Associations of physical activity, cardiorespiratory fitness and fatness with low-grade inflammation in adolescents: the AFINOS Study.
OBJECTIVE
To examine the independent associations of objectively measured physical activity (PA), cardiorespiratory fitness (CRF) and fatness with low-grade inflammatory markers in adolescents.


METHODS
Cross-sectional study in Spain.


METHODS
A sample of 192 adolescents aged 13-17 years.


METHODS
PA was assessed with an accelerometer for 7 days. A 20-m shuttle-run test was used to assess CRF. Skinfold thicknesses at six sites and WCs were measured. BMI was calculated from measured height and weight. C-reactive protein (CRP), interleukin-6 (IL-6) and complement factors C3 and C4 were assayed. The homeostasis model assessment of insulin resistance (HOMA-IR) was calculated from glucose and insulin. Regression analysis adjusted for potential confounders and HOMA-IR was used to determine the associations between PA, CRF and fatness with low-grade inflammatory markers.


RESULTS
Total PA, vigorous PA and MVPA were positively associated with CRF (r=0.25-0.48), whereas vigorous PA was negatively associated with skinfolds (r=-0.27). CRF was inversely associated with fatness, (r=-0.30 to -0.48). CRF and fatness were inversely and positively associated with HOMA-IR (r=-0.16 and 0.21, respectively). PA variables were not independently associated with inflammatory markers. CRF and fatness were inversely and positively associated with CRP, C3 and C4, respectively. Only body fat explained a relevant amount of the variance of the model in CRP (4%) and C4 (19%), whereas CRP and body fat jointly explained the variance in C3 (25%). All these observations were independent of HOMA-IR.


CONCLUSIONS
These findings support the key role of CRF and fatness on low-grade inflammation, as well as the possible indirect role of habitual PA through CRF and body fat in adolescents.
Martinez-Gomez
D
D
Immunonutrition Research Group, Department of Metabolism and Nutrition, Instituto del Frio, Institute of Food Science, Technology and Nutrition (ICTAN), Spanish National Research Council (CSIC), Madrid, Spain.
Eisenmann
J C
JC
Wärnberg
J
J
Gomez-Martinez
S
S
Veses
A
A
Veiga
O L
OL
Marcos
A
A
D000293:Adolescent; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D002097:C-Reactive Protein / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000517:prevention & control*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007249:Inflammation / Q000503:physiopathology; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D009043:Motor Activity; D009765:Obesity / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology; D012885:Skinfold Thickness; D013030:Spain / Q000453:epidemiology
D002097:C-Reactive Protein