Comparison of serum concentrations of C-reactive protein, TNF-α, and interleukin 6 between elderly Korean women with normal and impaired glucose tolerance

This study was performed to compare concentrations of pro-inflammatory cytokines, such as interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) as well as acute-phase protein, such as C-reactive protein (CRP) between subjects with normal glucose tolerance (NGT) and impaired glucose tolerance (IGT). The purpose of this study was to verify whether the pro-inflammatory cytokine-induced acute-phase response is a pathogenic mechanism in type 2 diabetes in elderly Korean women. A total of 1737 elderly subjects aged over 60 years participated in a population based study in Seoul, Korea (SWS Study 1999). Amongst them, a total of 232 non-smoking and non-diabetic female subjects aged 60-89 years was randomly selected and compared with each other. Higher serum high-sensitivity CRP (hs-CRP) concentrations were shown in subjects with IGT than those with normal glucose tolerance (median 1.2 versus 0.9, P<0.05). Moreover, a relationship between serum hs-CRP concentrations and many components of the metabolic syndrome were detected. Serum pro-inflammatory cytokine IL-6 or TNF-α concentrations, however, were neither increased in subjects with IGT nor closely correlated with the components of the metabolic syndrome. In multiple regression analysis with stepwise selection method using hs-CRP as a dependent variable, it was found that white blood cell (WBC) counts, body mass index (BMI), fasting insulin, post-load 2h glucose, hematocrit and LDL cholesterol were significant independent variables. Our study confirms that increased acute-phase reaction is associated with impaired glucose tolerance and the metabolic syndrome in elderly Korean women. However, the hypothesis that pro-inflammatory cytokine-induced systemic inflammation is an early metabolic defect prior to onset of type 2 diabetes, is not supported in our study of elderly Korean women.