Calcium intake is not associated with increased coronary artery calcification: the Framingham Study

Abstract

Background: Adequate calcium intake is known to protect the skeleton. However, studies that have reported adverse effects of calcium supplementation on vascular events have raised widespread concern.

Objective: We assessed the association between calcium intake (from diet and supplements) and coronary artery calcification, which is a measure of atherosclerosis that predicts risk of ischemic heart disease independent of other risk factors.

Design: This was an observational, prospective cohort study. Participants included 690 women and 588 men in the Framingham Offspring Study (mean age: 60 y; range: 36-83 y) who attended clinic visits and completed food-frequency questionnaires in 1998-2001 and underwent computed tomography scans 4 y later in 2002-2005.

Results: The mean age-adjusted coronary artery-calcification Agatston score decreased with increasing total calcium intake, and the trend was not significant after adjustment for age, BMI, smoking, alcohol consumption, vitamin D-supplement use, energy intake, and, for women, menopause status and estrogen use. Multivariable-adjusted mean Agatston scores were 2.36, 2.52, 2.16, and 2.39 (P-trend = 0.74) with an increasing quartile of total calcium intake in women and 4.32, 4.39, 4.19, and 4.37 (P-trend = 0.94) in men, respectively. Results were similar for dietary calcium and calcium supplement use.

Conclusions: Our study does not support the hypothesis that high calcium intake increases coronary artery calcification, which is an important measure of atherosclerosis burden. The evidence is not sufficient to modify current recommendations for calcium intake to protect skeletal health with respect to vascular calcification risk.

FIGURE 1.

Mean (95% CI) coronary artery–calcification Agatston scores (2002–2005) adjusted for age and total energy according to total calcium intake quartile at baseline (1998–2001) in 690 women (open bars) and 588 men (filled bars) in the Framingham Offspring Study.

FIGURE 2.

Mean (95% CI) coronary artery–calcification Agatston scores (2002–2005) adjusted for age and total energy according to dietary calcium intake quartile at baseline (1998–2001) in 690 women (open bars) and 588 men (filled bars) in the Framingham Offspring Study.

FIGURE 3.

Mean (95% CI) coronary artery–calcification Agatston scores (2002–2005) adjusted for age and total energy according to supplemental calcium intake at baseline (1998–2001) in 690 women (open bars) and 588 men (filled bars) in the Framingham Offspring Study.