Dairy Intake and Coronary Artery Calcification: The Coronary Artery Risk Development in Young Adults (CARDIA) Prospective Cohort Study

Background: Studies on the association of dairy intake and coronary artery disease have been inconsistent. Little is known about the relationship between dairy consumption in young adulthood and coronary artery calcification (CAC), a marker of subclinical coronary atherosclerosis. Objectives: This prospective cohort study assessed the association of dairy intake and the presence of CAC. Methods: We followed 3110 participants of the coronary artery risk development in young adults (CARDIA) study for 25 y after enrollment during 1985–1986 (ages 18–30 y). Dairy intake (averaged over the year 0 and 7 examinations) was derived from the CARDIA diet history. CAC assessment occurred at years 15, 20, and 25. Cox proportional hazards regression was used to investigate the association of CAC and total, whole-fat, and low-fat dairy as well as other dairy subgroups. Results: A total of 904 participants were observed to have CAC during follow-up. After covariate adjustment, higher intake of whole-fat dairy was inversely associated with risk of CAC [hazard ratio for the highest compared with the lowest quartile: 0.76 (95% confidence interval: 0.61, 0.96)]. Further adjustment for body mass index, which was slightly lower in those who consumed more dairy, attenuated these results (P for trend across quartiles: 0.13). Associations with CAC of total and low-fat dairy, as well as individual dairy products and fermented dairy, were not statistically significant. Conclusions: Among young adults in the CARDIA study, whole-fat dairy was inversely associated with the future presence of CAC. These results do not support dietary guidelines that emphasize low-fat dairy intake for the prevention of coronary artery disease.