Reference values for bone metabolism in a Japanese cohort survey randomly sampled from a basic elderly resident registry

The aim of this study was to provide definitive reference values for bone mineral density (BMD) and bone turnover markers in the general elderly population. Registered citizens of 50 to 89 years old were targeted for this survey. After random sampling from the resident registry of Obuse town, we established eight groups based on age (50 s, 60 s, 70 s, and 80 s) and gender. A total of 411 people were enrolled. We used a dual-energy x-ray absorptiometry device to measure and evaluate BMD. The bone formation marker bone alkaline phosphatase (BAP) was measured as a bone turnover marker. Bone quality marker pentosidine, and bone resorption markers including urinary total deoxypyridinoline (DPD), tartrate-resistant acid phosphatase 5b (TRACP-5b), 25-hydroxyvitamin D (25[OH]D), and whole parathyroid hormone (PTH) were also measured as bone turnover markers. Sixty-three people (15.3%) were diagnosed as osteoporosis. BMD decreased with age in the femoral neck and total hip. On the other hand, there was no characteristic change with age in the lumber spine. As for bone markers, pentosidine and DPD increased with aging, although 25(OH)D, whole PTH, and BAP showed no characteristic associations with gender and aging. In terms of the relationship between low BMD and bone markers, there was a significant independent association between low BMD and TRACP-5b in females. In conclusions, hip BMD decreased with aging in men and women. However, there was no characteristic decline with aging in the lumbar spine. All bone markers showed no significant independent characteristics associated with age or gender in a multivariate analysis model, except for a significant association between low BMD and TRACP-5b in females. TRACP-5b was a potentially useful marker for the detection of low BMD.