High prevalence of low femoral bone mineral density in elderly women living in nursing homes or community-dwelling: a plausible role of increased parathyroid hormone secretion.

The present study was designed to visit elderly women living in nursing homes and to compare their femoral neck bone mineral density (BMD) and circulating levels of parathyroid hormone (PTH) and 25-OH vitamin D (25-OHD) with those of subjects living at home, in the immediate vicinity of the nursing homes. Of 1483 women, aged 70 years and older, who were selected, 993 agreed to participate in this trial. Their femoral neck BMD (n = 993) was measured by dual-energy X-ray absorptiometry, with a specific device installed in a mobile truck. The circulating levels of 25-OHD and PTH were assessed after an overnight fast (n = 748). After stratification for age, there were no significant differences in mean femoral neck BMD values, prevalence of femoral neck osteoporosis, mean serum 25-OHD and prevalence of absolute or relative 25-OHD deficiency between the two groups. Serum levels of PTH were significantly higher in women over 80 years old living in nursing homes, compared with the community-dwelling women. After adjustment for age, a significant relation was found between femoral neck BMD and PTH levels in the whole population (p = 0.004) and in community-dwelling subjects (p = 0.039). When stratifying our population by quartiles of serum PTH values, the odds ratios for femoral neck osteoporosis were significantly increased for the top two quartiles compared with the lowest one both before (p = 0.00146) and after (p = 0.0013) adjustment for age and type of housing. From this study we conclude that femoral osteoporosis is largely underestimated in European women. Living in a nursing home is not, per se, a risk factor for decreased femoral BMD, and circulating PTH levels are a key determinant of low femoral bone density and osteoporosis.