Appropriate calcium intake is necessary for the accrual and maintenance of bone mass. A significant proportion of the world's population does not have adequate calcium intake, and thus, supplementation plays a key role in maintaining bone homeostasis and other aspects of health. Since a series of reports from the Auckland calcium study and meta-analysis indicated that calcium supplementation was associated with an increased risk for adverse cardiovascular events, concern over the safety of calcium supplementation has grown; however, considerable inconsistencies in the reproducibility were found and questions regarding the study methodologies have been raised. In addition, since the increased adverse cardiovascular events by calcium supplementation were observed in calcium-replete subjects, it should be clarified whether the same risk profile would be observed in countries with low calcium intake. Dietary calcium intake varies widely across the world; cardiovascular event risk factors and outcomes also vary and appear to be the opposite of calcium intake levels. Furthermore, the effects of calcium supplementation were shown to depend on dietary calcium intake, with a better bone mineral density response for low calcium intake subjects compared to that in calcium-replete subjects. Based on these evidences, the risk-benefit ratio of calcium supplement is likely to be different in different region of the world. Therefore, accumulation of evidence to establish population-specific guidelines for calcium supplementation is warranted before extrapolating the results obtained from a limited number of studies to the other people with different age, gender, ethnicity and risk profile across the world.
Keywords: CALCIUM SUPPLEMENTATION; CARDIOVASCULAR EVENTS; DIETARY INTAKE; GLOBAL HEALTH.
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