[Effects of survival bias on the prevalence of malnutrition in six-year-old children in Brazil, based on the national survey on health and nutrition, 1989].

Child growth as measured by anthropometric indicators is an important tool for assessing children's nutritional status and society's developmental stage. This study uses the height-for-age indicator with the cutoff point at -2 Z to estimate prevalence of malnutrition in a population of six-year-old children included in the Brazilian National Survey on Health and Nutrition (PNSN). Prevalence variability was analyzed according to gender, trimestral age range, per capita family income, and region of residence. Based on estimates of mortality rates for children under five whose deaths could be ascribed to malnutrition, the survival bias correction was performed using the Boerma methodology. This correction, in turn, was more conspicuous within the low-income and less-developed segment of the population. There was an increase in the number of malnourished children in relation to those surviving at the time of investigation. When comparing less and more developed areas of the country (the Northeast and Southeast, respectively), we observed that malnutrition prevalence rates within the six-year-old group showed no change in the Southeast region, while in the Northeast they increased from 26% to 34%, thus representing a 31% increase in the malnutrition rate. Therefore, in absolute figures, these rates account for the addition of 90,100 children to the malnourished group.