Associations between the Number of Natural Teeth and the Maternal Age at Childbirth or History of Parity in Postmenopausal Women: The 2010–2012 Korea National Health and Nutrition Examination Survey

The relationship between reproductive factors, including pregnancy and delivery, and the number of teeth in postmenopausal women remains to be revealed.The aim of this study was to evaluate the relationship between age at first and last delivery, parity and the number of natural teeth in postmenopausal women, using nationally representative data.Data from the Korea National Health and Nutrition Examination Survey between 2010 and 2012 were used, and the analysis in this study was confined to a total of 4,060 respondents who had gone through menopause and had no missing values for the reproductive factors and outcome variables. The total number of natural teeth was then calculated after excluding third molars, and frequency of tooth brushing was recorded as oral health behavior. Univariate and multivariate logistic regression analyses were used to assess the associations between the number of natural teeth and reproductive factors.Both a woman's age at her last childbirth and the number of pregnancies had statistically significant effects on the number of natural teeth remaining after menopause. With each one-year increase of age at a woman's last delivery, the number of natural teeth decreased by a value of 0.12 (p < 0.05). Similar trends were seen with increases in parity, which resulted in decreases in the number of natural teeth by 0.65 (p < 0.05). The odds ratios of the percentage of individuals with a 20 or fewer teeth tended to increase with increases in the woman's age at her last childbirth.This study identified an association between the number of natural teeth and a woman's age at her last childbirth as well as between the number of natural teeth and parity. Higher ages at last childbirth and higher parity were found to be potential risk indicators for tooth loss in postmenopausal women.