In Reply In their study of a Hong Kong Chinese population, whose calcium intake is substantially lower than the Western population, Chan et al reported there was a protective effect of dietary calcium intake on total mortality and cardiovascular mortality. The lower cutoff of their highest intake category (>762 mg/d for men and >668 mg/d for women) are around the median intake values (739 mg/d for men and 648 mg/d for women) found in our US cohort. As shown in Figure 2 of our article,1 we observed a nonlinear association between total calcium intake and total cardiovascular disease mortality in men: risk decreased at a calcium intake up to approximately 1200 mg/d, but started to increase at an intake of 1500 mg/d and higher. Therefore, a study with population that has relatively low calcium intake and narrow range of intake is likely to observe an inverse association between calcium intake and mortality, especially cardiovascular disease mortality.
Xiao Q, Park Y. Dietary and Supplemental Calcium Intake and Mortality—Reply. JAMA Intern Med. 2013;173(19):1841-1842. doi:10.1001/jamainternmed.2013.9232