Association between C-reactive protein levels and physical fitness in 7 to 9 year old children at poor elementary schools in Surakarta, Indonesia

Background Data regarding inflammatory factors in children are not so well developed as in adults. Higher levels of physical fitness may be helpful in modifying the low-grade inflammatory state that is indexed by C-reactive protein (CRP) levels. Objective To evaluate the association of physical fitness with CRP levels in children and to identify the possible related factors. Methods This cross-sectional study was conducted at poor elementary schools in Surakarta, Indonesia using a group of 217 underweight children aged from 7 to 9 years old. Physical fitness was assessed using a modified Harvard Step Test. CRP levels were measured using a high-sensitivity assay. The association between physical fitness and CRP level was assessed using linear regression analysis. Multivariate analyses were used to adjust covariates, and statistical analyses were performed using SPSS for Windows software version 15.0. Results Subjects were 48% female and 52% male, and eleven children (5%) had a CRP level > 5 mg/L. Mean fitness level and CRP level did not differ by age and gender. Fitness level was not inversely correlated with CRP (r=0.10, P=0.14). Physical fitness was significantly correlated with BMI (r=0.14; P=0.04), physical activity [0R=3.3 (95% CI 1.7 to 6.4)], and fat intake [0R=0.5 (95% CI 0.2 to 0.9) ]. Conclusion These findings indicate that physical fitness is not inversely correlated to CRP levels in children. However, our study reveased an association between high fat intake and low physical fitness as well as a significant association between high physical activiry and physical fitness