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.
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.
D
D
Martinez-Gomez
J C
JC
Eisenmann
J
J
Wärnberg
S
S
Gomez-Martinez
A
A
Veses
O L
OL
Veiga
A
A
Marcos
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