O2-6.6 Maternal smoking during pregnancy and smoking in the offspring who were followed from birth to adulthood: findings from the 1958 NCDS British birth cohort

Background Early life factors, such as smoking during pregnancy, have been suggested to influence smoking in the offspring particularly during teenage years. It remains unclear if this relation persists over time considering that longer duration and increased amounts of smoking are associated with premature deaths. Method The prospective relation of maternal smoking during pregnancy and smoking in 15 151 offspring in a British birth cohort (1958 National Child Development Study) over the life course was investigated using logistic regression. Results Heavy smoking (≥10 cigarettes/day) during (but not before) pregnancy was related to increased risk of heavy smoking in the offspring, with sex- and concurrent social class-adjusted OR [95% CI] of 1.32 (1.16 to 1.50), 1.60 (1.39 to 1.84), 1.82 (1.56 to 2.13), 1.46 (1.21 to 1.76), 1.53 (1.26 to 1.84) and 1.51 (1.17 to 1.94) at ages 16, 23, 42, 46 and 50 years, respectively. The OR for being a heavy smoker across all ages was 5.25 (95% CI 2.65 to 10.40), after adjusting for sex and social class across the life course. Conclusion The consistency and magnitude of the risk estimates suggest that the association could be aetiologically important but the absolute risk due to maternal smoking during pregnancy was small, suggesting limited public health relevance. Other factors, such as social circumstances, are more important considerations for addressing the burden of smoking in the population.