Associations between body mass index and serum levels of C-reactive protein

Background. Obesity leads to increased risk of cardiovascular disease and glucose intolerance, which are phenomena of chronic inflammation. This study was performed to determine whether a higher body mass index (BMI) and central obesity are associated with low-grade inflammation. Methods. An analysis of 8 453 adults aged ≥20 years was performed. Every subject completed a household interview and a questionnaire regarding personal health, and their BMI and serum C-reactive protein (CRP) level were measured. The BMI data were divided into quint iles, using multiple linear regression to estimate the relationship between CRP level and BMI quintiles. An extended-model approach was used for covariate adjustment. The association between central obesity and CRP level was examined by this method as well. Results. After controlling for demographics, chronic diseases, health behaviours and levels of folate and vitamin B₁₂, the β coefficient (which represents the change of natural-log-transformed levels of CRP for each kg/m² increase in BMI) was 0.078 (p<0.001). The CRP levels also increased across increasing quintiles of BMI (p for trend <0.001). The β coefficient, representing the change of natural-log-transformed levels of CRP comparing subjects with central obesity to those without, was 0.876 (p<0.001). Conclusion. Higher BMIs as well as central obesity are independently associated with higher levels of CRP.