Smoking by maternal grandmothers during pregnancy is associated with a diagnosis of autism in grandchildren according to a study in Scientific Reports. The authors stress that it is important that this association is confirmed in other studies.
Using data collected from the Avon Longitudinal Study of Parents and Children (ALSPAC) - which has followed approximately 14,000 children since birth - Jean Golding and colleagues investigated whether four traits that are linked with autism (based on scores in tests for social communication, speech coherence, sociability temperament, and repetitive behaviour) were associated with either grandmother smoking during pregnancy. The authors found that scores suggestive of autism for two of these traits - social communication and repetitive behaviour - were found more often in grandchildren if the maternal grandmother smoked during pregnancy. Grand-daughters were more likely to be affected than grandsons, and the association was more apparent if the mother herself did not smoke in pregnancy.
The authors then looked at the 174 children in the study diagnosed as having autism and also found an association with the maternal grandmother smoking during pregnancy. However, they were unable to assess whether there were sex-specific results as found with social communication and repetitive behaviour.
The authors note that their analysis relies on the accuracy of reports by the study parents concerning their own parents’ smoking habits and that the mechanisms that may underlie these associations warrant further investigation.