Although cardiorespiratory fitness (CRF) and muscular fitness (MF) are modifiable factors for metabolic risk, the role of weight status in these factors has not been clarified in the pediatric population. We examined associations between metabolic indices and CRF or MF according to weight categories and compared the prevalence of metabolic abnormalities among four groups stratified by combinations of PF and weight categories. Cross-sectionally analyzed were 1744 Japanese adolescents aged 13-14 years. The PF test included measurements of CRF (20-m shuttle run test), upper-limb strength (handgrip test), lower limb strength (standing long jump test), and muscular endurance (sit-ups). Participants were classified as non-overweight (non-OW) or overweight/obese (OW) according to BMI cutoffs by the International Obesity Task Force. Metabolic risk was defined as ≥1 SD of the clustered metabolic risk (estimated by summing standardized sex-specific Z scores of HbA1c, MAP, and non-HDL-C). After adjusting for BMI and other characteristics, linear regression analysis showed that non-HDL-C was inversely associated with CRF in the non-OW group (P <0.001) and with muscular endurance in the OW group (P = 0.002). In the OW group, coefficient of correlation showed that the clustered metabolic risk was slightly lower in those with higher sit-up scores even after adjusting for BMI and CRF (P = 0.06). As to the combination of weight status and PF, upper-limb strength or muscular endurance but not CRF were additively associated with metabolic risk; in comparison with the non-OW group in the second-lowest to highest quintiles, even the OW group in the second-lowest to highest quintiles of muscular endurance were 1.8 (1.1-2.8) times more likely to have metabolic risk while those in the lowest quintile had a 3.1 (1.7-5.7) greater likelihood.
In summary, relationships of metabolic risk with components of PF differed according to weight status. In OW adolescents, MF might be more useful for stratifying metabolic risk than CRF.
S.Y. Morikawa: None. K. Fujihara: None. R. Nedachi: None. I. Ikeda: None. Y. Takeda: None. M. Takeuchi: None. M. Hatta: None. H. Ishiguro: None. T. Yamada: None. H. Sone: Research Support; Self; Kyowa Hakko Kirin Co., Ltd., Novartis AG, Ono Pharmaceutical Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co.