Maternal smoking, biofuel smoke exposure and child height-for-age in seven developing countries

Background Children are at high risk of exposure to environmental tobacco smoke and biofuel smoke at home in developing countries. This study examines whether exposure to cigarette and biofuel smoke is associated with height-for-age of children (0-59 months) in seven developing countries. Methods The data are from Demographic and Health Surveys conducted in Cambodia, Dominican Republic, Haiti, Jordan, Moldova, Namibia and Nepal between 2005 and 2007. The respondents were women (15-49 years) and their children in seven countries (n = 28 439), and men (15-59 years) from four countries. The outcome is a physical measurement of child height-for-age in standard deviation units. Results Multilevel regression analysis showed that the country of residence modified the association between maternal smoking and child height-for-age. Exposure to maternal smoking was associated negatively with child height-for-age in Cambodia, Namibia and Nepal, whereas it was not in other countries. Multilevel regression analysis revealed that biofuel smoke exposure was associated with a decrease in child height-for-age [b = -0.13, 95% confidence interval (CI) = -0.19 to -0.07, P < 0.001]. No interaction was found between country of residence and biofuel smoke exposure. Multinomial logistic regression results showed that biofuel smoke exposure was associated with both stunting [odds ratio (OR) = 1.25, 95% CI = 1.08-1.44, P = 0.002) and severe stunting (OR = 1.27, 95% CI = 1.02-1.59, P = 0.04), after controlling for covariates. Conclusion The findings suggest that exposure to maternal smoking and biofuel smoke may contribute to growth deficiencies in young children. Programmes are needed to ensure smoke-free home environments for children.