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.