An association between body mass index and high-sensitivity C-reactive protein concentrations is influenced by age in community-dwelling persons

Background: High sensitivity C-reactive protein (hsCRP) is an acute phase reactant and a sensitive marker of inflammation. Age and adiposity can potentially promote the production of C-reactive protein (CRP). However, only a few studies have investigated any interaction between age and adiposity on hsCRP concentrations. Methods: We recruited 822 men (mean age, 61 +/- 14 years) and 1097 women (63 +/- 12 years) during their annual health examination from a single community. We cross-sectionally examined whether age, body mass index (BMI), and the interaction are significantly associated with hsCRP concentrations, independent of confounding factors. Results: Multiple linear regression analyses for hsCRP showed that in men, age (=0.169, P<0.001) and BMI (=0.114, P=0.004) as well as smoking status, triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), uric acid, and gamma-glutamyl transferase (GGT) were significantly associated with hsCRP; and in women, age (=0.203, P<0.001) and BMI (=0.225, P<0.001) as well as HDL-C, fasting plasma glucose (FPG), uric acid, GGT and high-molecular weight adiponectin were significantly associated with hsCRP. In addition to their direct associations, the interaction between age and BMI was also a significant and independent determinant for hsCRP in both men (F=4.407, P=0.036) and women (F=5.487, P=0.019). In participants aged<75 years, overweight (BMI 25.0kg/m(2)) persons were more likely to have a prevalence of elevated hsCRP concentrations (1.00 mg/L) compared with the normal-weight (BMI <22.0kg/m(2)), but such an association was not observed in those aged 75 years. Conclusions: Adiposity promotes low-grade systemic inflammation in community-dwelling persons aged <75 years.