J HEALTH POPUL NUTR 2012 Mar;30(1):66-72 ISSN 1606-0997 | $ 5.00+0.20 ©INTERNATIONAL CENTRE FOR DIARRHOEAL DISEASE RESEARCH, BANGLADESH Physical Inactivity Is Correlated with Levels of Quantitative C-reactive Protein in Serum, Independent of Obesity: Results of the National Surveillance of Risk Factors of Non-communicable Diseases in Iran Alireza Esteghamati, Afsaneh Morteza, Omid Khalilzadeh, Mehdi Anvari, Sina Noshad, Ali Zandieh, and Manouchehr Nakhjavani Endocrinology and Metabolism Research Center, Vali-Asr Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran ABSTRACT Increased C-reactive protein (CRP) levels are associated with coronary heart disease, stroke, and mortality. Physical activity prevents cardiovascular disorders, which can be partly mediated through reducing inflam- mation, including serum CRP levels. The association of different intensities of physical activity, sedentary behaviours, and C-reactive protein (CRP) levels in serum was examined after adjustment for markers of adiposity, including waist-circumference and body mass index (BMI), in a large population-based study. Using data of the SuRFNCD-2007 study, a large national representative population-based study in Iran, the relationship between quantitative CRP concentrations in serum and physical activity was examined in a sample of 3,001 Iranian adults. The global physical activity questionnaire (GPAQ) was used for evaluating the duration and intensity of physical activity. Total physical activity (TPA) was calculated using metabolic equivalents for the intensity of physical activity. Quantitative CRP concentrations in serum were meas- ured with high-sensitivity enzyme immunoassay. The CRP levels in serum significantly correlated with TPA (r=-0.103, p=0.021 in men and r=-0.114, p=0.017 in women), duration of vigorous-intensity activity (r=-0.122, p=0.019 in men and r=-0.109, p=0.026 in women), duration of moderate-intensity activity (r=- 0.107, p=0.031 in men and r=-0.118, p=0.020 in women), and duration of sedentary behaviours (r=0.092, p=0.029 in men and r=0.101, p=0.022 in women) after multiple adjustments for age, area of residence, BMI, waist-circumference, smoking, and diabetes mellitus. Physical activity (of both moderate and vigor- ous intensity) is inversely associated with the quantitative CRP levels in serum, independent of diabetes and body adiposity. Key words: Cardiovascular diseases; C-reactive protein; Physical activity; Physical exercise; Risk factors; Iran INTRODUCTION Adipose tissue in obesity, diabetes, and metabolic syndrome is in a state of chronic inflammation (1-5). Quantitative C-reactive protein (CRP), an acute-phase reactant produced dominantly by liv- Correspondence and reprint requests should be addressed to: Dr. Alireza Esteghamati Professor of Endocrinology and Metabolism Endocrinology and Metabolism Research Center Vali-Asr Hospital, School of Medicine Tehran University of Medical Sciences PO Box 13145-784, Tehran Iran Email: esteghamati@tums.ac.ir Fax: +9821 64432466 er, is a plasma protein that circulates in increased amounts during inflammation and often damages the tissue (6,7). Results of studies showed that the increased CRP levels were associated with func- tional impairment, coronary heart disease, stroke, and mortality (8). So, reducing the CRP levels can reduce mortality and morbidity due to cardiovas- cular disorders. Physical activity can prevent cardiovascular disor- ders (9). This effect can be partly mediated through reducing inflammation, including serum CRP lev- els (10). Results of some population-based studies showed a negative association between physical activity and the circulating levels of CRP (7,10-14). However, the pattern of this association with res- pect to different intensities and metabolic equiva-