The nutrition transition in Mexico 1988-2016: the role of wealth in the social patterning of obesity by education.

Abstract

The present study investigates whether the reversal of the social gradient in obesity, defined as a cross-over to higher obesity prevalence among groups with lower education level, has occurred among men and women in urban and rural areas of Mexico. Cross-sectional series of nationally representative surveys (1988, 1999, 2006, 2012 and 2016). The association between education and obesity was investigated over the period 1988-2016. Effect modification of the education-obesity association by household wealth was tested. Mexico. Women (n 54 816) and men (n 20 589) aged 20-49 years. In both urban and rural areas, the association between education and obesity in women varied by level of household wealth in the earlier surveys (1988, 1999 and 2006; interaction P<0·001). In urban areas in 1988, one level lower education was associated (prevalence ratio; 95 % CI) with 45 % higher obesity prevalence among the richest women (1·45; 1·24, 1·69), whereas among the poorest the same education difference was protective (0·84; 0·72, 0·99). In the latest surveys (2012, 2016), higher education was protective across all wealth groups. Among men, education level was not associated with obesity in urban areas; there was a direct association in rural areas. Wealth did not modify the association between education and obesity. The reversal of the educational gradient in obesity among women occurred once a threshold level of household wealth was reached. Among men, there was no evidence of a reversal of the gradient. Policies must not lose sight of the populations most vulnerable to the obesogenic environment.