Association between bone turnover rate and bone microarchitecture in men: the STRAMBO study.

Few data concern the relationship between bone turnover and microarchitecture in men. We investigated the association between levels of biochemical markers of bone turnover (BTM) and bone microarchitecture in 1149 men aged 19 to 85 years. Bone microarchitecture was assessed by high-resolution peripheral quantitative computed tomography at the distal radius and tibia. Bone formation was assessed by serum osteocalcin, bone alkaline phosphatase, and N-terminal extension propeptide of type I collagen. Bone resorption was assessed by serum C-terminal telopeptide of type I collagen and urinary excretion of total deoxypyridinoline. BTM levels were high in young men and decreased until age 50 years. Urinary deoxypyridinoline (DPD) increased after age 70 years, whereas other BTMs remained stable. Before 50 years of age, only cortical volumetric bone mineral density (D(cort)) correlated negatively with BTM levels. Between 50 and 70 years of age, D(cort) and some microarchitectural parameters correlated significantly with BTM at the radius and tibia. After 70 years of age, higher BTM levels were associated with lower cortical thickness and D(cort) at both the skeletal sites. At the distal radius, men in the highest BTM quartile had lower trabecular density, number (Tb.N), and thickness (Tb.Th) and more heterogeneous trabecular distribution compared with men in the lower quartiles. At the distal tibia, higher BTM levels were associated with lower Tb.N and Tb.Th in the central but not subendocortical area. Thus, in men, bone microarchitecture depends weakly on the current bone turnover rate until age 70. Thereafter, bone turnover seems to be a significant determinant of bone microarchitecture.