Secular trends in malnutrition and obesity among children in S. Paulo city, Brazil (1974-1996)

Objective Data from three household surveys undertaken in the city of S. Pa ulo, Brazil, from mid-80s to mid-90s allow to characterize and analyse secu lar 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 an d 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 t he mean values expected according to the international growth reference. Th e obesity status was determined when weight-for-height indices fell two sta ndard deviations above the reference. The study of the social distribution of malnutrition and obesity in each survey took into account tertiles of th e per capita family income. For the study of the the determinants of secula r trends, hierarchical causal models, multivariate regression analyses and calculations analogous to the ones used to assess population attributable r isks were applied. Results/Conclusions In the period of 22 years covered by the three surveys, child malnutrition was controlled in the city a,ld became relatively rare even among the poorest families. The risk of obesity remained low and restr icted to the richest families. Positive changes in distal (family income an d maternal schooling) and intermediate determinants (sanitation access to h eath services and reproductive past history) of child nutritional status su bstantially explained part of the decline in the prevalence of malnutrition seen in the mid-80s to mid-90s.