- Email: [email protected]
Trends of obesity prevalence among Spanish adults with diabetes, 1987–2012
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Brief report
Trends of obesity prevalence among Spanish adults with diabetes, 1987–2012 Francisco Javier Basterra-Gortari a,b , Maira Bes-Rastrollo b,c , Miguel Ruiz-Canela b,c , Alfredo Gea b,c , Carmen Sayón-Orea b,d , Miguel Ángel Martínez-González b,c,e,∗ a Department of Internal Medicine (Endocrinology), Hospital Reina Sofia, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Servicio Navarro de Salud-Osasunbidea, Tudela, Spain b University of Navarra, Department of Preventive Medicine and Public Health, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain c Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain d Department of Preventive Medicine, Complejo Hospitalario de Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Servicio Navarro de Salud-Osasunbidea, Pamplona, Spain e Department of Nutrition, Harvard TH Chan School of Public Health, Boston, USA
a r t i c l e
i n f o
Article history: Received 5 January 2018 Accepted 22 March 2018 Available online xxx Keywords: Obesity Diabetes Epidemiology Prevalence
a b s t r a c t Introduction and objective: Our aim was to examine the secular trends in obesity prevalence among Spanish adults with diabetes. Material and methods: Data were collected from 8 waves (from 1987 to 2012) of the National Health Surveys (NHS). NHS are cross-sectional studies conducted in representative samples of the Spanish adult population. Data of 7378 adults (≥16 years) who reported having been diagnosed of diabetes were analyzed. Previously validated self-reported weight and height were used to estimate body mass index (BMI). Obesity was defined as a BMI of 30 kg/m2 or greater. Age-adjusted obesity prevalence for each wave was calculated by the direct standardization method. Results: From 1987 to 2012 age-adjusted prevalence of obesity among persons with diabetes increased from 18.2% (95% confidence interval [CI]: 14.2–22.2%) to 39.8% (95% CI: 36.8–42.8%). Age-adjusted prevalence of obesity in males with diabetes increased from 13.2% (95% CI: 7.3–19.1%) to 38.0% (95% CI: 33.8–42.1%) and in females from 23.0% (95% CI: 17.6–28.4%) to 42.3% (95% CI: 38.0–46.6%). Conclusions: Between 1987 and 2012 the prevalence of obesity markedly increased in Spain among adults with diabetes. ˜ S.L.U. All rights reserved. © 2018 Elsevier Espana,
˜ Tendencia de la prevalencia de obesidad en adultos espanoles con diabetes, 1987-2012 r e s u m e n Palabras clave: Obesidad Diabetes Epidemiología Prevalencia
Introducción y objetivo: Nuestro objetivo fue conocer la tendencia de la prevalencia de obesidad entre ˜ adultos espanoles con diabetes. Material y métodos: Se utilizaron 8 (1987-2012) Encuestas Nacionales de Salud (ENS). Las ENS son estudios ˜ transversales realizados en muestras representativas de la población adulta espanola. Se analizaron datos ˜ de 7.378 adultos (≥ 16 anos) que refirieron un diagnóstico de diabetes. El índice de masa corporal (IMC) se calculó a partir de los datos auto-referidos de peso y talla validados previamente. Se definió obesidad como un IMC ≥ 30 kg/m2 . Se calculó para cada encuesta la prevalencia de obesidad ajustada por edad con el método directo de estandarización.
∗ Corresponding author. E-mail address: [email protected] (M.Á. Martínez-González). https://doi.org/10.1016/j.medcli.2018.03.016 ˜ S.L.U. All rights reserved. 0025-7753/© 2018 Elsevier Espana,
Please cite this article in press as: Basterra-Gortari FJ, et al. Trends of obesity prevalence among Spanish adults with diabetes, 1987–2012. Med Clin (Barc). 2017. https://doi.org/10.1016/j.medcli.2018.03.016
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Resultados: Desde 1987 a 2012 la prevalencia de obesidad ajustada aumentó en adultos con diabetes del 18,2% (intervalo de confianza [IC] 95%: 14,2-22,2%) al 39,8% (IC 95%: 36,8-42,8%). La prevalencia ajustada de obesidad en varones con diabetes aumentó del 13,2% (IC 95%: 7,3-19,1%) al 38,0% (IC 95%: 33,8-42,1%); en mujeres con diabetes aumentó del 23,0% (IC 95%: 17,6-28,4%) al 42,3% (IC 95%: 38,0-46,6%). ˜ Conclusiones: Entre 1987 y 2012 la prevalencia de obesidad aumentó notablemente en adultos espanoles con diabetes. ˜ S.L.U. Todos los derechos reservados. © 2018 Elsevier Espana,
weight and height of the NHS were previously validated.5 Participants with a BMI ≥ 30 kg/m2 were classified as obese. Weights from the overall Spanish population were used in the analyses of the survey data. Survey design data were not considered. Prevalence estimations are shown as percentages. Normal-based confidence intervals were estimated. Age was categorized in 3 groups: 16–39, 40–59 and ≥60 years. Age-adjusted prevalence for each wave was calculated by the direct standardization method (3 categories of age). The 2003 NHS population with diabetes was chosen as standard population. To assess the temporal trend of obesity we fitted logistic regression models. In these models the dependent variable is obesity and the independent variables are: age (3 categories), sex and NHS year (continuous). The annualized Odds Ratios (ORs) show the estimated increase per year in the odds of obesity prevalence. A Poisson regression model was performed to estimate prevalence ratios. To examine if the temporal trend differed between males and females an interaction term was calculated between NHS year and sex and this new variable was introduced in the adjusted model. Finally, to assess if the temporal trend was quadratic a new variable with the square of the year of the NHS was introduced in the fitted model. STATA 12 was used for the analyses.
Introduction Obesity is an important risk factor for cardiovascular diseases and diabetes. An increasing trend in the prevalence of obesity has been reported worldwide, including Mediterranean countries such as Spain.1 Besides, obesity is a risk factor for premature death in patients with diabetes.2 However, few analyses of trends of obesity among persons with diabetes have been reported. In Spain, periodic NHS have been conducted since 1987 on representative samples of the non-institutionalized adult population. Data from these NHS offer the opportunity to track secular trends in the prevalence of obesity. The aim of this study was to provide updated estimates of the trend of age-standardized prevalence of obesity among patients with diabetes since 1987 in Spain. Material and methods The NHS are cross-sectional studies carried out on representative samples of the Spanish non-institutionalized adult (≥16 years) population.3 The data were taken from 8 waves of the NHS: 1987, 1993, 1995, 1997, 2001, 2003, 2006–2007 (2006/7) and 2011–12 (2011/2). More information about the methodology used in the NHSs is described in detail elsewhere.1 Diabetes status was self-reported and was previously validated.4 A total of 9265 participants reported to have diabetes. After excluding participants with height <100 cm (n = 1) or missing information for BMI (n = 1881) or age (n = 5), we finally included 7378 (Fig. 1 in the supplementary appendix). Participants had a mean age of 64.5 years (SD 13.7) and 53.4% were women. We calculated the BMI as weight (kg) divided by the square of height (m), using self-reported weight and height. Self-reported
Results The crude obesity prevalence in participants with diabetes in 2011/2 was 39.9% (95% CI: 36.9–42.9%). From 1987 to 2011/2 age-adjusted prevalence of obesity in participants with diabetes increased from 18.2% (95% CI: 14.2–22.2%) to 39.8% (95% CI: 36.8–42.8%) (Table 1). Age-adjusted prevalence of obesity in males with diabetes increased from 13.2% (95% CI: 7.3–19.1%) to 38.0%
BMI in adults with diabetes in spain, 1987-2012 100
3.9
4.0
14.3
15.3
Percentage
80
60
46.8
4.6
4.9
7.0
8.1
21.7
24.3
21.5
21.8
10.5
22.3
28.0
47.2 43.7
42.8
48.2
44.7
43.6
40
20
11.8
40.4
35.0
33.6
30.0
28.0
23.4
25.3
23.6
19.8
1997
2001
2003
2006/7
2011/2
0 1987
1993
1995
National health survey BMI <25
BMI 25-29.9
BMI 30-34.9
BMI ≥35
Fig. 1. Distribution of adjusted body mass index categories among Spanish adults with diabetes, 1987–2011/2.
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BMI: body mass index; no obs: no observations. a Adjusted for age (3 categories: 16–39, 40–59 and ≥60 years) calculated by the direct standardization method. The 2003 survey population with diabetes was the standard population.
41.4 (37.2–45.7) 42.3 (38.0–46.6) 23.3 (7.4–39.1) 45.4 (35.6–55.3) 42.6 (37.7–47.4) 38.3 (33.8–42.8) 38.5 (34.1–43.0) 18.1 (5.5–30.7) 50.3 (40.7–59.9) 36.0 (30.7–41.3) 21.3 (16.3–26.3) 23.0 (17.6–28.4) 6.5 (0.0–13.6) 25.8 (16.1–35.5) 23.2 (16.4–30.1) Women Crude prevalence Adjusted prevalencea 16–39 years 40–59 years ≥60 years
23.6 (18.6–28.6) 23.4 (18.4–28.3) 24.6 (4.7–44.6) 28.1 (17.9–38.3) 21.7 (15.8–27.6)
33.3 (24.2–42.5) 33.7 (24.6–42.9) No obs 46.4 (28.0–64.9) 31.8 (20.6–43.1)
42.3 (33.5–51.0) 40.8 (31.8–49.7) 20.0 (0.0–55.1) 48.9 (34.6–63.2) 39.4 (28.1–50.8)
36.9 (31.9–41.9) 36.8 (31.8–41.8) 24.4 (7.3–41.4) 44.5 (34.3–54.6) 35.1 (29.0–41.1)
34.8 (30.5–39.3) 35.0 (30.8–39.2) 12.7 (0.0–26.9) 48.0 (37.3–58.7) 32.2 (27.6–36.8)
38.6 (34.3–42.8) 38.0 (33.8–42.1) 56.7 (35.3–78.1) 42.5 (34.1–50.9) 35.2 (30.3–40.0) 28.8 (24.4–33.2) 28.5 (24.2–32.9) 14.3 (0.3–28.2) 32.2 (24.3–40.2) 28.3 (22.8–33.8) 24.4 (20.1–28.8) 24.4 (20.1–28.7) 25.9 (2.8–49.0) 23.9 (15.1–32.7) 24.5 (19.4–29.5) 16.4 (9.4–23.3) 16.5 (9.5–23.5) No obs 18.8 (5.2–32.3) 16.9 (8.2–25.6) 19.6 (11.9–27.3) 19.3 (11.7–27.0) 20.0 (0.0–55.1) 24.1 (8.6–39.7) 17.6 (8.5–26.7) 13.7 (8.6–18.9) 13.2 (7.3–19.1) 4.5 (0.0–11.5) 17.7 (9.7–25.8) 12.3 (4.4–20.1) Men Crude prevalence Adjusted prevalencea 16–39 years 40–59 years ≥60 years
14.5 (10.0–19.0) 13.7 (9.4–18.1) 22.2 (2.7–41.6) 15.8 (7.8–23.7) 12.4 (7.1–17.8)
30.0 (24.2–35.9) 29.2 (23.3–35.1) 26.5 (20.4–32.5) 26.3 (20.3–32.3) 17.7 (14.1–21.3) 18.2 (14.2–22.2) All Crude prevalence Adjusted prevalencea
19.6 (16.1–23.1) 19.2 (15.8–22.7)
20.3 (16.3–24.4) 20.6 (16.5–24.7) 8.7 (0.0–20.9) 20.3 (12.8–27.7) 21.5 (16.4–26.7)
33.0 (29.8–36.2) 32.9 (29.7–36.0) 30.0 (26.9–33.0) 30.0 (26.9–33.0) 28.4 (25.1–31.6) 28.4 (25.1–31.7)
2006/7 2003 2001 1997 1995 1993 Obesity (BMI ≥30)
1987
Year of each National Health Survey
Table 1 Prevalence (%) of obesity (BMI ≥30) and 95% confidence intervals in Spanish adults (≥16 years) with diabetes, according to self-reported weight and height in the National Health Surveys.
2011/2
39.9 (36.9–42.9) 39.8 (36.8–42.8)
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(95% CI: 33.8–42.1%) and in females from 23.0% (95% CI: 17.6–28.4%) to 42.3% (95% CI: 38.0–46.6%) (Table 1) (Fig. 2 in the supplementary appendix). Age-adjusted categories of BMI from 1987 to 2011/2 are shown graphically in Fig. 1. Age-adjusted mean BMI was 26.6 kg/m2 (95% CI: 26.2–27.0) in 1987 and it increased to 29.2 kg/m2 (95% CI: 28.9–29.5) in 2011/2. Annualized OR, indicating the estimated increase per year in the OR, of obesity after adjusting for age (3 categories) and sex was 1.05 (95% CI: 1.04–1.06). This OR would be equivalent to a yearly increase in obesity prevalence of around 1 percentage point. Annualized prevalence ratio of obesity after adjusting for age (3 categories) and sex was 1.04 (95% CI: 1.03–1.04). Annualized ageadjusted ORs were 1.07 (95% CI: 1.05–1.08) for men and 1.04 (95% CI: 1.03–1.05) for women. The prevalence of obesity increased at a significantly greater rate in men compared with women (for interaction, p = 0.013). These increases were statistically significant in both sexes and in the 3 age categories (p < 0.001), except in women younger than 40 (p = 0.067). Finally, when the square of the year of the NHS was introduced in the adjusted model this variable was not statistically significant (p = 0.53). Discussion These trend estimates indicate that obesity in persons with diabetes increased rapidly over the 25-year period from 1987 through 2011/2. The 2011/2 NHS found a prevalence of obesity among patients with diabetes of 39.9% (95% CI: 36.9–42.9%). The current study has some limitations. First, the use of selfreported data, because self-report on average understates weight and overstates height.5 Therefore, our study probably might have underestimated the prevalence of obesity in patients with diabetes. However, as the underestimation is likely to be constant across waves, it probably did not impact significantly the observed trend. Second, a limitation of this study is that data were missing for a significant proportion (approximately 20%) of participants. The direction of this bias is unknown, however due to the magnitude of the observed trend we believe it is unlikely that the results might be explained by the missing data. Third, self-reported data also may underestimate diabetes prevalence.4 However, diabetes prevalence estimated in the NHS (≥16 years) in 2011/2 was 7.4%,1 which is similar to the 7.8% prevalence of known diabetes published in the [email protected] study (≥18 years),6 and to the 7.6% prevalence found in the report with data from anonymized patient records carried out in Catalonia (31–90 years).7 Fourth, the NHS cannot distinguish between types of diabetes. Finally, the 1995 and 1997 NHSs were smaller, thus there were fewer participants with diabetes and, consequently, their estimated confidence intervals are wider. Our study has several strengths. These include the use of representative data of the Spanish population, the long period studied, the large sample size, or the estimation of adjusted trends. The prevalence we found is lower than the 50.2% published in the [email protected] study in participants with known diabetes conducted in 2009/10 in a representative sample of the Spanish population,6 and also lower than other cross-sectional study carried out in Catalonia (Spain) in 2009 with data from anonymized patient records, that reported an obesity prevalence of 45.4%.7 These differences may be explained because self-report on average underestimates BMI.5 Another cross-sectional study carried out in Spain in 2002 estimated a prevalence of obesity of 35.1% in patients with diabetes.8 This prevalence was lower than the prevalence reported in the studies conducted in 20096,7 which confirms the significant increase found in the NHS. Our results suggest that the prevalence continued to increase at a similar rate over the 25-year period examined. In all the waves of the NHS obesity prevalence was higher in women with diabetes than in men with diabetes, which was
Please cite this article in press as: Basterra-Gortari FJ, et al. Trends of obesity prevalence among Spanish adults with diabetes, 1987–2012. Med Clin (Barc). 2017. https://doi.org/10.1016/j.medcli.2018.03.016
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also found in the study conducted in Catalonia.7 However, obesity increase over time was faster among men with diabetes. This is consistent with results of obesity trend estimated in the Spanish general population.1 This trend of body weight is clinically relevant, because BMI is usually taken into account by clinicians when they start an antihyperglycemic therapy9 and it is directly associated with insulin needs. Besides, obesity is a risk factor for mortality in patients with type 2 diabetes2 and diabetes prevalence has been steadily increasing over the past few decades,1 thus the observed obesity trend among patients with type 2 diabetes has become a public health problem. Conclusions Our results provide nationally representative snapshots of obesity trends between 1987 and 2011/2 among Spanish adults with diabetes. A marked increase in the prevalence of obesity was found especially in men. Our estimates do not suggest that obesity trend in patients with diabetes were slowing or leveling off in this Mediterranean country. Funding No funding. Conflict of interest The authors declared no conflict of interest.
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/ j.medcli.2018.03.016 References 1. Basterra-Gortari FJ, Bes-Rastrollo M, Ruiz-Canela M, Gea A, Martínez-González MA. Prevalence of obesity and diabetes in Spanish adults 1987–2012. Med Clin (Barc). 2017;148:250–6. 2. Tobias DK, Pan A, Jackson CL, O’Reilly EJ, Ding EL, Willet WC, et al. Body-mass index and mortality among adults with incident type 2 diabetes. N Engl J Med. 2014;16:233–44. 3. Ministerio de Sanidad, Servicios Sociales e Igualdad. Instituto de Información Sanitaria. Encuesta Nacional de Salud. http://www.msssi.gob.es/estadEstudios/ estadisticas/encuestaNacional/home.htm [accessed 04.01.18]. 4. Basterra-Gortari FJ, Forga L, Bes-Rastrollo M, Martínez JA, Martínez-González MA. Validation of self-reported diabetes mellitus, hypertension and hypercholesterolemia in the Spanish national health survey. Endocrinol Nutr. 2007;54: 462–6. 5. Basterra-Gortari FJ, Bes-Rastrollo M, Forga L, Martínez JA, Martínez-González MA. Validity of self-reported body mass index in the National Health Survey. An Sist Sanit Navar. 2007;30:373–81. 6. Soriguer F, Goday A, Bosch-Comas A, Bordiú E, Calle-Pascual A, Carmena R, et al. Prevalence of diabetes mellitus and impaired glucose regulation in Spain: the [email protected] study. Diabetologia. 2012;55:88–93. 7. Vinagre I, Mata-Cases M, Hermosilla E, Morros R, Fina F, Rossell M, et al. Control of glycemia and cardiovascular risk factors in patients with type 2 diabetes in primary care in Catalonia (Spain). Diabetes Care. 2012;35:774–9. 8. Orozco-Beltrán D, Gil-Guillen VF, Quirce F, Navarro-Perez J, Pineda M, Gomez-dela-Cámara A, et al. Control of diabetes and cardiovascular risk factors in patients with type 2 diabetes in primary care. The gap between guidelines and reality in Spain. Int J Clin Pract. 2007;61:909–15. 9. Artola Menéndez S. Actualización del algoritmo de hiperglucemia 2017. Diabetes Práctica. 2017;8:57–60.
Please cite this article in press as: Basterra-Gortari FJ, et al. Trends of obesity prevalence among Spanish adults with diabetes, 1987–2012. Med Clin (Barc). 2017. https://doi.org/10.1016/j.medcli.2018.03.016
ARTICLE IN PRESS Med Clin (Barc). 2017;xxx(xx):xxx–xxx
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Brief report
Trends of obesity prevalence among Spanish adults with diabetes, 1987–2012 Francisco Javier Basterra-Gortari a,b , Maira Bes-Rastrollo b,c , Miguel Ruiz-Canela b,c , Alfredo Gea b,c , Carmen Sayón-Orea b,d , Miguel Ángel Martínez-González b,c,e,∗ a Department of Internal Medicine (Endocrinology), Hospital Reina Sofia, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Servicio Navarro de Salud-Osasunbidea, Tudela, Spain b University of Navarra, Department of Preventive Medicine and Public Health, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain c Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain d Department of Preventive Medicine, Complejo Hospitalario de Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Servicio Navarro de Salud-Osasunbidea, Pamplona, Spain e Department of Nutrition, Harvard TH Chan School of Public Health, Boston, USA
a r t i c l e
i n f o
Article history: Received 5 January 2018 Accepted 22 March 2018 Available online xxx Keywords: Obesity Diabetes Epidemiology Prevalence
a b s t r a c t Introduction and objective: Our aim was to examine the secular trends in obesity prevalence among Spanish adults with diabetes. Material and methods: Data were collected from 8 waves (from 1987 to 2012) of the National Health Surveys (NHS). NHS are cross-sectional studies conducted in representative samples of the Spanish adult population. Data of 7378 adults (≥16 years) who reported having been diagnosed of diabetes were analyzed. Previously validated self-reported weight and height were used to estimate body mass index (BMI). Obesity was defined as a BMI of 30 kg/m2 or greater. Age-adjusted obesity prevalence for each wave was calculated by the direct standardization method. Results: From 1987 to 2012 age-adjusted prevalence of obesity among persons with diabetes increased from 18.2% (95% confidence interval [CI]: 14.2–22.2%) to 39.8% (95% CI: 36.8–42.8%). Age-adjusted prevalence of obesity in males with diabetes increased from 13.2% (95% CI: 7.3–19.1%) to 38.0% (95% CI: 33.8–42.1%) and in females from 23.0% (95% CI: 17.6–28.4%) to 42.3% (95% CI: 38.0–46.6%). Conclusions: Between 1987 and 2012 the prevalence of obesity markedly increased in Spain among adults with diabetes. ˜ S.L.U. All rights reserved. © 2018 Elsevier Espana,
˜ Tendencia de la prevalencia de obesidad en adultos espanoles con diabetes, 1987-2012 r e s u m e n Palabras clave: Obesidad Diabetes Epidemiología Prevalencia
Introducción y objetivo: Nuestro objetivo fue conocer la tendencia de la prevalencia de obesidad entre ˜ adultos espanoles con diabetes. Material y métodos: Se utilizaron 8 (1987-2012) Encuestas Nacionales de Salud (ENS). Las ENS son estudios ˜ transversales realizados en muestras representativas de la población adulta espanola. Se analizaron datos ˜ de 7.378 adultos (≥ 16 anos) que refirieron un diagnóstico de diabetes. El índice de masa corporal (IMC) se calculó a partir de los datos auto-referidos de peso y talla validados previamente. Se definió obesidad como un IMC ≥ 30 kg/m2 . Se calculó para cada encuesta la prevalencia de obesidad ajustada por edad con el método directo de estandarización.
∗ Corresponding author. E-mail address: [email protected] (M.Á. Martínez-González). https://doi.org/10.1016/j.medcli.2018.03.016 ˜ S.L.U. All rights reserved. 0025-7753/© 2018 Elsevier Espana,
Please cite this article in press as: Basterra-Gortari FJ, et al. Trends of obesity prevalence among Spanish adults with diabetes, 1987–2012. Med Clin (Barc). 2017. https://doi.org/10.1016/j.medcli.2018.03.016
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Resultados: Desde 1987 a 2012 la prevalencia de obesidad ajustada aumentó en adultos con diabetes del 18,2% (intervalo de confianza [IC] 95%: 14,2-22,2%) al 39,8% (IC 95%: 36,8-42,8%). La prevalencia ajustada de obesidad en varones con diabetes aumentó del 13,2% (IC 95%: 7,3-19,1%) al 38,0% (IC 95%: 33,8-42,1%); en mujeres con diabetes aumentó del 23,0% (IC 95%: 17,6-28,4%) al 42,3% (IC 95%: 38,0-46,6%). ˜ Conclusiones: Entre 1987 y 2012 la prevalencia de obesidad aumentó notablemente en adultos espanoles con diabetes. ˜ S.L.U. Todos los derechos reservados. © 2018 Elsevier Espana,
weight and height of the NHS were previously validated.5 Participants with a BMI ≥ 30 kg/m2 were classified as obese. Weights from the overall Spanish population were used in the analyses of the survey data. Survey design data were not considered. Prevalence estimations are shown as percentages. Normal-based confidence intervals were estimated. Age was categorized in 3 groups: 16–39, 40–59 and ≥60 years. Age-adjusted prevalence for each wave was calculated by the direct standardization method (3 categories of age). The 2003 NHS population with diabetes was chosen as standard population. To assess the temporal trend of obesity we fitted logistic regression models. In these models the dependent variable is obesity and the independent variables are: age (3 categories), sex and NHS year (continuous). The annualized Odds Ratios (ORs) show the estimated increase per year in the odds of obesity prevalence. A Poisson regression model was performed to estimate prevalence ratios. To examine if the temporal trend differed between males and females an interaction term was calculated between NHS year and sex and this new variable was introduced in the adjusted model. Finally, to assess if the temporal trend was quadratic a new variable with the square of the year of the NHS was introduced in the fitted model. STATA 12 was used for the analyses.
Introduction Obesity is an important risk factor for cardiovascular diseases and diabetes. An increasing trend in the prevalence of obesity has been reported worldwide, including Mediterranean countries such as Spain.1 Besides, obesity is a risk factor for premature death in patients with diabetes.2 However, few analyses of trends of obesity among persons with diabetes have been reported. In Spain, periodic NHS have been conducted since 1987 on representative samples of the non-institutionalized adult population. Data from these NHS offer the opportunity to track secular trends in the prevalence of obesity. The aim of this study was to provide updated estimates of the trend of age-standardized prevalence of obesity among patients with diabetes since 1987 in Spain. Material and methods The NHS are cross-sectional studies carried out on representative samples of the Spanish non-institutionalized adult (≥16 years) population.3 The data were taken from 8 waves of the NHS: 1987, 1993, 1995, 1997, 2001, 2003, 2006–2007 (2006/7) and 2011–12 (2011/2). More information about the methodology used in the NHSs is described in detail elsewhere.1 Diabetes status was self-reported and was previously validated.4 A total of 9265 participants reported to have diabetes. After excluding participants with height <100 cm (n = 1) or missing information for BMI (n = 1881) or age (n = 5), we finally included 7378 (Fig. 1 in the supplementary appendix). Participants had a mean age of 64.5 years (SD 13.7) and 53.4% were women. We calculated the BMI as weight (kg) divided by the square of height (m), using self-reported weight and height. Self-reported
Results The crude obesity prevalence in participants with diabetes in 2011/2 was 39.9% (95% CI: 36.9–42.9%). From 1987 to 2011/2 age-adjusted prevalence of obesity in participants with diabetes increased from 18.2% (95% CI: 14.2–22.2%) to 39.8% (95% CI: 36.8–42.8%) (Table 1). Age-adjusted prevalence of obesity in males with diabetes increased from 13.2% (95% CI: 7.3–19.1%) to 38.0%
BMI in adults with diabetes in spain, 1987-2012 100
3.9
4.0
14.3
15.3
Percentage
80
60
46.8
4.6
4.9
7.0
8.1
21.7
24.3
21.5
21.8
10.5
22.3
28.0
47.2 43.7
42.8
48.2
44.7
43.6
40
20
11.8
40.4
35.0
33.6
30.0
28.0
23.4
25.3
23.6
19.8
1997
2001
2003
2006/7
2011/2
0 1987
1993
1995
National health survey BMI <25
BMI 25-29.9
BMI 30-34.9
BMI ≥35
Fig. 1. Distribution of adjusted body mass index categories among Spanish adults with diabetes, 1987–2011/2.
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BMI: body mass index; no obs: no observations. a Adjusted for age (3 categories: 16–39, 40–59 and ≥60 years) calculated by the direct standardization method. The 2003 survey population with diabetes was the standard population.
41.4 (37.2–45.7) 42.3 (38.0–46.6) 23.3 (7.4–39.1) 45.4 (35.6–55.3) 42.6 (37.7–47.4) 38.3 (33.8–42.8) 38.5 (34.1–43.0) 18.1 (5.5–30.7) 50.3 (40.7–59.9) 36.0 (30.7–41.3) 21.3 (16.3–26.3) 23.0 (17.6–28.4) 6.5 (0.0–13.6) 25.8 (16.1–35.5) 23.2 (16.4–30.1) Women Crude prevalence Adjusted prevalencea 16–39 years 40–59 years ≥60 years
23.6 (18.6–28.6) 23.4 (18.4–28.3) 24.6 (4.7–44.6) 28.1 (17.9–38.3) 21.7 (15.8–27.6)
33.3 (24.2–42.5) 33.7 (24.6–42.9) No obs 46.4 (28.0–64.9) 31.8 (20.6–43.1)
42.3 (33.5–51.0) 40.8 (31.8–49.7) 20.0 (0.0–55.1) 48.9 (34.6–63.2) 39.4 (28.1–50.8)
36.9 (31.9–41.9) 36.8 (31.8–41.8) 24.4 (7.3–41.4) 44.5 (34.3–54.6) 35.1 (29.0–41.1)
34.8 (30.5–39.3) 35.0 (30.8–39.2) 12.7 (0.0–26.9) 48.0 (37.3–58.7) 32.2 (27.6–36.8)
38.6 (34.3–42.8) 38.0 (33.8–42.1) 56.7 (35.3–78.1) 42.5 (34.1–50.9) 35.2 (30.3–40.0) 28.8 (24.4–33.2) 28.5 (24.2–32.9) 14.3 (0.3–28.2) 32.2 (24.3–40.2) 28.3 (22.8–33.8) 24.4 (20.1–28.8) 24.4 (20.1–28.7) 25.9 (2.8–49.0) 23.9 (15.1–32.7) 24.5 (19.4–29.5) 16.4 (9.4–23.3) 16.5 (9.5–23.5) No obs 18.8 (5.2–32.3) 16.9 (8.2–25.6) 19.6 (11.9–27.3) 19.3 (11.7–27.0) 20.0 (0.0–55.1) 24.1 (8.6–39.7) 17.6 (8.5–26.7) 13.7 (8.6–18.9) 13.2 (7.3–19.1) 4.5 (0.0–11.5) 17.7 (9.7–25.8) 12.3 (4.4–20.1) Men Crude prevalence Adjusted prevalencea 16–39 years 40–59 years ≥60 years
14.5 (10.0–19.0) 13.7 (9.4–18.1) 22.2 (2.7–41.6) 15.8 (7.8–23.7) 12.4 (7.1–17.8)
30.0 (24.2–35.9) 29.2 (23.3–35.1) 26.5 (20.4–32.5) 26.3 (20.3–32.3) 17.7 (14.1–21.3) 18.2 (14.2–22.2) All Crude prevalence Adjusted prevalencea
19.6 (16.1–23.1) 19.2 (15.8–22.7)
20.3 (16.3–24.4) 20.6 (16.5–24.7) 8.7 (0.0–20.9) 20.3 (12.8–27.7) 21.5 (16.4–26.7)
33.0 (29.8–36.2) 32.9 (29.7–36.0) 30.0 (26.9–33.0) 30.0 (26.9–33.0) 28.4 (25.1–31.6) 28.4 (25.1–31.7)
2006/7 2003 2001 1997 1995 1993 Obesity (BMI ≥30)
1987
Year of each National Health Survey
Table 1 Prevalence (%) of obesity (BMI ≥30) and 95% confidence intervals in Spanish adults (≥16 years) with diabetes, according to self-reported weight and height in the National Health Surveys.
2011/2
39.9 (36.9–42.9) 39.8 (36.8–42.8)
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(95% CI: 33.8–42.1%) and in females from 23.0% (95% CI: 17.6–28.4%) to 42.3% (95% CI: 38.0–46.6%) (Table 1) (Fig. 2 in the supplementary appendix). Age-adjusted categories of BMI from 1987 to 2011/2 are shown graphically in Fig. 1. Age-adjusted mean BMI was 26.6 kg/m2 (95% CI: 26.2–27.0) in 1987 and it increased to 29.2 kg/m2 (95% CI: 28.9–29.5) in 2011/2. Annualized OR, indicating the estimated increase per year in the OR, of obesity after adjusting for age (3 categories) and sex was 1.05 (95% CI: 1.04–1.06). This OR would be equivalent to a yearly increase in obesity prevalence of around 1 percentage point. Annualized prevalence ratio of obesity after adjusting for age (3 categories) and sex was 1.04 (95% CI: 1.03–1.04). Annualized ageadjusted ORs were 1.07 (95% CI: 1.05–1.08) for men and 1.04 (95% CI: 1.03–1.05) for women. The prevalence of obesity increased at a significantly greater rate in men compared with women (for interaction, p = 0.013). These increases were statistically significant in both sexes and in the 3 age categories (p < 0.001), except in women younger than 40 (p = 0.067). Finally, when the square of the year of the NHS was introduced in the adjusted model this variable was not statistically significant (p = 0.53). Discussion These trend estimates indicate that obesity in persons with diabetes increased rapidly over the 25-year period from 1987 through 2011/2. The 2011/2 NHS found a prevalence of obesity among patients with diabetes of 39.9% (95% CI: 36.9–42.9%). The current study has some limitations. First, the use of selfreported data, because self-report on average understates weight and overstates height.5 Therefore, our study probably might have underestimated the prevalence of obesity in patients with diabetes. However, as the underestimation is likely to be constant across waves, it probably did not impact significantly the observed trend. Second, a limitation of this study is that data were missing for a significant proportion (approximately 20%) of participants. The direction of this bias is unknown, however due to the magnitude of the observed trend we believe it is unlikely that the results might be explained by the missing data. Third, self-reported data also may underestimate diabetes prevalence.4 However, diabetes prevalence estimated in the NHS (≥16 years) in 2011/2 was 7.4%,1 which is similar to the 7.8% prevalence of known diabetes published in the [email protected] study (≥18 years),6 and to the 7.6% prevalence found in the report with data from anonymized patient records carried out in Catalonia (31–90 years).7 Fourth, the NHS cannot distinguish between types of diabetes. Finally, the 1995 and 1997 NHSs were smaller, thus there were fewer participants with diabetes and, consequently, their estimated confidence intervals are wider. Our study has several strengths. These include the use of representative data of the Spanish population, the long period studied, the large sample size, or the estimation of adjusted trends. The prevalence we found is lower than the 50.2% published in the [email protected] study in participants with known diabetes conducted in 2009/10 in a representative sample of the Spanish population,6 and also lower than other cross-sectional study carried out in Catalonia (Spain) in 2009 with data from anonymized patient records, that reported an obesity prevalence of 45.4%.7 These differences may be explained because self-report on average underestimates BMI.5 Another cross-sectional study carried out in Spain in 2002 estimated a prevalence of obesity of 35.1% in patients with diabetes.8 This prevalence was lower than the prevalence reported in the studies conducted in 20096,7 which confirms the significant increase found in the NHS. Our results suggest that the prevalence continued to increase at a similar rate over the 25-year period examined. In all the waves of the NHS obesity prevalence was higher in women with diabetes than in men with diabetes, which was
Please cite this article in press as: Basterra-Gortari FJ, et al. Trends of obesity prevalence among Spanish adults with diabetes, 1987–2012. Med Clin (Barc). 2017. https://doi.org/10.1016/j.medcli.2018.03.016
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also found in the study conducted in Catalonia.7 However, obesity increase over time was faster among men with diabetes. This is consistent with results of obesity trend estimated in the Spanish general population.1 This trend of body weight is clinically relevant, because BMI is usually taken into account by clinicians when they start an antihyperglycemic therapy9 and it is directly associated with insulin needs. Besides, obesity is a risk factor for mortality in patients with type 2 diabetes2 and diabetes prevalence has been steadily increasing over the past few decades,1 thus the observed obesity trend among patients with type 2 diabetes has become a public health problem. Conclusions Our results provide nationally representative snapshots of obesity trends between 1987 and 2011/2 among Spanish adults with diabetes. A marked increase in the prevalence of obesity was found especially in men. Our estimates do not suggest that obesity trend in patients with diabetes were slowing or leveling off in this Mediterranean country. Funding No funding. Conflict of interest The authors declared no conflict of interest.
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/ j.medcli.2018.03.016 References 1. Basterra-Gortari FJ, Bes-Rastrollo M, Ruiz-Canela M, Gea A, Martínez-González MA. Prevalence of obesity and diabetes in Spanish adults 1987–2012. Med Clin (Barc). 2017;148:250–6. 2. Tobias DK, Pan A, Jackson CL, O’Reilly EJ, Ding EL, Willet WC, et al. Body-mass index and mortality among adults with incident type 2 diabetes. N Engl J Med. 2014;16:233–44. 3. Ministerio de Sanidad, Servicios Sociales e Igualdad. Instituto de Información Sanitaria. Encuesta Nacional de Salud. http://www.msssi.gob.es/estadEstudios/ estadisticas/encuestaNacional/home.htm [accessed 04.01.18]. 4. Basterra-Gortari FJ, Forga L, Bes-Rastrollo M, Martínez JA, Martínez-González MA. Validation of self-reported diabetes mellitus, hypertension and hypercholesterolemia in the Spanish national health survey. Endocrinol Nutr. 2007;54: 462–6. 5. Basterra-Gortari FJ, Bes-Rastrollo M, Forga L, Martínez JA, Martínez-González MA. Validity of self-reported body mass index in the National Health Survey. An Sist Sanit Navar. 2007;30:373–81. 6. Soriguer F, Goday A, Bosch-Comas A, Bordiú E, Calle-Pascual A, Carmena R, et al. Prevalence of diabetes mellitus and impaired glucose regulation in Spain: the [email protected] study. Diabetologia. 2012;55:88–93. 7. Vinagre I, Mata-Cases M, Hermosilla E, Morros R, Fina F, Rossell M, et al. Control of glycemia and cardiovascular risk factors in patients with type 2 diabetes in primary care in Catalonia (Spain). Diabetes Care. 2012;35:774–9. 8. Orozco-Beltrán D, Gil-Guillen VF, Quirce F, Navarro-Perez J, Pineda M, Gomez-dela-Cámara A, et al. Control of diabetes and cardiovascular risk factors in patients with type 2 diabetes in primary care. The gap between guidelines and reality in Spain. Int J Clin Pract. 2007;61:909–15. 9. Artola Menéndez S. Actualización del algoritmo de hiperglucemia 2017. Diabetes Práctica. 2017;8:57–60.
Please cite this article in press as: Basterra-Gortari FJ, et al. Trends of obesity prevalence among Spanish adults with diabetes, 1987–2012. Med Clin (Barc). 2017. https://doi.org/10.1016/j.medcli.2018.03.016