Double burden of diseases worldwide: coexistence of undernutrition and overnutrition-related non-communicable chronic diseases.

Objective: This systematic examination and meta-analysis examined the scope and variation of the worldwide double burden of diseases and identified related socio-demographic factors.

Design: We searched PubMed for studies published in English from January 1, 2000, through September 28, 2016, that reported on double disease burden. Twenty-nine studies from 18 high-income, middle-income and low-income countries met inclusion criteria and provided 71 obesity-undernutrition ratios, which were included in meta-regression analysis.

Results: All high-income countries had a much higher prevalence of obesity than undernutrition (i.e. all the obesity/undernutrition ratios >1); 55% of the ratios in lower middle-income and low-income countries were <1, but only 28% in upper middle-income countries. Meta-analysis showed a pooled obesity-undernutrition ratio of 4.3 (95% CI = 3.1-5.5), which varied by country income level, subjects' age and over time. The average ratio was higher in high-income rather than that in lower middle-income and low-income countries (β [SE] = 10.8 [2.6]), in adults versus children (7.1 [2.2]) and in data collected since 2000 versus before 2000 (5.2 [1.5]; all P values < 0.05).

Conclusions: There are considerable differences in the obesity versus undernutrition ratios and in their prevalence by country income level, age groups and over time, which may be a consequence of the cumulative exposure to an obesogenic environment.