The Effect of Maternal Smoking During Pregnancy and Postnatal Household Smoking on Dental Caries in Young Children

Abstract

A number of environmental factors appear to be involved in the etiology of dental caries in Japanese children. Several reports have suggested an association between environmental tobacco smoke (ETS) and the occurrence of dental caries. However, other studies in Japan as well as Western nations have failed to show this association and it is unclear whether there is such a relationship. The role of maternal smoking during pregnancy on the etiology of dental caries in young children is also unclear. The only 2 cross-sectional epidemiological studies addressing this issue had conflicting results. The aim of this cross-sectional study was to investigate whether maternal smoking during pregnancy and postnatal exposure to ETS were associated with an increased prevalence of dental caries among young Japanese children. Data were obtained from dental examination of 2015 children, age 3 years, and use of postal questionnaires completed by parents or guardians of those children on the extent of maternal smoking during pregnancy and postnatal ETS exposure at home. Based on their smoking history, women and their children were placed in one of 3 groups for analysis: women who smoked throughout pregnancy, those who stopped at some time during pregnancy, and those who did not smoke during pregnancy. A total of 419 (20.8%) of the 2015 children had dental caries, and the mean number of dental caries was 0.71. The prevalence of dental caries in the children of women who did not smoke at all during pregnancy was considered the background rate; compared to this group, the prevalence of dental caries was significantly higher in the children of women who smoked throughout pregnancy without stopping (adjusted prevalence ratio: 1.43; 95% CI: 1.07-1.91). The prevalence of dental caries was not significantly increased in the children of women who smoked but then stopped at some time during pregnancy. With respect to postnatal ETS, current smoking at home was independently associated with an increased prevalence of dental caries, whereas former smoking in the household had no effect on prevalence. There was a statistically significant dose-response relationship between cumulative household postnatal ETS and the prevalence of dental caries in the children (P for linear trend = 0.006). The investigators conclude from these findings that both maternal smoking during pregnancy and postnatal exposure to ETS at home may be independently associated with an increased prevalence of dental caries in young Japanese children.