Biphasic effect of alcohol intake on the development of fatty liver disease

Background: Fatty liver is an important clinical feature not only in alcoholic and non-alcoholic fatty liver diseases, but in other chronic liver diseases as well. Our aim was to elucidate the effect and relationship between habitual alcohol intake and obesity in the development of fatty liver disease.Methods: We enrolled 8,029 subjects undergoing abdominal ultrasonography with general medical examinations, and analyzed the factors associated with fatty liver based on daily alcohol intake, body mass index (BMI), and waist circumference. Results: For fatty liver, BMI, waist circumference, total cholesterol, triglycerides, and fasting plasma glucose were significant and independent risk factors. Heavy alcohol intake (50 g/day) was a significant risk factor for fatty liver in women (odds ratio [OR], 3.35). Analysis based on the presence or absence of obesity revealed that moderate alcohol intake was a significant negative risk factor for fatty liver in both male and female obese (BMI ≥25 kg/m2) subjects (OR, 0.74 for non-obese and 0.39 for obese patients, respectively). Heavy alcohol intake was also a significant negative risk factor in obese males (0.62). In contrast, heavy alcohol intake was a risk factor in non-obese males (OR, 1.29) and in all females (OR, 2.22 for non-obese and 6.6 for obese patients, respectively). Conclusions: The influence of alcohol intake on fatty liver differed depending on the level of alcohol consumption, gender, and the presence of obesity, and showed biphasic effects.