JCEM：女性钙摄入增加与死亡率风险降低有关

钙和维生素D被推荐用于维持骨骼健康，但是他们的不利风险受到关注。一些临床研究暗示钙摄入可能有心脏保护作用，，然而，另外一些研究报道心血管风险增加与补充钙有关系。低和高血清25–羟维生素D水平都与死亡率的增加有关系。为了确定总钙和维生素D摄入与死亡率和来源异质性的关系，来自加拿大麦吉尔大学皇家维多利亚医院的David Goltzman教授及其团队进行了一项研究，该研究发现在女性，钙剂补充达到1000mg/d，以及膳食钙摄入增加可能与死亡率风险降低有关系。该研究结果在线发表在2013年5月23日的《临床内分泌代谢杂志》（The journal of clinical endocrinology & metabolism）上。

该研究是加拿大多中心骨质疏松研究队列，一项基于人群、10年随访（1995–2007）的纵向队列。随机选拔的社区居住的男性和女性。共有9033例钙和维生素D摄入数据和随访数据没有缺失的受试者接受研究。记录总钙摄入（乳制品、非乳制品食物，以及补充的钙）和总维生素D摄入（牛奶、奶酪和补充的维生素D）。主要评价指标是全因死亡率。

该研究结果表明，在10年随访期间，有1160例受试者死亡。仅在女性发现较高的总钙摄入可能有益，每日钙摄入每增加500mg的风险比为0.95（95%可信区间，0.89–1.01），并且没有发现来源异质性的证据；使用钙剂补充同样与死亡率的降低有关系，在那些钙剂量达到1000mg/d的受试者中仍有统计学意义的减少，使用者与未使用者相比，风险比为0.78（95%可信区间，0.66–0.92）。同时摄入维生素D，这些相关的水平没有改变。在男性之间，没有发现明确的关系。

该研究发现，钙剂补充达到1000mg/d，以及膳食钙摄入增加可能与死亡率风险降低有关系。没有发现维生素D摄入与死亡率利害关系的证据。

Calcium and Vitamin D Intake and Mortality: Results from the Canadian Multicentre Osteoporosis Study (CaMos).
Abstract
Context:Calcium and vitamin D are recommended for bone health, but there are concerns about adverse risks. Some clinical studies suggest that calcium intake may be cardioprotective, whereas others report increased risk associated with calcium supplements. Both low and high serum levels of 25-hydroxyvitamin D have been associated with increased mortality.Objective:The purpose of this study was to determine the association between total calcium and vitamin D intake and mortality and heterogeneity by source of intake.Design:The Canadian Multicentre Osteoporosis Study cohort is a population-based longitudinal cohort with a 10-year follow-up (1995-2007).Setting:This study included randomly selected community-dwelling men and women.Participants:A total of 9033 participants with nonmissing calcium and vitamin D intake data and follow-up were studied.Exposure:Total calcium intake (dairy, nondairy food, and supplements) and total vitamin D intake (milk, yogurt, and supplements) were recorded.Outcome:The outcome variable was all-cause mortality.Results:There were 1160 deaths during the 10-year period. For women only, we found a possible benefit of higher total calcium intake, with a hazard ratio of 0.95 (95% confidence interval, 0.89-1.01) per 500-mg increase in daily calcium intake and no evidence of heterogeneity by source; use of calcium supplements was also associated with reduced mortality, with hazard ratio of 0.78 (95% confidence interval, 0.66-0.92) for users vs nonusers with statistically significant reductions remaining among those with doses up to 1000 mg/d. These associations were not modified by levels of concurrent vitamin D intake. No definitive associations were found among men.Conclusions:Calcium supplements, up to 1000 mg/d, and increased dietary intake of calcium may be associated with reduced risk of mortality in women. We found no evidence of mortality benefit or harm associated with vitamin D intake.