Grandmother’s smoking when pregnant with the mother and asthma in the grandchild: the Norwegian Mother and Child Cohort Study. The Norwegian Mother and Child Cohort Study includes about 100,000 mothers and children. The grandmother’s smoking when pregnant with the mother was examined in relation to asthma outcomes in the grandchild. For 23.5% of children, mothers stated their own mothers had smoked when pregnant with them. Asthma was reported in 5.7% of 53,169 children with follow up data at age 36 months, and 5.1% of 25,394 children with data at age 7. There was prescription registry data on dispensed asthma drugs for 4.8% of 45,607 children with data available at age 7. There was positive association between grandmother’s smoking when pregnant and asthma in all 3 groups of grandchildren, independent of mother’s smoking status. Because of few information about the socioeconomic status and asthma status of the grandmothers, unmeasured confounding factors may be present. Magnus MC et al. Thorax. 2015 Jan 8. pii: thoraxjnl-2014-206438. Read the publication: http://www.ncbi.nlm.nih.gov/pubmed/25572596