C-reactive protein in type 1 diabetes and its relationship to coronary artery calcification

OBJECTIVE: In 196 type 1 diabetic subjects and 195 nondiabetic subjects aged 30-55 years, we examined whether C-reactive protein (CRP) is elevated in diabetes and whether CRP is associated with coronary artery calcification (CAC). RESEARCH DESIGN AND METHODS: CRP was measured with a highly sensitive immunoassay. CAC was measured using electron beam computed tomography. RESULTS: CRP was elevated in diabetic women compared with nondiabetic women (median 1.62 vs. 0.85 mg/l, P < 0.001) independently of other factors, but was similar in diabetic and nondiabetic men (median 0.82 vs. 0.81 mg/l). Insulin dose per day was positively correlated with CRP in diabetic women (Spearman's rho = 0.36, P = 0.0003) but much less so in men (rho = 0.16, P = 0.09). Being in the top tertile for CRP was associated with CAC in diabetic and nondiabetic men even after adjustment for other risk factors (adjusted odds ratio [OR] = 4.6 and 4.3, respectively, P = 0.02 for both). In nondiabetic women, being in the top tertile for CRP was associated with CAC (OR 3.1, P = 0.04), but not independently of BMI (OR = 1 after adjustment). Among diabetic women the association was not significant even before adjustment for BMI (OR = 2.6, P = 0.07). CONCLUSIONS: Elevated CRP in diabetic women might reflect a particular sensitivity to insulin levels or might reflect insulin resistance. In general, CRP is an important marker of subclinical atherosclerosis, but the clinical significance of elevated CRP in diabetic women needs to be addressed in prospective studies, since CRP was not clearly associated with CAC in this group.