Background and aims: Cardiorespiratory fitness has been postulated to lower chronic inflammation in obesity. We assessed sex-specific associations of inflammation with cardiorespiratory fitness in overweight and obese persons.
Methods and results: Peak oxygen uptake (VO2max) was measured by treadmill in 566 participants (age 48 ± 9 years, 60% women) with body mass index >27.0 kg/m2 in the FAT associated CardiOvasculaR dysfunction (FATCOR) study. Fitness was identified from age- and sex specific reference levels of VO2max. The inflammatory markers C-reactive protein (CRP), serum amyloid A (SAA), kynurenine:tryptophan ratio (KTR) and pyriodoxic acid ratio (PAr) were measured by mass spectrometry. In the total study population 63% had obesity and 74% were cardiorespiratory unfit. Unfit women had the highest fat percentage and the highest serum levels of CRP and SAA (p < 0.05). In multivariable linear regression analyses in women, higher CRP (β -0.15, p = 0.001), SAA (β -0.10, p = 0.03) and PAr (β -0.09, p = 0.03) were associated with lower VO2max after adjusting for confounders. In multivariable analyses in men, higher PAr (β -0.14, p = 0.02) was associated with lower VO2max. In multivariable analyses in obese women, higher CRP and PAr remained associated with lower VO2max (p < 0.05), while in obese men there was no significant association. When normalizing VO2max for fat-free mass (VO2maxFFM) higher CRP, SAA and PAr index were associated with lower VO2maxFFM in women, while only higher PAr index was associated with lower VO2maxFFM in men.
Conclusion: The association of inflammation with lower cardiorespiratory fitness was more pronounced in women than men, in particular when obesity was present.
Clinical trial registration: URL: http://www.
Clinicaltrials: gov NCT02805478.
Keywords: CRP; Cardiorespiratory fitness; Inflammation; Obesity; Sex; Women.
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