CHARLESTON, S.C. — The association between maternal periodontal disease and increased risk for preterm birth is strongest among black women with moderate or severe periodontal disease, Kim A. Boggess, M.D., reported at the annual meeting of the Infectious Disease Society for Obstetrics and Gynecology.
In a longitudinal observational study of 958 women, 30% had no periodontal disease at enrollment, 60% had mild periodontal disease, and 14% had moderate/severe periodontal disease. Of those with moderate/severe disease, 79% were black, suggesting that the rate of periodontal disease in the pregnant population mirrors that of the nonpregnant population, said Dr. Boggess of the University of North Carolina at Chapel Hill.
The literature shows that, compared with white women, black women have a higher rate of periodontal disease, she noted.
Black women also have a higher rate of preterm birth, and this was true in the current study, as well. Preterm birth occurred in 23% of the 471 black women in the study, compared with 6% of the 487 white women.
Furthermore, the study supports previous research that suggests periodontal disease is associated with preterm delivery. Delivery before 37 weeks' gestation occurred in 29% of those with moderate/severe disease, compared with 19% of those with mild disease, and 11% of those with periodontal health, Dr. Boggess said.
A multivariable logistic regression model that adjusted for maternal age, parity, marital status, insurance use, smoking, and prior preterm birth showed that, taken together, the risk ratios for preterm birth before 37 weeks' and 35 weeks' gestation were highest for those who were black and had moderate or severe periodontal disease. (See box.)
The rate of preterm birth in this population was much higher than would have been expected if race and disease were acting independently. “It looks like race and periodontal disease are acting together in a multiplicative way,” she said.
Possible mechanisms for the differences between black and white women in this study include access to care issues and differences between black and white women in oral microbiology, maternal host response to oral microbes, and stress levels (which have been identified as a risk factor for periodontal disease), Dr. Boggess said, noting that further study is warranted.
Teasing out the mechanisms for the findings in this study could help in the development—and appropriate targeting—of intervention strategies, she said.