Regional body fat distribution may represent an independent risk factor for several conditions, especially metabolic and cardiovascular diseases; recent findings have shown that abdominal fat accumulation can be an independent predictor of hepatic steatosis. Very few studies, mostly using selected clinical samples, have focused on the relationship between indices of abdominal visceral fat accumulation and the most commonly used biochemical liver tests, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyltransferase (GGT). The aim of the present study was to evaluate the relation between central fat accumulation, as assessed by abdominal height, relative weight, as determined by body mass index (BMI), and liver function tests (ALT, AST, and GGT) in a random sample of 2,704 residents of Erie and Niagara Counties in New York State, 35-80 years of age and free from known hepatic disease. Multiple linear regression models were used, with liver enzymes as dependent variables with abdominal height and BMI as independent variables, and the inclusion of several covariates (age, race, education, smoking status, pack-years of smoking, drinking status, and total ounces of ethanol in the past 30 days). Abdominal height was consistently a better correlate of ALT and GGT levels than BMI in both sexes. In addition, abdominal height was the most powerful independent predictor of ALT in both sexes as well as of GGT among women. In conclusion, these findings support a role for central adiposity independent from BMI in predicting increased levels of hepatic enzymes, likely as a result of unrecognized fatty liver. (HEPATOLOGY 2004;39:754 -763.)
O besity is an important predictor of several diseases, 1 as well as one of the risk factors most frequently associated with increased liver enzymes. [2][3][4][5][6][7] In the last several years, many epidemiological studies strongly indicated that regional body fat distribution, with abdominal accumulation, irrespective of total body fat quantity, as assessed by body mass index (BMI), may represent a major independent risk factor for several conditions, especially metabolic and cardiovascular dis-eases. 8,9 Furthermore, recent findings have shown that central adiposity can be an independent predictor of hepatic steatosis (fatty liver), 10,11 a common clinical and histological condition frequently associated with alcohol consumption and excessive body weight. In addition, obesity seems to represent a better predictor of fatty liver than heavy drinking and the coexistence of both conditions (obesity and heavy drinking) may produce a very high risk of developing this condition. 12 Increased levels primarily of alanine aminotransferase (ALT) and triglycerides, and secondarily of gamma-glutamyltransferase (GGT), appear to be the most sensitive biochemical indicators of the presence of hepatic steatosis. 11,12 Despite the growing body of evidence on the importance of visceral adiposity and the independent role of weight with respect to alcohol consumption in determining fat accumulation in the liver, to date very few studies, mostly related to restricted samples and often in clinical settings, [13][14][15] have focused on the relationship between simply assessed anthropometric indices of abdominal visceral adipose tissue accumulation and the most commonly used biochemical liver tests, such as ALT, aspartate aminotransferase (AST), and GGT. Very recently, Ruhl and Everhart, 16 using data Abbreviations: ALT, alanine amino-transferase; AST, aspartate amino-transferase; GGT, gamma-glutamyltransferase; BMI, body mass index; WHR, waist-tohip ratio.