Interleukin-6 modulates plasma cholesterol and C-reactive protein concentrations in nonagenarians

OBJECTIVES: To establish whether the relationship between interleukin-6 (IL-6) and plasma lipid and C-reactive protein (CRP) concentrations is different in Finnish nonagenarians than in middle-aged subjects with lower inflammatory status. DESIGN: Cross-sectional. SETTING: Observational cohort study concentrating on the oldest old. PARTICIPANTS: Nonagenarians (n = 291, mean age +/- standard deviation 90 +/- 1; 68 men, 223 women) who lived in the Tampere municipality in southern Finland and a middle-aged control population from the same area (n = 227, aged 44 +/- 8). MEASUREMENTS: Plasma high sensitive CRP and lipid concentrations were analyzed using an automatic analyzer and IL-6 levels using enzyme-linked immunosorbent assay. RESULTS: Plasma concentrations of IL-6 (4.39 +/- 5.25 vs 1.88 +/- 1.98 pg/mL) and CRP (3.54 +/- 4.98 vs 1.53 +/- 1.91 mg/L) were significantly higher in nonagenarians than in middle-aged subjects (P < .001). In nonagenarians, plasma CRP levels increased (P < .001) and plasma total cholesterol (P = .006), low-density lipoprotein cholesterol (P = .02), and high-density lipoprotein cholesterol (P = .002) levels decreased according to IL-6 quartiles. In middle-aged subjects, similar associations were not found. CONCLUSION: The relationship between IL-6 and plasma CRP and cholesterol levels in nonagenarians with enhanced systemic inflammation differs from that of middle-aged subjects.