Background: Fatty liver (FL) is the most frequent liver disease in Western countries. We used data from the Dionysos Nutrition & Liver Study to develop a simple algorithm for the prediction of FL in the general population. Methods: 216 subjects with and 280 without suspected liver disease were studied. FL was diagnosed by ultrasonography and alcohol intake was assessed using a 7-day diary. Bootstrapped stepwise logistic regression was used to identify potential predictors of FL among 13 variables of interest [gender, age, ethanol intake, alanine transaminase, aspartate transaminase, gamma-glutamyl-transferase (GGT), body mass index (BMI), waist circumference, sum of 4 skinfolds, glucose, insulin, triglycerides, and cholesterol]. Potential predictors were entered into stepwise logistic regression models with the aim of obtaining the most simple and accurate algorithm for the prediction of FL. Results: An algorithm based on BMI, waist circumference, triglycerides and GGT had an accuracy of 0.84 (95%CI 0.81–0.87) in detecting FL. We used this algorithm to develop the "fatty liver index" (FLI), which varies between 0 and 100. A FLI < 30 (negative likelihood ratio = 0.2) rules out and a FLI ≥ 60 (positive likelihood ratio = 4.3) rules in fatty liver. Conclusion: FLI is simple to obtain and may help physicians select subjects for liver ultrasonography and intensified lifestyle counseling, and researchers to select patients for epidemiologic studies. Validation of FLI in external populations is needed before it can be employed for these purposes.

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are increasingly a cause of cirrhosis and hepatocellular carcinoma globally. This burden is expected to increase as epidemics of obesity, diabetes and metabolic syndrome continue to grow. The goal of this analysis was to use a Markov model to forecast NAFLD disease burden using currently available data. A model was used to estimate NAFLD and NASH disease progression in eight countries based on data for adult prevalence of obesity and type 2 diabetes mellitus (DM). Published estimates and expert consensus were used to build and validate the model projections. If obesity and DM level off in the future, we project a modest growth in total NAFLD cases (0-30%), between 2016-2030, with the highest growth in China as a result of urbanization and the lowest growth in Japan as a result of a shrinking population. However, at the same time, NASH prevalence will increase 15-56%, while liver mortality and advanced liver disease will more than double as a result of an aging/increasing population. NAFLD and NASH represent a large and growing public health problem and efforts to understand this epidemic and to mitigate the disease burden are needed. If obesity and DM continue to increase at current and historical rates, both NAFLD and NASH prevalence are expected to increase. Since both are reversible, public health campaigns to increase awareness and diagnosis, and to promote diet and exercise can help manage the growth in future disease burden. Non-alcoholic fatty liver disease and non-alcoholic steatohepatitis can lead to advanced liver disease. Both conditions are becoming increasingly prevalent as the epidemics of obesity and diabetes continue to increase. A mathematical model was built to understand how the disease burden associated with non-alcoholic fatty liver disease and non-alcoholic steatohepatitis will change over time. Results suggest increasing cases of advanced liver disease and liver-related mortality in the coming years.

The prevalence of and the risk factors for fatty liver have not undergone a formal evaluation in a representative sample of the general population. We therefore performed a cross-sectional study in the town of Campogalliano (Modena, Italy), within the context of the Dionysos Project. Of 5,780 eligible persons aged 18 to 75 years, 3,345 (58%) agreed to participate in the study. Subjects with suspected liver disease (SLD), defined on the basis of elevated serum alanine aminotransferase (ALT) and γ-glutamyl-transferase (GGT) activity, hepatitis B surface antigen (HBsAg), or hepatitis C virus (HCV)-RNA positivity, were matched with randomly selected subjects of the same age and sex without SLD. A total of 311 subjects with and 287 without SLD underwent a detailed clinical, laboratory, and anthropometrical evaluation. Fatty liver was diagnosed by ultrasonography, and alcohol intake was assessed by using a 7-day diary. Multinomial logistic regression was used to detect risk factors for normal liver versus nonalcoholic fatty liver disease (NAFLD) and for alcoholic fatty liver (AFLD) versus NAFLD. The prevalence of NAFLD was similar in subjects with and without SLD (25 vs. 20%, P = .203). At multivariable analysis, normal liver was more likely than NAFLD in older subjects and less likely in the presence of obesity, hyperglycemia, hyperinsulinemia, hypertriglyceridemia, and systolic hypertension; AFLD was more likely than NAFLD in older subjects, males, and in the presence of elevated GGT and hypertriglyceridemia, and less likely in the presence of obesity and hyperglycemia. In conclusion, NAFLD is highly prevalent in the general population, is not associated with SLD, but is associated with many features of the metabolic syndrome. (Hepatology 2005.)

Although hepatic steatosis is seen with increasing frequency in clinical practice, its prevalence and risk factors are unknown. To investigate the prevalence of and risk factors for hepatic steatosis, such as alcohol consumption and obesity. Cross-sectional, observational study. Participants in the Dionysos Study. 257 participants assigned to one of four categories (67 controls, 66 obese persons, 69 heavy drinkers, and 55 obese heavy drinkers). Ethanol intake, assessed by a validated questionnaire and expressed as daily (g/d) and lifetime (kg) consumption, and body mass, expressed as body mass index. Biochemical tests of liver and metabolic function and hepatic ultrasonography were done. The prevalence of steatosis was increased in heavy drinkers (46.4% [95% CI, 34% to 59%]) and obese persons (75.8% [CI, 63% to 85%]) compared with controls (16.4% [CI, 8% to 25%]). Steatosis was found in 94.5% (CI, 85% to 99%) of obese heavy drinkers. Compared with controls, the risk for steatosis was higher by 2.8-fold (CI, 1.4-fold to 7.1-fold) in heavy drinkers, 4.6-fold (CI, 2.5-fold to 11.0-fold) in obese persons, and 5.8-fold (CI, 3.2-fold to 12.3-fold) in persons who were obese and drank heavily. In heavy drinkers, obesity increased the risk for steatosis by twofold (CI, 1.5-fold to 3.0-fold) (P < 0.001), but heavy drinking was associated with only a 1.3-fold (CI, 1.02-fold to 1.6-fold) increase in risk in obese persons (P = 0.0053). Elevated alanine aminotransferase and triglyceride levels are the most reliable markers of steatosis. Steatosis is frequently encountered in healthy persons and is almost always present in obese persons who drink more than 60 g of alcohol per day. Steatosis is more strongly associated with obesity than with heavy drinking, suggesting a greater role of overweight than alcohol consumption in accumulation of fat in the liver.

Non-alcoholic fatty liver disease (NAFLD) is rapidly becoming the most common liver disease worldwide. The prevalence of NAFLD in the general population of Western countries is 20–30%. About 2–3% of the general population is estimated to have non-alcoholic steatohepatitis (NASH), which may progress to liver cirrhosis and hepatocarcinoma. As a rule, the prevalence of NAFLD is higher in males and increases with increasing age, and it is influenced by the diagnostic method and the characteristics of the population, especially lifestyle habits. Population-based studies provide better estimates of the prevalence of NAFLD as compared to autoptic and clinical studies, but few such studies have been performed to date. The diagnosis of NAFLD in population studies is usually obtained by ultrasonography, which is known to underestimate the prevalence of fatty liver. The Dallas Heart Study and the Dionysos Study reported that 30% of the adults in the USA and 25% in Italy have NAFLD. In these studies, 79% and 55% of patients with NAFLD had normal aminotransferase levels, showing that liver enzymes are not surrogate markers of NAFLD in the general population. Noninvasive markers such as the fatty liver index obtained from the Dionysos Study may be useful to screen for NAFLD in the general population. The most important risk factors for NAFLD are male gender, age, obesity, insulin resistance and the cardiometabolic alterations that define the metabolic syndrome. The prevalence of NAFLD is 80–90% in obese adults, 30–50% in patients with diabetes and up to 90% in patients with hyperlipidemia. The prevalence of NAFLD among children is 3–10%, rising up to 40–70% among obese children. Moreover, pediatric NAFLD increased from about 3% a decade ago to 5% today, with a male-to-female ratio of 2:1. The incidence and natural history of NAFLD are still not well defined, but it is recognized that the majority of individuals with NAFLD do not develop NASH. The incidence of NAFLD is probably increasing in Western countries, strictly linked to lifestyle habits.