Interaction of obesity and skeletal bone mineral density in tooth retention in Japanese postmenopausal women.

Objective: To investigate whether being overweight is associated with increased or decreased risk of tooth loss in Japanese postmenopausal women.

Design: The number of remaining teeth (total, anterior, and posterior teeth), mandibular bone height, and mandibular cortical mass were evaluated on the dental panoramic radiographs of 450 Japanese postmenopausal women. The bone mineral densities (BMDs) at the lumbar spine and femoral neck were measured by dual-energy x-ray absorptiometry. These measurements were compared among participants in three body mass index (BMI) categories (underweight, normal BMI, and overweight).

Results: Analysis of covariance adjusted for confounding variables revealed that participants who were overweight had a significantly lower number of total (P = 0.019) and anterior (P = 0.012) remaining teeth than did those with normal BMI, although the former had significantly higher skeletal BMD values than the latter. No significant difference was observed in mandibular bone height between the overweight participants and those with normal BMI. There were no significant differences in the number of remaining teeth between the under- and overweight participants. Overweight participants had significantly higher skeletal BMDs (P < 0.001) and tended to have larger mandibular cortical masses than those who were underweight.

Conclusions: Despite their higher skeletal BMD, postmenopausal women who are overweight may have an increased risk of tooth loss, especially of the anterior teeth, compared with women who have normal BMI. This risk appears to be similar to that for underweight women.