Hormonal determinants of bone turnover before and after attainment of peak bone mass.

INTRODUCTION

Bone turnover decreases from adolescence into adulthood, but does not reach a nadir until the fourth decade. Biochemical markers of bone turnover reflect different processes before and after peak bone mass, so hormonal influences on bone turnover may differ before and after peak bone mass.

OBJECTIVES

To describe the changes in bone turnover and hormones relevant to bone metabolism from adolescence into adulthood, and to identify which hormones correlate with bone turnover before and after peak bone mass.

DESIGN/PARTICIPANTS: Two measurements of bone turnover markers and hormones were obtained 5-9 years apart in 116 healthy males and females recruited from secondary schools and general practices. Correlations were examined cross-sectionally and longitudinally.

RESULTS

Dehydroepiandrosterone sulphate (DHEAS) correlated negatively with bone turnover cross-sectionally and longitudinally (r-0.59 to -0.69) in males and females under the age of 25 years. IGF-1 correlated positively with aminoterminal propeptide of type I procollagen (PINP) cross-sectionally and longitudinally (r 0.35) in women over the age of 25 years. After correction for change in BMI, there were significant longitudinal correlations between DHEAS and bone turnover in women under 25 years (r-0.62, -0.66) and IGF-1 and PINP in women over 25 years (r 0.56).

CONCLUSIONS

We have described changes in bone turnover and hormones from adolescence into adulthood. Dehydroepiandrosterone sulphate correlates with bone turnover before peak bone mass which may represent a direct effect on bone metabolism or the role of dehydroepiandrosterone sulphate as a substrate for conversion to other sex steroids. IGF-1 is correlated with aminoterminal propeptide of type I procollagen in women after peak bone mass, which may reflect an influence on cortical modelling.