Combined effects of lifestyle risk factors on fatty liver index

Background Factors of lifestyle may have a major impact on liver-related morbidity and mortality. We examined independent and joint effects of lifestyle risk factors on fatty liver index (FLI), a biomarker of hepatic steatosis, in a population-based cross-sectional national health survey. Methods The study included 12,368 participants (5784 men, 6584 women) aged 25–74 years. Quantitative estimates of alcohol use, smoking, adiposity and physical activity were used to establish a total score of risk factors, with higher scores indicating an unhealthier lifestyle. FLI was calculated based on an algorithm including body mass index, waist circumference, serum gamma-glutamyltransferase and triglycerides. Results The occurrence of FLI ≥ 60% indicating fatty liver increased from 2.4% in men with zero risk factors to 81.9% in those with a total risk score of 7–8 (p < 0.0005 for linear trend) and in women from 0 to 73.5% (p < 0.0005). The most striking individual impacts on the likelihood for FLI above 60% were observed for physical inactivity (p < 0.0005 for both genders) and alcohol consumption ( p < 0.0005 for men). Interestingly, coffee consumption was also found to increase with increasing risk factor scores (p < 0.0005 for linear trend in both genders). Conclusions The data indicates that unfavorable combinations of lifestyle risk factors lead to a high likelihood of hepatic steatosis. Use of FLI as a diagnostic tool may benefit the assessment of interventions aimed at maintaining a healthy lifestyle and prevention of liver-related morbidity.