Association between parity and dentition status among Japanese women: Japan public health center-based oral health study

BACKGROUND Several studies have shown that parity is associated with oral health problems such as tooth loss and dental caries. In Japan, however, no studies have examined the association. The purpose of this study was to determine whether parity is related to dentition status, including the number of teeth present, dental caries and filled teeth, and the posterior occlusion, in a Japanese population by comparing women with men. METHODS A total of 1,211 subjects, who participated both in the Japan Public Health Center-Based (JPHC) Study Cohort I in 1990 and the dental survey in 2005, were used for the study. Information on parity or number of children was collected from a self-completed questionnaire administered in 1990 for the JPHC Study Cohort I, and health behaviors and clinical dentition status were obtained from the dental survey in 2005. The association between parity or number of children and dentition status was analyzed, by both unadjusted-for and adjusted-for socio-demographic and health behavioral factors, using a generalized linear regression model. RESULTS Parity is significantly related to the number of teeth present and n-FTUs (Functional Tooth Units of natural teeth), regardless of socio-demographic and health behavioral factors, in female subjects. The values of these variables had a significantly decreasing trend with the rise of parity: numbers of teeth present (p for trend = 0.046) and n-FTUs (p for trend = 0.026). No relationships between the number of children and dentition status were found in male subjects. CONCLUSION Higher-parity women are more likely to lose teeth, especially posterior occluding relations. These results suggest that measures to narrow the discrepancy by parity should be taken for promoting women's oral health. Delivery of appropriate information and messages to pregnant women as well as enlightenment of oral health professionals about dental management of pregnant women may be an effective strategy.