Socioeconomic patterning of Overweight and Obesity between 1998 and 2015: Evidence from India

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1 Socioeconomic patterning of Overweight and Obesity between 1998 and 2015: Evidence from India Shammi Luhar Supervised by Lynda Clarke & Prof Sanjay Kinra The London School of Hygiene and Tropical Medicine September 29, Introduction Overweight (OW) and obesity (OB) are increasingly threatening health in transitioning economies [1][2], and are responsible for 3.4 million deaths per year globally[4][5][6][7]. In India, between 1998 and 2006, the prevalence of OW and OB among women (15-49) years increased from 10.6 to 12.6% [13][14]. Since then, the number of obese women has doubled[12]. OW/OB prevalence is associated with a high socioeconomic position (SEP) in developing countries, due to richer diets and more sedentary lifestyles compared to the relatively poor. In rapidly developing countries, the risk of OW/OB increases among the poor, in part due to cheaper costs of high calorie food, making the positive socioeconomic gradient in OW/OB become less positive and eventually turn negative. Studies also find a higher prevalence of OW/OB among women, in addition to a rise in OW/OB among poor women at earlier stages of development, compared to poor males [3]. Although some studies have attempted to explain variation in OW/OB in India using nationally representative data, there is little understanding of the socioeconomic patterning of OW/OB since sub-nationally, the level at which health policy is dictated. With the aim of identifying the groups currently most a ected by OW/OB, and understanding how the socioeconomic patterning of OW/OB is evolving, we aim to address the following questions: Is the overweight/obesity-sep association in India in less positive than in ( ) for women (men)? Is the overweight/obesity-sep association in India less positive among women, compared to men? Is the overweight/obesity-sep association less positive in , compared to the initial period, only in high GDP per capita (pc) states? 2 Data and Methods Nationally representative data from NFHS waves 2, 3 and 4 ( ; ; ) will be used for the study. In waves 2 and 3 health and sociodemographic data was collected on 90,303 and 124,385 women respectively, and 74,369 males in NFHS-3. The forthcoming 4th wave will contain data on 628,826 women and 94,324 men. Body Mass Index of ever-married individuals has been be used to create outcome variables of OW/OB (>22.99kg/m 2 )andob (>27.49 kg/m 2 ) as per guidelines for South Asian populations[8][9]. The following socioeconomic variables will be used as the key exposures. A time comparable Wealth index has been created and split into three tertiles, as per the method by Rutstein and Staveteig (2014). The NFHS Wealth Index aims to capture household economic status that mirrors their expenditure and income position based on ownership of particular assets and access to services. [17]. 1

2 Respondent s education has been categorised as individuals with no education, primary, secondary and higher education (based on the number of completed years of schooling) [10]. Residence is defined as either rural or urban, based on the census bureau s definition. Logistic multilevel regressions will be adopted for multivariate analysis in order to account for the clustered nature of the data and avoid standard error underestimation. Three level random intercept models will be used for the national level analysis, with individuals nested in PSUs, nested in states. Two level random intercept model will be used for subnational analysis, with individuals nested in PSUs. To examine a changing association between survey waves, the primary exposure will be interacted with a categorical variable representing the survey wave. In a fully adjusted model, controlling for all exposures at the same time, we would expect some covariates to lie on the pathway between the key exposure and Overweight/Obesity odds [18] (Figure 1). For instance, the association between higher education and Overweight/Obesity may be partially mediated by higher standard of living (Wealth Index). Therefore we provide results of minimally (adjusted for age and parity) and fully adjusted models, and expect the true odds ratios to lie between them. To investigate variation in the association by state-level development, the data will be subsetted to the following two groups, and analysis carried out on them separately: High GDP states:gujarat, Maharashtra, Tamil Nadu, and Kerala (average GDP pc = US $1,694.57) [19]. Low GDP states: Uttar Pradesh, Bihar, Madhya Pradesh, and Assam (average GDP pc = US $633.02) [19]. 3 Preliminary Results We currently await the release of NFHS-4 survey data to complete the analysis. Preliminary results show that in NFHS-2 and 3 across India, for men and women, the odds of OW/OB is highest for those with higher education, residents of urban areas, and those in the highest wealth tertile (Figures 2 and 3). As initially hypothesised, the social gradient in is less positive than in for women when considering Wealth index as the primary exposure. No change in the OW/OB-SEP association was observed when considering education or residence as the main exposure. In the data, we expect to find an even smaller odds of OW/OB among women in the highest wealth tertile, relative to women in the lowest, in addition to observing a less positive OW/OB-SEP association when using education and residence as the exposure of interest. As only one time period is currently available with which to analyse the association among men, any evidence of a less positive social gradient can only be ascertained upon release of the survey data. Each bar in Figure 4 shows the di erence between the predicted probability of OW/OB of the most and least advantageous strata of the three primary socioeconomic variables. A bar exceeding a value of zero indicates a positive OW/OB-SEP association, whereby the predicted probability is higher amongst the highly educated, the top wealth tertile or urban residents, compared to those with no education, those from the lowest wealth tertile, and rural residents, respectively. Initial results indicate a positive association between OW/OB and SEP, in high and low-gdp states among females in both waves, and males in wave 3. Some evidence is provided of a more positive social gradient in OW/OB in , compared to for women in low-gdp states, irrespective of the exposure. Conversely, there is some evidence of a less positive OW/OB-SEP association in high-gdp pc states, when using residence or education as the primary exposures, and a stagnation in the association when considering the wealth index. As high-gdp pc states have continued to develop at a faster pace than low-gdp pc states in the decade since , we expect to find a smaller positive association in NFHS 4, and a larger positive OW/OB-SEP association in low-gdp pc states. 4 Conclusion/Expected findings with NFHS-4 Using NFHS-4 survey data, we expect to find a persisting stronger positive social gradient in OW/OB in males compared to females, however, an overall decline relative to NFHS-2 and 3. Our findings thus far are similar to those of Sengupta et al [11], who find the strongest increase in OW/OB among women of the lowest band of standard of living index and rural areas in a handful of states defined by a high prevalence of OW. To our knowledge, this is the first study to examine the evolution of the socioeconomic patterning of OW/OB among both males and females using nationally representative Indian data post Identifying diverging trends between states with di erent levels of 2

3 economic development, highlights the limitations of such analysis for India as a whole. Given the doubling of the number of individuals classified as obese in the last decade, understanding the most a ected groups in society will crucial to developing e ective combative policy. Figure 1: Framework of potential pathways socio-economic variables can a ect overweight/obesity in a developing country setting (based on Samal et al s 2015 [18] framework) Figure 2: Association between socioeconomic characteristics and OW/OB for women in NFHS Waves 2, 3, and 4 3

4 Figure 3: Association between socioeconomic characteristics and OW/OB for men in NFHS Waves 3 and 4 Figure 4: Di erence between fully adjusted predicted probabilities of the most and least advantageous strata of SEP in each of the three NFHS waves that measure BMI (by state development and sex) 4

5 References [1] WHO. WHO Obesity and overweight. World Health Organization; Accessed 21 Feb 2016 [2] Tuoyire, D.A., Kumi-Kyereme, A. and Doku, D.T., Socio-demographic trends in overweight and obesity among parous and nulliparous women in Ghana. BMC obesity, 3(1), p.44. [3] Dinsa, G.D., Goryakin, Y., Fumagalli, E. and Suhrcke, M., Obesity and socioeconomic status in developing countries: a systematic review. Obesity reviews, 13(11), pp [4] Ng M, Fleming T, Thomson B, et al. Global, regional and national prevalence of overweight and obesity in children and adults : A systematic analysis. Lancet. 2014;384(9945): [5] Stevens GA, et al. National, regional, and global trends in adult overweight and obesity prevalence. Popul Health Metrics. 2012;10:22. [6] Abrha, S., Shiferaw, S. and Ahmed, K.Y., Overweight and obesity and its socio-demographic correlates among urban Ethiopian women: evidence from the 2011 EDHS. BMC Public Health, 16(1), p.636. [7] Lim SS, Vos T, Flaxman AD, et al. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, : a systematic analysis for the Global Burden of Disease Study Lancet. 2012;380: [8] World Health Organization. Expert Consultation: Appropriate body mass index for Asian populations and its implications for policy and intervention strategies. Lancet 2004; 363:15763 [9] Subramanian, S.V., Kawachi, I. and Smith, G.D., Income inequality and the double burden of under-and overnutrition in India. Journal of Epidemiology and Community Health, 61(9), pp [10] Kumar, A., Kumari, D. and Singh, A., Increasing socioeconomic inequality in childhood undernutrition in urban India: trends between , and Health policy and planning, 30(8), pp [11] Sengupta, Angan, et al. Overweight and obesity prevalence among Indian women by place of residence and socio-economic status: Contrasting patterns from underweight states and overweight states of India. Social Science & Medicine 138 (2015): [12] NFHS(2016) Key findings from NFHS-4, viewed 13 December 2016, [13] International Institute for Population Sciences (IIPS) and ORC Macro National Family Health Survey (NFHS-2), : India. Mumbai: IIPS. [14] International Institute for Population Sciences (IIPS) and Macro International National Family Health Survey (NFHS-3), : India: Volume I. Mumbai: IIPS. [15] Garcia Villar J, Quintana-Domeque C. Income and body mass index in Europe. Econ Hum Biol 2009; 7: [16] Case A, Menendez A. Sex di erences in obesity rates in poor countries: evidence from South Africa. Econ Hum Biol 2009; 7: [17] Rutstein, S.O. and Staveteig, S., Making the Demographic and Health Surveys wealth index comparable. Rockville: ICF International. [18] Samal, S., Panigrahi, P. and Dutta, A., Social epidemiology of excess weight and central adiposity in older Indians: analysis of Study on global AGEing and adult health (SAGE). BMJ open, 5(11), p.e [19] India. Ministry of Statistics & Programme Implementation Per Capita National Income. By Ministry of Statistics & Programme Implementation. Government of India, 22 July 2015 [online]. Available at: [Accessed 12 Jul. 2017] 5