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Managing threats to respiratory health in urban slums
Comment
Managing threats to respiratory health in urban slums More than half the world’s population lives in urban areas, and an estimated 863 million people currently live in urban slums.1 Although urbanisation is usually coupled with economic development, rural-to-urban migration can result in negative implications for respiratory health. Slum residents who live in informal settlements and who commonly have inadequate access to health services are at a particularly high risk of being affected by the dual burden of infectious and non-communicable respiratory diseases over the course of their lives. These diseases include pneumonia in early life; asthma beginning in childhood; and tuberculosis, COPD, and restrictive lung diseases during adulthood. Threats to respiratory health include infections due to poor housing quality and overcrowding; ambient, traffic-related, and household air pollution; tobacco and second-hand smoke; occupational exposures; allergenic sensitisation; micronutrient deficiencies; poor and inadequate diet; and a sedentary lifestyle (appendix). Here, we present three examples to illustrate the threats to respiratory health confronted by people living in slums. India has the second largest urban population in the world with 377 million people living in cities, which is projected to double by 2041.2 Among them, 65 million people (17%) live in overcrowded slums with poor amenities, often adjacent to large open drains and waste disposal sites, predisposing slum residents to an increased risk of infectious diseases.3 Additionally, half the adult population uses smokeless tobacco, one in three smoke, and one in six adults living in slums in India use alcohol routinely. Low physical activity coupled with low intake of fruits and vegetables has led to an increased prevalence of obesity in urban slums compared with the rural population.4 The burden of respiratory diseases caused by air pollution exceeds that due to tuberculosis, ischaemic heart disease, all cancers, and road accidents combined.5 Household air pollution is responsible for between 4·2% and 6·1% of total morbidity in India, affecting two-thirds of women and children.5 Nearly half of slum residents have respiratory diseases and spend more than 10% of their household income on associated treatment.6 Peru has witnessed rapid urbanisation over the past five decades. By 2015, 23·5 million (76%) of
the population lived in urban areas, and in 2014, 8·2 million (36% of the urban population) lived in slums.7 Periurban communities have had substantial improvements in basic infrastructure over the past two decades. Chronic diseases are now responsible for approximately 87 120 (66%) of deaths in Peru, and around 16% of adults are obese;8—the profile of respiratory diseases away from infectious diseases and towards chronic diseases reflects this transition. Pneumonia is still the leading cause of death in children in Peru, and tuberculosis is an important cause of morbidity and mortality. The capital city, Lima, has a high prevalence of childhood asthma9 by contrast with a low reported prevalence in rural settings.9,10 These differences probably result from high levels of allergic sensitisation from poor living conditions and traffic-related pollution.11 Moreover, chronic bronchitis is as prevalent in periurban settings as in rural settings in Peru.12 COPD has been linked to the history of both tuberculosis and asthma in urban slums,13 indicating that respiratory conditions from early life can interact to affect risk in later life. Findings from epidemiological studies have shown a low prevalence of daily tobacco smoking in resourcepoor settings,14 representing a potential opportunity for both primary and secondary prevention following WHO’s MPOWER Tobacco Free Initiative measures. Uganda is an example of a country in the early stages of slum development, and offers potential targets for early intervention. Uganda has high rates of urbanisation and fertility, which when compounded with high costs of land and a shortage of tenure, have led to a substantial proportion of the urban population living in slum conditions. Of 5 million urban residents in Uganda, around 2 million (60%) live in slums.15 Slum residents face unique risk factors for acute respiratory disease. The prevalence of COPD in adults and the prevalence of acute respiratory infections among children is highest in households exposed to household air pollution from biomass, which is disproportionately used in slums.5 A shortage of waste management and water-treatment systems (only around 420 000 [14%] of slum residents have access to piped water), high rates of malnutrition, and large household sizes are additional risk factors for acute
www.thelancet.com/respiratory Published online October 16, 2016 http://dx.doi.org/10.1016/S2213-2600(16)30245-4
Lancet Respir Med 2016 Published Online October 16, 2016 http://dx.doi.org/10.1016/ S2213-2600(16)30245-4
See Online for appendix
For more on WHO’s Tobacco Free Initiative see http://www. who.int/tobacco/mpower/en
1
Comment
Panel: Recommendations for research and opportunities in policy making to improve respiratory health in urban slums • Comprehensive strategies to meet clean air guidelines for ambient air and air in the home • Educational campaigns and packaged interventions to improve the home environment and reduce allergen exposure, improve diet, and encourage physical activity • Better understanding of the role of built environment in health, and the development of safe neighbourhoods and green spaces • Planning efforts to prevent urban sprawl, recognise where urbanisation will occur, and develop provisions for regulation of neighbourhood growth and land tenure • Expand access to primary and secondary preventive care, including vaccination against Streptococcus pneumoniae, Haemophilus influenzae, and influenza virus, and actions against tobacco smoke and for healthy eating • Governmental policies focused on poverty reduction and equity in health-care access
trials should guide better estimates of risk factor and outcome prevalence, and whether it is possible to adapt technology to reduce disease burden (panel). *William Checkley, Suzanne L Pollard, Trishul Siddharthan, Giridhara R Babu, Megha Thakur, Catherine H Miele, Onno CP Van Schayck Division of Pulmonary and Critical Care, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA (WC, SLP, TS, CHM); Public Health Foundation of India, Indian Institute of Public Health-Hyderabad, Bangalore campus, Bangalore, India (MT, GRB); Department of Family Medicine, CAPHRI, Maastricht University, Maastricht, Netherlands (OVS) [email protected] We declare no competing interests.
respiratory infections. 690 000 (23%) of Ugandan slum residents have acute respiratory infections, compared with about 280 000 (14%) in urban, nonslum areas. Urban populations in Uganda are also beginning to face a dual burden of chronic respiratory diseases: around 14% of primary school children reported symptoms of asthma in 2009.15 The challenge for cities in low-income and middleincome countries is to mitigate emerging risk factors and prioritise expanded access to preventive care for chronic diseases, while still managing infectious diseases. Urbanisation has the potential to lead to major health improvements given that health resources, infrastructure, and personnel tend to be concentrated in urban areas. But for improvements to occur, concerted actions will have to be taken by many stakeholders. First, efforts should be made by governments, academic institutions, industry, and other stakeholders to understand the determinants of respiratory health in slum residents and quantify their impact. Second, stakeholders should rigorously try to develop specific interventions such as clean-burning stoves and better smoke-reduction strategies that are context-specific, culturally appropriate, evidence based, and locally relevant. Pollution is a major public health problem affecting the poorest pool of slum residents in lowincome and middle-income countries, and an integrated approach to target both ambient air and household air pollution is necessary to achieve full health benefits. Well conducted observational studies and randomised 15
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UN Habitat. State of the World’s Cities 2012/13. Prosperity of cities. New York: Routledge/Taylor & Francis, 2013. Indian Census Bureau. Provisional population totals of 2011. http:// www.censusindia.gov.in/2011-prov-results/prov_results_paper1_india. html (accessed July 19, 2016). Joseph K. Municipal solid waste management in India. In: Pariatamby A, Tanaka M, eds. Municipal solid waste management in Asia and the Pacific Islands: challenges and strategic solutions. Singapore: Springer-Verlag, 2014. Acharyya T, Kaur P, Murhekar MV. Prevalence of behavioral risk factors, overweight and hypertension in the urban slums of North 24 Parganas District, West Bengal, India, 2010. Indian J Public Health 2014; 58: 195–98. Smith KR. National burden of disease in India from indoor air pollution. Proc Natl Acad Sci U S A 2000; 97: 13286–93. Chowdhury S. Financial burden of transient morbidity: a case study of slums in Delhi. Econ Politic Weekly 2011; 46: 59. UN. UN data. http://data.un.org (accessed Aug 18, 2016). WHO. Global World Health Organization Health Observatory data repository, 2016. http://www.who.int/nmh/countries/per_en.pdf?ua=1 (accessed Aug 18, 2016). Robinson CL, Baumann LM, Romero K, et al. Effect of urbanisation on asthma, allergy and airways inflammation in a developing country setting. Thorax 2011; 66: 1051–57. Gaviola C, Miele CH, Wise RA, et al. Urbanisation but not biomass fuel smoke exposure is associated with asthma prevalence in four resourcelimited settings. Thorax 2016; 71: 154–60. Baumann LM, Robinson CL, Combe JM, et al. Effects of distance from a heavily transited avenue on asthma and atopy in a periurban shantytown in Lima, Peru. J Allergy Clin Immunol 2011; 127: 875–82. Miele CH, Jaganath D, Miranda JJ, et al; CRONICAS Cohort Study Group. Urbanization and daily exposure to biomass fuel smoke both contribute to chronic bronchitis risk in a population with low prevalence of daily tobacco smoking. COPD 2016; 13: 186–95. Jaganath D, Miranda JJ, Gilman RH, et al; CRONICAS Cohort Study Group. Prevalence of chronic obstructive pulmonary disease and variation in risk factors across four geographically diverse resource-limited settings in Peru. Respir Res 2015; 16: 40. Weygandt PL, Vidal-Cardenas E, Gilman RH, Avila-Tang E, Cabrera L, Checkley W. Epidemiology of tobacco use and dependence in adults in a poor peri-urban community in Lima, Peru. BMC Pulm Med 2012; 12: 9. Uganda Ministry of Lands, Housing and Urban Development. Slums in Uganda: situation analysis national slum upgrading strategy and action plan. http://ssauganda.org/uploads/NATIONAL%20SLUM%20 UPGRADING%20STRATEGY%20UG%20(2).pdf (accessed 19 July, 2016).
www.thelancet.com/respiratory Published online October 16, 2016 http://dx.doi.org/10.1016/S2213-2600(16)30245-4
Managing threats to respiratory health in urban slums More than half the world’s population lives in urban areas, and an estimated 863 million people currently live in urban slums.1 Although urbanisation is usually coupled with economic development, rural-to-urban migration can result in negative implications for respiratory health. Slum residents who live in informal settlements and who commonly have inadequate access to health services are at a particularly high risk of being affected by the dual burden of infectious and non-communicable respiratory diseases over the course of their lives. These diseases include pneumonia in early life; asthma beginning in childhood; and tuberculosis, COPD, and restrictive lung diseases during adulthood. Threats to respiratory health include infections due to poor housing quality and overcrowding; ambient, traffic-related, and household air pollution; tobacco and second-hand smoke; occupational exposures; allergenic sensitisation; micronutrient deficiencies; poor and inadequate diet; and a sedentary lifestyle (appendix). Here, we present three examples to illustrate the threats to respiratory health confronted by people living in slums. India has the second largest urban population in the world with 377 million people living in cities, which is projected to double by 2041.2 Among them, 65 million people (17%) live in overcrowded slums with poor amenities, often adjacent to large open drains and waste disposal sites, predisposing slum residents to an increased risk of infectious diseases.3 Additionally, half the adult population uses smokeless tobacco, one in three smoke, and one in six adults living in slums in India use alcohol routinely. Low physical activity coupled with low intake of fruits and vegetables has led to an increased prevalence of obesity in urban slums compared with the rural population.4 The burden of respiratory diseases caused by air pollution exceeds that due to tuberculosis, ischaemic heart disease, all cancers, and road accidents combined.5 Household air pollution is responsible for between 4·2% and 6·1% of total morbidity in India, affecting two-thirds of women and children.5 Nearly half of slum residents have respiratory diseases and spend more than 10% of their household income on associated treatment.6 Peru has witnessed rapid urbanisation over the past five decades. By 2015, 23·5 million (76%) of
the population lived in urban areas, and in 2014, 8·2 million (36% of the urban population) lived in slums.7 Periurban communities have had substantial improvements in basic infrastructure over the past two decades. Chronic diseases are now responsible for approximately 87 120 (66%) of deaths in Peru, and around 16% of adults are obese;8—the profile of respiratory diseases away from infectious diseases and towards chronic diseases reflects this transition. Pneumonia is still the leading cause of death in children in Peru, and tuberculosis is an important cause of morbidity and mortality. The capital city, Lima, has a high prevalence of childhood asthma9 by contrast with a low reported prevalence in rural settings.9,10 These differences probably result from high levels of allergic sensitisation from poor living conditions and traffic-related pollution.11 Moreover, chronic bronchitis is as prevalent in periurban settings as in rural settings in Peru.12 COPD has been linked to the history of both tuberculosis and asthma in urban slums,13 indicating that respiratory conditions from early life can interact to affect risk in later life. Findings from epidemiological studies have shown a low prevalence of daily tobacco smoking in resourcepoor settings,14 representing a potential opportunity for both primary and secondary prevention following WHO’s MPOWER Tobacco Free Initiative measures. Uganda is an example of a country in the early stages of slum development, and offers potential targets for early intervention. Uganda has high rates of urbanisation and fertility, which when compounded with high costs of land and a shortage of tenure, have led to a substantial proportion of the urban population living in slum conditions. Of 5 million urban residents in Uganda, around 2 million (60%) live in slums.15 Slum residents face unique risk factors for acute respiratory disease. The prevalence of COPD in adults and the prevalence of acute respiratory infections among children is highest in households exposed to household air pollution from biomass, which is disproportionately used in slums.5 A shortage of waste management and water-treatment systems (only around 420 000 [14%] of slum residents have access to piped water), high rates of malnutrition, and large household sizes are additional risk factors for acute
www.thelancet.com/respiratory Published online October 16, 2016 http://dx.doi.org/10.1016/S2213-2600(16)30245-4
Lancet Respir Med 2016 Published Online October 16, 2016 http://dx.doi.org/10.1016/ S2213-2600(16)30245-4
See Online for appendix
For more on WHO’s Tobacco Free Initiative see http://www. who.int/tobacco/mpower/en
1
Comment
Panel: Recommendations for research and opportunities in policy making to improve respiratory health in urban slums • Comprehensive strategies to meet clean air guidelines for ambient air and air in the home • Educational campaigns and packaged interventions to improve the home environment and reduce allergen exposure, improve diet, and encourage physical activity • Better understanding of the role of built environment in health, and the development of safe neighbourhoods and green spaces • Planning efforts to prevent urban sprawl, recognise where urbanisation will occur, and develop provisions for regulation of neighbourhood growth and land tenure • Expand access to primary and secondary preventive care, including vaccination against Streptococcus pneumoniae, Haemophilus influenzae, and influenza virus, and actions against tobacco smoke and for healthy eating • Governmental policies focused on poverty reduction and equity in health-care access
trials should guide better estimates of risk factor and outcome prevalence, and whether it is possible to adapt technology to reduce disease burden (panel). *William Checkley, Suzanne L Pollard, Trishul Siddharthan, Giridhara R Babu, Megha Thakur, Catherine H Miele, Onno CP Van Schayck Division of Pulmonary and Critical Care, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA (WC, SLP, TS, CHM); Public Health Foundation of India, Indian Institute of Public Health-Hyderabad, Bangalore campus, Bangalore, India (MT, GRB); Department of Family Medicine, CAPHRI, Maastricht University, Maastricht, Netherlands (OVS) [email protected] We declare no competing interests.
respiratory infections. 690 000 (23%) of Ugandan slum residents have acute respiratory infections, compared with about 280 000 (14%) in urban, nonslum areas. Urban populations in Uganda are also beginning to face a dual burden of chronic respiratory diseases: around 14% of primary school children reported symptoms of asthma in 2009.15 The challenge for cities in low-income and middleincome countries is to mitigate emerging risk factors and prioritise expanded access to preventive care for chronic diseases, while still managing infectious diseases. Urbanisation has the potential to lead to major health improvements given that health resources, infrastructure, and personnel tend to be concentrated in urban areas. But for improvements to occur, concerted actions will have to be taken by many stakeholders. First, efforts should be made by governments, academic institutions, industry, and other stakeholders to understand the determinants of respiratory health in slum residents and quantify their impact. Second, stakeholders should rigorously try to develop specific interventions such as clean-burning stoves and better smoke-reduction strategies that are context-specific, culturally appropriate, evidence based, and locally relevant. Pollution is a major public health problem affecting the poorest pool of slum residents in lowincome and middle-income countries, and an integrated approach to target both ambient air and household air pollution is necessary to achieve full health benefits. Well conducted observational studies and randomised 15
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1 2
3
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5 6 7 8
9
10
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UN Habitat. State of the World’s Cities 2012/13. Prosperity of cities. New York: Routledge/Taylor & Francis, 2013. Indian Census Bureau. Provisional population totals of 2011. http:// www.censusindia.gov.in/2011-prov-results/prov_results_paper1_india. html (accessed July 19, 2016). Joseph K. Municipal solid waste management in India. In: Pariatamby A, Tanaka M, eds. Municipal solid waste management in Asia and the Pacific Islands: challenges and strategic solutions. Singapore: Springer-Verlag, 2014. Acharyya T, Kaur P, Murhekar MV. Prevalence of behavioral risk factors, overweight and hypertension in the urban slums of North 24 Parganas District, West Bengal, India, 2010. Indian J Public Health 2014; 58: 195–98. Smith KR. National burden of disease in India from indoor air pollution. Proc Natl Acad Sci U S A 2000; 97: 13286–93. Chowdhury S. Financial burden of transient morbidity: a case study of slums in Delhi. Econ Politic Weekly 2011; 46: 59. UN. UN data. http://data.un.org (accessed Aug 18, 2016). WHO. Global World Health Organization Health Observatory data repository, 2016. http://www.who.int/nmh/countries/per_en.pdf?ua=1 (accessed Aug 18, 2016). Robinson CL, Baumann LM, Romero K, et al. Effect of urbanisation on asthma, allergy and airways inflammation in a developing country setting. Thorax 2011; 66: 1051–57. Gaviola C, Miele CH, Wise RA, et al. Urbanisation but not biomass fuel smoke exposure is associated with asthma prevalence in four resourcelimited settings. Thorax 2016; 71: 154–60. Baumann LM, Robinson CL, Combe JM, et al. Effects of distance from a heavily transited avenue on asthma and atopy in a periurban shantytown in Lima, Peru. J Allergy Clin Immunol 2011; 127: 875–82. Miele CH, Jaganath D, Miranda JJ, et al; CRONICAS Cohort Study Group. Urbanization and daily exposure to biomass fuel smoke both contribute to chronic bronchitis risk in a population with low prevalence of daily tobacco smoking. COPD 2016; 13: 186–95. Jaganath D, Miranda JJ, Gilman RH, et al; CRONICAS Cohort Study Group. Prevalence of chronic obstructive pulmonary disease and variation in risk factors across four geographically diverse resource-limited settings in Peru. Respir Res 2015; 16: 40. Weygandt PL, Vidal-Cardenas E, Gilman RH, Avila-Tang E, Cabrera L, Checkley W. Epidemiology of tobacco use and dependence in adults in a poor peri-urban community in Lima, Peru. BMC Pulm Med 2012; 12: 9. Uganda Ministry of Lands, Housing and Urban Development. Slums in Uganda: situation analysis national slum upgrading strategy and action plan. http://ssauganda.org/uploads/NATIONAL%20SLUM%20 UPGRADING%20STRATEGY%20UG%20(2).pdf (accessed 19 July, 2016).
www.thelancet.com/respiratory Published online October 16, 2016 http://dx.doi.org/10.1016/S2213-2600(16)30245-4