The nutrition transition in Mexico 1988–2016: the role of wealth in the social patterning of obesity by education
AbstractObjectiveThe 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.DesignCross-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.SettingMexico.SubjectsWomen (n 54 816) and men (n 20 589) aged 20–49 years.ResultsIn 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.ConclusionThe 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.