The association of smoking and subclinical atherosclerosis in Type 2 diabetes: modification by duration of diabetes.
BACKGROUND
Diabetes is a relatively common disease in the United States, and cardiovascular disease is the major cause of morbidity and mortality among persons with diabetes. While smoking is one of the most well-established risk factors for heart disease and atherosclerosis, the effect of smoking on atherosclerosis among diabetic patients has not been thoroughly investigated. The primary objective of this paper was to evaluate the impact of smoking on atherosclerosis among Type 2 diabetic patients and to evaluate whether smoking associations with atherosclerosis are modified by diabetes-related variables.


METHODS
We used cross-sectional baseline data from a randomized controlled trial to evaluate the associations between smoking and common carotid artery intima-media thickness (IMT) in 299 subjects with Type 2 diabetes. There were 34 (11%) current cigarette smokers, 73 (24%) former cigarette smokers, and 192 (64%) subjects who had never smoked regularly.


RESULTS
There was an increasing trend in mean carotid IMT with both longer duration and increased frequency of smoking (adjusted P for trend 0.04 and 0.02, respectively). The mean +/- SE carotid IMT was non-significantly thicker (0.872 +/- 0.01 mm) in diabetic patients who had ever smoked than never smokers (0.842 +/- 0.01 mm) after controlling for age, gender and other potential confounders (P = 0.08). The negative effects of ever smoking (P = 0.01 for interaction), number of cigarettes smoked daily (P = 0.003 for interaction) and duration of smoking (P = 0.03 for interaction) on carotid IMT were accentuated with longer duration of diabetes.


CONCLUSIONS
Smoking is associated with subclinical atherosclerosis in diabetic persons and interacts with duration of diabetes to accentuate atherosclerosis. The association between carotid IMT and duration of diabetes increases with both the frequency and duration of smoking.
Karim
R
R
Department of Preventive Medicine, Keck School of Medicine, University of South Carlifornia, Los Angeles, CA, USA. rkarim@usc.edu
Buchanan
T A
TA
Hodis
H N
HN
Li
Y
Y
Mack
W J
WJ
D000328:Adult; D000368:Aged; D001161:Arteriosclerosis / Q000209:etiology* / Q000473:pathology; D002340:Carotid Artery Diseases / Q000209:etiology* / Q000473:pathology; D003924:Diabetes Mellitus, Type 2; D003925:Diabetic Angiopathies / Q000209:etiology* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D017540:Tunica Media / Q000473:pathology*