Relative contributions of cardiorespiratory fitness and visceral fat to metabolic syndrome in patients with diabetes mellitus

The objective of this study was to examine the contribution of endurance fitness and visceral fat accumulation on the prevalence of metabolic syndrome in Japanese male patients with either an impaired glucose tolerance (IGT) or type 2 diabetes mellitus (DM). The subjects of this cross-sectional study consisted of 135 Japanese male patients with either IGT or type 2 DM who had not taken any medication or intervention. They were classified into three fitness categories (low, moderate, and high) based on the tertiles of their maximal oxygen uptake (V̇O₂max) predicted by the Åstrand nomogram using a cycle ergometer. Metabolic syndrome was defined based on the WHO criteria. The visceral fat area (VFA) was determined using a computed tomography scan. The age- and VFA-adjusted odds ratio was 3.49 (95% CI, 1.13-10.82) for subjects in the low fitness category in comparison to those in the high fitness category. We calculated the odds ratio for the prevalence of metabolic syndrome in the nine categories classified based on the three VFA and three V̇O₂max levels. In Moderate- and Low-V̇O₂max categories, the odds ratios increased in line with increases in the VFA level. The highest odds ratios were observed in the low fitness and high visceral fat group. In the High-V̇O₂max category, no significant odds ratios were observed in the Moderate- and High-VFA categories. These results indicate that a high degree of cardiorespiratory fitness positively contributed to the low prevalence of metabolic syndrome in Japanese male patients with IGT and type 2 DM.