Secondary hyperparathyroidism and bone turnover in elderly blacks and whites.

This study was undertaken to describe the prevalence of secondary hyperparathyroidism in African-American and Caucasian participants in the Boston Low-Income Elderly Osteoporosis Study and to examine and compare associations of hyperparathyroidism with biochemical markers of bone turnover and bone density in the two racial groups. Serum osteocalcin and serum cross-linked N-telopeptides of type I collagen, and calcaneal bone mineral density were measured in February or March in 255 men and women, 64 yr of age and older. Subjects were categorized as normal or as having hyperparathyroidism, based on a serum PTH concentration below or above the top of the normal range (6.9 pmol/liter), respectively. The prevalence of hyperparathyroidism was 38% in the 144 black subjects and 20% in the 111 white subjects. Serum osteocalcin and cross-linked N-telopeptides of type I collagen were significantly higher in both black and white hyperparathyroid subjects (P < 0.05), and the hyperparathyroid-related difference in osteocalcin was greater among black than white subjects. Hyperparathyroidism was significantly associated with reduced heel bone mineral density in blacks (P = 0.008) but not in whites. This study provides evidence that secondary hyperparathyroidism is prevalent in elderly adults, both black and white, and that it should not be viewed as a benign condition in either group. Recent public health efforts to promote higher calcium and vitamin D intakes, targeted predominantly to older Caucasians, should also be directed to older African-Americans.