Long-term calcium supplementation may have adverse effects on serum cholesterol and carotid intima-media thickness in postmenopausal women: a double-blind, randomized, placebo-controlled trial.

Background: Several studies have focused on the effects of calcium intake on serum lipid concentrations in postmenopausal women. However, many premenopausal women are taking calcium supplements in China. To our knowledge, no studies have assessed whether the effects of calcium supplementation on blood lipids are similar between premenopausal and postmenopausal women.

Objective: We assessed the effects of calcium supplementation on blood lipid concentrations in premenopausal and postmenopausal women with dyslipidemia.

Design: A total of 190 premenopausal women (30-40 y old) and 182 postmenopausal women (50-60 y old) with dyslipidemia were given 800 mg Ca/d or a placebo for 2 y in a double-blind, randomized, placebo-controlled trial. Blood pressure, fasting glucose and serum lipid concentrations, carotid intima-media thickness (CIMT), dietary nutrient intakes, and physical activity levels were determined at baseline and after 2 y.

Results: There was a significant interaction between calcium supplementation and menopausal status on serum cholesterol concentrations (P < 0.001) and CIMT (P = 0.017). Serum cholesterol concentrations and CIMT were significantly increased in postmenopausal women (P < 0.01) after 2 y. Serum triglyceride, low-density lipoprotein-cholesterol, and high-density lipoprotein-cholesterol concentrations were not affected after 2 y.

Conclusions: Calcium supplementation in postmenopausal women with dyslipidemia increases serum total cholesterol concentrations and CIMT. In postmenopausal women with dyslipidemia, calcium supplements should be prescribed with caution. This trial was registered at http://www.chictr.org/cn/ as ChiCTR-TRC-12002806.