Effect of late night calcium supplements on overnight urinary calcium excretion in premenopausal and postmenopausal women.

The overnight urinary calcium/creatinine ratio is higher in the early years after the menopause than before it. However, the increment of urinary calcium/creatinine after a late evening calcium supplement is less in early postmenopausal than in premenopausal women. It is suggested that calcium therapy in postmenopausal osteoporosis may be best administered as a single late evening dose rather than in divided doses throughout the day.