Antenatal and early life tobacco smoke exposure in an African birth cohort study

Exposure to tobacco smoke in African infants has not been well studied, despite the high burden of childhood respiratory disease in these communities.

To investigate the prevalence of antenatal and early life tobacco smoke exposure and associations with infant birth outcomes in an African birth cohort, the Drakenstein Child Health Study.

Self-report questionnaires assessing maternal and household smoking were administered. Maternal and infant urine cotinine testing was conducted antenatally, at birth and at 6-10 weeks of life to measure tobacco smoke exposure. Multivariate regression models explored the associations between exposure to smoke and infant birth outcomes.

Of 789 pregnant women included, 250 (32%) were active smokers on cotinine testing. At birth and at 6-10 weeks of life, respectively 135/241 (56%) and 154/291 (53%) infants had urine cotinine levels indicating tobacco smoke exposure. Household smoking was prevalent and was associated with positive infant cotinine test results. Antenatal maternal smoking was associated with decreased infant birthweight-for-age Z-score (0.3, 95%CI 0.1-0.5).

Antenatal and early life tobacco smoke exposure is highly prevalent in this community, and may impact on birth outcomes and subsequent child health. Smoking cessation interventions are urgently needed to reduce tobacco smoke exposure in African communities.