Cohort studyindependent cross-checkabstract checked I-ORG-140 standard review
Ovary removal and dementia in Danish nurses
Oophorectomy and rate of dementia: a prospective cohort study.
Overview
Uldbjerg CS et al.. Menopause 2022 · PMID 35102101 · DOI 10.1097/GME.0000000000001943
Nurses who had both ovaries removed had a slightly higher dementia rate, but the result could be due to chance.
Does the study support the specific claim? Unclear · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Test oophorectomy and dementia
- How was the study done?
Prospective cohort
- How many people, animals or samples were studied?
24,851 nurses
- What was actually found?
aRR 1.18, not significant
- How large was the observed effect?
aRR 1.18 (0.89-1.56)
- What do the results mean in everyday life?
Possible small risk, not proven
- What are the study's limitations?
Limited power
- What does it say about Elawady's specific claim?
Inconclusive for the claim
- Do the results apply to Germany and Europe?
Applicable
- What can explicitly not be concluded from this study?
Cannot confirm or exclude an effect
Scientific in-depth review
1. Full reference
- Authors
- Uldbjerg CS et al.
- Journal
- Menopause
- Year
- 2022
- Identifier
- PMID 35102101 DOI 10.1097/GME.0000000000001943
- Verification
- verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Non-commercial support (PubMed).
2. Research question
Is oophorectomy associated with dementia, and does this depend on age, hysterectomy or HT?
3. Study design and population
- Study design
- Cohort study – Prospective cohort (Danish Nurse Cohort)
- Population
24,851 female nurses followed from age 60
- Country
Denmark
- Period
Follow-up to 2018
- Sample size
24,851; 1238 dementia cases
- Inclusion and exclusion criteria
Danish Nurse Cohort
4. Methods and endpoints
- Exposure / intervention
Bilateral / unilateral oophorectomy
- Comparator
Ovaries retained
- Endpoints
Incident dementia
- Statistical methods
Poisson regression (aRR)
5. Actual results
- Results
Bilateral oophorectomy aRR 1.18 (0.89-1.56); unilateral aRR 0.87 (0.59-1.23); similar after stratification by age at oophorectomy; no modification by hysterectomy or HT.
- Absolute risks
Dementia in 5.0% overall.
- Authors' conclusion
Bilateral oophorectomy was associated with an increased rate of dementia but limited power hampers precision.
6. Strengths
- Prospective
- Registry outcomes
7. Weaknesses
- CI includes 1
- Limited power
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Observational; imprecise.
9. Assessment of the statistical interpretation
aRR CI includes 1, so the authors' wording 'associated' overstates the statistical evidence.
10. Relevance to the specific claim
Independent cohort testing the claim.
11. Independent contrary findings
n/a
12. Transferability to Germany and Europe
Danish.
13. Overall methodological judgement
Compatible with a modest increase but statistically inconclusive.
| 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) | not applicable |
14. Open questions
n/a
15. Linked fact checks
- Oophorectomy before menopause raises the risk of cognitive impairment or dementia (HR 1.46), more so the younger the age at surgery (Rocca 2007). – Studies with mixed or unclear results