This cross-sectional study aimed to investigate the association between periodontitis and osteoporosis among US adults as well as the subgroup of menopausal women.Periodontitis and osteoporosis are both chronic inflammatory diseases characterized by local or systemic bone resorption. Since they share many risk factors, and the significant decrease in estrogen along with menopause is unfavorable for both diseases, it's reasonable to assume that there exists some links between the two diseases, especially during the menopause.We analyzed data from the National Health and Nutrition Examination Survey (NHANES) 2009-2010 and 2013-2014. Periodontitis (defined according to the CDC/AAP definition) and osteoporosis (assessed by the dual-energy radiation absorptiometry) data were available for 5736 participants, and 519 subjects were enrolled in the subgroup of menopausal women aged 45-60 years old. We used binary logistic regression analysis to examine the association between the two diseases both in crude and fully adjusted model.In the fully adjusted model, osteoporosis was significantly associated with an increased risk of periodontal disease (OR:1.66, 95% CI: 1.00-2.77) in the whole population. As to the subgroup of menopausal women, osteoporosis group had an adjusted OR of 9.66 (95% CI: 1.13-82.38) for developing severe periodontitis in the fully adjusted model.Osteoporosis is significantly associated with periodontitis and the association is even more pronounced in menopausal women with severe periodontitis.© 2023. The Author(s).