DOES LEPTIN HAVE AN EFFECT ON BONE IN ADULT WOMEN

Recent studies have implicated leptin in the modulation of bone mass d uring skeletal development. Whether leptin also exerts an influence on bone after growth has stopped is unknown at present. In this cross-se ctional study on 94 women (60 premenopausal, 34 postmenopausal) aged 4 0-60 years, we analyzed the relationship between serum leptin and bone density and bone cortex geometry and bone metabolism. Total and trabe cular bone density as well as total and cortical bone area were determ ined by quantitative computed tomography (QCT) at the distal radius. B one metabolism was assessed by measuring bone-specific alkaline phosph atase, osteocalcin, procollagen type I C-terminal propeptide (PICP) an d collagen type I C-terminal telopeptide in serum, and deoxypyridinoli ne in urine samples. None of the indices of bone density or geometry w as significantly related to leptin serum concentrations (P > 0.05) bef ore or after adjustment for body mass index (BMI). PICP was associated with serum leptin in the postmenopausal group only (r = -0.40 after a djustment for BMI; P = 0.009). Yet, as none of the other markers of bo ne metabolism exhibited a significant correlation with serum leptin in any of the menopausal groups, this association is likely to be due to the influence of extraskeletal factors on PICP serum levels. Thus, it appears that leptin has less influence on the mature than on the grow ing skeleton.