Some biochemical indices of bone turnover in elderly Chinese.

Biochemical indices of bone turnover were determined in a cluster sample of 427 apparently healthy elderly subjects aged 60 years and over. Plasma calcium concentrations corrected for albumin were not significantly different between elderly men and women, but were higher compared with values in younger Chinese of the same sex. The prevalence of hypercalcemia (greater than 2.75 mmol/L) in the elderly (0.2%) was lower than in Caucasian populations. Plasma phosphate concentrations were higher in women, but lower than in young adults. Plasma alkaline phosphatase activity was higher in women compared with values for men, and higher compared with values for young adults. Plasma 25-hydroxyvitamin D was lower in elderly women than elderly men, but was similar to values in younger subjects. Urinary calcium: creatinine and hydroxyproline: creatinine ratios were higher in women. The values were comparable to those for Caucasian postmenopausal women, suggesting that Chinese elderly subjects had similar bone turnover rates.