Fitness is associated with lower inflammatory markers in obesity: the FATCOR study

Abstract

Abstract Background Obesity is associated with chronic low-grade inflammation, but exercise has anti-inflammatory properties. It is unknown whether the anti-inflammatory effects of fitness may influence the obesity-associated inflammation. Purpose To assess levels of inflammatory markers in fit vs. unfit overweight and obese subjects without known cardiovascular disease. Methods Peak oxygen uptake (VO2max) was measured by treadmill cardiopulmonary exercise testing in 566 subjects (mean age 48±9 years, 60% women) with body mass index >27.0 kg/m2 in the FAT associated CardiOvasculaR dysfunction (FATCOR) study. Fitness was defined from age- and sex adjusted reference levels of VO2max. Serum levels of C-reactive protein (CRP), serum amyloid A (SAA) and calprotectin were assessed by Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight (MALDI-TOF) mass spectrometry and log transformed before inclusion in analyses. Results Fit subjects (n=147) were older and had less metabolic syndrome, obesity and hypertension compared to unfit subjects (n=419) (all p<0.05). Serum levels of CRP and SAA were lower in fit subjects vs. unfit (p<0.01), while serum calprotectin showed no difference (p=0.06). In multivariable logistic regression analyses, lower CRP (odds ratio [OR] 0.73, 95% confidence interval [CI] 0.61–0.87, p<0.001) and SAA (OR 0.61, 95% CI 0.40–0.93, p=0.02) remained associated with being fit after adjusting for age, sex, obesity, metabolic syndrome and hypertension. When looking at obese (n=357, fit n=53) and overweight subjects (n=209, fit n=94) separately, lower CRP (OR 0.60, 95% CI 0.46–0.78, p<0.001) and SAA (OR 0.44, 95% CI 0.24–0.83, p=0.01) remained associated with being fit in obese, but not in overweight subjects after adjustment for age, sex and metabolic syndrome. Conclusion Fitness was associated with lower circulatory inflammatory markers in obesity independent of cardiometabolic risk factors. Our results suggest that fitness may promote cardiovascular benefit through the anti-inflammatory properties of exercise also in obesity. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Western Norway Regional Health Authority