Plasma calcium as a predictor of cardiovascular disease in a community-based cohort

Objective Primary hyperparathyroidism and calcium supplementation have been linked to cardiovascular outcomes. The study objective was to examine plasma calcium as a predictor of cardiovascular disease in the general population, as results from previous cohort studies are conflicting. Design, participants and measurements Plasma calcium was measured in 4003 participants (aged 2584years) in the 1994/1995 Busselton Health Survey. Using a Cox proportional hazards model, we examined albumin-corrected calcium as a predictor of total mortality, cardiovascular mortality and cardiovascular events up to the end of 2010. Results At baseline, there were significant positive relationships between plasma calcium and each of body mass index, systolic and diastolic blood pressure, glucose and total cholesterol. During the follow-up period, 666 participants died (278 from cardiovascular disease) and 652 had incident cardiovascular events. After adjustment for age and sex, each additional 0 center dot 1mm of albumin-corrected calcium at baseline was associated with a hazard ratio (HR) of 1 center dot 09 [95% confidence interval (CI) 0 center dot 99, 1 center dot 20; P=0 center dot 062] for total mortality, 1 center dot 06 (95% CI 0 center dot 92, 1 center dot 23; P=0 center dot 41) for cardiovascular mortality and 1 center dot 13 (95% CI 1 center dot 03, 1 center dot 24; P=0 center dot 012) for cardiovascular events. These associations were attenuated by further adjustment for standard cardiovascular risk factors with HR 1 center dot 03 (95% CI 0 center dot 94, 1 center dot 14), 0 center dot 99 (95% CI 0 center dot 86, 1 center dot 16) and 1 center dot 05 (95% CI 0 center dot 95, 1 center dot 15), respectively. Conclusion After adjustment for age and sex, plasma calcium is a predictor of cardiovascular events. This appears to be mediated by conventional cardiovascular risk factors, and calcium is not an independent predictor of cardiovascular disease.