LONGITUDINAL-STUDY OF THE EFFECT OF CALCIUM PIDOLATE ON BONE MASS IN EUGONADAL WOMEN

Seventy-two eugonadal women, mean age 39 +/- 4 years, with a z score f or total body bone mineral content (BMC) of less than - 1.5 (mean - 1. 80 +/- 0.12) were selected from a previous screening study of normal v alues of total body and regional BMC in women using dual-energy X-ray absorptiometry. The women were distributed into two groups: 36 women u ndergoing treatment with 1 g/day of elemental calcium in the form of c alcium pidolate and 36 women not treated. One year later, total body B MC, regional BMC in arms, legs and trunk, 24-hour urinary calcium excr etion (Ca 24 hour), fasting urinary calcium/creatinine ratio, and seru m tartrate-resistant acid phosphatase concentration were measured in b oth groups. There was a significant increase in total body and regiona l BMC (P < 0.001) in the group taking calcium pidolate. The increase w as greater in arms and legs (2.5%) than in trunk (1.7%), being 2.6% fo r total body BMC. The z score increased from - 1.81 +/- 0.13 to - 1.52 +/- 0.12 (16%, P < 0.001). The corporal index did not change, and tot al body BMC corrected for fat-free body mass increased by 6.7% (P < 0. 001). These changes were accompanied by an increase in 24-hour urinary calcium excretion and a decrease in urinary calcium/creatinine ratio and serum tartrate-resistant acid phosphatase concentration (P < 0.05 for all). There was a correlation between cumulative calcium dose at t he end of treatment and gain in total body BMC (r(2) = 0.925, P < 0.00 1). The untreated group showed no changes. These results indicate that administration of 1 g/day of elemental calcium in the form of calcium pidolate to eugonadal women increases total and regional bone mass.