To the Editor Several recent articles documented increased cardiovascular mortality associated with high calcium intake, in particular supplemental calcium.1 Most epidemiological studies of calcium intake and cardiovascular health have been conducted in white individuals with moderate to high calcium intake. Only a few specifically focused on cardiovascular mortality. Xiao et al2 reported that supplemental calcium was associated with elevated cardiovascular disease (CVD) mortality in men but not in women, whereas dietary calcium intake was unrelated to CVD death in either sex.2 In contrast, another female cohort study showed that dietary calcium intake above 1400 mg/d was associated with higher all-cause and CVD mortality compared with lower intakes. Interestingly, among women with dietary calcium intake exceeding 1400 mg/d, the addition of calcium supplements further increased risk of death in a dose-dependent manner.3 Results of both studies reveal that increasing calcium intake increases mortality, in particular CVD mortality, but the relationship is possibly dependent on habitual calcium intake.4,5 In a Chinese population with comparatively low habitual calcium intake, high calcium intake has a protective effect.
Chan R, Leung J, Woo J. Dietary and Supplemental Calcium Intake and Mortality. JAMA Intern Med. 2013;173(19):1840. doi:10.1001/jamainternmed.2013.9276