A longitudinal study of bone-related biochemical changes at the menopause

Summary objective To evaluate the effects of the menopause on bone‐related biochemical variables in a longitudinal study. design Recruitment by advertisement of premenopausal women over the age of 44 for measurement of selected variables and collection of blood and urine samples for deep freezing, followed by annual check of menopausal status and repeat collection of blood and urine samples for deep freezing after the menopausal transition. patients A total of 104 women with confirmed premenopausal status and on no treatment likely to affect calcium or bone metabolism were admitted to the study over a period of 2 years. After 8 years, 43 of the volunteers had passed through the menopause and the study was closed. measurements Radiocalcium absorption was measured at the first attendance and again after the menopausal transition. Calcium and other relevant variables were measured consecutively on paired thawed‐out samples of blood and urine. results The data were complete in 34 subjects. In these women, there were highly significant correlations between the first and second measurements of most variables – serum calcium and fractions, radiocalcium absorption, vitamin D metabolites, PTH and others – indicating significant ‘tracking’ of these variables across the menopause. Within that framework there were significant rises in serum total and calculated ionized calcium (both P