Randomised controlled trialcited by the Tayebat archiveabstract only checked A-SUP-15 standard review
Selenium and diabetes
Effects of long-term selenium supplementation on the incidence of type 2 diabetes: a randomized trial.
Overview
Stranges S et al.. Ann Intern Med 2007 · PMID 17620655 · DOI 10.7326/0003-4819-147-4-200708210-00175
Selenium pills were linked to more new diabetes (HR 1.55).
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Diabetes with selenium.
- How was the study done?
RCT secondary analysis.
- How many people, animals or samples were studied?
1,202.
- What was actually found?
More diabetes.
- How large was the observed effect?
HR 1.55.
- What do the results mean in everyday life?
Avoid selenium pills.
- What are the study's limitations?
Secondary outcome.
- What does it say about Elawady's specific claim?
Partly supports.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Firm harm.
Scientific in-depth review
1. Full reference
- Authors
- Stranges S, Marshall JR, Natarajan R, Donahue RP, Trevisan M, Combs GF, Cappuccio FP, Ceriello A, Reid ME
- Journal
- Ann Intern Med
- Year
- 2007
- Identifier
- PMID 17620655 DOI 10.7326/0003-4819-147-4-200708210-00175
- Verification
- verified – PubMed E-utilities efetch, 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract
2. Research question
Effect of selenium on incidence of type 2 diabetes
3. Study design and population
- Study design
- Randomised controlled trial – Secondary analysis of a randomised double-blind placebo-controlled trial (NPC)
- Population
Dermatology clinic patients without T2D, low-selenium areas
- Country
USA
- Period
mean 7.7 years
- Sample size
1,202
- Inclusion and exclusion criteria
see abstract
4. Methods and endpoints
- Exposure / intervention
Selenium 200 µg/d
- Comparator
Placebo
- Endpoints
Incident T2D (self-report, mostly validated)
- Statistical methods
Cox
5. Actual results
- Results
T2D 58 vs 39 cases; 12.6 vs 8.4 per 1,000 person-years; HR 1.55 (1.03–2.33); highest baseline selenium tertile HR 2.70.
- Absolute risks
12.6 vs 8.4 cases per 1,000 person-years
- Authors' conclusion
Selenium does not seem to prevent T2D and may increase risk.
6. Strengths
- Randomised
7. Weaknesses
- Secondary outcome
- Self-reported diagnosis
- Small
8. Risk of bias
- Orienting tool
- RoB 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Secondary outcome of an RCT.
9. Assessment of the statistical interpretation
See results.
10. Relevance to the specific claim
11. Independent contrary findings
12. Transferability to Germany and Europe
High: biology and trial populations comparable to European adults.
13. Overall methodological judgement
Signal of harm from secondary analysis.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | essentially correct but incomplete |
14. Open questions
15. Linked fact checks
Use by the Tayebat archive
Note: according to the archive, the studies were compiled by the archive operators. Whether Dr. Elawady himself cited this study is not established.
- What the archive says about the study
Listed in the archive bibliography of the oral-supplements rule without its own interpretation; used implicitly to support the rule summary that supplements 'failed or caused harm' in large trials.
- A. What was actually studied?
Effect of selenium on incidence of type 2 diabetes
- B. What did the authors find?
T2D 58 vs 39 cases; 12.6 vs 8.4 per 1,000 person-years; HR 1.55 (1.03–2.33); highest baseline selenium tertile HR 2.70.
- C. What conclusions do the authors themselves draw?
Selenium does not seem to prevent T2D and may increase risk.
- D. What does the archive derive from it?
Supports selenium harm.
- E. Is this derivation scientifically justified?
Partly (secondary outcome).
- Adequacy of the interpretation (by the archive)
- essentially correct but incomplete