Increased serum levels of N-telopeptides (NTx) of bone collagen in postmenopausal Nigerian women

Serum levels of cross-linked N-telopeptides (NTx) of bone collagen, alkalin e phosphatase (ALP), and intact parathyroid hormone (PTH) were determined i n 64 premenopausal (PRM) and 86 postmenopausal (PSM) women living in northe rn Nigeria. Serum NTx values were correlated with ALP activity (r = 0.31-0. 58, P < 0.01) and PTH (0.32-0.35, P < 0.01) in all of the subjects studied, and were also related to age (-0.47, P < 0.001) and body mass index (-0.45 , P < 0.001) in PPM women. Menopause had the effect of increasing the circu lating concentrations of NTx and ALP activity by 15% (P = 0.001) and 11% (P = 0.02), respectively; however, serum levels of PTH were not different bet ween these two groups of women. Compared with Caucasian counterparts matche d for age and body mass index, PSM Nigerian women had significantly increas ed circulating concentrations of NTx (21.7 versus 16.2 nmol BCE/liter, P = 0.01) and demonstrated a trend towards higher ALP activities and PTH levels . These results indicate that (1) discrete reference intervals should be de fined for biochemical markers of bone metabolism in African populations, (2 ) Nigerian women have relatively higher rates of bone turnover, and (3) fur ther investigation of the implications of increased serum NTx should be und ertaken using physical methods such as dual X-ray absorptiometry (DXA) and bone ultrasound attenuation.