CONTEXT Nonalcoholic fatty liver disease (NAFLD) is associated with coronary artery calcification (CAC) in cross-sectional studies. However, whether NAFLD itself affects CAC development or progression remains unknown.

OBJECTIVE This study investigated the longitudinal association between NAFLD and CAC score.

DESIGN AND SETTING This study is a longitudinal cohort study performed in a healthcare center.

PARTICIPANTS Among 1732 subjects who underwent serial CAC evaluation, we evaluated 846 subjects with NAFLD and 886 subjects without NAFLD, as diagnosed via ultrasonography.

MAIN OUTCOME MEASURES CAC score was compared at baseline and follow-up. In subjects without calcification (CAC score = 0) at baseline, any incidental calcification (CAC score >0) at follow-up was defined as development of CAC. In subjects with CAC (CAC score > 0) at baseline, confirmed CAC aggravation was defined as progression. Logistic regression analysis was performed.

RESULTS More subjects with NAFLD than without showed CAC development or progression (48.8 vs 38.4%; P < .001). The impact of NAFLD on a change in CAC score significantly differed according to the CAC score at baseline. In subjects without calcification at baseline, NAFLD significantly affected the development of calcification (odds ratio, 1.49; 95% confidence interval, 1.01-2.21; P = .045) after adjusting for traditional metabolic risk factors. However, in subjects with baseline CAC, NAFLD did not significantly affect progression (P = .734). Additionally, the severity of NAFLD was important. The severity of NAFLD was dose-dependently associated with the development of CAC (P for trend = .043).

CONCLUSIONS NAFLD plays a role in the early development of CAC, but not the progression. Ultrasonographic severity of NAFLD is dose-dependently associated with CAC development in subjects with a CAC score of 0 at baseline, independent of traditional risk factors.