Aminotransferase and gamma-glutamyltranspeptidase levels in obesity are associated with insulin resistance and the metabolic syndrome.

Fatty liver at ultrasounds, with/ without raised plasma levels of hepatic enzymes, is common in obesity. In most cases, it is the hallmark of non-alcoholic fatty liver disease (NAFLD), a potentially progressive disease associated with insulin resistance and the metabolic syndrome (MS). We tested the hypothesis that insulin resistance per se might be associated with hepatocellular necrosis. Alanine and aspartate aminotransferases (ALT and AST; no.=799) and gamma-glutamyltranspeptidase (GGT; no.=459) were analyzed in a group of treatment-seeking obese patients recruited in 12 Italian medical centers. Insulin resistance was calculated by the homeostasis model assessment method (HOMA-IR; no.=522). Median ALT and AST increased with increasing obesity class (p=0.001 and p=0.005) and exceeded normal limits in 21.0% of cases. Also HOMA-IR increased with the obesity class (p<0.0001), and was higher in subjects with elevated ALT (median, 4.93 vs 2.89; p<0.0001). A significant correlation was observed between HOMA-IR and ALT (R2=0.208; p<0.0001), as well as between HOMA-IR and AST or GGT (R2=0.112 and R2=0.080; p<0.0001). The correlation was maintained when cases with elevated enzyme levels were omitted from analysis. Diabetes and hypertriglyceridemia were the features of the MS most commonly associated with raised liver enzymes. In logistic regression, after correction for age, gender, BMI and features of the MS, HOMA-IR maintained a highly predictive value for raised ALT, AST and GGT. We conclude that in obesity insulin resistance is a risk factor for raised liver enzyme levels, possibly related to NAFLD.

Weight cycling in treatment-seeking obese persons: data from the QUOVADIS study.

OBJECTIVE: To determine parameters of weight history useful for the assessment of weight cycling and their association with psychological distress and binge eating. DESIGN: Cross-sectional. SUBJECTS: A total of 1889 treatment-seeking obese subjects, enrolled by 25 Italian centers (78% female subject), aged 20-65 y (median 45); 1691 reported previous efforts to lose weight (median age of first dieting, 30 y). MEASUREMENTS: The number of yearly attempts to lose weight, weight gain since age 20 y, cumulative weight loss and gain were checked by a predefined structured interview. Psychological distress was tested by means of Symptom Check-List 90 (SCL-90), Binge Eating Scale (BES) and Three Factor Eating Questionnaire (TFEQ). RESULTS: Differences in anthropometric, clinical and psychological parameters were observed in relation to previous attempts to lose weight. Patients in the upper quartile of parameters of weight history were considered weight cyclers. In multivariate logistic regression analysis, after correction for age, sex and BMI, a high BES score was the only factor systematically associated with a high frequency of dieting (OR, 1.70; 95% confidence interval, 1.22-2.36; P=0.022), with higher cumulative weight loss (1.42; 1.12-1.80; P=0.003) and cumulative weight gain (1.38; 1.06-1.79; P=0.017). However, the sensitivity, specificity and positive predictive value of a high BES score were very low to detect cyclers. Weight cycling did not carry a higher risk of complicating diseases. CONCLUSIONS: Weight cycling is associated with psychological distress, and binge eating independently increases the risk, but cannot be used to predict cycling. Also, obese patients who do not experience overeating as a loss of control discontinue treatment or regain weight following therapy.