Effects of long-term selenium supplementation on the incidence of type 2 diabetes: a randomized trial.
BACKGROUND
Findings from animal models suggest that selenium supplementation improves glucose metabolism.


OBJECTIVE
To examine the effect of long-term selenium supplementation on the incidence of type 2 diabetes.


METHODS
Secondary analysis of a randomized, double-blind, placebo-controlled trial.


METHODS
Areas of low selenium consumption of the eastern United States.


METHODS
1202 persons seen in dermatology clinics who did not have type 2 diabetes at baseline.


METHODS
Oral administration of selenium, 200 microg/d, or placebo.


METHODS
Incidence of type 2 diabetes.


RESULTS
During an average follow-up of 7.7 years (SD, 2.7), type 2 diabetes developed in 58 selenium recipients and 39 placebo recipients (incidence, 12.6 cases per 1000 person-years vs. 8.4 cases per 1000 person-years, respectively; hazard ratio, 1.55 [95% CI, 1.03 to 2.33]). The lack of benefit of selenium supplementation on the incidence of type 2 diabetes persisted in analyses stratified by age, sex, body mass index, and smoking status. An exposure-response gradient was found across tertiles of baseline plasma selenium level, with a statistically significantly increased risk for type 2 diabetes in the highest tertile of baseline plasma selenium level (hazard ratio, 2.70 [CI, 1.30 to 5.61]).


CONCLUSIONS
Diabetes was a secondary outcome in the parent trial. Diagnoses of diabetes were self-reported but were validated in most participants. The sample was mostly older and white.


CONCLUSIONS
Selenium supplementation does not seem to prevent type 2 diabetes, and it may increase risk for the disease. Click here for related information on selenium.
Stranges
Saverio
S
State University of New York at Buffalo and Cancer Prevention and Population Sciences, Roswell Park Cancer Institute, Buffalo, New York, USA. s.stranges@warwick.ac.uk
Marshall
James R
JR
Natarajan
Raj
R
Donahue
Richard P
RP
Trevisan
Maurizio
M
Combs
Gerald F
GF
Cappuccio
Francesco P
FP
Ceriello
Antonio
A
Reid
Mary E
ME
D000368:Aged; D000975:Antioxidants / Q000008:administration & dosage* / Q000009:adverse effects / Q000378:metabolism; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control*; D019587:Dietary Supplements / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012643:Selenium / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood; D013997:Time Factors; D014481:United States
D000975:Antioxidants; D001786:Blood Glucose; D012643:Selenium