scholarly journals Hemochromatosis Mutations, Brain Iron Imaging, and Dementia in the UK Biobank Cohort

2021 ◽  
pp. 1-9
Author(s):  
Janice L. Atkins ◽  
Luke C. Pilling ◽  
Christine J. Heales ◽  
Sharon Savage ◽  
Chia-Ling Kuo ◽  
...  
Keyword(s):  
Iron Reduction ◽  
Brain Mri ◽  
European Ancestry ◽  
Uk Biobank ◽  
Brain Iron ◽  
Mri Features ◽  
Incident Dementia ◽  
Hfe Mutations ◽  
The Uk

Background: Brain iron deposition occurs in dementia. In European ancestry populations, the HFE p.C282Y variant can cause iron overload and hemochromatosis, mostly in homozygous males. Objective: To estimated p.C282Y associations with brain MRI features plus incident dementia diagnoses during follow-up in a large community cohort. Methods: UK Biobank participants with follow-up hospitalization records (mean 10.5 years). MRI in 206 p.C282Y homozygotes versus 23,349 without variants, including T2 * measures (lower values indicating more iron). Results: European ancestry participants included 2,890 p.C282Y homozygotes. Male p.C282Y homozygotes had lower T2 * measures in areas including the putamen, thalamus, and hippocampus, compared to no HFE mutations. Incident dementia was more common in p.C282Y homozygous men (Hazard Ratio HR = 1.83; 95% CI 1.23 to 2.72, p = 0.003), as was delirium. There were no associations in homozygote women or in heterozygotes. Conclusion: Studies are needed of whether early iron reduction prevents or slows related brain pathologies in male HFE p.C282Y homozygotes.

scholarly journals Hemochromatosis mutations, dementia and brain iron deposition: a prospective cohort study

2020 ◽  
Author(s):  
David Melzer ◽  
Janice L Atkins ◽  
Luke C Pilling ◽  
Christine J Heales ◽  
Sharon Savage ◽  
...  
Keyword(s):  
Iron Overload ◽  
Gray Matter ◽  
Brain Mri ◽  
Iron Deposition ◽  
European Ancestry ◽  
Brain Iron ◽  
Incident Dementia ◽  
Gray Matter Volumes ◽  
Brain Iron Deposition

ABSTRACTImportanceBrain iron deposition is common in dementia, but its causal significance is uncertain. The HFE p.C282Y homozygous mutation in European ancestry populations can lead to iron overload and hemochromatosis, mainly in males. Data on brain outcomes in homozygotes are scarce.ObjectiveTo estimate HFE variant associations with MRI features plus incident dementia diagnoses during follow-up in a large community based cohort.DesignUK Biobank cohort with follow-up in routine hospitalization records (mean 8.8 years). MRI imaging available on a participant subset scanned 2014 to 2018.SettingCommunity cohort participants across England, Wales and Scotland.ParticipantsEuropean ancestry participants (n=451,186) aged 40 to 70 years at baseline, including 2,890 p.C282Y homozygotes (predominantly without baseline haemochromatosis diagnoses). MRI scanning on 9,464 males and 10,475 females, including 40 male and 75 female p.C282Y homozygotes.ExposureHFE C282Y and H63D genetic variantsMain outcome and measuresBrain MRI site specific T2* measures (lower values associated with iron deposition) and gray matter volumes. Incident dementia diagnoses during follow-up.ResultsMale p.C282Y homozygotes had lower T2* measures in several brain areas including the thalamus (beta = -1.04 standard deviations, 95% CI -1.33 to -0.76, multiple testing adjusted p-value=4.9*10-10), putamen and hippocampus, compared to those without HFE mutations. Male homozygotes also had smaller gray matter volumes in the putamen (beta -0.80 sd, 95%CI -1.12 to - 0.47, adjusted p=2.2*10-4) and ventral striatum.Diagnoses of incident dementia (Hazard Ratio HR=2.27; 95% CI 1.36 to 3.80, p=0.002) were more common in p.C282Y homozygous men, as were delirium diagnoses (HR=2.04, CI 1.09 to 3.82, p=0.03), but there was no association with Stroke.In p.C282Y homozygote females and p.C282Y/H63D heterozygotes, MRI associations were less marked.Conclusion and RelevanceIn a community sample, men with the HFE p.C282Y homozygote genotype had more brain iron deposition, smaller specific gray matter volumes, and increased incidence of dementia. As iron overload in hemochromatosis is treatable, early intervention may prevent or limit related brain pathology in male HFE p.C282Y homozygotes.Key PointsQuestionIs the hemochromatosis HFE p.C282Y homozygous variant in men associated with brain MRI features and incident dementia?FindingsOn MRI, p.C282Y homozygote males had evidence of more iron deposition in areas including the thalamus, putamen and hippocampus, plus smaller putamen gray matter volumes, compared to men without HFE mutations. In 451,186 UK Biobank participants during the mean 8.8 year follow-up, incident dementia diagnoses were more than twice as common in the 1,294 homozygous men.MeaningAs iron overload in hemochromatosis is treatable, early intervention may prevent or limit related brain pathology in male HFE p.C282Y homozygotes.

Associations of ophthalmic and systemic conditions with incident dementia in the UK Biobank

2021 ◽  
pp. bjophthalmol-2021-319508
Author(s):  
Xianwen Shang ◽  
Zhuoting Zhu ◽  
Yu Huang ◽  
Xueli Zhang ◽  
Wei Wang ◽  
...  
Keyword(s):  
Heart Disease ◽  
Age Related Macular Degeneration ◽  
Hospital Inpatient ◽  
Uk Biobank ◽  
Age Related ◽  
Incident Dementia ◽  
Increased Risk ◽  
The Uk ◽  
Systemic Condition

AimsTo examine independent and interactive associations of ophthalmic and systemic conditions with incident dementia.MethodsOur analysis included 12 364 adults aged 55–73 years from the UK Biobank cohort. Participants were assessed between 2006 and 2010 at baseline and were followed up until the early of 2021. Incident dementia was ascertained using hospital inpatient, death records and self-reported data.ResultsOver 1 263 513 person-years of follow-up, 2304 cases of incident dementia were documented. The multivariable-adjusted HRs (95% CI) for dementia associated with age-related macular degeneration (AMD), cataract, diabetes-related eye disease (DRED) and glaucoma at baseline were 1.26 (1.05 to 1.52), 1.11 (1.00 to 1.24), 1.61 (1.30 to 2.00) and (1.07 (0.92 to 1.25), respectively. Diabetes, heart disease, stroke and depression at baseline were all associated with an increased risk of dementia. Of the combination of AMD and a systemic condition, AMD-diabetes was associated with the highest risk for incident dementia (HR (95% CI): 2.73 (1.79 to 4.17)). Individuals with cataract and a systemic condition were 1.19–2.29 times more likely to develop dementia compared with those without cataract and systemic conditions. The corresponding number for DRED and a systemic condition was 1.50–3.24. Diabetes, hypertension, heart disease, depression and stroke newly identified during follow-up mediated the association between cataract and incident dementia as well as the association between DRED and incident dementia.ConclusionsAMD, cataract and DRED but not glaucoma are associated with an increased risk of dementia. Individuals with both ophthalmic and systemic conditions are at higher risk of dementia compared with those with an ophthalmic or systemic condition only.

Contrasting Broad- and Clinically- defined Polygenic Indicators of Depression and Depression-related Phenotypes in Adults and Children

2020 ◽  
Author(s):  
John E. McGeary ◽  
Chelsie Benca-Bachman ◽  
Victoria Risner ◽  
Christopher G Beevers ◽  
Brandon Gibb ◽  
...  
Keyword(s):  
Suicidal Ideation ◽  
Cognitive Reappraisal ◽  
Twin Studies ◽  
European Ancestry ◽  
Summary Statistics ◽  
Depression Severity ◽  
Uk Biobank ◽  
Polygenic Scores ◽  
Adults And Children ◽  
The Uk

Twin studies indicate that 30-40% of the disease liability for depression can be attributed to genetic differences. Here, we assess the explanatory ability of polygenic scores (PGS) based on broad- (PGSBD) and clinical- (PGSMDD) depression summary statistics from the UK Biobank using independent cohorts of adults (N=210; 100% European Ancestry) and children (N=728; 70% European Ancestry) who have been extensively phenotyped for depression and related neurocognitive phenotypes. PGS associations with depression severity and diagnosis were generally modest, and larger in adults than children. Polygenic prediction of depression-related phenotypes was mixed and varied by PGS. Higher PGSBD, in adults, was associated with a higher likelihood of having suicidal ideation, increased brooding and anhedonia, and lower levels of cognitive reappraisal; PGSMDD was positively associated with brooding and negatively related to cognitive reappraisal. Overall, PGS based on both broad and clinical depression phenotypes have modest utility in adult and child samples of depression.

scholarly journals Machine Learning Prediction of Biomarkers from SNPs and of Disease Risk from Biomarkers in the UK Biobank

Genes ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 991
Author(s):  
Erik Widen ◽  
Timothy G. Raben ◽  
Louis Lello ◽  
Stephen D. H. Hsu
Keyword(s):  
Disease Risk ◽  
Smoking Status ◽  
Glycated Haemoglobin ◽  
European Ancestry ◽  
Risk Scores ◽  
Common Disease ◽  
Atherosclerotic Cardiovascular Disease ◽  
Uk Biobank ◽  
Lipoprotein A ◽  
The Uk

We use UK Biobank data to train predictors for 65 blood and urine markers such as HDL, LDL, lipoprotein A, glycated haemoglobin, etc. from SNP genotype. For example, our Polygenic Score (PGS) predictor correlates ∼0.76 with lipoprotein A level, which is highly heritable and an independent risk factor for heart disease. This may be the most accurate genomic prediction of a quantitative trait that has yet been produced (specifically, for European ancestry groups). We also train predictors of common disease risk using blood and urine biomarkers alone (no DNA information); we call these predictors biomarker risk scores, BMRS. Individuals who are at high risk (e.g., odds ratio of >5× population average) can be identified for conditions such as coronary artery disease (AUC∼0.75), diabetes (AUC∼0.95), hypertension, liver and kidney problems, and cancer using biomarkers alone. Our atherosclerotic cardiovascular disease (ASCVD) predictor uses ∼10 biomarkers and performs in UKB evaluation as well as or better than the American College of Cardiology ASCVD Risk Estimator, which uses quite different inputs (age, diagnostic history, BMI, smoking status, statin usage, etc.). We compare polygenic risk scores (risk conditional on genotype: PRS) for common diseases to the risk predictors which result from the concatenation of learned functions BMRS and PGS, i.e., applying the BMRS predictors to the PGS output.

scholarly journals Genetic overlap between Alzheimer’s disease and depression mapped onto the brain

2021 ◽  
Author(s):  
Jennifer Monereo Sánchez ◽  
Miranda T. Schram ◽  
Oleksandr Frei ◽  
Kevin O’Connell ◽  
Alexey A. Shadrin ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Genome Wide Association Study ◽  
Brain Mri ◽  
Genetic Correlations ◽  
Gaussian Mixture ◽  
Brain Morphology ◽  
Uk Biobank ◽  
Genetic Overlap ◽  
The Uk

ABSTRACTBackgroundAlzheimer’s disease (AD) and depression are debilitating brain disorders that are often comorbid. Shared brain mechanisms have been implicated, yet findings are inconsistent, reflecting the complexity of the underlying pathophysiology. As both disorders are (partly) heritable, characterizing their genetic overlap may provide etiological clues. While previous studies have indicated negligible genetic correlations, this study aims to expose the genetic overlap that may remain hidden due to mixed directions of effects.MethodsWe applied Gaussian mixture modelling, through MiXeR, and conjunctional false discovery rate (cFDR) analysis, through pleioFDR, to genome-wide association study (GWAS) summary statistics of AD (n=79,145) and depression (n=450,619). The effects of identified overlapping loci on AD and depression were tested in 403,029 participants of the UK Biobank (mean age 57.21 52.0% female), and mapped onto brain morphology in 30,699 individuals with brain MRI data.ResultsMiXer estimated 98 causal genetic variants overlapping between the two disorders, with 0.44 concordant directions of effects. Through pleioFDR, we identified a SNP in the TMEM106B gene, which was significantly associated with AD (B=-0.002, p=9.1×10−4) and depression (B=0.007, p=3.2×10−9) in the UK Biobank. This SNP was also associated with several regions of the corpus callosum volume anterior (B>0.024, p<8.6×10−4), third ventricle volume ventricle (B=-0.025, p=5.0×10−6), and inferior temporal gyrus surface area (B=0.017, p=5.3×10−4).DiscussionOur results indicate there is substantial genetic overlap, with mixed directions of effects, between AD and depression. These findings illustrate the value of biostatistical tools that capture such overlap, providing insight into the genetic architectures of these disorders.

scholarly journals 925Ethnic differences and determinants of vitamin D deficiency in the UK Biobank

2021 ◽  
Vol 50 (Supplement_1) ◽  
Author(s):  
Joshua Sutherland ◽  
Ang Zhou ◽  
Matthew Leach ◽  
Elina Hyppönen
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Asian Population ◽  
European Ancestry ◽  
Uk Biobank ◽  
Mixed Ancestry ◽  
Black African ◽  
Hydroxyvitamin D ◽  
The Uk ◽  
Summer Time

Abstract Background While controversy remains regarding optimal vitamin D status, the public health relevance of true vitamin D deficiency is undisputed. There are few contemporary cross-ethnic studies investigating the prevalence and determinants of very low 25-hydroxyvitamin D [25(OH)D] concentrations. Methods We used data from 440,581 UK Biobank participants, of which 415,903 identified as white European, 7,880 Asian, 7,602 black African, 1,383 Chinese, and 6,473 of mixed ancestry. 25(OH)D concentrations were measured by DiaSorin Liaison XL and deficiency defined as ≤ 25 nmol/L 25(OH)D. Results The prevalence of 25(OH)D deficiency was highest among participants of Asian ancestry (57.2% in winter/spring and 50.8% in summer/autumn; followed by black African [38.47%/30.78%], mixed ancestry [36.53%/22.48%], Chinese [33.12%/20.68%] and white European [17.45%/5.90%], P &lt; 1.0E-300). Participants with higher socioeconomic deprivation were more likely to have 25(OH)D deficiency compared to less deprived (P &lt; 1.0E-300 for all comparisons), with the pattern being more apparent among those of white European ancestry and in summer (Pinteraction&lt;6.4E-5 for both). In fully-adjusted analyses, regular consumption of oily fish was effective in mitigating ≤25 nmol/L 25(OH)D deficiency across all ethnicities, whilst outdoor-summer time was less effective for black Africans than white Europeans (OR: 0.89; 95% CI: 0.70, 1.12 and OR: 0.40; 95% CI: 0.38, 0.42, respectively). Conclusions Vitamin D deficiency remains an issue throughout the UK, particularly in lower socioeconomic areas and the UK Asian population, half of whom have vitamin D deficiency across seasons. Key messages The prevalence of 25(OH)D deficiency in the UK is alarming, with certain ethnic and socioeconomic groups considered particularly vulnerable.

scholarly journals Homozygosity for TYK2 P1104A underlies tuberculosis in about 1% of patients in a cohort of European ancestry

2019 ◽  
Vol 116 (21) ◽  
pp. 10430-10434 ◽  
Author(s):  
Gaspard Kerner ◽  
Noe Ramirez-Alejo ◽  
Yoann Seeleuthner ◽  
Rui Yang ◽  
Masato Ogishi ◽  
...  
Keyword(s):  
Odds Ratio ◽  
Genetic Basis ◽  
Sub Saharan Africa ◽  
European Ancestry ◽  
Uk Biobank ◽  
The United Kingdom ◽  
The Common ◽  
Sub Saharan ◽  
The Uk ◽  
High Level

The human genetic basis of tuberculosis (TB) has long remained elusive. We recently reported a high level of enrichment in homozygosity for the common TYK2 P1104A variant in a heterogeneous cohort of patients with TB from non-European countries in which TB is endemic. This variant is homozygous in ∼1/600 Europeans and ∼1/5,000 people from other countries outside East Asia and sub-Saharan Africa. We report a study of this variant in the UK Biobank cohort. The frequency of P1104A homozygotes was much higher in patients with TB (6/620, 1%) than in controls (228/114,473, 0.2%), with an odds ratio (OR) adjusted for ancestry of 5.0 [95% confidence interval (CI): 1.96–10.31, P = 2 × 10−3]. Conversely, we did not observe enrichment for P1104A heterozygosity, or for TYK2 I684S or V362F homozygosity or heterozygosity. Moreover, it is unlikely that more than 10% of controls were infected with Mycobacterium tuberculosis, as 97% were of European genetic ancestry, born between 1939 and 1970, and resided in the United Kingdom. Had all of them been infected, the OR for developing TB upon infection would be higher. These findings suggest that homozygosity for TYK2 P1104A may account for ∼1% of TB cases in Europeans.

Associations of BMI and Serum Urate with Developing Dementia: A Prospective Cohort Study

2020 ◽  
Vol 105 (12) ◽  
pp. e4688-e4698
Author(s):  
Zhi Cao ◽  
Chenjie Xu ◽  
Hongxi Yang ◽  
Shu Li ◽  
Fusheng Xu ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Cohort Study ◽  
Lower Risk ◽  
Serum Urate ◽  
Healthy Weight ◽  
Uk Biobank ◽  
Health Records ◽  
Increased Risk ◽  
The Uk

Abstract Context Recent studies have suggested that a higher body mass index (BMI) and serum urate levels were associated with a lower risk of developing dementia. However, these reverse relationships remain controversial, and whether serum urate and BMI confound each other is not well established. Objectives To investigate the independent associations of BMI and urate, as well as their interaction with the risk of developing dementia. Design and Settings We analyzed a cohort of 502 528 individuals derived from the UK Biobank that included people aged 37–73 years for whom BMI and urate were recorded between 2006 and 2010. Dementia was ascertained at follow-up using electronic health records. Results During a median of 8.1 years of follow-up, a total of 2138 participants developed dementia. People who were underweight had an increased risk of dementia (hazard ratio [HR] = 1.91, 95% confidence interval [CI]: 1.24–2.97) compared with people of a healthy weight. However, the risk of dementia continued to fall as weight increased, as those who were overweight and obese were 19% (HR = 0.81, 95%: 0.73–0.90) and 22% (HR = 0.78, 95% CI: 0.68–0.88) were less likely to develop dementia than people of a healthy weight. People in the highest quintile of urate were also associated with a 25% (HR = 0.75, 95% CI: 0.64–0.87) reduction in the risk of developing dementia compared with those who were in the lowest quintile. There was a significant multiplicative interaction between BMI and urate in relation to dementia (P for interaction = 0.004), and obesity strengthens the protective effect of serum urate on the risk of dementia. Conclusion Both BMI and urate are independent predictors of dementia, and there are inverse monotonic and dose-response associations of BMI and urate with dementia.

scholarly journals Altered Cortical Brain Structure and Increased Risk for Disease Seen Decades After Perinatal Exposure to Maternal Smoking: A Study of 9000 Adults in the UK Biobank

2019 ◽  
Vol 29 (12) ◽  
pp. 5217-5233 ◽  
Author(s):  
Lauren E Salminen ◽  
Rand R Wilcox ◽  
Alyssa H Zhu ◽  
Brandalyn C Riedel ◽  
Christopher R K Ching ◽  
...  
Keyword(s):  
Brain Structure ◽  
Brain Mri ◽  
Population Based ◽  
Smoke Exposure ◽  
Sensitivity Analyses ◽  
Uk Biobank ◽  
Increased Risk ◽  
Increase Risk ◽  
Sensory Cortices ◽  
The Uk

Abstract Secondhand smoke exposure is a major public health risk that is especially harmful to the developing brain, but it is unclear if early exposure affects brain structure during middle age and older adulthood. Here we analyzed brain MRI data from the UK Biobank in a population-based sample of individuals (ages 44–80) who were exposed (n = 2510) or unexposed (n = 6079) to smoking around birth. We used robust statistical models, including quantile regressions, to test the effect of perinatal smoke exposure (PSE) on cortical surface area (SA), thickness, and subcortical volumes. We hypothesized that PSE would be associated with cortical disruption in primary sensory areas compared to unexposed (PSE−) adults. After adjusting for multiple comparisons, SA was significantly lower in the pericalcarine (PCAL), inferior parietal (IPL), and regions of the temporal and frontal cortex of PSE+ adults; these abnormalities were associated with increased risk for several diseases, including circulatory and endocrine conditions. Sensitivity analyses conducted in a hold-out group of healthy participants (exposed, n = 109, unexposed, n = 315) replicated the effect of PSE on SA in the PCAL and IPL. Collectively our results show a negative, long term effect of PSE on sensory cortices that may increase risk for disease later in life.

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