Saverio Stranges, MD, PhD; James R. Marshall, PhD; Raj Natarajan, MS; Richard P. Donahue, PhD; Maurizio Trevisan, MD; Gerald F. Combs, PhD; Francesco P. Cappuccio, MD; Antonio Ceriello, MD; Mary E. Reid, PhD
Potential Financial Conflicts of Interest: None disclosed.
Requests for Single Reprints: Saverio Stranges, MD, PhD, Clinical Sciences Research Institute, Warwick Medical School, University Hospital Coventry and Warwickshire, Clifford Bridge Road, Coventry CV2 2DX, United Kingdom; e-mail, email@example.com.
Current Author Addresses: Drs. Stranges, Cappuccio, and Ceriello: Clinical Sciences Research Institute, Warwick Medical School, University Hospital Coventry and Warwickshire, Clifford Bridge Road, Coventry CV2 2DX, United Kingdom.
Drs. Marshall and Reid and Mr. Natarajan: Roswell Park Cancer Institute, Carlton House Building, Elm and Carlton Streets, Buffalo, NY 14263.
Drs. Donahue and Trevisan: Department of Social and Preventive Medicine, State University of New York at Buffalo, South Campus, 3435 Main Street, Farber Hall, Buffalo, NY 14214.
Dr. Combs: Human Nutrition Research Center, U.S. Department of Agriculture, 2420 Second Avenue North, Stop 9034, Grand Forks, ND 58202.
Author Contributions: Analysis and interpretation of the data: S. Stranges, R. Natarajan, R.P. Donahue, M. Trevisan, G.F. Combs, F.P. Cappuccio.
Drafting of the article: S. Stranges, R.P. Donahue, M. Trevisan.
Critical revision of the article for important intellectual content: S. Stranges, R.P. Donahue, M. Trevisan, G.F. Combs, F.P. Cappuccio.
Final approval of the article: S. Stranges, M. Trevisan, F.P. Cappuccio.
Statistical expertise: R. Natarajan, M. Trevisan.
Administrative, technical, or logistic support: G.F. Combs, F.P. Cappuccio.
Collection and assembly of data: G.F. Combs.
Findings from animal models suggest that selenium supplementation improves glucose metabolism.
To examine the effect of long-term selenium supplementation on the incidence of type 2 diabetes.
Secondary analysis of a randomized, double-blind, placebo-controlled trial.
Areas of low selenium consumption of the eastern United States.
1202 persons seen in dermatology clinics who did not have type 2 diabetes at baseline.
Oral administration of selenium, 200 μg/d, or placebo.
Incidence of type 2 diabetes.
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]).
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.
Selenium supplementation does not seem to prevent type 2 diabetes, and it may increase risk for the disease.
Research suggests that selenium supplements may improve glucose metabolism.
The investigators examined the incidence of type 2 diabetes among participants in a clinical trial designed to assess the effects of selenium supplementation on skin cancer. Participants randomly assigned to receive selenium were more likely to develop type 2 diabetes than were those assigned to placebo.
Diabetes was a secondary outcome of the original trial. The diagnosis was self-reported, and most participants were older and white.
Long-term selenium supplementation appears to increase the risk for type 2 diabetes.
Mean plasma selenium levels.
Flow diagram of the Nutritional Prevention of Cancer Trial, 1983–1996.
Table 1. Baseline Characteristics
Cumulative incidence of type 2 diabetes.P
Table 2. Incidence of Type 2 Diabetes
Table 3. Incidence of Type 2 Diabetes, by Baseline Plasma Selenium Level
A study found that selenium supplements are not effective in reducing the risk of type 2 diabetes, and in fact increase the risk of developing the disease.
Stranges S, Marshall JR, Natarajan R, et al. Effects of Long-Term Selenium Supplementation on the Incidence of Type 2 Diabetes: A Randomized Trial. Ann Intern Med. 2007;147:217–223. doi: https://doi.org/10.7326/0003-4819-147-4-200708210-00175
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Published: Ann Intern Med. 2007;147(4):217-223.
Cardiology, Coronary Risk Factors, Diabetes, Endocrine and Metabolism.
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