Hyperglycemia promotes microinflammation as evaluated by C-reactive protein in the very elderly

Objective: C-reactive protein (CRP) is not only an acute phase reactant but also a sensitive marker of sub-clinical inflammation associated with atherosclerosis. The aim of the present study was to determine whether glycemic control or blood pressure influences the vascular microinflammation as evaluated by CRP levels in the very elderly. Methods: The study group consisted of 195 residents aged 85 years. The subjects were divided into three groups according to their CRP levels; a low (<1 mg/L), an average (1 to 3 mg/L), and a high (3 to 10 mg/L) CRP group. Hemoglobin A_1c (HbA_1c) levels were used as an index of glycemic control. Results: The HbA_1c level showed a significant positive correlation with the CRP level (r=0.289, p<0.0001). In contrast, systolic and diastolic blood pressures failed to correlate with the CRP level. The Hb_1c was significantly greater in the high CRP group compared to the average and the low CRP groups (6.01±0.29%, 5.57±0.09% and 5.42±0.05%, respectively). Furthermore, the HbA_1c adjusted by sex, body mass index, systolic blood pressure, serum triglyceride and current smoking status was significantly higher in the high CRP group than in the average and the low CRP groups. Multiple regression analysis also revealed that the HbA_1c level was significantly and independently associated with the CRP level. Conclusions: These results suggest that tight good glycemic control, even in very elderly subjects, may be able to reduce the systemic inflammation that contributes to leads to atherosclerosis.