Independent effects of income and education on the risk of obesity in the Brazilian adult population

With a view to assess the independent effects of income and education on th e risk of obesity we studied cross-sectional randomly selected samples of t he adult population (20 y and over) living in 1996/97 in the less (northeas tern) and the more (southeastern) developed region of Brazil (1971 and 2588 northeastern and 2289 and 2549 southeastern men and women, respectively). Independent effects of income and education on obesity (BMI greater than or equal to 30 kg/m(2)) were assessed through logistic regression analyses th at controlled for age, ethnicity, household setting (urban or rural) and ei ther education or income. The risk of obesity in men strongly increased wit h income in the two regions. The level of education did not influence the r isk of male obesity in the less developed region but, in the more developed one, better-educated men had slightly less chance to be obese. In the less developed region obesity in women was strongly associated with both income (direct association) and education (inverse association). In the more deve loped region only the women's education influenced the risk of obesity, and the association between the two variables was inverse and strong as in the less developed region. Findings from this study reveal a scenario that is far from what has been generally admitted for the social distribution of ob esity in the developing countries. They indicate that in transition societi es income tends to be a risk factor for obesity, whereas education tends to be protective and that both gender and level of economic development are r elevant modifiers of the influence exerted by these variables.