National income and macro-economic correlates of the double burden of malnutrition: an ecological study of adult populations in 188 countries over 42 years.

BACKGROUND: The double burden of malnutrition (DBM) represents a growing global challenge with adverse health and economic consequences. We aimed to investigate the associative roles of national income (gross domestic product per capita [GDPPC]) and macro-environmental factors on the DBM trends among national adult populations. METHODS: In this ecological study we assembled extensive historical data on GDPPC from the World Bank World Development Indicators database and population-level DBM data of adults (aged ≥18 years) from the WHO Global Health Observatory database in 188 countries over 42 years (1975-2016). In our analysis, a country was considered to have the DBM in a year when adult overweight (BMI ≥25·0 kg/m2) and underweight (BMI <18·5 kg/m2) prevalence was each 10% or more in that year. We used a Type 2 Tobit model to estimate the association of GDPPC and selected macro-environmental factors (globalisation index, adult literacy rate, female share in the labour force, share of agriculture in the national gross domestic product [GDP], prevalence of undernourishment, and percentage of principal display area mandated to be covered by health warnings on cigarette packaging) with DBM in 122 countries. FINDINGS: We find a negative association between GDPPC and the likelihood of a country having the DBM. However, conditional on its presence, DBM level exhibits an inverted-U shaped association with GDPPC. We found an upward shift in DBM levels from 1975 to 2016 across countries at the same level of GDPPC. Among the macro-environmental variables, share of females in the labour force and share of agriculture in the national GDP are negatively associated with DBM presence in a country, whereas the prevalence of undernourishment in the population is positively associated. Further, globalisation index, adult literacy rate, share of females in the labour force, and health warnings on cigarette packaging are negatively associated with DBM levels in countries. INTERPRETATION: DBM level in national adult populations rises with GDPPC until US$11 113 (in 2021 constant dollar terms) and then starts declining. Given their current GDPPC levels, most low-income and middle-income countries are thus unlikely to have a decline in the DBM levels in the near future, ceteris paribus. Those countries will also be expected to experience a higher DBM level at similar levels of national income than were historically experienced by the current high-income countries. Our findings point to a further intensification of the DBM challenge in the near future for the low-income and middle-income countries as they continue to have income growth. FUNDING: None.

The association between national income and adult obesity prevalence: Empirical insights into temporal patterns and moderators of the association using 40 years of data across 147 countries.

BACKGROUND: At a country level, population obesity prevalence is often associated with economic affluence, reflecting a potential adverse outcome concomitant with economic growth. We estimated the pattern and strength of the empirically observed relationship between national income and adult obesity prevalence, and the moderating role of countries' macro-environments on this relationship. METHODS: We assembled data on national obesity prevalence, income and a range of variables that characterize macro-environments related to 147 countries from multiple international organizations and databases. We used a Bayesian hierarchical model to estimate the relationship (elasticities) between national income (using Gross Domestic Product Per Capita, GDPPC) and adult obesity prevalence, and the moderating effects of five different dimensions (globalization orientation, demographic characteristics, economic environment, labor market characteristics, and strength of health policies) of countries' macro-environments on the income elasticities. Using the latest (2019-2024) available national income growth projections from the International Monetary Fund, we forecast future global trends in obesity prevalence. FINDINGS: Over the 40-years 1975-2014, adult obesity prevalence increased at a declining rate with GDPPC across the 147 countries. The mean income elasticity estimates were 1.23 (95% credible interval 1.04-1.42) for males and 1.01 (0.82-1.18) for females. The elasticities were positively associated with the extent of political globalization and negatively associated with urbanization and share of agriculture in the national GDP. Income based projections indicate that obesity prevalence would continue to grow at an average annual rate of 2.47% across the studied countries during 2019-2024. CONCLUSIONS: Population obesity prevalence exhibits a positive relationship with national income and there is no evidence that the relationship, while weakening, actually turns negative at higher income levels ("obesity Kuznets curve"). Based on current trends, global obesity prevalence will continue to increase during 2019-2024, with the rate of growth higher in low- and middle-income countries. As most people currently live in low- and middle-income countries with rising incomes, our findings underscore the urgent societal imperatives for effective policy initiatives, especially those that target the concomitant "nutrition transition" process with economic affluence, to break or at least further weaken the positive relationship of population obesity prevalence with national income.