RESUMO
BACKGROUND: Barriers to early childhood development (ECD) are a global concern. Limited research exists on prenatal smoking and ECD in vulnerable populations, especially as it relates to school readiness (SR). AIMS: To examine how maternal cigarette use during pregnancy is associated with SR in a sample of Brazilian preschool-age children. STUDY DESIGN: We used the Brazilian Preschool Mental Health Study, a cross-sectional, epidemiological study of preschool-age children in Embu das Artes, São Paulo. SR was assessed using the Engle Scale of Child Development (ESCD). We restricted analyses to biological mothers, who represented 81.9% (n = 591) of the total 722 with ESCD data. Logistic regression models, adjusting for birth and child characteristics (year of preschool, sex, race, history of head trauma, coma, convulsions or epilepsy), sociodemographic factors and school environment, were used to estimate odds ratios and 95% confidence intervals. RESULTS: Prenatal smoking was negatively associated with SR. Children of mothers who smoked during pregnancy were more likely to be in the lowest ESCD quartile (aOR = 1.26, 95%CI: [1.02-1.55]) compared to those of non-smoking mothers, and each cigarette resulted in additional risk (aOR = 1.03, 95%CI:[1.01-1.05]). Children of heavy smokers had worse ESCD scores compared to children of non-smokers (aOR = 1.69, 95%CI:[1.18-2.44]), as well as when compared to children of moderate and non-smokers combined (aOR = 1.77, 95%CI:[1.22-2.57]). This relationship was not seen when comparing children of moderate smokers to children of non-smokers. Inferences were robust when examining very heavy smoking. CONCLUSION: Maternal tobacco use during pregnancy may affect child SR. Additional studies in other populations are needed to corroborate these results.