Background Calcium-phosphate levels, linked to vascular dysfunction in chronic kidney disease, may represent novel risk factors for coronary heart disease, stroke, and death in community-dwelling adults. Methods We tested this hypothesis over 12.6 years of follow-up in the prospective, community-based Atherosclerosis Risk in Communities Study (n = 15,732). Results At baseline, mean (SD) values were 9.8 (0.4) mg/dL for serum calcium, 3.4 (0.5) mg/dL for serum phosphate, 33.6 (5.3) mg(2)/dL(2) for calcium-phosphate product, 54.2 (5.7) years for age, and 93.1 (21.5) mL/min per 1.73 m(2) for glomerular filtration rate (GFR). Shared associations of calcium, phosphate, and calcium-phosphate product included older age, female sex, African American race, cigarette-years, current cigarette smoking, low body mass index, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, low serum albumin, low GFR, low caloric intake, and phosphorus intake. With adjustment for age, demographic characteristics, comorbid conditions, albumin, and GFR, calcium-associated hazards ratios for coronary heart disease, stroke, and death were, respectively, 1.01 (95% confidence interval 0.96-1.06), 1.16 (1.07-1.26, P = .0005), and 1.03 (0.98-1.08); phosphate-associated hazards ratios were 1.03 (0.98-1.08), 1.11 (1.02-1.21, P = .0219), and 1.14 (1.09-1.20, P < .0001); calcium-phosphate product-associated hazards ratios were 1.03 (0.98-1.08), 1.15 (1.05-1.26, P = .0017), and 1.15 (1.09-1.20, P < .0001). Conclusions Although calcium, phosphate, and calcium-phosphate product levels exhibit complex associations with traditional cardiovascular risk factors and outcomes, they may be potentially modifiable risk factors for stroke and death in community-dwelling adults.
