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Background: It is unclear how sedentary behavior (SED), physical activity (PA), and cardiorespiratory fitness (CRF) influence vascular structure in children of varying body size. This study examined whether associations between SED, PA, and CRF with intima-media thickness (IMT) added to that of abdominal fatness and IMT. Differences in physiological measures among waist circumference (WC) percentiles were tested., Methods: We assessed IMT of the carotid artery in 265 children aged 11 to 13 years (135 girls). Measures included IMT assessed with high-resolution ultrasonography, WC, body fat mass (BFM) from DXA, and CRF determined using a maximal cycle test. SED and PA were assessed by accelerometry. Association between IMT and CRF adjusted for PA variables, and body composition phenotypes were tested with multiple linear regression analysis., Results: CRF was related to IMT independently of moderate to vigorous PA (MVPA) and SED (P < .05). When WC was added to the model CRF was no longer associated with IMT (P > .05). Children in the higher WC group had increased mean values of BMI, BFM, WC, and IMT and lower MVPA and CRF (P < .05)., Conclusion: Full modeling of SED, MVPA, CRF, and WC revealed that regional adiposity appears to have the biggest role in arterial structure of children.

It is unclear if cardiorespiratory fitness (CRF) can be used as a screening tool for premature changes in carotid intima-media thickness (cIMT) in paediatric populations. The purpose of this cross-sectional study was 3-fold: (i) to determine if CRF can be used to screen increased cIMT; (ii) to determine an optimal CRF cut-off to predict increased cIMT; and (iii) to evaluate its ability to predict increased cIMT among children in comparison with existent CRF cut-offs. cIMT was assessed with high-resolution ultrasonography and CRF was determined using a maximal cycle test. Receiver operating characteristic analyses were conducted in boys (n = 211) and girls (n = 202) aged 11-12 years to define the optimal sex-specific CRF cut-off to classify increased cIMT (≥75th percentile). Logistic regression was used to examine the association between the CRF cut-offs with the risk of having an increased cIMT. The optimal CRF cut-offs to predict increased cIMT were 45.81 and 34.46 mL·kg(-1)·min(-1) for boys and girls, respectively. The odds-ratios for having increased cIMT among children who were unfit was up to 2.8 times the odds among those who were fit (95% confidence interval: 1.40-5.53). Considering current CRF cut-offs, only those suggested by Adegboye et al. 2011. (Br. J. Sports Med. 45(9): 722-728) and Boddy et al. 2012 (PLoS One, 7(9): e45755) were significant in predicting increased cIMT. In conclusion, CRF cut-offs (boys: ≤ 45.8; girls: ≤ 34.5 mL·kg(-1)·min(-1)) are associated with thickening of the arterial wall in 11- to 12-year-old children. Low CRF is an important cardiovascular risk factor in children and our data highlight the importance of obtaining an adequate CRF.

Unlabelled: Early detection of impairment in vascular structure is an important clinical pursuit. However, it is unknown which measure of body composition best predicts vascular wall changes. We assess the differences in body composition among intima-media thickness (IMT) tertiles and determined which measures of body composition are associated with IMT in 385 children aged 11-13 years (196 girls). In this cross-sectional study, body mass index (BMI), waist circumference (WC), body fat mass (BFM), and trunk fat mass (TFM) from dual-energy radiographic absorptiometry and IMT through high-resolution ultrasonography were collected. Differences in body composition measures among IMT tertiles [low IMT (LIMT), ≤ 0.46 mm; middle IMT, 0.46-0.53 mm; higher IMT (HIMT), ≥0.53 mm] were assessed with ANOVA/ANCOVA after categorization. Regression analysis was used to assess the relationships between body composition and IMT. The groups were similar for sex, age, and maturity (p > 0.05). As compared with LIMT group, subjects with HIMT had higher mean values of BMI, BFM, TFM, and WC (p < 0.05). Significant differences were found for WC even when controlling for BMI (p < 0.05). Combining all subjects, IMT was significantly correlated to BMI, BFM, TFM, and WC (p < 0.05). In multiple regression, WC was the only predictor of IMT (β = 0.22, p < 0.001)., Conclusion: Differences exist in body composition variables among IMT tertiles. In the overall model, WC was the only obesity-related predictor of increased IMT in 11-13-year-old children.