Parental smoking and risk of coeliac disease in offspring

Objective. In adults, smoking seems to give protection against coeliac disease (CD). But, only one study has thus far investigated the association between maternal smoking during pregnancy and risk of CD in offspring. However, that study did not adjust for duration of exclusive breastfeeding, or look at passive smoking after birth. Material and methods. The current study was part of a prospective cohort study of infants born between 1 October 1997 and 1 October 1999 (the ABIS study; All Babies in Southeast Sweden). Data on smoking and exclusive breastfeeding were obtained through questionnaires distributed at infant birth and at 1 year of age. Coeliac disease was confirmed through small-bowel biopsy. Subgroup analyses were carried out according to maternal body mass index. Results. Nine out of 53 (17%) children with CD as opposed to 1699 out of 15,344 (11.1%) non-coeliac children had mothers who had smoked during pregnancy (p = 0.172). Mothers who had smoked during pregnancy were hence not at increased risk of having a child with CD (OR = 1.64; 95% CI OR = 0.80-3.37). Adjusting for duration of exclusive breastfeeding and the sex of infants in some 9585 children with data on exclusive breastfeeding lowered the OR for CD in mothers who smoked (adjusted OR (AOR) = 0.89; 95% CI AOR = 0.27-2.93; p = 0.843). Parents who smoked during the child's first year of life were not at increased risk of having an offspring with CD (OR = 1.94; 95% CI AOR = 0.69-5.47; p = 0.203). Conclusions. No association was found between CD and parental smoking habits during pregnancy or during the child's first year of life. However, further studies with larger numbers of coeliac children are needed.