Association of obesity and type II diabetes mellitus as a risk factor for gallstones

Age, female sex, and obesity are well-known risk factors for gallstones; in contrast the possible role of type 2 diabetes mellitus (type-2 DM) is controversial. One reason for this discrepancy might be that type 2 DM is often accompanied by obesity. Therefore, the aim of this study was to evaluate the importance of obesity and of type 2 DM, separately and together, as risk factors for gallstones. In all, 203 obese patients with normal glucose tolerance (obese NGT), 446 obese patients with type 2 DM (obese type 2 DM), 269 lean patients with type 2 DM (lean type 2 DM) and 250 lean subjects with a normal glucose tolerance (lean NGT) were evaluated by ultrasonography for the presence of gallstones. At univariate analysis patients with gallstones (177) were older and were more frequently affected by both obesity and type 2 DM, and had higher triglycerides and fasting blood glucose levels. At multiple logistic regression analysis, only age and obesity, both in the presence or in absence of type 2 DM, were strongly associated with gallstones (P < 0.001); diabetes alone had a lower level of statistical significance (P = 0.07). These data suggest that obesity is a stronger risk factor for gallstones than type 2 DM.