Cross‐sectional associations between physical fitness and biomarkers of inflammation in children : the PANIC study

Abstract

Background Systemic low-grade inflammation has been proposed as an underlying pathophysiological mechanism for cardiometabolic diseases. We investigated the associations of physical fitness with systemic low-grade inflammatory state in a population sample of children.

Methods Altogether 391 children aged 6–9 years were examined. Cardiorespiratory fitness (maximal power output, Wmax) was assessed by a maximal cycle ergometer test and neuromuscular fitness by hand grip strength, sit-up, standing long jump, 50-metre shuttle run, static balance, sit-and-reach, and box and block tests. Body fat percentage (BF%) and lean mass (LM) were assessed by dual-energy X-ray absorptiometry. High sensitivity C-reactive protein (hs-CRP), leptin, leptin receptor, high molecular weight adiponectin (HMW-adiponectin), interleukin-6 (IL-6), tumour necrosis factor alpha (TNF-α), and glycoprotein acetyls (GlycA) were assessed from fasting blood samples. The modified inflammatory score (IS) was calculated using the population specific z-scores and formula (zhs-CRP + zleptin + zIL-6 + zTNF-α + zGlycA) – zleptin receptor – zHMW-adiponectin. The data were analysed using linear regression analyses.

Results Higher Wmax/kg of body mass (β=-0.416, 95% CI=-0.514 to -0.318), higher number of completed sit-ups (β=-0.147, 95% CI=-0.244 to -0.049), a longer distance jumped in the standing long jump test (β=-0.270, 95% CI=-0.371 to -0.169), and a shorter time in the 50 metre shuttle run test (β=0.123, 95% CI=0.022 to 0.223) were associated with lower IS. None of these associations remained statistically significant after adjustment for BF%

Conclusions Higher physical fitness is associated with more favourable inflammatory biomarker profile in children. However, the associations were explained by BF%.