Elevated serum creatine kinase predicts first-ever myocardial infarction: a 12-year population-based cohort study in Japan, the Suita study.
BACKGROUND
In myocardial infarction (MI), it is well known that serum creatine kinase (s-CK) increases after onset, but it is unclear whether s-CK elevates before MI onset. The present analysis examined whether elevated s-CK levels predicted first-ever MI or stroke.


METHODS
This study was a population-based cohort study in a Japanese urban area. Study subjects were comprised of 5026 initially healthy Japanese (2370 men and 2656 women, mean age: 54.5 years) without a history of MI or stroke. They were followed-up for 11.8 years on average, and 103 MIs (definite: 45; probable: 58) and 168 strokes (definite: 126; probable: 42) were observed. There was no subject who developed MI just at baseline (the follow-up period among those with definite MI was, at earliest, 0.20 years).


RESULTS
The adjusted hazard ratio for definite MI was 4.18 (95% confidence interval 1.66-10.53) with s-CK levels of >or=200 IU/l, compared with the reference category (s-CK levels of <or=99 IU/l), whereas no relationship was observed between s-CK levels and the risk for stroke. With regard to definite MI, an interaction between s-CK levels and dyslipidaemia was observed. Among subjects with hypercholesterolaemia, the hazard ratio linearly elevated with increased s-CK levels. On the other hand, no linear elevation was observed among subjects without hypercholesterolaemia (P for interaction = 0.011).


CONCLUSIONS
The present study suggested that screening for elevated s-CK levels in initially healthy Japanese subjects was useful to predict first-ever MI in the future, especially in subjects with dyslipidaemia.
Watanabe
Makoto
M
Department of Preventive Cardiology, National Cardiovascular Center, Osaka, Japan. makotow@hsp.ncvc.go.jp
Okamura
Tomonori
T
Kokubo
Yoshihiro
Y
Higashiyama
Aya
A
Okayama
Akira
A
D000328:Adult; D000368:Aged; D044466:Asian People; D015415:Biomarkers / Q000097:blood; D003402:Creatine Kinase / Q000097:blood* / Q000378:metabolism; D050171:Dyslipidemias / Q000097:blood / Q000150:complications; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000201:enzymology* / Q000453:epidemiology / Q000209:etiology; D016017:Odds Ratio; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000097:blood / Q000453:epidemiology / Q000209:etiology; D014505:Urban Population
D015415:Biomarkers; D003402:Creatine Kinase