Total physical activity (MET-min/day) Adjustment for Age and area of residence Age, area of residence, BMI, WC, and smoking Age, area of residence, BMI, WC, smoking, diabetes mellitus, and duration of sedentary behaviours Duration of vigorous activity (min/day) Adjustment for Age and area of residence Age, area of residence, BMI, WC, and smoking Age, area of residence, BMI, WC, smoking, diabetes mellitus, duration of moderate activity, and sedentary behaviours Duration of moderate activity (min/day) Adjustment for Age and area of residence Age, area of residence, BMI, WC, and smoking Age, area of residence, BMI, WC, smoking, diabetes mellitus, duration of vigorous activity, and sedentary behaviours Duration of sedentary behaviours (min/day) Adjustment for Age and area of residence Age, area of residence, BMI, WC, and smoking Age, area of residence, BMI, WC, smoking, diabetes mellitus, and TPA r -0.127 -0.103 -0.084 -0.131 -0.122 -0.116 -0.123 -0.107 -0.071 0.108 0.092 0.081 p 0.011 0.021 0.035 0.008 0.019 0.027 0.018 0.031 0.052 0.013 0.029 0.041 r -0.129 -0.114 -0.104 -0.117 -0.109 -0.106 -0.125 -0.118 -0.102 0.119 0.101 0.078 p 0.010 0.017 0.030 0.021 0.026 0.029 0.012 0.020 0.032 0.008 0.022 0.047 C-reactive protein and physical activity Esteghamati A et al. Table 2. Association between several features of physical activity and serum quantitative CRP after mul- tiple adjustments (SuRFNCD-2007, Iran) Male Female BMI=Body mass index; CRP=C-reactive protein; MET=Metabolic equivalent; min=Minute; SE=Standard error; TPA=Total physical activity; WC=Waist-circumference The correlation between quantitative CRP and TPA was independent of the duration of sedentary be- haviours (r=-0.084, p=0.035 in men and r=-0.104, p=0.030 in women) (Table 2). Considering the different categories of physical activity, there was a significant inverse correlation between quantitative CRP and higher physical ac- tivity in both men and women after multiple ad- justments for age, residential area, BMI, waist-cir- cumference, smoking, and diabetes mellitus (Fig.). Serum CRP concentrations of ≥10 mg/L are fre- quently observed in subjects with inflammatory conditions (23); therefore, in a separate analysis, we excluded these patients (n=70) and repeated the association analyses once more. This change could not considerably change the level of associations (r) in different models. Volume 30 | Number 1 | March 2012 DISCUSSION In this study, the duration and the intensity (vigo- rous and moderate) of physical activity in three domains of work, transportation, and leisure time were evaluated using the GPAQ. Our findings clear- ly demonstrated that physical activities of both moderate and vigorous intensity were associated with lower levels of quantitative CRP. Furthermore, we showed that this correlation was independent of several potential confounders, including BMI, waist-circumference, smoking status, diabetes mel- litus, age, and sex. Note that our study, in a large population-based sample, could show a mild but significant and independent inverse association be- tween physical activity and CRP. The mild degree of this association is expected because, in a general population, the level of CRP does not have a large variation, and the majority of people have normal 69