Racial and Ethnic Differences in Bone Turnover Markers in Men

Abstract

Whereas racial and ethnic differences in fracture risk and bone mineral density (BMD) in men have been well described, the influence of race and ethnicity on biochemical markers of bone turnover is less clear. To examine the relationship between bone turnover, BMD, and race and ethnicity in men, we measured BMD, serum intact osteocalcin (OC), and serum C-terminal telopeptides of type 1 collagen (CTx) in 1029 men (aged 30-79 yr) enrolled in the Boston Area Community Health/Bone Survey, a population-based random sample of Black, Hispanic, and White. Men with diseases or on medications known to affect bone metabolism were excluded from the analysis. Mean serum levels of OC and CTx were adjusted for age, month and time of blood sample, and 25-hydroxyvitamin D. Compared with Black men, adjusted mean OC levels were 17.6 and 20.5% higher in Hispanic (P = 0.02) and White men (P < 0.01), respectively. There was no significant difference between White and Hispanic men. Adjusted mean CTx levels were 14.3% higher in White men, compared with Black men (P = 0.04), but no other differences were significant. OC declined by 0.4%/yr from age 30 to 65 yr and increased thereafter by 2.1%/yr. The age trend in CTx appeared to follow a pattern consistent with a quadratic function of age. Model-estimated annual percent changes within age decade were as follows: 30-39 yr, -2.5%; 40-49 yr, -1.4%; 50-59 yr, -0.3%; 60-69 yr, +0.9%; 70-79 yr, +1.7%. There was no variation in the shape of the age trend in OC or CTx by race or ethnic group. Correlations between bone turnover markers and BMD (adjusted for age, height, weight, serum 25-hydroxyvitamin D, and PTH and month and time of blood sample) were generally weak. Bone turnover markers are lower in Black men, compared with White and Hispanic men. Age trends in bone turnover markers are not influenced by race or ethnicity. Future studies in this cohort and others are needed to explore further these reported differences in bone metabolism among Black, Hispanic, and White men.