Inflammation and cardiorespiratory fitness in overweight women and men: the FATCOR study

Background

Women have more body fat compared to men, and adipose tissue is associated with chronic inflammation. Cardiorespiratory fitness has on the other hand been postulated to lower chronic inflammation. However, sex-specific associations of inflammation with cardiorespiratory fitness is less studied.

Purpose

To assess inflammatory markers in overweight and obese women and men according to cardiorespiratory fitness in the FAT associated CardiOvasculaR dysfunction (FATCOR) study.

Methods

Cardiorespiratory fitness was assessed by maximal oxygen uptake (VO2max) by cardiopulmonary exercise testing in 566 subjects (mean age was 48±9 years, 60% women) with body mass index (BMI) >27.0 kg/m2. Participants were grouped according to sex, and fitness status identified from sex and age specific VO2max thresholds. C-reactive protein (CRP) and serum amyloid A (SAA) were analysed using Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight mass spectrometry. Serum levels of the kynurenine:tryptophan ratio (KTR) and pyriodoxic acid ratio (PAr) were measured by liquid chromatography tandem mass spectrometry. All inflammatory markers were log transformed before inclusion in linear regression analyses.

Results

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 compared to the other groups (p<0.05), while serum levels of KTR and PAr were higher only compared to fit men (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 age, fat percentage, hypertension and metabolic syndrome. In men, only higher PAr (β −0.14, p=0.02) was associated with lower VO2max in multivariable analyses adjusted for age, fat percentage and metabolic syndrome. In multivariable analyses in obese women only (n=213), higher CRP (β −0.15, p=0.01) and PAr (β −0.13, p=0.03) remained associated with lower VO2max, while in obese men (n=144) there was no significant associations between inflammatory markers and VO2max.

Conclusion

Among overweight subjects participating in the FATCOR study, cardiorespiratory unfit women had the highest serum levels of inflammatory markers. The association of inflammation with reduced cardiorespiratory fitness was more pronounced in women than men, in particular when obesity was present.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Western Regional Health Authority of Norway

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

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

Effect of fitness on cardiac structure and function in overweight and obesity (the FATCOR study)

BACKGROUND AND AIMS

Obesity is associated with reduced left ventricular (LV) systolic myocardial function. We aimed to explore by means of a cross-sectional study whether this effect is offset in the presence of good fitness.

METHODS AND RESULTS

We studied clinical and echocardiographic data from 469 overweight (body mass index [BMI] >27 kg/m²) and obese (BMI ≥30 kg/m²) women and men without known cardiovascular (CV) disease in the FAT associated CardiOvasculaR dysfunction (FATCOR) study. The participants were grouped according to obesity and sex- and age adjusted peak oxygen uptake, obtained by ergospirometry. LV systolic myocardial function was assessed by peak systolic global longitudinal strain (GLS) measured by speckle tracking echocardiography. The association of fitness with GLS was tested in logistic regression analyses and reported as odds ratio (OR) with 95% confidence interval (CI). In the total study population, participants were 47 years old, 60% were women, and mean BMI was 32.0 kg/m². GLS did not differ between fit and unfit subjects within the overweight and obese groups (both p > 0.05), but the overweight fit group had higher GLS (more negative value) compared to the obese unfit group (-20.1 ± 2.6 vs. -19.0 ± 3.0, p < 0.05). In obese subjects, fitness was associated with higher GLS (OR 0.88 [95% CI 0.79-0.99, p < 0.05) in multivariable logistic regression analysis, independent of significant associations with higher arterial stiffness and lower fat percentage (all p < 0.05). In the overweight group, fitness was not significantly associated with GLS.

CONCLUSION

In obesity, fitness was independently associated with higher GLS, while no association was found in overweight.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.govNCT02805478.

Sex differences in subclinical cardiac disease in overweight and obesity (the FATCOR study)

BACKGROUND AND AIMS

Subclinical cardiac disease, like abnormal left ventricular (LV) geometry or left atrial (LA) dilatation, is common in obesity. Less is known about sex differences in the prevalence and type of subclinical cardiac disease in obesity.

METHODS AND RESULTS

Clinical and echocardiographic data from 581 women and men without established cardiovascular disease and body mass index (BMI) > 27.0 kg/m² participating in the FAT associated CardiOvasculaR dysfunction (FATCOR) study was analyzed. LA dilatation was recognized as LA volume indexed for height² ≥16.5 ml/m² in women and ≥18.5 ml/m² in men, and abnormal LV geometry as LV hypertrophy and/or increased relative wall thickness. On average, the participants were 48 years old, 60% women and mean BMI was 32.1 kg/m². Overall, the prevalence of subclinical cardiac disease was higher in women than men (77% vs. 62%, p < 0.001). Women had a higher prevalence of LA dilatation than men (74% vs. 56%, p < 0.001), while men had a higher prevalence of abnormal LV geometry (30% vs. 21%, p = 0.011). After adjusting for confounders in multivariable logistic regression analysis, female sex was associated with a 2-fold higher risk of subclinical cardiac disease, in particular LA dilatation (confidence interval [CI] 1.67-3.49, p < 0.001), while male sex was associated with a 2-fold higher risk of abnormal LV geometry (CI 1.30-3.01, p = 0.001).

CONCLUSION

The majority of overweight and obese participants in the FATCOR study had subclinical cardiac disease, which may contribute to the impaired prognosis observed in obesity. Women had a higher prevalence of subclinical cardiac disease than men.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.govNCT02805478.

Does fitness improve the cardiovascular risk profile in obese subjects?

BACKGROUND AND AIMS

Good cardiorespiratory fitness has been suggested to reduce the risk of cardiovascular disease in obesity. We explored the association of fitness with the prevalences of major cardiovascular risk factor like hypertension (HT), diabetes and metabolic syndrome (MetS) in overweight and obese subjects.

METHODS AND RESULTS

Clinical data from 491 participants in the FAT associated CardiOvasculaR dysfunction (FATCOR) study were analyzed. Physical fitness was assessed by ergospirometry, and subjects with at least good level of performance for age and sex were classified as fit. HT subtypes were identified from clinic and 24-h ambulatory blood pressure in combination. Diabetes was diagnosed by oral glucose tolerance test. MetS was defined by the American Heart Association and National Heart, Lung and Blood Institute criteria. The participants were on average 48 years old (60% women), and mean body mass index (BMI) was 32 kg/m². 28% of study participants were classified as fit. Fitness was not associated with lower prevalences of HT or HT subtypes, diabetes, MetS or individual MetS components (all p > 0.05). In multivariable regression analysis, being fit was characterized by lower waist circumference, BMI < 30 kg/m², non-smoking and a higher muscle mass (all p < 0.05).

CONCLUSION

In the FATCOR population, fitness was not associated with a lower prevalence of major cardiovascular risk factors like HT, diabetes or MetS. Given the strong association of cardiovascular risk factor burden with risk of clinical cardiovascular disease, these findings challenge the notion that fitness alone is associated with lower risk of cardiovascular disease in obesity.