C-reactive protein, cardiovascular risk factors, and mortality in a prospective study in the elderly

Abstract

Serum C-reactive protein (CRP) reflects inflammation and predicts cardiovascular disease in middle-aged individuals. We investigated CRP, risk factors, and 10-year mortality in 3 elderly cohorts (aged 75, 80, and 85 years; n=455) of the population-based Helsinki Ageing Study. Clinical and laboratory examinations were performed at baseline, and in 1998, CRP was measured by a sensitive method (sensitivity 0.3 mg/L) from frozen serum samples. Mortality data were retrieved from national registers. Serum CRP ranged from 0.18 to 170.0 mg/L (interquartile range 0.68 to 4.10 mg/L, median 1.60 mg/L). CRP correlated significantly with body mass index and plasma insulin and was associated with smoking at baseline. An inverse correlation was found with albumin and total and HDL cholesterol. CRP was not associated with diabetes or cardiovascular disease but was significantly (P=0.015) higher in persons with (n=70) than without (n=385) dementia. During the 10-year follow-up, 61% (n=278) of the cohort died; half of the deaths were due to cardiovascular diseases. Mean CRP in survivors and nonsurvivors was 3.16 and 5.22 mg/L (P=0.017), respectively. After controlling for age and sex, baseline CRP (per 10 mg/L) significantly predicted the 10-year total mortality (risk ratio 1.20, 95% CI 1.08 to 1.32) and cardiovascular mortality (risk ratio 1.22, 95% CI 1.10 to 1.35). Predictive value was found in the 75-year-old cohort, but it was clearly attenuated in the 80- and 85-year-old cohorts. The results indicate that CRP is associated with several cardiovascular risk factors in the elderly. CRP alone predicts overall and cardiovascular mortality, but the prediction was significant in only the 75-year-old cohort.