John P Walsh1, Mark L Divitini, Matthew W Knuiman. 1. Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, WA, Australia. john.walsh@health.wa.gov.au
Abstract
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 25-84 years) 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 0.1 mm of albumin-corrected calcium at baseline was associated with a hazard ratio (HR) of 1.09 [95% confidence interval (CI) 0.99, 1.20; P = 0.062] for total mortality, 1.06 (95% CI 0.92, 1.23; P = 0.41) for cardiovascular mortality and 1.13 (95% CI 1.03, 1.24; P = 0.012) for cardiovascular events. These associations were attenuated by further adjustment for standard cardiovascular risk factors with HR 1.03 (95% CI 0.94, 1.14), 0.99 (95% CI 0.86, 1.16) and 1.05 (95% CI 0.95, 1.15), 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.
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 25-84 years) 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 0.1 mm of albumin-corrected calcium at baseline was associated with a hazard ratio (HR) of 1.09 [95% confidence interval (CI) 0.99, 1.20; P = 0.062] for total mortality, 1.06 (95% CI 0.92, 1.23; P = 0.41) for cardiovascular mortality and 1.13 (95% CI 1.03, 1.24; P = 0.012) for cardiovascular events. These associations were attenuated by further adjustment for standard cardiovascular risk factors with HR 1.03 (95% CI 0.94, 1.14), 0.99 (95% CI 0.86, 1.16) and 1.05 (95% CI 0.95, 1.15), 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.