Optimal child growth requires adequate energy and nutrient intake, absence of disease and appropriate care. Poor living conditions, including household food insecurity, low parental education, lack of access to quality health care and an unhealthy living environment are among the main determinants of stunted growth. Poverty has a more detrimental effect on linear growth than on body weight. (1) Child stunting is associated with higher morbidity and mortality, shorter height in adulthood, lower educational achievement, and reduced productivity in adulthood. Child growth patterns are therefore strong predictors of future human capital and social progress and of the health of future generations. (1-4)
Estimates indicate that in 2005, one-third of all children less than 5 years of age (or approximately 178 million children) in low- and middle-income countries were stunted. (5) Projections of current trends to 2015 point to declines in the prevalence of both stunting (6) and underweight (5) among children, although such declines will still fall short of the 50% reduction in undernutrition established as an indicator for fulfilling the first Millennium Development Goal (MDG- 1), (7) to eradicate hunger. Of 70 low- or middle-income countries that conducted two or more surveys between 1971 and 1999, 42 showed a decline in child stunting, 17 showed no major change over the period, and 11 (9 of them in Africa) showed an increase. (8) In Brazil, three national health and nutrition surveys conducted between 1974-75 and 1996 have pointed to declining trends in child stunting prevalence. (9,10)
An analysis of data from 47 low- and middle-income countries showed pronounced within-country socioeconomic inequalities in child stunting, particularly in Latin America and the Caribbean. (11) Brazil ranked fifth among these 47 countries in terms of such inequality. (11) We are unaware of studies from low- or middle-income countries on how social inequalities in child stunting are evolving over time.
We have taken advantage of a Demographic and Health Survey carried out in Brazil in 2006-07 to assess trends in child stunting and in related socioeconomic disparities over the past three decades. The Brazilian government has prioritized the elimination of hunger and poverty (12) since 2003, and recent reports (13) suggest that redistributive policies have successfully redressed one of the most skewed income distributions in the world. (14) Because child stunting is a sensitive indicator of living conditions, we believe that the effectiveness of redistributive policies can be accurately assessed by studying the social distribution of child stunting over time.
Four national household surveys were carried out in Brazil over a period of 33 years: Estudo Nacional de Despesa Familiar [National Study on Family Expenditures] in 1974-75; Pesquisa Nacional de Saude e Nutricao [National Health and Nutrition Survey] in 1989; and two Demographic and Health Surveys, in 1996 and 2006-07, respectively. Nationwide probability house hold samples were obtained in each survey using similar census-based, multistage, stratified, cluster sampling procedures. The sampling schemes, variables, and data collection procedures are described elsewhere. (15-17)
In the four surveys, the height of all children aged 0-59 months living in the sampled households was measured. Children living in the sparsely populated rural areas of the Northern region, who comprise 3% of the country's child population, were only included in the most recent survey. Analyses were repeated after removing these children from the 2006-07 sample, but the results were virtually identical to those presented below, which apply to the entire sample of children studied in each survey.
In the four surveys, trained personnel measured the recumbent length of children aged up to 23 months and the standing height of older children. …