Changes in mineral content and biochemical bone markers at the menopause.

Serum alkaline phosphatase activity, serum bone gamma-carboxyglutamic acid protein, urinary hydroxyproline and bone mineral content were simultaneously measured in 30 age-matched pre- and postmenopausal women in order to define the temporal relationship between skeletal turnover and bone loss. In postmenopausal women, mean values of phosphatase activity, serum bone gamma-carboxyglutamic acid protein and urinary hydroxyproline were significantly higher, and mean values of mineral content were significantly lower than in premenopausal women. A marked loss of bone mineral content together with a persistent increase in skeletal turnover is already evident shortly after the menopause.