Creatine kinase is associated with glycated haemoglobin in a nondiabetic population. The Tromsø study

BACKGROUND: Creatine kinase (CK) has been associated with insulin resistance and identified as a risk marker of cardiovascular disease largely by its relationship with hypertension and increased body mass index. This study determined whether CK is a predictor of glycated haemoglobin (HbA(1C)) in a nondiabetic general population. METHODS: Associations between CK and the outcome variable HbA(1C) (%) were performed by variance and multivariate analyses in 11662 nondiabetic subjects defined as HbA(1C) (%) <6.5 who participated in the population based Tromsø study (Tromsø 6) in Norway. RESULTS: Abnormal elevated CK was detected in 543/11662 participants (4.66%). Mean HbA(1C) (%) in the “high CK” group was 5.62 (SD = 0.33) compared to 5.52 (SD = 0.36) in the “normal CK” group, P <0.001. CK increased significantly and linearly with higher levels of HbA(1C) (%) quartiles in women (P <0.001) and non-linearly in men (P <0.001). In a multivariate analysis, CK was independently associated with HbA(1C) (%) after adjusting for age, sex, body mass index, blood pressure, glucose, lipids, C-reactive protein, creatinine, alanine transaminase and aspartate aminotransferase. A 1-unit increase in log CK was associated with a 0.17-unit increase in HbA(1C) (%). CONCLUSION: These data demonstrate a positive and independent association between CK and glycated haemoglobin in a nondiabetic general population.