Calcium intake and hip fracture risk in men and women: a meta-analysis of prospective cohort studies and randomized controlled trials

Abstract

Background:The role of total calcium intake in the prevention of hip fracture risk has not been well established. Objective: The objective of the study was to assess the relation of calcium intake to the risk of hip fracture on the basis of meta-analyses of cohort studies and clinical trials. Results: In women (7 prospective cohort studies, 170 991 women, 2954 hip fractures), there was no association between total calcium intake and hip fracture risk [pooled risk ratio (RR) per 300 mg total Ca/d ҃ 1.01; 95% CI: 0.97, 1.05]. In men (5 prospective cohort studies, 68 606 men, 214 hip fractures), the pooled RR per 300 mg total Ca/d was 0.92 (95% CI: 0.82, 1.03). On the basis of 5 clinical trials (n ҃ 5666 women, primarily postmenopausal, plus 1074 men) with 814 nonvertebral fractures, the pooled RR for nonvertebral fractures between calcium supplementation (800 -1600 mg/d) and placebo was 0.92 (95% CI: 0.81, 1.05). On the basis of 4 clinical trials with separate results for hip fracture (6504 subjects with 139 hip fractures), the pooled RR between calcium and placebo was 1.64 (95% CI:1.02, 2.64). Sensitivity analyses including 2 additional small trials with 100 participants or per-protocol results did not substantially alter results. Conclusions: Pooled results from prospective cohort studies suggest that calcium intake is not significantly associated with hip fracture risk in women or men. Pooled results from randomized controlled trials show no reduction in hip fracture risk with calcium supplementation, and an increased risk is possible. For any nonvertebral fractures, there was a neutral effect in the randomized trials.Am J Clin Nutr 2007;86:1780 -90.

Milk intake and risk of hip fracture in men and women: A meta-analysis of prospective cohort studies

“…(1) Notably, the same metaanalysis also summarized data from double-blind RCTs of calcium supplementation without vitamin D and did not find a benefit on fracture risk compared with placebo at doses of 800 to 1600 mg of calcium per day. Based on five studies of 5666 primarily postmenopausal women plus 1074 men with 814 nonvertebral fractures, the pooled RR for nonvertebral fractures comparing calcium supplementation with placebo was 0.92 (95% CI 0.81-1.05).…”

“…However, the most recent meta-analysis suggested a neutral effect of a high dietary calcium intake on hip fracture risk in men and women based on data from prospective cohort studies. (1) Furthermore, the same meta-analysis suggested no significant overall benefit of calcium supplementation on risk of nonvertebral fractures based on five double-blind, randomized, controlled trials (RCTs). Indeed, a possible adverse effect on hip fracture risk was found [among 6504 individuals and 139 hip fractures, pooled relative risk (RR) ¼ 1.64; 95% confidence interval (CI) 1.02-2.64].…”

“…Indeed, a possible adverse effect on hip fracture risk was found [among 6504 individuals and 139 hip fractures, pooled relative risk (RR) ¼ 1.64; 95% confidence interval (CI) 1.02-2.64]. (1) Milk also may reduce fracture risk through vitamin D fortification, which is done routinely in the United States (100 IU vitamin D per 8-oz/237-mL glass of milk) and Sweden (45 IU vitamin D in a 300-mL glass of fat-reduced milk). The effects of ORIGINAL ARTICLE J JBMR oral vitamin D supplementation on nonvertebral fractures have been summarized in a 2009 meta-analyses of 12 double-blind RCTs (n ¼ 42,279).…”

Vitamin D and public health: an overview of recent research on common diseases and mortality in adulthood

“…Thus, it is not possible to conclude whether any beneficial effect on fracture incidence is from vitamin D by itself. Hence the inconsistent findings from recent meta-analyses, with some concluding that vitamin D is beneficial against fractures only when combined with Ca (23,29,30) and others concluding that vitamin D taken in higher doses (.17?5 mg/d) is effective by itself (31)(32)(33)(34) , while yet another concluded that Ca supplementation by itself had no effect on fracture incidence (35) . The eventual outcome of this debate has important implications for any future public health prevention strategies, should future research show that vitamin D (with or without Ca) is beneficial (see public health implications below).…”

The calcium quandary

“…Nevertheless, a recent meta-analysis [3] of all prospective cohort studies, including more than 3000 hip fractures, revealed no significant fracture risk reduction with increasing calcium intake. This general lack of effect has several possible explanations.…”