Beneficial effects of hormone replacement therapy on periodontitis are vitamin D associated

Background: Possible synergism between female sex hormones and vitamin D on periodontitis pathology has not been assessed. Here, the authors investigate effects of estrogen, progesterone, and vitamin D on periodontitis in a population-based sample and use cell studies to explore mechanistic explanations of the population-based findings. Methods: The epidemiologic analysis uses cross-sectional data from the continuous National Health and Nutrition Examination Survey 2001 to 2004. The cross sections include 1,230 women aged 40 to 85 years who received a periodontal examination, responded to questions regarding hormone replacement therapy (HRT), and provided a blood sample for serum vitamin D assessments. For mechanistic cell culture studies, human monocytes were cultured with or without lipopolysaccharide (LPS), estradiol, progesterone, and/or 1,25-dihydroxyvitamin D3; and transcriptional activity of interleukin (IL)-6, IL-1β, B lymphocyte chemoattractant (BLC), and regulated on activation normal T-cell expressed and secreted (RANTES) was assessed. Results: HRT use (versus none) was associated with higher attachment levels and more teeth only among participants who were vitamin D sufficient (>20 ng/mL). The odds ratio for having moderate/severe periodontitis among users of HRT versus participants who did not use HRT was 0.69 among participants who were vitamin D sufficient and 1.19 in participants who were vitamin D deficient. LPS-induced IL-6, IL-1β, and BLC expression was attenuated in human monocytes treated with estrogen and progesterone. Downregulation of IL-6 expression by estrogen and progesterone was potentiated when vitamin D was included. LPS-induced IL-6 and RANTES expression was decreased, and BLC expression was totally reversed, by vitamin D treatment. Conclusions: The association between HRT and clinical periodontal measures was strongest among women with high vitamin D levels. This association is plausibly mediated via an anti-inflammatory transcriptional mechanism.