Intake of antioxidants and risk of type 2 diabetes in a cohort of male smokers.
OBJECTIVE
Oxidative stress may induce insulin resistance in peripheral tissues and impair insulin secretion from pancreatic β-cells. Antioxidants are suggested to decrease the risk of diabetes through reduction of oxidative stress. However, only a few studies exist on dietary antioxidants and the risk of type 2 diabetes. We investigated the association of dietary antioxidants with incident type 2 diabetes in the α-Tocopherol, β-Carotene Cancer Prevention Study cohort.


METHODS
The study cohort included 29,133 male smokers aged 50-69 years. During a median follow-up of 10.2 years 660 incident cases of diabetes were observed among the 25,505 men with a completed baseline food frequency questionnaire.


RESULTS
Dietary α-tocopherol, β-tocopherol and β-tocotrienol were positively associated with the risk of diabetes when adjusted for age and supplementation (relative risk (RR) 1.17 (95% confidence interval (CI) 0.91-1.51) P for trend 0.02; RR 1.31 (95% CI 1.02-1.68) P for trend 0.01; RR 1.28 (95% CI 1.00-1.63) P for trend 0.01, respectively), but the association disappeared after multivariate adjustment (RR 0.92 (95% CI 0.71-1.19) P for trend 0.97; RR 1.06 (95% CI 0.82-1.36) P for trend 0.48; RR 1.04 (95% CI 0.80-1.35) P for trend 0.46, respectively). Other tocopherols and tocotrienols as well as vitamin C, carotenoids, flavonols and flavones had no association with risk of diabetes.


CONCLUSIONS
Dietary antioxidants were not associated with a decreased risk of incident diabetes in middle-aged male smokers.
Chronic Disease Epidemiology and Prevention Unit, National Institute for Health and Welfare, Helsinki, Finland. merja.kataja-tuomola@thl.fi
M K
MK
Kataja-Tuomola
J P
JP
Kontto
S
S
Männistö
D
D
Albanes
J
J
Virtamo
D000368:Aged; D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage; D002338:Carotenoids / Q000008:administration & dosage; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000517:prevention & control; D004032:Diet; D019587:Dietary Supplements; D004311:Double-Blind Method; D005419:Flavonoids / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D010919:Placebos; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D011795:Surveys and Questionnaires; D024505:Tocopherols / Q000008:administration & dosage; D024508:Tocotrienols / Q000008:administration & dosage
D000975:Antioxidants; D005419:Flavonoids; D010919:Placebos; D024508:Tocotrienols; D002338:Carotenoids; D001205:Ascorbic Acid; D024505:Tocopherols