Smoking as an independent risk factor for myocardial infarction or stroke in type 2 diabetes: a report from the Swedish National Diabetes Register.
BACKGROUND
Few earlier studies have analysed smoking as a risk factor for myocardial infarction (MI) or stroke in type 2 diabetic patients.


METHODS
A longitudinal study involved 13 087 female and male patients with type 2 diabetes from the Swedish National Diabetes Register with no previous MI or stroke at baseline, aged 30-74 years, and with data available for all analysed variables, followed up for mean 5.7 years.


RESULTS
Adjusted hazard ratios (HRs) for smoking and first-incident fatal/nonfatal MI, stroke and total mortality were 1.7 [95% confidence interval (CI): 1.4-2.0; P<0.001], 1.3 (95% CI: 1.1-1.6; P = 0.006) and 1.8 (95% CI: 1.5-2.2; P<0.001), respectively, by Cox regression analysis, adjusted for age, sex, diabetes duration, hypoglycaemic treatment, haemoglobin A1c, blood pressure, body mass index, microalbuminuria, antihypertensive and lipid-lowering drugs. Adjusted HR was higher for fatal MI, 2.1 (95% CI: 1.7-2.7; P<0.001), than for nonfatal MI, 1.4 (95% CI: 1.2-1.7; P<0.001). The highest HRs were observed in more frequently smoking (22%), middle-aged patients (age <60 years) for fatal/nonfatal MI, 2.3 (95% CI: 1.8-3.1; P<0.001) and for total mortality, 2.5 (95% CI: 1.6-3.8, P<0.001), whereas lower HRs were observed in older and less smoking patients. With predicted cessation of smoking in patients aged below 60 years, 24% (95% CI: 15-33%) of cases of fatal/nonfatal MI and 24% (11-37%) of cases of total mortality may have been prevented.


CONCLUSIONS
The risk for MI and total mortality associated with smoking is high in type 2 diabetes, especially in more frequently smoking, middle-aged patients, and was higher for MI than for stroke, and also higher for fatal than for nonfatal events. Smoking cessation would strongly affect risk reduction.
Nilsson
Peter M
PM
Department of Clinical Sciences, Lund University, University Hospital, Malmö, Sweden. Peter.Nilsson@med.lu.se
Cederholm
Jan
J
Eeg-Olofsson
Katarina
K
Eliasson
Björn
B
Zethelius
Björn
B
Fagard
Robert
R
Gudbjörnsdóttir
Soffia
S
D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality / Q000503:physiopathology*; D016016:Proportional Hazards Models; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology / Q000503:physiopathology*; D020521:Stroke / Q000453:epidemiology / Q000503:physiopathology*; D013548:Sweden / Q000453:epidemiology