious impediments to progress, especially in global efforts to limit the intake of highly refined sugars. Intervention programs are being introduced generally at the local level and evaluation must demonstrate sustained impact. It is not evidence based to suggest a self-help approach e the solutions being simply to take individual personal responsibility for intake and expenditure of calories, the message our patients often hear without any enquiry about the context of their lives or offering of specific programs that may be helpful. The global obesity epidemic will require an intersectoral approach and is more complex than tobacco smoking cessation from which many lessons can be learned if interventions on a local and global level are to address this significant public health problem and reverse its impact.
Practice points Obesity has a complex and multifactorial etiology. Women who are obese or overweight during pregnancy are at a risk of many complications antenatally, intrapartum and post partum. Due to societal stigma, overweight and obese women may experience significant barriers to reproductive health care.
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Research agenda
Accurate surveillance of obesity in LMICs. The role of food addiction in obesity. Effective intervention programs locally and globally. Impact of the in utero environment of obese women and the epigenetics of obesity.
Conflict of interest statement The authors listed, Sheona Mitchell and Dorothy Shaw, report no disclosures or conflicts of interest in the submitted article titled “The Worldwide Epidemic of Female Obesity.” Q5
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[30] Hensrud D, Klein S. Extreme obesity: a new medical crisis in the United States. Mayo Clinic Proceedings 2006;81(10): S5e10. [31] Katzmarzyk P. Obesity and physical activity among aboriginal Canadians. Obesity 2008;16:184e90. e M, et al. Preferences for female body size in Britain and the South Pacific. Body Image 2007;4: [32] Swami V, Knight D, Tove 219e23. [33] Kuhnlein H, Receveur O, Soueida R, et al. Artic indigenous peoples experience the nutrition transition with changing dietary patterns and obesity. Community and International Nutrition 2004;134(6):1447e53. [34] Porter C, Skinner T, Ellis I. The current state of Indigenous and Aboriginal women with diabetes in pregnancy: a systematic review. Diabetes Research and Clinical Practice 2012;98:209e25. [35] McDermott R, Campbell S, Li M, et al. The health and nutrition of young indigenous women in north Queensland e intergenerational implications of poor food quality, obesity, diabetes, tobacco smoking and alcohol use. Public Health Nutrition 2009;12(11):2143e9. [36] Uauy R, Albala C, Kain J. Obesity trends in Latin America: transitioning from under- to overweight. Journal of Nutrition 2001;131(3):893Se9S. [37] Mansour D. Implications of the growing obesity epidemic on contraception and reproductive health. Journal of Family Planning and Reproductive Health Care 2004;30(4):209e11. [38] Nohr E, Timpson N, Andersen C, et al. Severe obesity in young women and reproductive health: the Danish national birth cohort. PlosOne 2009;4(12):e8444. [39] Maguire Lash M, Armstrong A. Impact of obesity on women's health. Fertility and Sterility 2009;91(5):1712e6. [40] ESHRE. Nutrition and reproduction in women. Hum Reprod Update 2006;12(3):193e207. [41] Pedram P, Wadden D, Amini P, et al. Food addiction: its prevalence and significant association with obesity in the general population. PlosOne 2013;8(9):e74832. [42] Anderson J, Konz E, Frederich R, et al. Long-term weight-loss maintenance: a meta-analysis of US studies. American Journal of Clinical Nutrition 2001;74:579e84. [43] Sacks G, Swinburn B, Xuereb G. Population-based approaches to childhood obesity prevention. Geneva: WHO; 2012. [44] CDC. CDC'S LEAN works!. In: A workplace obesity prevention program. Centers for Disease Control and Prevention; 2011. http://www.cdc.gov/leanworks/.
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Best Practice & Research Clinical Obstetrics and Gynaecology xxx (2014) 1e11
Contents lists available at ScienceDirect
Best Practice & Research Clinical Obstetrics and Gynaecology journal homepage: www.elsevier.com/locate/bpobgyn
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The worldwide epidemic of obesity Q6 Q1
Sheona Mitchell, MD, MPH, FRCSC a, 1, Dorothy Shaw, MB, ChB, FRCSC a, b, * a
University of British Columbia, Northern Medical Program, 3333 University Way, Prince George, BC V2N 4Z9, Canada b British Columbia Women's Hospital and Health Center, B242, 4500 Oak Street, Vancouver, BC V6H 3N1, Canada
Keywords: obesity reproductive health LMIC
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The rapidly rising number of individuals who are overweight and obese has been called a worldwide epidemic of obesity with >35% of adults today considered to be overweight or obese. Women are more likely to be overweight and obese than their male counterparts, which has far-reaching effects on reproductive health and specifically pregnancy, with obese women facing an increased risk of gestational diabetes, preeclampsia, operative delivery, fetal macrosomia, and neonatal morbidity. The etiology of obesity is highly complex encompassing genetic, environmental, physiologic, cultural, political, and socioeconomic factors, making it challenging to develop effective interventions on both a local and global scale. This article describes the extent and the cost of the obesity epidemic, which, although historically seen as a disease of high-income countries, is now clearly a global epidemic that impacts low- and middle-income countries and indigenous groups who bear an ever-increasing burden of this disease. © 2014 Elsevier Ltd. All rights reserved.
* Corresponding author. British Columbia Women's Hospital and Health Center, B242, 4500 Oak Street, Vancouver, BC V6H 3N1, Canada. Tel.: þ1 604 875 3536. E-mail addresses: [email protected] (S. Mitchell), [email protected] (D. Shaw). 1 Tel.: þ1 250 960 5430.
http://dx.doi.org/10.1016/j.bpobgyn.2014.10.002 1521-6934/© 2014 Elsevier Ltd. All rights reserved.
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Definition Obesity was first recognized as a disease by the World Health Organization (WHO) in 1948 at the time of its formation [1], and since then multiple measures have been trialed to accurately measure body fat percentage, the most accepted of which is body mass index (BMI) measured in kilograms of weight per meter squared of height [2]. Although, historically, obesity has been considered a disease primarily of industrialized countries, there are now growing data on the rising prevalence of obesity across the world as it becomes a leading cause of morbidity and mortality globally [3,4]. Much controversy exists over the use of BMI as an indicator of body fat mass because the percentage of body fat differs by sex, age, and ethnicity making it an imperfect tool for categorizing individuals who are overweight and obese [5]. Two individuals with the same BMI may have markedly differing percentages of total body fat. Other guidelines suggest the use of waist circumference as an assessment of visceral fat as this is a better correlate with insulin resistance and metabolic dysfunction [6]. Despite its limitations, BMI is a general reflection of body fat mass and is widely used globally [2,5,7]; it also correlates with the risk of morbidity and mortality associated with obesity [8,9] as well as all-cause mortality. Adults with a BMI of 25e30 kg/m2 are considered overweight and those with a BMI of >30 kg/m2 are defined as obese [2]. Scope of the epidemic An estimated 1.1 billion adults were considered overweight in 2005 [9], and this is predicted to increase to 1.5 billion by 2015, 300 million of whom are classified as obese [10] (see Fig. 1). A staggering 35.8 million disability-adjusted life years (DALYs) are lost due to overweight and obesity accounting for 2.3% of global DALYs with 35% of adults globally considered overweight or obese [10]. Global obesity has doubled in the period between 1980 and 2008 with 2.8 million deaths attributable to this disease. Significant challenges present themselves in measuring the scope of obesity globally with additional barriers in low- and middle-income countries (LMICs). BMI is often calculated based on self-reported height and weight with inherent limitations of underestimating weight [1]. In LMICs, the country reporting is skewed by disparate accessing of health-care systems, with those of higher socioeconomic
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Fig. 1. Global prevalence of overweight and obesity in females aged 15 years and older, 2010. Reproduced, with permission of the publisher from “WHO Global Comparable Estimates”, 2010. (https://apps.who.int/infobase/Comparisons.aspx, accessed 22 August, 2014).
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status (SES) having more encounters with medical care and therefore passive surveillance of BMI rates disproportionately representing segments of society of higher SES [3,11]. According to the most recent data published in 2011 from the WHO, there is significant variation across the globe with the estimated overweight and obesity prevalence for women aged 15 years globally ranging from a low of 3.7% in Ethiopia to a high of 93% in Nauru [12] (see Table 1). The WHO region for the Americas represents the highest prevalence rates with 62% of both men and women Q7
Table 1 Prevalence of obesity by country and WHO world region. Reproduced with permission of publisher from “WHO Global Comparable Estimates,” 2010. (https://apps.who.int/infobase/Comparisons.aspx, accessed 22 August 2014). AFR
Ethiopia
AFR SEAR SEAR SEAR WPR WPR AFR
3.7 EUR 6.3 6.7 7.9 9.9 12.2 13.8 15.8
SEAR EUR EUR AFR AFR EUR WPR
Kazakhstan
38.9 AFR
Thailand Italy Romania Comoros Senegal Denmark Malaysia
Equatorial Guinea 52.3 WPR Brunei Darussalam 39.9 EUR Albania 52.5 EMR Jordan 40 AMR Honduras 52.5 EUR Slovenia 40.6 EUR Armenia 52.8 EUR Turkey 40.7 WPR Solomon Islands 52.9 AMR Bahamas 41 AFR Botswana 53.5 EMR Qatar 41.4 EMR Iraq 53.6 EMR Saudi Arabia 42.2 EUR Georgia 53.8 WPR Australia
65.4 65.7 65.7 65.9 65.9 65.9 66.5
67.2 67.2 67.3
Eritrea Bangladesh Sri Lanka Nepal Viet Nam Cambodia Democratic Republic of the Congo WPR Japan SEAR India AFR Burkina Faso
16.2 EUR 18.1 AFR 19.4 EUR
Belgium Benin Lithuania
42.9 EUR Finland 43.8 WPR Marshall Islands 43.9 EUR Austria
AFR
20
EUR
Kyrgyzstan
43.9 AMR Ecuador
AFR EMR AFR AFR AFR AFR AFR EMR AFR AFR
Central African Republic Zambia Afghanistan Burundi Rwanda Chad Kenya Uganda Somalia Madagascar Guinea-Bissau
54.5 AMR Cuba 54.7 WPR Vanuatu 55.2 AMR Venezuela (Bolivarian Republic of) 55.5 EUR San Marino
20 20.8 21.1 21.7 22.9 23.3 23.9 24 24.1 25.1
EUR EUR EUR AFR EUR EUR AFR EUR EUR SEAR
Ireland Poland Latvia Liberia Turkmenistan Bulgaria Cameroon Norway Netherlands Myanmar
43.9 44.3 44.7 45.4 45.5 45.5 45.8 45.8 46.1 47
55.8 56 56.1 56.2 56.7 56.8 56.8 56.8 57.1 57.4
AFR AFR
Niger Malawi
25.1 EUR 25.2 EUR
Sweden Hungary
Guyana Paraguay Suriname Luxembourg Lebanon Azerbaijan El Salvador Mauritius Germany The former Yugoslav Republic of Macedonia 47.2 EMR Morocco 47.4 AMR Belize
WPR Singapore
26.7 EUR
Tajikistan
47.4 AMR Haiti
AFR
Congo
26.8 AFR
Cape Verde
48
AFR Mozambique AFR Gambia SEAR Indonesia
26.9 EUR 27 EUR 27.1 EUR
Croatia Ukraine Serbia and Montenegro Sierra Leone
AFR
United Republic 28.7 AFR of Tanzania EMR Pakistan 29.5 WPR Lao People's Democratic Republic AFR Sao Tome 30.5 EUR Czech Republic and Principe WPR China 32 AFR Algeria
65.2
67.4
Malta Monaco South Africa Andorra Fiji Bahrain Belarus Peru Lesotho Guatemala
67.6 67.6 68.5 68.7 69.5 69.5 69.9 70.1 70.8 70.9
71.2 71.6
AMR Saint Vincent and the Grenadines 48.3 AFR Mauritania 48.5 EUR Switzerland 48.5 AMR Panama
57.5 AMR Argentina 57.6 EMR United Arab Emirates 57.7 AMR Dominican Republic 58.3 AMR Mexico
58.6 AMR Nicaragua 58.9 AMR Bolivia 58.9 AMR Chile
73.1 73.2 73.3
49.1 EUR
59.3 AFR
Seychelles
73.8
49.2 AMR Canada
59.5 AMR Saint Lucia
74.1
49.3 EMR Syrian Arab Republic 49.4 EMR Libyan Arab Jamahiriya
59.6 WPR New Zealand 74.2
AMR AMR AMR EUR EMR EUR AMR AFR EUR EUR
Israel
EUR EUR AFR EUR WPR EMR EUR AMR AFR AMR
59.8 WPR Mongolia
71.7 73
74.4
(continued on next page)
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Table 1 (continued)
Q3
EMR
Yemen
32.2 SEAR Bhutan
AFR
Ghana
EMR WPR EUR WPR AFR
Sudan Philippines Estonia Papua New Guinea Namibia
32.5 SEAR Democratic People's Republic of Korea 32.5 EUR Spain 33.6 EUR Uzbekistan 33.8 AFR Zimbabwe 34 EUR Republic of Moldova 34.4 EMR Oman
EMR AFR
Djibouti Guinea
AFR
Togo
AFR
Cote d'Ivoire
AFR EUR
AFR AFR
49.6 EMR Iran (Islamic Republic of) 49.7 AMR Brazil
60.3 AMR United States 76.7
49.8 49.9 50.6 50.7
Grenada Colombia Tunisia Antigua and Barbuda 50.8 AMR Saint Kitts and Nevis 50.8 WPR Tuvalu 51 EUR Slovakia
60.4 61.1 61.4 62.1
51
AMR AMR EMR AMR
Nigeria France
34.5 SEAR Maldives 34.9 WPR Republic of Korea 35.5 EUR Bosnia and Herzegovina 36 SEAR Democratic Republic of Timor-Leste 36.8 EUR Portugal 36.9 EUR Russian Federation
Angola Mali
37.2 AFR 38.4 AFR
51.9 AMR Costa Rica 52.2 AMR Uruguay
Swaziland Gabon
60.2 EMR Egypt
WPR AMR EMR AMR
76
Kiribati Jamaica Kuwait Trinidad and Tobago 62.6 AMR Dominica
77.1 79 80.4 80.8
62.9 AMR Barbados 62.9 WPR Samoa
83.3 84.1 84.5
WPR Palau
80.8
EUR
Cyprus
63
51.1 EUR
Greece
63.2 WPR Niue
86.7
51.2 EUR 51.7 EUR
Iceland United Kingdom
63.7 WPR Cook Islands 63.8 WPR Micronesia, Federated States of 63.8 WPR Tonga 64.4 WPR Nauru
90.3 91.1
92.1 93
*AFR: African Region, AMR: Region of the Americas, SEAR: South-East Asia Region, EUR; European Region, EMR: Eastern Mediterranean Region, WPR: Western Pacific Region.
overweight and 26% obese compared to the WHO region for Southeast Asia, with only 14% of men and women considered overweight and 3% obese [10] as shown in Fig. 1. Overall, the Americas, Europe, and the Eastern Mediterranean report the highest rates of overweight and obese individuals. Women are more likely to be obese than their male counterparts matched for ethnicity and age [5]. Of the 193 countries for which data are available, 107 (55.4%) have reported overweight/obesity rates of >50% for women over the age of 15 (see Table 2). Any discussion of the global epidemic of obesity would be remiss if childhood obesity was not mentioned as this encompasses present and future challenges. As in adults, childhood obesity has drastically increased in high-income countries starting in the 1980s [13]. Instead of using BMI measurements, childhood overweight and obesity is measured by percentiles of height and weight for age with >85th percentile defined as overweight and children >95th percentile considered obese [14]. Not only are obese children more likely to become obese adults, but the children of obese parents also have a two to three times increased risk of becoming obese adults [15]. Estimates from both North America and European countries show that the prevalence of overweight and obesity have increased between 60% and 70% in the past two decades [14]. To a greater degree than overweight and obese adults, these children have drastically increased risks of developing diabetes, hypertension, dyslipidemia, and heart disease during their lifetime. Table 2 Prevalence of overweight and obesity in 193 countries. Source: “WHO Global Comparable Estimates,” 2010. (https://apps.who.int/infobase/Comparisons.aspx, accessed 22 August, 2014). Prevalence of overweight/obesity: ranges (%)
No. of countries total 193
3.7e19.9 20e34.9 35e49.9 50e64.9 65e79.9 80e93
12 31 43 59 37 11
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A neglected health issue Although obesity was always recognized as a disease by the WHO, it was primarily seen as a health problem of the developed world with the WHO focusing its efforts on low-income countries where undernutrition and infectious diseases were their priority. Despite reports in the 1970s and 1980s by both the American and British governments warning of the growing public health impacts of obesity on a global level, the WHO, with many competing priorities, did not identify it as a global priority [1]. A panel of experts from the United Nations, the WHO, and the Food and Agriculture Organization (FAO) in 1981 was formed to examine protein and energy requirements but obesity was still not seen as a leading health issue [16]. It is only more recently that the WHO has described obesity as a global disease that has been largely neglected; this change was catalyzed by many factors including a report in 1988 by the European region of the WHO calling the WHO on a global level to bring attention to obesity and significant work by the International Obesity Task Force (IOTF) [2,17]. It was not until an interim report published in 1998 on the prevention of the global epidemic of obesity after much lobbying by the IOTF that the WHO officially addressed the issue and distributed its recommendations to health ministries in all member states [2]. Cost of the epidemic Much of the cost of overweight and obesity comes from the related comorbidities associated with this disease. Obesity is the third most significant risk factor contributing to burden of disease in highincome countries [11]. It is estimated that nearly 45% of the health costs of diabetes are associated with obesity and nearly 25% of the burden of cardiovascular disease, specifically ischemic heart disease, is related to overweight and obesity [10]. The burden associated with several cancers can also be attributed to obesity, with an estimated 10% of cancer correlated with obesity [9]. Obesity increases the risk of hypertension, diabetes, venous thromboembolism (VTE), dyslipidemia, coronary artery disease, ischemic strokes, and arthritis, and has significant implications for reproductive health throughout the life course. With increasing awareness of the impact of overweight and obesity on health economics in the past decade, many high-income countries have estimated both the direct and indirect costs of obesity. Direct costs are those associated with medical treatment including medication, admission to hospital, rehabilitation, and cost of health-care workers, whereas indirect costs are often much larger encompassing costs that result from loss of work and decreased productivity due to disease or disability [18]. A 2010 prediction for the United Kingdom (UK) showed that treating obesity costs £9.4 million annually with comorbidities caused by obesity costing an additional £470 million each year [6]. Further indirect impact on the economy of the UK was estimated at £2 billion a year. The United States (US) total healthcare costs that are due to overweight and obesity have been predicted to double each decade and reach as much as $956 billion by 2030, which represents 18% of total health expenditures [19]. In the European Union, examination of the obesity trends of the 15 member states prior to 2004 estimated the direct and indirect costs of obesity to be nearly V33 billion [20]. A meta-analysis in Canada found that the total cost of obesity by 2004 estimates was $4.3 billion yearly with obesity representing 2.2% of total health-care costs and an additional 2.5% of health-care costs attributed to physical inactivity [21]. These amounts had more than doubled in the previous decade. Etiology The etiology of obesity is multifactorial, and there is much about the pathophysiology, genetics, and epigenetics of obesity that are not fully understood. There is evidence that the in utero environment plays a role in future obesity [22]; the most well-known study was done on a cohort of men whose mothers were pregnant during the Dutch famine in the mid-1940s. Those whose mothers had very poor nutrition during the first half of their pregnancy were more likely to be obese as adults suggesting the impact on hypothalamic centers in the brain during pregnancy [23]. Such findings raise questions about the impact of poor nutrition due to poverty and conflict in developing countries and fragile states as well as marginalized populations. The etiology is further compounded by cultural, political, Please cite this article in press as: Mitchell S, Shaw D, The worldwide epidemic of obesity, Best Practice & Research Clinical Obstetrics and Gynaecology (2014), http://dx.doi.org/10.1016/j.bpobgyn.2014.10.002
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socioeconomic, ethnic, and geographic differences. The global market has been flooded with caloriedense foods including those with high-fructose corn syrup and much higher contents of refined fats contributing to changing patterns of food consumption and the rise of fast food in higher-income countries [7]. Additionally, the built environment, particularly in high-income countries, is designed to decrease the distance that individuals need to walk during their daily activities and this decreased energy expenditure is also postulated to exacerbate the obesity epidemic [24]. The etiology of obesity is complex and encompasses deeply held cultural beliefs, societal structure, genetic predisposition, socioeconomic issues, physiological changes to the endocrine system of the body, and potentially epigenetic contributions over the course of generations [22]. Global efforts to limit the intake of highly refined sugars have also been limited by powerful lobbying from the food industry who have attempted to draw attention to the economic impact that recommendations to restrict sugar intake may have [5]. The Expert Technical Consensus on Diet, Nutrition and the Prevention of Chronic Diseases produced by the WHO in the late 1980s recommended a sugar intake of 0e10%; the evidence base for this was immediately questioned by several large players in the food industry representing the larger sugar lobby despite its logical public health implications [1]. These recommendations around carbohydrate intake were later removed from WHO publications as a result of this controversy and do not appear in the interim report published in 1988 [2]. The increasing availability of low-cost highly refined oils and the increasing contribution of carbohydrates to traditional diets in LMICs contribute to the growing number of overweight and obese people [4]. Drastic changes in physical activity with a preference for sedentary activities such as video games and television in high-income countries and changing lifestyles in LMICs, with migration from rural to urban settings, are further exacerbating the epidemic across the globe. Globalization has been central to the changing availability of affordable high-caloric-density foods across the world, and the resulting cultural changes are challenging to quantify as populations shift away from traditional lifestyles to ones that involve less physical activity. All of these factors contribute to the complex nature of the obesity epidemic. Low- and middle-income countries Unique challenges and trends present themselves in LMICs. Despite a recent worldwide economic recession and a growing global food crisis, the number of overweight individuals is growing across LMICs and the number of those underweight, historically seen as the main population of concern in LMICs, is decreasing [25]. Surprisingly, approximately two-thirds of women in the Middle East and North Africa are overweight or obese and half of the women in Central and South America and the Caribbean are in this category. In response to the growing number of overweight and obese populations across Latin America, the Pan America Health Organization (PAHO) has specifically targeted obesity and recognized its association with poverty at an organizational level. However, much of the impact of their recommendations relies on individual governments where investment to address obesity has thus far been lacking [26]. The greatest impact of the epidemic has thus far been in primarily urban areas in these low-resource setting but is having a growing presence in more rural environments [11]. Obesity is more prevalent in women of higher socioeconomic classes in LMICs; however, as these countries have developed economically and national gross domestic product (GDP) rises, obesity disproportionately affects women of lower SES [4]. Although we have seen that higher levels of education are associated with lower rates of obesity in high-income countries, this is not the case in LMICs and, in fact, higher rates of obesity may be seen in more educated populations in LMICs. Globalization with its spread of fast-food chains and traditionally “western” foods that are often calorie dense, high fat, and more likely to contain high-fructose corn syrup in beverages has been postulated as contributing to growing levels of obesity in LMICs [4,7]. This is reflected in the increasing consumption of fast food in developing countries, which are initially mostly consumed by higher-SES groups but later affect lower socioeconomic groups over time as fast food becomes more economical and affordable. Additionally, cultural norms in certain countries associated overweight and obesity with wealth, power, and higher education for both men and women, however more markedly affecting women as appearing healthy for childbearing [5,27]. In sub-Saharan Africa specifically, where human immunodeficiency virus (HIV)/ Please cite this article in press as: Mitchell S, Shaw D, The worldwide epidemic of obesity, Best Practice & Research Clinical Obstetrics and Gynaecology (2014), http://dx.doi.org/10.1016/j.bpobgyn.2014.10.002
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acquired immunodeficiency syndrome (AIDS) is associated with malnutrition, wasting, and thinness, being overweight is associated with health instead of illness [4]. It is estimated that over one in five pregnant women are overweight and obese putting them at a risk of preeclampsia, gestational diabetes, fetal macrosomia, and cesarean delivery [6]. A recent study from Iraq demonstrates the health-care systems level implications of the increased need for cesarean sections in overweight and obese pregnant women stressing health systems that are already stretched to their limits [28]. If overweight and obese populations in LMICs continue to increase as predicted, there are significant implications for increased maternal and neonatal morbidity and mortality as access to timely cesarean sections is already a challenge in many LMICs. Prentice has described the added cost of obesity in low-income countries as a “double burden,” adding to the already overwhelming burden of infectious diseases such as malaria, HIV/AIDS, and tuberculosis [4]. Obesity, diabetes, and a long list of comorbidities associated with these will continue to complicate delivery of reproductive care in many resource-poor settings. Although more women than men across high- and low-income countries are overweight and obese, the gender divide is most stark in some of the poorest countries; a study from Gambia reported that 17 times as many women than men were obese and this is reflected in several African countries [4]. Cultural and ethnic differences Culture is the single most powerful factor that influences how, when, and why people eat and the amount of physical activity that they engage in recreationally or as part of their daily activities [24]. Culture varies over time and with migration as people from diverse areas of the world move and resettle. Sociologic studies have attempted to look at perceptions of weight across cultures and have found that 80% of over 60 cultures that were examined preferred fatter body types [29] noting that the preference for slim body types seems to be isolated to postindustrial societies [24]. Trends in obesity show much variation between ethnicities. In the US, significant differences are seen among Mexican American, non-Hispanic black, and non-Hispanic white women with the lowest rates of obesity in nonHispanic whites, but these disparities are not present for men across ethnicities [5]. Women are more likely to be obese than men, and in the US the rates of obesity overall are higher in African American women than in white and Hispanic women [30]. Similarly, in the UK, obesity is more prevalent in people of Black Caribbean or Black African ancestry or in those of Irish descent relative to the rest of the population [7]. In Canada, the lowest rates of obesity occur in their Southeast Asian population and is markedly lower than other ethnic groups [31]. Interestingly, the gendered differences in obesity despite ethnicity are attributed to both physiological and cultural differences. Predictions from the US for the year 2030 based on current trends in obesity are that >50% of the population will be obese with >85% overweight, and those most significantly affected by obesity will be black women and Mexican American men with >90% of both of these groups predicted to be overweight [19]. Indigenous populations Overweight and obesity disproportionately impact indigenous populations from as disparate areas of the world as the Canadian Arctic to South Pacific islanders [31,32]. Maori populations in the South Pacific have the highest prevalence of obesity in the world with >90% of the population classified as overweight and obese [10]. Historically, much of this has been attributed to the positive light that an overweight body habitus is seen in as representing health, wealth, and potential evolutionary benefits [32]. This draws attention to the powerful influence of culture on the rates of obesity and sheds light on how diverse cultures have differing views of obesity and may not see being overweight as a disease state, but instead a sign of health. Canada's aboriginal population, which makes up an estimated 3.4% of the total population, have a much higher prevalence of obesity than their non-aboriginal counterparts for both childhood and adult obesity, a trend that is most marked for on-reserve aboriginals [31]. Explanations for this are varied but, in a large part, are attributed to transitioning away from traditional lifestyles that in the past involved manual labor and a hunter-gatherer culture to more sedentary lifestyles and drastic dietary changes [33]. A higher prevalence of type 2 diabetes and cardiovascular disease has also been described for the aboriginal population than for non-aboriginals across Canada Please cite this article in press as: Mitchell S, Shaw D, The worldwide epidemic of obesity, Best Practice & Research Clinical Obstetrics and Gynaecology (2014), http://dx.doi.org/10.1016/j.bpobgyn.2014.10.002
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[34]. Specific challenges present themselves during pregnancy due to the high rates of gestational diabetes and preexisting diabetes in pregnant Canadian aboriginal women with implications for the provision of clinical services for those who do not dwell in urban centers and populate geographically disparate regions that are located far from centers able to provide caesarean sections if required. Higher rates of overweight and obesity are also seen in indigenous populations in Australia. McDermott et al. have described aboriginal and Torres Strait Islander (TSI) women in rural and remote populations in Northern Queensland with an obesity prevalence of 40% for aboriginal women and nearly 70% for TSI women [35]. High rates of micronutrient deficiency, alcohol, and tobacco use were also reported, and nutritional intake was poor in a population with overall very low socioeconomic indicators and an incidence of diabetes between three and six times the national average. Obesity in these populations along with its significant comorbidities are impossible to separate from SES, food insecurity, and a history of colonialism, which has historically pushed them to the margins of society. Latin America has undergone an enormous economic transformation over the past two decades with a widening gap between the richest and poorest in many Latin American nations as we see a growing prevalence of overweight and obesity. Indigenous populations have also been impacted by this economic growth; studies of the Mapuche in Chile and Aymara in Bolivia have described increases in obesity as a result of changing lifestyles to adapt to the industrialization that has occurred in those countries [36]. Urban indigenous populations are particularly affected by these changes compared to their rural counterparts who retain more of their traditional diets and physically active lifestyles. Indigenous populations around the world are diverse and generalizations should not be made on a global level, yet repeatedly in many countries we see that aboriginal and indigenous peoples have been disproportionately hit by the epidemic of obesity and the role that poverty and SES play in this cannot be discounted. Reproductive health Several comorbidities associated with obesity relate specifically to women's reproductive health and also have implications for female cancers. Obesity is associated with abnormal uterine bleeding, polycystic ovarian syndrome (PCOS), earlier age of puberty, infertility, and subsequently higher rates of spontaneous abortion if pregnancy is achieved [30]. Stress urinary incontinence is more common due to increased intra-abdominal pressure in overweight and obese women, and any surgery that they may require for gynecological or obstetrical indications are associated with an increased risk of VTE, larger blood loss, and a higher incidence of wound infections [37,38]. From an oncological perspective, obesity is a risk factor for postmenopausal breast cancer, endometrial cancer, and ovarian cancer. Infertility is more common in overweight and obese women due to ovulatory disorders; however, interestingly, decreased efficacy of several types of contraception leads to more unplanned pregnancies [39]. The only contraceptive option that does not have altered efficacy, including tubal ligation, in overweight and obese women is the intrauterine device [40]. The risk of hormonal contraception is also higher due to the increased risk of VTE. Issues around contraception in the growing number of overweight and obese women in LMICs will be of increasing importance as lesser options for contraception are available in these resource-limited settings. The obstetrical comorbidities contribute significantly to the cost of the obesity epidemic with prolonged hospital visits for both maternal and neonatal indications. These include higher rates of congenital anomalies, specifically neural tube and abdominal wall defects, VTE, hypertension, gestational diabetes, postpartum hemorrhage, and a higher chance of requiring an operative vaginal delivery or a cesarean section [6,38]. Neonatal outcomes are worse in obese mothers with higher rates of macrosomia, stillbirth, and admission to the neonatal intensive care unit. Future challenges The global epidemic of overweight and obesity poses a significant public health and clinical crisis, as it is a complex medical, epidemiological, social, and political issue. Stigmatization of obese women in many high-income countries, where thinness is currently portrayed as the ideal, though clearly not the norm, adds further complication and creates needless barriers to engaging in care. Little is acknowledged about the challenges of losing weight for those who are obese, even when they are motivated. Please cite this article in press as: Mitchell S, Shaw D, The worldwide epidemic of obesity, Best Practice & Research Clinical Obstetrics and Gynaecology (2014), http://dx.doi.org/10.1016/j.bpobgyn.2014.10.002
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Food addiction has not been well studied, but may be a contributing factor [41]. Although structured weight loss programs show impressive results in short-term weight loss, the long-term maintenance of a lower weight is much more difficult to achieve [42]. Developing health policy to effect change has thus far been limited by the complexity of the factors involved and ultimately by poor quality of data on a global level regarding effective interventions as well as the sheer cost due to the number of individuals affected [7]. Due to the diverse geographic and ethnic populations affected by obesity, targeted interventions for these different settings are critical, with an emphasis on indigenous and lowerSES individuals in both high- and low-income countries. Earlier interventions and sustained approaches that are population based and supportive are required. The WHO has introduced a population-based childhood obesity prevention strategy that requires policies and interventions at the government level, population-wide policies, and initiatives as well as community-based interventions [43]. This illustrates the complexity of addressing the obesity epidemic. There are also other interesting approaches including workplace obesity prevention programs such as the one developed by the Centre for Disease Control [44]. It is unclear how effective or sustainable such programs may be. From a clinical obstetrical perspective, adjustments need to be made to provide high levels of care for overweight and obese women who are at the risk for several complications in pregnancy. Care providers should avoid judgmental attitudes and be encouraged to see pregnancy in overweight and obese women as an opportunity for engaging in lifestyle and dietary changes that will benefit both the women and their children in the long term at a time when they may have additional motivation. The growing epidemic in LMICs that is now being recognized will require significant resources and political will to implement changes to health-care delivery and health interventions to address overweight and obesity at early stages and prevent childhood obesity. Summary Obesity in obstetrics is a timely and critical public health issue that has growing implications for an ever-increasing global obesity epidemic. Many limitations exist in the epidemiology of obesity worldwide, not the least of which is getting accurate surveillance in LMICs where there are many competing health needs. Although there is no question of the magnitude of the problem of obesity in high-income countries, there is also an urgent need to prevent the rising rates of obesity in LMICs and in so doing avoid a much larger catastrophe. Appreciation of the role of culture is lacking in suggested interventions to date, including cultures where overweight and obesity are identified as positive attributes, especially for women. Little is acknowledged about the challenges of losing weight for those who are obese. More research is needed regarding epigenetic factors and how they can be influenced as well as the role of food addiction. Economic drivers of the food industry are serious impediments to progress, especially in global efforts to limit the intake of highly refined sugars. Intervention programs are being introduced generally at the local level and evaluation must demonstrate sustained impact. It is not evidence based to suggest a self-help approach e the solutions being simply to take individual personal responsibility for intake and expenditure of calories, the message our patients often hear without any enquiry about the context of their lives or offering of specific programs that may be helpful. The global obesity epidemic will require an intersectoral approach and is more complex than tobacco smoking cessation from which many lessons can be learned if interventions on a local and global level are to address this significant public health problem and reverse its impact.
Practice points Obesity has a complex and multifactorial etiology. Women who are obese or overweight during pregnancy are at a risk of many complications antenatally, intrapartum and post partum. Due to societal stigma, overweight and obese women may experience significant barriers to reproductive health care.
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Research agenda
Accurate surveillance of obesity in LMICs. The role of food addiction in obesity. Effective intervention programs locally and globally. Impact of the in utero environment of obese women and the epigenetics of obesity.
Conflict of interest statement The authors listed, Sheona Mitchell and Dorothy Shaw, report no disclosures or conflicts of interest in the submitted article titled “The Worldwide Epidemic of Female Obesity.” Q5
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Please cite this article in press as: Mitchell S, Shaw D, The worldwide epidemic of obesity, Best Practice & Research Clinical Obstetrics and Gynaecology (2014), http://dx.doi.org/10.1016/j.bpobgyn.2014.10.002