UC San Diego

Background & aims

Nonalcoholic fatty liver disease (NAFLD) is related closely to risk factors for coronary artery disease, but it is unclear whether NAFLD independently contributes to atherosclerosis. We investigated the association between NAFLD and coronary artery calcium (CAC) scores, determined based on noncontrast cardiac computed tomography data, in an elderly cohort.

Methods

We conducted a longitudinal, cross-sectional study of data from 250 participants (mean age, 67.6 ± 7.0 y; 43.2% men) in the Rancho Bernardo Study-a prospective population-based study of mostly white adults in suburban Southern California. We compared CAC scores, liver-to-spleen attenuation ratio, and volumes of visceral adipose tissue (VAT) at baseline and after a 5-year follow-up period.

Results

We assigned participants to groups based on CAC scores (0, 0-10, 11-100, 101-400, and >400). Among groups, the liver-to-spleen attenuation ratio did not vary significantly, but VAT increased with CAC score (median and interquartile range values were as follows: 50.0 [33.3-77.4] cm(3), 63.0 [33.9-93.1] cm(3), 66.1 [48.2-80.2] cm(3), 69.1 [48.1-85.0] cm(3), 76.1 [53.1-108.5] cm(3) for CAC groups; P = .0054). In multivariable regression analysis, NAFLD at baseline was not associated with an increased risk of a CAC score greater than 0. Longitudinal analysis showed that visceral fat, but not hepatic steatosis, increased in participants with increasing CAC scores (interquartile range 57.1-92.4) vs 55.2 cm(3) in patients without (interquartile range 36.5-81.1, P = .0401). The proportion of patients with NAFLD decreased after the 5-year follow-up period (from 29.3% before to 14.1% afterward; P = .0081), despite increased mean CAC scores and VAT volume in patients.

Conclusions

In adults age 67.6 ± 7.0 years, the proportion with NAFLD decreased despite increasing CAC score and VAT with age. There was no clear association between NAFLD and CAC score. However, VAT was associated with baseline and increasing CAC scores. Visceral adiposity therefore might be a risk factor for coronary artery disease.