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Thyroid function and cognitive decline in the MRC Cognitive Function and Ageing Study
Hogervorst E, Huppert F, Matthews FE, Brayne C.. Psychoneuroendocrinology, 2008-07-21
Topic: Risk, prevention and care in population studies
Hypothyroidism and subclinical hyperthyroidism have both been associated with cognitive impairment and dementia. The association between thyroid stimulating hormone (TSH), free thyroid hormone or thyroxine (FT4) levels and cognition was investigated at baseline and after a 2 year follow-up in 1047 participants over 64 years of age, without physical frailty or severe cognitive impairment at baseline. Results indicated that high log transformed TSH levels were associated with lower MMSE performance (B=-0.24 (S.E.=0.09), 95% CI=-0.41 to -0.07) at baseline, independent of FT4, age, sex, education and mood, and, in separate analyses, cardiovascular (risk) factors.
Key findings
- The association between thyroid stimulating hormone (TSH), free thyroid hormone or thyroxine (FT4) levels and cognition was investigated at baseline and after a 2 year follow-up in 1047 participants over 64 years of age, without physical frailty or severe cognitive impairment at baseline.
- Results indicated that high log transformed TSH levels were associated with lower MMSE performance (B=-0.24 (S.E.=0.09), 95% CI=-0.41 to -0.07) at baseline, independent of FT4, age, sex, education and mood, and, in separate analyses, cardiovascular (risk) factors.
- Importantly, half of all hypothyroid cases were untreated and unaware of having this disorder.
- In analyses which excluded cases with thyroid disorders, stroke and those suspected of possible dementia/cognitive impairment (MMSE less than 25) or psychiatric mood disorders at baseline, high-normal FT4 levels were associated with worse MMSE performance and a greater risk for a drop of at least 4 points on the MMSE after 2 years (per pmol/l O.R.=1.13, 95% C.I.=1.03-1.22).
Why it matters
In 1047 participants over 64 without severe cognitive impairment at baseline, higher log-transformed TSH levels were associated with lower MMSE performance at baseline, independent of several other factors. This links thyroid function to cognitive test performance, but it does not show that treating thyroid problems prevents or cures dementia.
Study details
- Participants1,047
- Evidence strengthLow
How this study scored 50/100
Published in a peer-reviewed journal. Scored zero for study design, effect reported and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Psychoneuroendocrinology) |
| Journal's citation record | 3 / 4 | Psychoneuroendocrinology: journal h-index 254 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2008 — within 20 year(s) of the newest study here |
| Sample size | 3 / 4 | 1,047 participants |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| 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 | 5 / 7 | Cited 142 times (OpenAlex, 2026-10-10) |
| Citations per year | 2 / 5 | 7.1 citations a year over 20 year(s) since 2008 |
| Impact for its field and year | 3 / 6 | Cited 4.8× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 1 / 6 | Cited by 2 other studies in this library |
| Still being cited | 1 / 4 | Cited 11 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 4 / 4 | Last-listed author Carol Brayne: h-index 159 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | University of Cambridge: institution h-index 1,973 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | PubMed indexes it as a multicentre study |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 18640783) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 50 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
- DOI: 10.1016/j.psyneuen.2008.05.008
- PubMed: 18640783
- Original source →
- Free full text: Repository@Hull (Worktribe) (University of Hull) →
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
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Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
APA 7th
Hogervorst, E., Huppert, F., Matthews, F. E., & Brayne, C. (2008). Thyroid function and cognitive decline in the MRC Cognitive Function and Ageing Study. Psychoneuroendocrinology. https://doi.org/10.1016/j.psyneuen.2008.05.008
Vancouver
Hogervorst E, Huppert F, Matthews FE, Brayne C. Thyroid function and cognitive decline in the MRC Cognitive Function and Ageing Study. Psychoneuroendocrinology. 2008. doi:10.1016/j.psyneuen.2008.05.008. PMID: 18640783.
BibTeX
@article{hogervorst2008-18640783,
author = {Hogervorst, E. and Huppert, F. and Matthews, F. E. and Brayne, C.},
title = {{Thyroid function and cognitive decline in the MRC Cognitive Function and Ageing Study}},
journal = {Psychoneuroendocrinology},
year = {2008},
doi = {10.1016/j.psyneuen.2008.05.008},
pmid = {18640783},
url = {https://doi.org/10.1016/j.psyneuen.2008.05.008}
}
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