[Secular trends in malnutrition and obesity among children in the city of São Paulo, Brazil (1974-1996)]

Abstract

Objective: Data from three household surveys undertaken in the city of S. Paulo, Brazil, from mid-80s to mid-90s allow to characterize and analyse secular trends in malnutrition and obesity among infants and children.

Methods: The three surveys included random population samples aged from zero to 59 months (1,008 children in the period of 1974-75; 1,016 in 1984-85 and 1,280 in 1995-96). The malnourished status was diagnosed when height-for-age and/or weight-for-height indices were below two standard deviation of the mean values expected according to the international growth reference. The obesity status was determined when weight-for-height indices fell two standard deviations above the reference. The study of the social distribution of malnutrition and obesity in each survey took into account tertiles of the per capita family income. For the study of the determinants of secular trends, hierarchical causal models, multivariate regression analyses and calculations analogous to the ones used to assess population attributable risks were applied.

Results/conclusions: In the period of 22 years covered by the three surveys, child malnutrition was controlled in the city and became relatively rare even among the poorest families. The risk of obesity remained low and restricted to the richest families. Positive changes in distal (family income and maternal schooling) and intermediate determinants (sanitation, access to heath services and reproductive past history) of child nutritional status substantially explained part of the decline in the prevalence of malnutrition seen in the mid-80s to mid-90s.