Heart disease is the most common cause of death in patients with nonalcoholic fatty liver disease (NAFLD). Emerging data have shown that NAFLD may affect subclinical myocardial remodeling, mainly left ventricular hypertrophy; however, evidence from the prospective studies is still lacking.

Prospective analyses were performed to investigate the association of fatty liver index (FLI) with left ventricular mass (LVM) among 1962 participants from the Bogalusa Heart Study (BHS, 1995–2010) and 1547 participants from the Cardiovascular Risk in Young Finns Study (YFS, 2001–2011) free of cardiovascular diseases (CVD) at baseline. LVM was assessed by two-dimensional guided M-mode echocardiography and indexed (LVMI) to body height (m^2.7). Multivariable regression models were applied after adjustment for traditional CVD risk factors.

In both cohorts, we observed significant and positive associations between FLI and LVM (BHS: β=0.59, P < 0.001; YFS: β=0.41, P < 0.001) and LVMI (BHS: β=0.14, P < 0.001; YFS: β=0.09, P < 0.001). In addition, we found that the relationship between FLI and LVMI was stronger in women than men (BHS: P-interaction = 0.01; YFS: P-interaction < 0.01); and the relationship between FLI and LVM/LVMI was stronger in black than white individuals (LVM: P-interaction = 0.02; LVMI: P-interaction = 0.04). Moreover, we found that the associations of FLI with LVM and LVMI were attenuated by high physical activity, especially in BHS (P-interaction = 0.02).

Our findings from two independent prospective cohorts indicate that FLI is positively associated with LVM/LVMI, independent of traditional cardiovascular risk factors. Such relationships are more pronounced among women and black individuals and are attenuated by high physical activity.