Peroxisome proliferator-activated receptor (PPAR) γ polymorphism, vitamin D, bone mineral density and periodontitis in postmenopausal women

OBJECTIVES: PPARg regulates bone metabolism and inflammation. Our previous study suggested PPARg Pro12Ala polymorphism to represent a susceptibility factor for periodontitis in pregnant Japanese women. Several recent papers have drawn attention to a possible link between low bone mineral density (BMD) and periodontitis in postmenopausal women. Since the pathogenesis for both involve bone remodeling, they might share common risk factors such as gene polymorphisms and vitamin D level. The present study investigated possible associations between the PPARgPro12Ala polymorphism, periodontitis, BMD and serum 25(OH)D in postmenopausal Japanese women. MATERIALS AND METHODS: PPARgPro12Ala genotypes of 359 women were determined by PCR-RFLP. BMD and periodontal parameters of each woman were measured. Serum 25(OH)D levels were determined by radioimmunoassay. RESULTS: PPARgPro12Ala polymorphism was not associated with periodontitis or BMD as an independent factor. Serum 25(OH)D was significantly higher in Ala allele carriers compared to non-carriers. Only in the Ala allele carriers, positive correlations were found between mean clinical attachment level and BMD, between BMD and 25(OH)D, and between percentage of sites with probing depth >= 4 mm and 25(OH)D. CONCLUSIONS: PPARgPro12Ala polymorphism was not independently associated with periodontitis or BMD. However, the polymorphism might be a modulator of the relationship between the two conditions in postmenopausal Japanese women.