Is the burden of overweight shifting to the poor across the globe? Time trends among women in 39 low- and middle-income countries (1991–2008)

Abstract
Overweight prevalence has increased globally; however, current time trends of overweight by social class in lower income countries are unknown. We used repeated cross-sectional, nationally representative data from the Demographic and Health Surveys on women aged 18–49 with young children (n=421,689) in 39 lower income countries. We present overweight (body mass index ≥25) prevalence at each survey wave, prevalence difference and prevalence growth rate for each country over time is presented separately by wealth quintile and educational attainment. We present the correlation between nation wealth and differential overweight prevalence growth by wealth and education was estimated. In the majority of countries the highest wealth and education groups still have the highest prevalence of overweight and obesity. However, in a substantial number of countries (31% when wealth is used as the indicator of SES and 54% for education) the estimated increases in overweight prevalence over time have been greater in the lowest compared to the highest wealth and education groups. Gross Domestic Product per capita was associated with a higher overweight prevalence growth rate for the lowest wealth group compared to the highest (Pearson’s correlation coefficient: 0.45). Higher (versus lower) wealth and education groups had higher overweight prevalence across most developing countries. However, some countries show a faster growth rates in overweight in the lowest (versus highest) wealth and education groups, indicative of an increasing burden of overweight among lower wealth and education groups in lower income countries.