Background Innovative strategies beyond the health system are required to reduce the prevalence of smoking. Early child development interventions are examples of interventions that can help set children on positive social and educational trajectories, which in turn may also reduce the prevalence of smoking. The aim of this study was to examine the effect of attendance at Kindergarten Union preschools on tobacco smoking in adulthood.

Methods Kindergarten Union preschools delivered comprehensive services to children and their families, including education, parenting and health services, with a number of features consistent with contemporary ideas of high-quality service delivery. Using a retrospective cohort design with data from the North West Adelaide Health Study, this study examined different aspects of smoking behaviour in adults aged 34–67 years who attended a Kindergarten Union preschool at some stage between 1940 and 1972. Data were analysed using generalised linear model poisson regression with robust variance estimates, adjusting for both child and adult socio-economic factors and history of parental smoking.

Results People who attended preschool had a reduced risk of ever smoking (prevalence ratio 0.87, 95% CI 0.77 to 0.98) and a reduced risk of current smoking in adulthood (prevalence ratio 0.77 (95% CI 0.59 to 1.00)), compared with those who did not attend preschool. There was no effect of preschool attendance on age at smoking uptake, age at quitting or the probability of quitting smoking.

Conclusion Attendance at the high-quality Kindergarten Union preschools was associated with a reduction in the initial uptake of smoking and thus the probability of being a current smoker. Among their other potential social benefits, high-quality, universal preschool programmes have the potential to help reduce smoking prevalence across the population.