Calcium Supplementation with and without Hormone Replacement Therapy To Prevent Postmenopausal Bone Loss

Abstract

Objective: To determine whether augmentation of dietary calcium is effective in the prevention of early postmenopausal bone loss.

Design: Three-arm, placebo-controlled, randomized parallel trial. The study duration was 2.9 ±1.1 (SD) years.

Setting: General community.

Participants: 118 healthy, white women 3 to 6 years after spontaneous menopause, recruited by community announcement.

Interventions: Random allocation to daily intake of 1700 mg of calcium (calcium carbonate given in divided doses with meals); placebo; or conjugated equine estrogens (0.625 mg; days 1 to 25), progesterone (10 mg; days 16 to 25), and 1700 mg of elemental calcium daily. Each participant received 400 IU of vitamin D daily.

Main Outcome Measures: Total body calcium measured by delayed γ neutron activation analysis and whole-body counting; bone mineral density of the spine, femur, and radius measured by photon absorptiometry.

Results: Bone mineral density declined in the placebo group for the lumbar spine ( −2.1%/y;95% CI, −3.3 to −0.9),femoral neck ( −2.0%/y;CI,-2.6 to −1.2),trochanter ( −1.6%/y;CI, −2.4 to −0.8),Ward triangle ( −2.7%/y;CI, −3.7 to −1.7),and total body calcium ( −2.0%/y;CI, −2.2 to −1.8).Rates of change were intermediate for calcium augmentation compared with placebo and estrogen-progesterone-calcium but statistically significant compared with placebo for total body calcium ( −0.5%/y;CI, −0.9 to −0.1;P = 0.006) and the femoral neck ( −0.8%/y;CI, −1.4 to −0.2;P = 0.03).

Conclusions: Although less effective than estrogen-progesterone-calcium, calcium augmentation alone significantly retards bone loss from the femoral neck and improves calcium balance in recently postmenopausal women. Dietary calcium augmentation should be recommended as a strategic option in helping to prevent early postmenopausal bone loss.