Abstract
Background: Fitness and obesity are both independently associated with cardiovascular events and mortality. C-reactive protein (CRP), a predictor of cardiovascular events is associated with obesity; but its association with cardiorespiratory fitness in early adulthood is uncertain. The aim of this study was to examine the relationship between cardiorespiratory fitness and CRP, controlling for obesity in an unselected cohort of young adults. DESIGN: A cross-sectional study in a representative birth cohort.
Methods: We measured CRP levels, cardiorespiratory fitness, anthropometric variables, blood pressure and smoking in 26-year-old men (n=400) and women (n=315). Log CRP levels were compared across cardiorespiratory fitness with adjustment for body mass index (BMI), sex, blood pressure, smoking and combined oral contraceptive use.
Results Geometric mean CRP levels were higher in women (3.23 mg/l, 95% CI 2.85-3.64) compared with men (1.70 mg/l, 1.52-1.89). Regression analysis adjusting for sex and weight showed an inverse association between fitness and CRP (beta=-0.16, P<0.001). This association held after statistical controls were added for BMI, systolic blood pressure and smoking and combined oral contraceptive use (P</=0.01).
Conclusions: Cardiorespiratory fitness levels are inversely associated with CRP levels in young adults independent of obesity, blood pressure, smoking and combined oral contraceptive use in women. Physical fitness may decrease the risk of cardiovascular events by reducing inflammation.