A LONGITUDINAL-STUDY OF THE EFFECT OF SODIUM AND CALCIUM INTAKES ON REGIONAL BONE-DENSITY IN POSTMENOPAUSAL WOMEN

The influence of urinary sodium excretion and dietary calcium intake w as examined in a 2-y longitudinal study of bone density in 124 women p ostmenopausal for > 10 y. Analysis of bone density changes showed that urinary sodium excretion was negatively correlated with changes in bo ne density at the intertrochanteric and total hip sites. Multiple-regr ession analysis of dietary calcium intake and urine sodium excretion o n the change in bone density showed that both dietary calcium and urin ary sodium excretion were significant determinants of the change in bo ne mass over 2 y at the hip and ankle sites. These data suggest that a n effect of reducing bone loss equivalent to that achieved by a daily dietary increase of 891 mg (22 mmol) Ca can also be achieved by halvin g daily sodium excretion. No bone loss occurred at the total hip site at a calcium intake of 1768 mg/d (44 mmol/d) or a urine sodium excreti on of 2110 mg/d (92 mmol/d). We report a significant effect of sodium excretion on bone loss in this population.