[Show abstract][Hide abstract] ABSTRACT: The relationships between metabolic risk factors and abdominal fat distribution determined using computed tomography (CT) are poorly defined in large populations. We investigated the cutoff values of the visceral fat area (VFA) to detect subjects with multiple risk factors of metabolic syndrome (MS) by sex and age groups, and attempted to examine whether sex- and age-specific cutoff values are needed. The subjects of this study were 11,561 Japanese men and women who participated in the Hitachi Health Study, received CT examination, and answered questionnaires on lifestyles between 2004 and 2009. VFA and waist circumference were measured using CT. The VFA cutoff values yielding an 80% sensitivity for the detection of multiple risk factors of MS were typically smaller among men under the age of 40 years (<40 years vs. ≥40 years; 86.4 cm(2) vs. 103.9 cm(2)). The area under the receiver operator characteristic curve of VFA for the detection tended to decrease according to age (P = 0.056 and P = 0.020 for trends in men and women). Age- and sex-specific cutoff values are needed. The sensitivity of the subjects under the age of 40 years is relatively smaller (70.0% for men and 60.0% for women) compare to other age groups when the same cutoff value is used regardless of age (e.g., cutoff value calculated to correspond to 80% sensitivity for subjects of all ages). Therefore, a smaller VFA cutoff point should be used among men under the age of 40 years.