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Is dementia incidence declining? Trends in dementia incidence since 1990 in the Rotterdam Study
Schrijvers EMC, Verhaaren BFJ, Koudstaal PJ, Hofman A, Ikram MA, Breteler MMB. Neurology, 2012-05-08
Topic: Risk, prevention and care in population studies
This Dutch cohort study compared dementia rates in two groups of older adults enrolled ten years apart. Dementia incidence was about 25% lower in the more recent group, alongside larger brain volumes and less small-vessel brain damage on MRI, though the reduction fell just short of standard statistical significance. Mortality was clearly lower in the more recent group, which is consistent with, but does not prove, healthier brain aging.
Key findings
- Incidence rate ratio for dementia was 0.75 (95% CI 0.56-1.02) comparing the 2000 vs 1990 subcohort
- Mortality rate ratio was 0.63 (95% CI 0.52-0.77), showing lower mortality in the more recent cohort
- Brain MRI in the more recent cohort showed larger total brain volumes (p<0.001) and less cerebral small vessel disease
- One of the earliest cohort studies to suggest a possible decline in dementia incidence over time
Why it matters
Comparing two periods, dementia incidence was lower in the later group but the difference was not statistically significant. The study does not show that dementia incidence is declining or provide a treatment or prevention.
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Study details
- Study designcohort
- Participants7,496
- Effect sizeIncidence rate ratio 0.75 (95% CI 0.56-1.02) for the 2000 subcohort vs the 1990 subcohort; mortality rate ratio 0.63 (95% CI 0.52-0.77)
- Evidence strengthPreliminary
Limitations
The headline incidence-rate-ratio finding (0.75, 95% CI 0.56-1.02) did not reach conventional statistical significance, and the more recent (2000) subcohort was substantially smaller than the 1990 subcohort, limiting statistical power.
How this study scored 61/100
Published in a leading specialty journal, and it is a cohort study following people over time. Scored zero for randomised / blinded and indexed in PubMed because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, still being cited, senior author's track record, institution's track record, multi-centre collaboration and free to read, so those were left out: it earned 38 of the 62 points we could judge it on, which is 61 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Neurology) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 7 / 12 | A cohort study following people over time |
| Strength of evidence | 2 / 5 | Rated “preliminary” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2012 — within 20 year(s) of the newest study here |
| Sample size | 3 / 4 | 7,496 participants |
| Effect reported | 3 / 3 | Effect reported with a statistic (interval, p-value, ratio or similar) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 0 / 2 | No PubMed ID and no DOI — scores zero (not stated in the record — scored 0) |
| Free to read | — / 2 | Access not recorded — left out of this score |
| Points | 38 / 62 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 38 of the 62 points we could judge it on is 61 out of 100. |
| Total | 61 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
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Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. This record has no DOI, so the citation leaves it out. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
APA 7th
Schrijvers, E. M. C., Verhaaren, B. F. J., Koudstaal, P. J., Hofman, A., Ikram, M. A., & Breteler, M. M. B. (2012). Is dementia incidence declining? Trends in dementia incidence since 1990 in the Rotterdam Study. Neurology.
Vancouver
Schrijvers EMC, Verhaaren BFJ, Koudstaal PJ, Hofman A, Ikram MA, Breteler MMB. Is dementia incidence declining? Trends in dementia incidence since 1990 in the Rotterdam Study. Neurology. 2012.
BibTeX
@article{schrijvers2012-8a41b10b,
author = {Schrijvers, E. M. C. and Verhaaren, B. F. J. and Koudstaal, P. J. and Hofman, A. and Ikram, M. A. and Breteler, M. M. B.},
title = {{Is dementia incidence declining? Trends in dementia incidence since 1990 in the Rotterdam Study}},
journal = {Neurology},
year = {2012}
}
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