Ultrasonography (US) is a validated method to accurately measure abdominal visceral adipose thickness (VAT), a parameter related to the risk of cardiovascular diseases but whose predictive cut-off values for the metabolic syndrome (MS) are unavailable. This study aimed to 1) investigate the association of VAT to MS components; 2) identify predictive cut-off values of MS risk according to sex and age in a large Caucasian sample.

Anthropometry, blood pressure, fasting plasma glucose (PG), HDL-cholesterol, triglycerides and VAT (distance from aortic anterior wall to rectus abdominis posterior surface measured above the umbilicus by US) were assessed in 3431 subjects (71,4% females, 46,8 ± 13,4 years). MS was diagnosed by IDF criteria (2005).

MS prevalence was 34,6% (54,2% in men and 26,8% in women). VAT was positively associated to waist (r2=0,645 p<0,001), triglycerides (r2=0,134 p<0,001), PG (r2=0,14 p<0,001), systolic (r2=0,24 p<0,001) and diastolic pressures (r2=0,185 p<0,001), and negatively to HDL-cholesterol (r2=0,153 p<0,001). After ROC curve analysis, the optimal VAT cut-off points for MS prediction were 7,6cm in males (sensitivity: 68%, specificity: 77%, AUC: 0,78, p<0,001) and 5,3cm in females (sensitivity: 68%, specificity: 77%, AUC: 0,78, p<0,001), that were increased with age strata in both genders. In conclusion, intra-abdominal fat thickness was related to MS and to all of its components with predictive cut-off values greater in males and in the elderly.