Obesity and socioeconomic status in developing countries: a systematic review

Abstract

We undertook a systematic review of studies assessing the association between socioeconomic status (SES) and measured obesity in low- and middle-income countries (defined by the World Bank as countries with per capita income up to US$12,275) among children, men and women. The evidence on the subject has grown significantly since an earlier influential review was published in 2004. We find that in low-income countries or in countries with low human development index (HDI), the association between SES and obesity appears to be positive for both men and women: the more affluent and/or those with higher educational attainment tend to be more likely to be obese. However, in middle-income countries or in countries with medium HDI, the association becomes largely mixed for men and mainly negative for women. This particular shift appears to occur at an even lower level of per capita income than suggested by an influential earlier review. By contrast, obesity in children appears to be predominantly a problem of the rich in low- and middle-income countries.

Figure 1

Electronic search and screening methods.

Figure 2

Summary of associations between socioeconomic status (SES) and obesity by main SES indicators. Black, studies with positive association; white, studies with negative association; grey, studies with no significant association.

Figure 3

Summary of associations between socioeconomic status (SES) and obesity by gross national income. Black, studies with positive association; white, studies with negative association; grey, studies with no significant association.

Figure 4

Association between socioeconomic status (SES) and obesity for men and women, in relation to human development index (HDI). Black, studies with positive association; white, studies with negative association; grey, studies with no significant association.

Figure 5

Predicted level of obesity for women by SES and GNI per capita. Notes: (i) With GNI per capita (Atlas method), obesity shifts from the higher-SES individuals to the lower-SES ones at point A, which corresponds to a GNI per capita of about US$ 1,000. With the PPP method, however, this shift takes place at point B, which corresponds to a GNI per capita slightly lower than US$4,000. (ii) The coefficients of GNI per capita using the Atlas method are higher than those of GNI with the PPP (0.0063 versus 0.0035 for low SES and 0.0012 versus 0.0007 for high SES), implying that the choice of GNI metric affects the strength of the relationship between obesity and income per capita. Long dash dot, low SES, Atlas; long dash dot dot, low SES, PPP; solid, high SES, Atlas; round dot, high SES, PPP; SES, socioeconomic status; GNI, gross national income; PPP, purchasing power parity.