Cited by 178Lipoproteins and Cardiovascular HealthDementia and Cognitive Impairment ResearchGenetic Associations and Epidemiology

Low LDL cholesterol,PCSK9 and HMGCR genetic variation, and risk of Alzheimer’s disease and Parkinson’s disease: Mendelian randomisation study

Open access
Benn, Marianne, Nordestgaard, Børge G, Frikke-Schmidt, Ruth, Tybjærg-Hansen, Anne·2017·BMJ

Abstract

Objective To test the hypothesis that low density lipoprotein (LDL) cholesterol due to genetic variation in the genes responsible for LDL cholesterol metabolism and biosynthesis(PCSK9 and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), respectively) is associated with a high risk of Alzheimer’s disease, vascular dementia, any dementia, and Parkinson’s disease in the general population. Design Mendelian randomisation study. Setting Copenhagen General Population Study and Copenhagen City Heart Study. Participants 111 194 individuals from the Danish general population. Main outcome measures Risk of Alzheimer’s disease, vascular dementia, all dementia, and Parkinson’s disease. Results In observational analyses, the multifactorially adjusted hazard ratio for Parkinson’s disease in participants with an LDL cholesterol level <1.8 mmol/L versus ≥4.0 mmol/L was 1.70 (95% confidence interval 1.03 to 2.79), whereas the corresponding hazard ratios for Alzheimer’s disease, vascular dementia, or any dementia did not differ from 1.0. PCSK9 and HMGCR variants combined were associated with a 9.3% lower LDL cholesterol level. In genetic, causal analyses adjusted for age, sex, and year of birth, the risk ratios for a lifelong 1 mmol/L lower LDL cholesterol level were 0.57 (0.27 to 1.17) for Alzheimer’s disease, 0.81 (0.34 to 1.89) for vascular dementia, 0.66 (0.34 to 1.26) for any dementia, and 1.02 (0.26 to 4.00) for Parkinson’s disease. Summary level data from the International Genomics of Alzheimer’s Project using Egger Mendelian randomisation analysis gave a risk ratio for Alzheimer’s disease of 0.24 (0.02 to 2.79) for 26 PCSK9 and HMGCR variants, and of 0.64 (0.52 to 0.79) for 380 variants of LDL cholesterol level lowering. Conclusion Low LDL cholesterol levels due to PCSK9 and HMGCR variants had no causal effect on high risk of Alzheimer’s disease, vascular dementia, any dementia, or Parkinson’s disease; however, low LDL cholesterol levels may have a causal effect in reducing the risk of Alzheimer’s disease.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1136/bmj.j1648

Cites

49 of 49 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • PCSK9 loss-of-function mutation carriers are at neutral risk of developing Alzheimer's disease.

    “PCSK9 loss of function mutations carriers are at neutral risk of developing AD (86, 100, 101)”

    From PCSK9 and the nervous system: a no-brainer? (2023) · cites this paper as [100]

    The Results (Genotypes and risk of disease; page unavailable) report no statistically significant difference in Alzheimer’s disease risk for participants with higher scores of PCSK9 LDL-lowering alleles. The Methods (Genotyping; page unavailable) describe an allele-score analysis, not a finding for all PCSK9 loss-of-function mutation carriers. Calling their risk definitively neutral also goes beyond a nonsignificant result. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • There is no consensus for an association between PCSK9 genetic variants and Alzheimer's disease.

    “there is no consensus for an association between PCSK9 genetic variants and AD”

    From PCSK9 and the nervous system: a no-brainer? (2023) · cites this paper as [100]

    The Results (‘Genotypes and risk of disease: genetic estimates’; page not provided) found no statistically significant difference in Alzheimer’s disease risk across PCSK9 allele scores. The Discussion (‘Strengths and weaknesses of this study’; page not provided) says power to exclude a genetic association was limited for some endpoints. These findings support uncertainty about an association, but the paper does not establish whether there is a broader scientific consensus. (LLM, conf=0.82)

    Experimental — accuracy not yet measured
  • Some genetic studies suggest that PCSK9 loss-of-function variants confer protection against Alzheimer's disease, whereas others show no association.

    “Some genetic studies suggest that PCSK9 loss-of-function variants confer protection against AD, whereas others show no association.”

    From The Roles of PCSK9 in Alzheimer’s Disease: A Systematic Review of Clinical, Genetic, and Preclinical Evidence (2025) · cites this paper as [23]

    The Results section ("Genotypes and risk of disease: genetic estimates"; page unavailable) reports no statistically significant association between PCSK9 LDL-lowering alleles and Alzheimer’s disease, supporting the no-association part. The Discussion reports a suggested reduction in Alzheimer’s risk for a broader set of 380 LDL-lowering variants, not specifically PCSK9 loss-of-function variants, so it does not support the claimed PCSK9-specific protection. (LLM, conf=0.85)

    Experimental — accuracy not yet measured
  • Mendelian randomization studies have generally suggested that PCSK9 is unlikely to be a causal determinant of Alzheimer's disease.

    “Similarly, Mendelian randomization studies—which test whether genetically determined changes in PCSK9 influence disease susceptibility—have generally suggested that PCSK9 is unlikely to be a causal determinant of AD [23].”

    From The Roles of PCSK9 in Alzheimer’s Disease: A Systematic Review of Clinical, Genetic, and Preclinical Evidence (2025) · cites this paper as [23]

    The Results (Genotypes and risk of disease; page unavailable) found no statistically significant difference in Alzheimer’s disease risk by PCSK9 LDL-lowering allele score. But the Discussion (Conclusion and future research; page unavailable) limits the finding to no observed increase in risk, notes a possible protective effect of low LDL cholesterol, and calls for more powerful studies. It does not establish that PCSK9 is unlikely to have any causal role in Alzheimer’s disease. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • Mendelian randomization in the Danish population found no causal effects of PCSK9 genetic variants on the risk of AD, other dementias, and Parkinson's disease.

    “an analysis based on the Mendelian randomization approach in the Danish population enrolled in two different prospective studies evidenced no causal effects of PCSK9 genetic variants on the risk of AD and also of other forms of dementia and Parkinson’s disease [123].”

    From The Emerging Role of PCSK9 in the Pathogenesis of Alzheimer’s Disease: A Possible Target for the Disease Treatment (2024) · cites this paper as [123]

    The Results (page not provided) found no statistically significant differences in Alzheimer’s disease, vascular dementia, any dementia, or Parkinson’s disease risk by PCSK9 allele score in the two Danish cohorts. But the claim’s categorical 'no causal effects' goes beyond the paper’s conclusion of no evidence for increased risk; the Discussion notes a possible causal reduction in Alzheimer’s disease risk from genetically lower LDL cholesterol. (LLM, conf=0.87)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

Research works printed but not linked: 2

  1. [26]Nordestgaard BG, Palmer TM, Benn M, et al. The effect of elevated body mass index on ischemic heart disease risk: causal estimates from a Mendelian randomisation approach. PLoS Med 2012; 9: e1001212 10.1371/journal.pmed.1001212 pmid:22563304. 22563304 PMC3341326 · DOI
  2. [35]Instrumental variables and GMM: estimation and testing. Stata J 2003; 3: 1- 33.

Cited by

Sorted by citations

Authors
Benn, M., Nordestgaard, B. G., Frikke-Schmidt, R., & Tybjærg-Hansen, A.
Affiliations
University of Copenhagen (DK)
Corresponding author
Benn, Marianne
Venue
BMJ
Publisher
BMJ
Published
2017-04-24
Volume
357
Pages
j1648
ISSN
  • 1756-1833 (ISSN-L)
  • 0959-8138
OpenAlex
W2607529696
Cited by
178
References
49
Citations by year
2026: 11 · 2025: 14 · 2024: 22 · 2023: 14 · 2022: 21 · 2021: 23 · 2020: 22 · 2019: 18 · 2018: 22 · 2017: 10
FWCI
20.18
Type
journal article
Language
en
Open access
Locations
  • BMJ (publishedVersion, cc-by-nc)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by-nc)
  • PubMed Central (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
  • Research at the University of Copenhagen (University of Copenhagen) (publishedVersion, cc-by-nc)
  • HighWire Press Open Archive (submittedVersion)
Funders
  • Sundhed og Sygdom, Det Frie Forskningsråd
  • Gentofte Hospital
  • Herlev Hospital
  • Lundbeckfonden (R126-2012-12556, R211-2015-3977)
  • Danmarks Frie Forskningsfond
Topics
  • Health Sciences › Medicine › Surgery › Lipoproteins and Cardiovascular Health
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Genetic Associations and Epidemiology
Keywords
low LDL cholesterol, PCSK9, HMGCR, Alzheimer's disease, Parkinson's disease, vascular dementia, dementia, LDL cholesterol metabolism, genetic variants
MeSH terms
Proprotein Convertase 9, Adult, Aged, Alzheimer Disease, Denmark, Female, Follow-Up Studies, Genotype, Humans, Hydroxymethylglutaryl CoA Reductases, Cholesterol, LDL, Male, Middle Aged, Parkinson Disease, Prospective Studies, Genetic Variation, Biomarkers, Proportional Hazards Models, Genetic Predisposition to Disease, Mendelian Randomization Analysis

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review