Maternal smoking during pregnancy and multiple sclerosis amongst offspring

An association between parental smoking and multiple sclerosis (MS) in offspring has been reported. This study examined whether maternal smoking during pregnancy is associated with MS in offspring. Swedish general population registers provided prospectively recorded information on maternal smoking during pregnancy. The study identified 143 cases with MS diagnosed by 2006 and 1730 matched controls. Subjects were born since 1982 and individually matched by year of birth, age, sex and region of residence. Conditional logistic regression assessed the association of maternal smoking with MS in offspring with adjustment for socioeconomic index. Maternal smoking during pregnancy was not associated with MS in offspring, with an odds ratio (and 95% confidence interval) of 0.96 (0.65-1.44). When stratified by paediatric or later MS onset there was no association with maternal smoking in either stratum. It is unlikely that smoking during pregnancy represents a risk for early-onset MS amongst offspring.