Inflammation and the Metabolic Syndrome: Clustering and Impact on Survival in a Swedish Community-Based Cohort of 75 Year Olds

Background: High blood concentrations of inflammatory markers, including white blood cell (WBC) count, are closely related to the metabolic syndrome. Both conditions predict dismal survival. We determined prospective associations between mortality and factors derived by a factor analysis of WBC count and the basic components of the metabolic syndrome. Methods and Results: We performed a factor analysis of WBC count and the continuous components of the metabolic syndrome in 196 men and 200 women, comprising 64% of the originally invited 75 year olds from the Swedish city Vasteras. The analysis revealed three factors in men and two in women. The first factor included fasting glucose, high-density lipoprotein cholesterol, triglycerides, and waist circumference in men and in addition WBC count in women. The second factor included diastolic blood pressure and systolic blood pressure in both sexes. In men, the third factor included fasting glucose and WBC count. These factors explained 66% (first factor, 28%; second factor, 23%; third factor, 15%) of the variation in men and 57% (first factor, 34%; second factor, 23%) in women. Prospective associations of the derived factors and all-cause mortality during 10-year follow-up were assessed by Cox regression [hazard ratio (HR)]. The first factor was significantly related to increased mortality in men: HR=1.22 [95% confidence interval (CI) 1.05-1.41; p = 0.008] and women: HR=1.25 (95% CI 1.06-1.48; p = 0.010). Pooling men and women adjusting for established cardiovascular risk factors gave HR= 1.16 (95% CI 1.04-1.29; p = 0.010). In men the third factor was significantly related to mortality; HR= 1.29 (95% CI 1.07-1.57; p = 0.009). Conclusions: A metabolic inflammatory factor and a blood pressure factor were identified. In men, the former was split into a metabolic and an inflammatory factor. Factors including metabolic and inflammatory components were significantly related to 10-year mortality and the relation remained after adjusting for established cardiovascular risk factors.