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Jeong S, Lin L, Leone AP, Hsu YH. Type 2 diabetes and late-onset Alzheimer's disease and related dementia: A longitudinal cohort study integrating polygenic risk score. J Alzheimers Dis 2025; 105:107-119. [PMID: 40129417 DOI: 10.1177/13872877251326107] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2025]
Abstract
BackgroundThe inherent genetic effects were not established between type 2 diabetes (T2DM) and Alzheimer's disease and related dementia (ADRD).ObjectiveWe aimed to investigate the association between T2DM and ADRD by integrating T2DM polygenic risk score (PRS) and applying matching in every subgroup.MethodsWe utilized UK Biobank First-occurrences datasets. T2DM were 1:1 matched to non-T2DM using propensity scores generated by 8 covariates; age at diagnosis, sex, cerebrovascular disease, ischemic heart disease, hypertensive disorders, lipid disorders, obesity, and mood disorders. T2DM PRS was additionally matched in T2DM PRS matched analysis. Subgroup analyses by age at diagnosis, sex, and APOE4 genotype were performed with the same matching criteria within each subgroup. Cox proportional hazard and Fine & Gray competing risk model were utilized.ResultsIn T2DM PRS unmatched cohort, 24,583 T2DM were 1:1 matched to non-T2DM. The mean age at diagnosis was around 62 years old, with females constituting around 40%. Up to 25-year follow-up, ADRD rate/1000 person-years was 0.88 versus 1.52 (Non-T2DM versus T2DM); PRS unmatched (cHR: 1.72, 95% CI: 1.46-2.03) and matched (cHR:1.75, 95% CI: 1.47-2.09). Except for older age onset (≥75 years), the other subgroups demonstrated significantly increased ADRD risks in T2DM. T2DM PRS was higher in non-ADRD group across all subgroups. Contrarily, T2DM PRS was higher in ADRD in younger onset group (<55 years).ConclusionsT2DM is one of the strong risk factors of ADRD but genetic T2DM effect does not contribute to ADRD risk. However, a genetic link might be present in younger age onset group.
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Affiliation(s)
- Sohyun Jeong
- Department of Pharmacy Practice, College of Pharmacy, Massachusetts College of Pharmacy and Health Science, Boston, MA, USA
| | - Lisha Lin
- Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA
| | - Alvaro-Pascual Leone
- Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
- Deanna and Sidney Wolk Center for Memory Health, Hebrew SeniorLife, Boston, MA, USA
| | - Yi-Hsiang Hsu
- Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard University, Cambridge, MA, USA
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Han S, Lelieveldt T, Sturkenboom M, Biessels GJ, Ahmadizar F. Evaluating the Causal Association Between Type 2 Diabetes and Alzheimer's Disease: A Two-Sample Mendelian Randomization Study. Biomedicines 2025; 13:1095. [PMID: 40426922 PMCID: PMC12108868 DOI: 10.3390/biomedicines13051095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2025] [Revised: 04/15/2025] [Accepted: 04/22/2025] [Indexed: 05/29/2025] Open
Abstract
Background/Objectives: Type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) are significant global health issues. Epidemiological studies suggest T2DM increases AD risk, though confounding factors and reverse causality complicate this association. This study aims to clarify the causal relationship between T2DM and AD through a systematic review and meta-analysis of Mendelian randomization (MR) studies and a new two-sample MR analysis. Methods: A literature search across major databases was conducted through May 2024 to identify MR studies linking T2DM and AD. Fixed/random-effect models provided pooled odds ratios (ORs) with 95% confidence intervals (CIs), and heterogeneity was assessed with the I2 statistic. For our MR analysis, we pooled genetic variants from selected studies and analyzed AD outcomes using IGAP, EADB, and UKB databases. Multiple MR methods, including inverse variance weighted (IVW) and pleiotropy-robust approaches, were applied for validation. Results: Of 271 articles, 8 MR studies were included (sample sizes: 68,905 to 788,989), all from European ancestry. Our meta-analysis found no significant causal link between T2DM and AD (OR = 1.02, 95% CI: 1.00-1.04) with moderate heterogeneity (I2 = 31.3%). Similarly, our MR analysis using 512 SNPs as instrumental variables showed no significant associations in IGAP, EADB, or UKB data, which is consistent across sensitivity analyses. Conclusions: This meta-MR and MR analysis revealed no significant causal association between T2DM and AD, indicating that genetic predisposition to T2DM does not appear to causally influence AD risk, though modifiable clinical or environmental aspects of T2DM may still contribute to neurodegenerative processes. Further research should explore other mechanisms linking these conditions.
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Affiliation(s)
- Si Han
- Department of Data Science and Biostatistics, Julius Global Health, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands; (S.H.); (M.S.)
| | - Tom Lelieveldt
- Department of Biomedical Science, University College Utrecht, Utrecht University, 3508 TC Utrecht, The Netherlands;
| | - Miriam Sturkenboom
- Department of Data Science and Biostatistics, Julius Global Health, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands; (S.H.); (M.S.)
| | - Geert Jan Biessels
- Department of Neurology, Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands;
| | - Fariba Ahmadizar
- Department of Data Science and Biostatistics, Julius Global Health, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands; (S.H.); (M.S.)
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
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Hernández CF, Villaman C, Leu C, Lal D, Mata I, Klein AD, Pérez-Palma E. Polygenic score analysis identifies distinct genetic risk profiles in Alzheimer's disease comorbidities. Sci Rep 2025; 15:11407. [PMID: 40181078 PMCID: PMC11968852 DOI: 10.1038/s41598-025-95755-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2024] [Accepted: 03/24/2025] [Indexed: 04/05/2025] Open
Abstract
Alzheimer's disease (AD) is usually accompanied by comorbidities such as type 2 diabetes (T2D), epilepsy, major depressive disorder (MDD), and migraine headaches (MH) that can significantly affect patient management and progression. As AD, these comorbidities have their own cumulative common genetic risk component that can be explored in a single individual through polygenic scores. Utilizing data from the UK Biobank, we investigated the correlation between polygenic scores (PGS) for these comorbidities and their actual presentation in AD patients. We show that individuals with higher PGS values showed an elevated risk of developing T2D (OR 2.1, p = 1.07 × 10-11) and epilepsy (OR 1.5, p = 0.0176). High T2D-PGS is also associated with an earlier AD onset in individuals at high genetic risk for AD (AD-PGS). In contrast, no significant genetic associations were found for MDD and MH. Our findings show distinct common genetic risk factors for T2D and epilepsy carried by AD patients that are associated with increased prevalence and earlier disease onset. These results highlight the contribution of common genetic variation to the broader clinical landscape of AD and will contribute to future tailored patient management strategies for individuals at high genetic risk.
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Affiliation(s)
- Carlos F Hernández
- Universidad del Desarrollo, Centro de Genética y Genómica, Facultad de Medicina Clínica Alemana, 7610658, Santiago, Chile
| | - Camilo Villaman
- Universidad del Desarrollo, Centro de Genética y Genómica, Facultad de Medicina Clínica Alemana, 7610658, Santiago, Chile
| | - Costin Leu
- Center for Neurogenetics, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Dennis Lal
- Center for Neurogenetics, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
- Department of Neurology, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Cologne Center for Genomics (CCG), Medical Faculty of the University of Cologne, 50923, Köln, Germany
| | - Ignacio Mata
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Andrés D Klein
- Universidad del Desarrollo, Centro de Genética y Genómica, Facultad de Medicina Clínica Alemana, 7610658, Santiago, Chile
| | - Eduardo Pérez-Palma
- Universidad del Desarrollo, Centro de Genética y Genómica, Facultad de Medicina Clínica Alemana, 7610658, Santiago, Chile.
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Wolf EJ, Miller MW, Zhang R, Sherva R, Harrington KM, Fonda JR, Daskalakis NP, Gaziano JM, Logue MW. No Replication of Alzheimer's Disease Genetics as a Moderator of Combat Exposure's Association with PTSD risk in 138,592 Combat Veterans. NATURE. MENTAL HEALTH 2024; 2:553-561. [PMID: 39247144 PMCID: PMC11378975 DOI: 10.1038/s44220-024-00225-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 03/01/2024] [Indexed: 09/10/2024]
Abstract
Large-scale cohort and epidemiological studies suggest that posttraumatic stress disorder (PTSD) confers risk for late-onset Alzheimer's disease (AD) and related dementias (ADRD); however, the basis for this association remains unclear. Several prior studies of military Veterans have reported that carriers of the apolipoprotein E (APOE) ε4 gene variant are at heightened risk for the development of PTSD following combat exposure, suggesting that PTSD and ADRD may share some genetic risk. This cohort study was designed to further examine the hypothesis that ADRD genetic risk also confers risk for PTSD. To do so, we examined APOE ε4 and ε2 genotypes, an AD polygenic risk score (PRS), and other Veteran-relevant risk factors for PTSD in age-stratified groups of individuals of European (n = 123,372) and African (n = 15,220) ancestry in the US Department of Veterans Affairs' Million Veteran Program. Analyses revealed no significant main effect associations between the APOE ε4 (or ε2) genotype or the AD PRS on PTSD severity or diagnosis. There were also no significant interactions between measures of AD genetic risk and either combat exposure severity or history of head injury in association with PTSD in any age group. We conclude that the association between PTSD and the primary ADRD genetic risk factor, APOE ε4, that was reported previously was not replicable in the largest relevant dataset in the world. Thus, the epidemiological association between PTSD and ADRD is not likely to be driven by the major genetic factors underlying ADRD risk.
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Affiliation(s)
- Erika J Wolf
- National Center for PTSD, Behavioral Science Division, VA Boston Healthcare System, Boston, MA, 02130, USA
- Boston University Chobanian & Avedisian School of Medicine, Department of Psychiatry, Boston, MA, 02118, USA
| | - Mark W Miller
- National Center for PTSD, Behavioral Science Division, VA Boston Healthcare System, Boston, MA, 02130, USA
- Boston University Chobanian & Avedisian School of Medicine, Department of Psychiatry, Boston, MA, 02118, USA
| | - Rui Zhang
- National Center for PTSD, Behavioral Science Division, VA Boston Healthcare System, Boston, MA, 02130, USA
| | - Richard Sherva
- Boston University Chobanian & Avedisian School of Medicine, Biomedical Genetics, Boston, MA, 02118, USA
| | - Kelly M Harrington
- Boston University Chobanian & Avedisian School of Medicine, Department of Psychiatry, Boston, MA, 02118, USA
- Massachusetts Veterans Epidemiology Research and Information Center (MAVERIC), VA Boston Healthcare System, Boston, MA, 02130, USA
| | - Jennifer R Fonda
- Boston University Chobanian & Avedisian School of Medicine, Department of Psychiatry, Boston, MA, 02118, USA
- Translational Research Center for TBI and Stress Disorders (TRACTS) and Geriatric Research, Educational and Clinical Center (GRECC), VA Boston Healthcare System, Boston, MA, 02130, USA
- Harvard Medical School, Department of Psychiatry, Boston, MA, 02215, USA
| | - Nikolaos P Daskalakis
- Harvard Medical School, Department of Psychiatry, Boston, MA, 02215, USA
- McLean Hospital, Belmont, MA, 02478, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - J Michael Gaziano
- Massachusetts Veterans Epidemiology Research and Information Center (MAVERIC), VA Boston Healthcare System, Boston, MA, 02130, USA
- Division of Aging, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, 02215, USA
| | - Mark W Logue
- National Center for PTSD, Behavioral Science Division, VA Boston Healthcare System, Boston, MA, 02130, USA
- Boston University Chobanian & Avedisian School of Medicine, Department of Psychiatry, Boston, MA, 02118, USA
- Boston University Chobanian & Avedisian School of Medicine, Biomedical Genetics, Boston, MA, 02118, USA
- Boston University School of Public Health, Department of Biostatistics, Boston, MA, 02118, USA
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Huang J, Kee MZL, Law EC, Sum KK, Silveira PP, Godfrey KM, Daniel LM, Tan KH, Chong YS, Chan SY, Eriksson JG, Meaney MJ, Huang JY. Parental and child genetic burden of glycaemic dysregulation and early-life cognitive development: an Asian and European prospective cohort study. Transl Psychiatry 2024; 14:2. [PMID: 38177108 PMCID: PMC10766615 DOI: 10.1038/s41398-023-02694-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 01/06/2024] Open
Abstract
Insulin resistance and glucose metabolism have been associated with neurodevelopmental disorders. However, in the metabolically more susceptible Asian populations, it is not clear whether the genetic burden of glycaemic dysregulation influences early-life neurodevelopment. In a multi-ethnic Asian prospective cohort study in Singapore (Growing Up in Singapore Towards healthy Outcomes (GUSTO)), we constructed child and parental polygenic risk scores (PRS) for glycaemic dysregulation based on the largest genome-wide association studies of type 2 diabetes and fasting glucose among Asians. We found that child PRS for HOMA-IR was associated with a lower perceptual reasoning score at ~7 years (β = -0. 141, p-value = 0.024, 95% CI -0. 264 to -0. 018) and a lower WIAT-III mean score at ~9 years (β = -0.222, p-value = 0.001, 95% CI -0.357 to -0.087). This association were consistent in direction among boys and girls. These inverse associations were not influenced by parental PRS and were likely mediated via insulin resistance rather than mediators such as birth weight and childhood body mass index. Higher paternal PRS for HOMA-IR was suggestively associated with lower child perceptual reasoning at ~7 years (β = -0.172, p-value = 0.002, 95% CI -0.280 to -0.064). Replication analysis in a European cohort, the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort, showed that higher child PRS for fasting glucose was associated with lower verbal IQ score while higher maternal PRS for insulin resistance was associated with lower performance IQ score in their children at ~8.5 years. In summary, our findings suggest that higher child PRS for HOMA-IR was associated with lower cognitive scores in both Asian and European replication cohorts. Differential findings between cohorts may be attributed to genetic and environmental factors. Further investigation of the functions of the genetic structure and ancestry-specific PRS and a more comprehensive investigation of behavioural mediators may help to understand these findings better.
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Affiliation(s)
- Jian Huang
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, Norfolk Place, London, UK.
| | - Michelle Z L Kee
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Evelyn C Law
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Paediatrics, Khoo Teck Puat-National University Children's Medical Institute, National University Hospital, Singapore, Singapore
| | - Ka Kei Sum
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Patricia Pelufo Silveira
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Psychiatry, Faculty of Medicine and Ludmer Centre for Neuroinformatics and Mental Health, Douglas Hospital Research Centre, McGill University, Montreal, Quebec, Canada
| | - Keith M Godfrey
- MRC Lifecourse Epidemiology Centre and NIHR Southampton Biomedical Research Centre, University of Southampton & University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Lourdes Mary Daniel
- Department of Child Development, KK Women's and Children's Hospital, Singapore, Singapore
| | - Kok Hian Tan
- Department of Maternal Fetal Medicine, KK Women's and Children's Hospital, Singapore, Singapore
| | - Yap Seng Chong
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Obstetrics & Gynaecology, National University Health System, Singapore, Singapore
- Yong Loo Lin School of Medicine, Human Potential Translational Research Programme, National University of Singapore, Singapore, Singapore
| | - Shiao-Yng Chan
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Yong Loo Lin School of Medicine, Human Potential Translational Research Programme, National University of Singapore, Singapore, Singapore
- Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Johan G Eriksson
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Yong Loo Lin School of Medicine, Human Potential Translational Research Programme, National University of Singapore, Singapore, Singapore
- Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of general practice and primary health care, University of Helsinki, Helsinki, Finland
- Folkhälsan Research Center, Helsinki, Finland
| | - Michael J Meaney
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Psychiatry, Faculty of Medicine and Ludmer Centre for Neuroinformatics and Mental Health, Douglas Hospital Research Centre, McGill University, Montreal, Quebec, Canada
- Brain-Body Initiative, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Jonathan Yinhao Huang
- Singapore Institute for Clinical Sciences (SICS), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Centre for Quantitative Medicine, Duke-NUS Medical School, Singapore, Singapore
- Thompson School of Social Work & Public Health, Office of Public Health Studies, University of Hawai'i at Mānoa, Honolulu, HI, USA
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Wang L, Sang B, Zheng Z. The risk of dementia or cognitive impairment in patients with cataracts: a systematic review and meta-analysis. Aging Ment Health 2024; 28:11-22. [PMID: 37416949 DOI: 10.1080/13607863.2023.2226616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 06/04/2023] [Indexed: 07/08/2023]
Abstract
OBJECTIVES The aim of this study was to investigate whether cataract disease is associated with the risk of developing dementia or cognitive impairment. METHODS A systematic search of the literature in PubMed, the Extracts Database (Embase), the Cochrane Library and the Web of Science databases was performed from the inception data of each database until 1 September 2022. Sensitivity analyses were performed to assess the robustness and reliability of the overall findings. All extracted data were statistically analyzed using Stata software v.16.0. Publication bias was assessed using funnel plots and the Egger test. RESULTS There were 11 publications included in this study, which consisted of 489,211participants, spanning 10 countries from 2012 to 2022. Aggregation suggested that cataracts were associated with cognitive impairment (odds ratio [OR] = 1.32; 95% CI: 1.21-1.43; I 2 = 45.4.%; p = 0.000). The presence of cataracts is significantly associated with an increased risk of developing all-cause dementia (relative risk [RR] = 1.17; 95% CI: 1.08-1.26; I2 = 0.0%; p = 0.000). In subgroup analyses, having cataracts may increase the risk of Alzheimer's disease (hazard ratio [HR] = 1.28; 95% CI: 1.13-1.45; I2 = 0.0%; p = 0.000) and vascular dementia (HR = 1.35; 95% CI = 1.06-1.73; I2 = 0.0%, p = 0.015). The data from the Egger's test showed no significant evidence of publication bias. CONCLUSIONS Cataracts are associated with the risk of cognitive impairment and dementia, including Alzheimer's disease, and vascular dementia.
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Affiliation(s)
- Luping Wang
- Heilongjiang University of Traditional Chinese Medicine, Harbin, China
| | - Bowen Sang
- Heilongjiang University of Traditional Chinese Medicine, Harbin, China
| | - Zuyan Zheng
- Department of Acupuncture, The First Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, China
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Dybjer E, Kumar A, Nägga K, Engström G, Mattsson-Carlgren N, Nilsson PM, Melander O, Hansson O. Polygenic risk of type 2 diabetes is associated with incident vascular dementia: a prospective cohort study. Brain Commun 2023; 5:fcad054. [PMID: 37091584 PMCID: PMC10118265 DOI: 10.1093/braincomms/fcad054] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/28/2022] [Accepted: 03/02/2023] [Indexed: 03/09/2023] Open
Abstract
Type 2 diabetes and dementia are associated, but it is unclear whether the two diseases have common genetic risk markers that could partly explain their association. It is also unclear whether the association between the two diseases is of a causal nature. Furthermore, few studies on diabetes and dementia have validated dementia end-points with high diagnostic precision. We tested associations between polygenic risk scores for type 2 diabetes, fasting glucose, fasting insulin and haemoglobin A1c as exposure variables and dementia as outcome variables in 29 139 adults (mean age 55) followed for 20-23 years. Dementia diagnoses were validated by physicians through data from medical records, neuroimaging and biomarkers in cerebrospinal fluid. The dementia end-points included all-cause dementia, mixed dementia, Alzheimer's disease and vascular dementia. We also tested causal associations between type 2 diabetes and dementia through two-sample Mendelian randomization analyses. Seven different polygenic risk scores including single-nucleotide polymorphisms with different significance thresholds for type 2 diabetes were tested. A polygenic risk score including 4891 single-nucleotide polymorphisms with a P-value of <5e-04 showed the strongest association with different outcomes, including all-cause dementia (hazard ratio 1.11; Bonferroni corrected P = 3.6e-03), mixed dementia (hazard ratio 1.18; Bonferroni corrected P = 3.3e-04) and vascular dementia cases (hazard ratio 1.28; Bonferroni corrected P = 9.6e-05). The associations were stronger for non-carriers of the Alzheimer's disease risk gene APOE ε4. There was, however, no significant association between polygenic risk scores for type 2 diabetes and Alzheimer's disease. Furthermore, two-sample Mendelian randomization analyses could not confirm a causal link between genetic risk markers of type 2 diabetes and dementia outcomes. In conclusion, polygenic risk of type 2 diabetes is associated with an increased risk of dementia, in particular vascular dementia. The findings imply that certain people with type 2 diabetes may, due to their genetic background, be more prone to develop diabetes-associated dementia. This knowledge could in the future lead to targeted preventive strategies in clinical practice.
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Affiliation(s)
- Elin Dybjer
- Department of Clinical Sciences Malmö, Lund University, Jan Waldenströms gata 35, SE-21428 Malmö, Sweden
| | - Atul Kumar
- MultiPark: Multidisciplinary Research focused on Parkinson's disease, Lund University, Box 117, SE-22100 Lund, Sweden
- Clinical Memory Research Unit, Department of Clinical Sciences Malmö, Lund University, Skånes universitetssjukhus, VE Minnessjukdomar, SE-20502 Malmö, Sweden
| | - Katarina Nägga
- Department of Clinical Sciences Malmö, Lund University, Jan Waldenströms gata 35, SE-21428 Malmö, Sweden
- Clinical Memory Research Unit, Department of Clinical Sciences Malmö, Lund University, Skånes universitetssjukhus, VE Minnessjukdomar, SE-20502 Malmö, Sweden
- Department of Acute Internal Medicine and Geriatrics, Linköping University, SE-58183 Linköping, Sweden
| | - Gunnar Engström
- Department of Clinical Sciences Malmö, Lund University, Jan Waldenströms gata 35, SE-21428 Malmö, Sweden
| | - Niklas Mattsson-Carlgren
- MultiPark: Multidisciplinary Research focused on Parkinson's disease, Lund University, Box 117, SE-22100 Lund, Sweden
- Clinical Memory Research Unit, Department of Clinical Sciences Malmö, Lund University, Skånes universitetssjukhus, VE Minnessjukdomar, SE-20502 Malmö, Sweden
- Brain Injury After Cardiac Arrest Research Group, Lund University, Box 117, SE-22100 Lund, Sweden
- WCMM – Wallenberg Centre for Molecular Medicine, Lund University, Sölvegatan 19, BMC D11, SE-22184 Lund, Sweden
| | - Peter M Nilsson
- Department of Clinical Sciences Malmö, Lund University, Jan Waldenströms gata 35, SE-21428 Malmö, Sweden
- EpiHealth: Epidemiology for Health Strategic Research Area, Lund University, SUS Malmö, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - Olle Melander
- Department of Clinical Sciences Malmö, Lund University, Jan Waldenströms gata 35, SE-21428 Malmö, Sweden
- EpiHealth: Epidemiology for Health Strategic Research Area, Lund University, SUS Malmö, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
- Department of Emergency and Internal Medicine, Skåne University Hospital, SE-20502 Malmö, Sweden
- EXODIAB: Excellence in Diabetes Research in Sweden, Lund University, Box 117, SE-22100 Lund, Sweden
| | - Oskar Hansson
- MultiPark: Multidisciplinary Research focused on Parkinson's disease, Lund University, Box 117, SE-22100 Lund, Sweden
- Clinical Memory Research Unit, Department of Clinical Sciences Malmö, Lund University, Skånes universitetssjukhus, VE Minnessjukdomar, SE-20502 Malmö, Sweden
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