Biology subjects

Pedersen, N. L.

Publications and source records attributed to Pedersen, N. L..

13 recordsLinked to original sources

bioRxiv2019

A decade of epigenetic change in aging twins: genetic and environmental contributions to longitudinal DNA methylation

Summary/AbstractO_ST_ABSBackgroundC_ST_ABSEpigenetic changes may result from the interplay of environmental exposures and genetic influences and contribute to differences in age-related disease, disability and mortality risk. However, the etiologies contributing to stability and change in DNA methylation have rarely been examined longitudinally. MethodsWe considered DNA methylation in whole blood leukocyte DNA across a 10-year span in two samples of same-sex aging twins: (a) Swedish Adoption Twin Study of Aging (SATSA; N = 53 pairs, 53% female; 62.9 and 72.5 years, SD=7.2 years); (b) Longitudinal Study of Aging Danish Twins (LSADT; N = 43 pairs, 72% female, 76.2 and 86.1 years, SD=1.8 years). Joint biometrical analyses were conducted on 358,836 methylation probes in common. Bivariate twin models were fitted, adjusting for age, sex and country. ResultsOverall, results suggest genetic contributions to DNA methylation across 358,836 sites tended to be small and lessen across 10 years (broad heritability M=23.8% and 18.0%) but contributed to stability across time while person-specific factors explained emergent influences across the decade. Aging-specific sites identified from prior EWAS and methylation age clocks were more heritable than background sites. The 5,037 sites that showed the greatest heritable/familial-environmental influences (p<1E-07) were enriched for immune and inflammation pathways while 2,020 low stability sites showed enrichment in stress-related pathways. ConclusionsAcross time, stability in methylation is primarily due to genetic contributions, while novel experiences and exposures contribute to methylation differences. Elevated genetic contributions at age-related methylation sites suggest that adaptions to aging and senescence may be differentially impacted by genetic background.

genetics↗

bioRxiv2019

Comprehensive longitudinal study of epigenetic mutations in aging

BackgroundThe role of DNA methylation in aging has been widely studied. However, epigenetic mutations, here defined as aberrant methylation levels compared to the distribution in a population, are less understood. Hence, we investigated longitudinal accumulation of epigenetic mutations, using 994 blood samples collected at up to five time points from 375 individuals in old ages.\n\nResultsWe verified earlier cross-sectional evidence on the increase of epigenetic mutations with age, and identified important contributing factors including sex, CD19+ B cells, genetic background, cancer diagnosis and technical artifacts. We further classified epigenetic mutations into High/Low Methylation Outliers (HMO/LMO) according to their changes in methylation, and specifically studied methylation sites (CpGs) that were prone to mutate (frequently mutated CpGs). We validated four epigenetically mutated CpGs using pyrosequencing in 93 samples. Furthermore, by using twins, we concluded that the age-related accumulation of epigenetic mutations was not related to genetic factors, hence driven by stochastic or environmental effects.\n\nConclusionsHere we conducted a comprehensive study of epigenetic mutation and highlighted its important role in aging process and cancer development.

genetics↗

bioRxiv2019

Neuroticism as a predictor of frailty in old age: a genetically informative approach

ObjectiveNeuroticism is associated with poor health outcomes, but its contribution to the accumulation of health deficits in old age, i.e. frailty, is largely unknown. We aimed to explore associations between neuroticism and frailty cross-sectionally and over up to 29 years, and to investigate the contribution of shared genetic influences. MethodData were derived from the UK Biobank (UKB, n=502,631), the Australian Over 50s Study (AO50, n=3,011) and the Swedish Twin Registry (SALT n=23,744, SATSA n=1,637). Associations between neuroticism and the Frailty Index were investigated using regression analysis cross-sectionally in UKB, AO50 and SATSA, and longitudinally in SALT (25-29y follow-up) and SATSA (6 and 23y follow-up). The co-twin control method was applied to explore the contribution of underlying shared familial factors (SALT, SATSA, AO50). Genome-wide polygenic risk scores for neuroticism in all samples were used to further assess whether common genetic variants associated with neuroticism predict frailty. ResultsHigh neuroticism was consistently associated with greater frailty cross-sectionally (adjusted {beta}, 95% confidence intervals in UKB= 0.32, 0.32-0.33; AO50= 0.35, 0.31-0.39; SATSA= 0.33, 0.27-0.39) and longitudinally up to 29 years (SALT= 0.24; 0.22-0.25; SATSA 6y= 0.31, 0.24-0.38; SATSA 23y= 0.16, 0.07-0.25). When controlling for underlying shared genetic and environmental factors the neuroticism-frailty association remained significant, although decreased. Polygenic risk scores for neuroticism significantly predicted frailty in the two larger samples (meta-analyzed total {beta}= 0.06, 0.05-0.06). ConclusionHigh neuroticism is associated with the development and course of frailty. Both environmental and genetic influences, including neuroticism-associated genetic variants, contribute to this relationship.

epidemiology↗

bioRxiv2019

Asthma and affective traits in adults: a genetically informative study

Depression, anxiety and high neuroticism (affective traits) are often comorbid with asthma. A causal direction between the affective traits and asthma is difficult to determine, however, it may be that there is a common underlying pathway attributable to shared genetic factors. Our aim was to determine whether a common genetic susceptibility exists for asthma and each of the affective traits. An adult twin cohort from the Swedish Twin Register underwent questionnaire-based health assessments (n=23 693) and genotyping (n=15 908). Firstly, questionnaire-based associations between asthma and affective traits were explored. This was followed by genetic analyses: a) polygenic risk scores (PRS) for affective traits were used as predictors of asthma, and b) linkage-disequilibrium score regression based on genome-wide association results from UK Biobank was used to quantify genetic correlations. Analyses found that the questionnaire-based associations between asthma and each affective trait were associated (OR 1.7, 95%CI 1.5-1.9 major depression, OR 1.5, 95%CI 1.3-1.6 anxiety, and OR 1.6, 95% 1.4-1.8 high neuroticism). Genetic susceptibility for neuroticism explained the variance in asthma with a dose response effect; that is, those in the highest neuroticism PRS quartile were more likely to have asthma than those in the lowest quartile (OR 1.4, 95%CI 1.2-1.6). Genetic correlations were found between depression and asthma (rg= 0.17), but not for anxiety or neuroticism score. We conclude that the observed comorbidity between asthma and the affective traits may in part be due to shared genetic influences between asthma and depression and neuroticism, but not anxiety.

genetics↗

bioRxiv2018

Genetic variation in the Major Histocompatibility Complex and association with depression

BackgroundThe prevalence of depression is higher in individuals suffering from autoimmune diseases, but the mechanisms underlying the observed comorbidities are unknown. Epidemiological findings point to a bi-directional relationship - that depression increases the risk of developing an autoimmune disease, and vice-versa. Shared genetic etiology is a plausible explanation for the overlap between depression and autoimmune diseases. In this study we tested whether genetic variation in the Major Histocompatibility Complex (MHC), which is associated with risk for autoimmune diseases, is also associated with risk for depression.\n\nMethodWe fine-mapped the classical MHC (chr6: 29.6-33.1 Mb), imputing 216 Human Leukocyte Antigen (HLA) alleles and four Complement Component 4 (C4) haplotypes in studies from the Psychiatric Genomics Consortium (PGC) Major Depressive Disorder (MDD) working group and the UK Biobank (UKB). In the 26 PGC-MDD studies, cases met a lifetime diagnosis of MDD, determined by a structured diagnostic interview. In the UKB, cases and controls were identified from an online mental health questionnaire. The total sample size was 45,149 depression cases and 86,698 controls. We tested for association between depression status and imputed MHC variants in each study and performed an inverse-variance weighted meta-analysis across the PGC-MDD and UKB samples, applying both a conservative region-wide significance threshold (3.9-e6) and a candidate threshold (1.6e-4).\n\nResultsNo HLA alleles or C4 haplotypes were associated with depression at the conservative threshold in the PGC, UKB or meta-analysis. HLA-B*08:01 was associated with modest protection for depression at the candidate threshold in the meta-analysis. Under the conservative threshold, 70 SNPs were detected in the UKB and 143 SNPs were detected in the meta-analysis, mirroring previous findings from highly powered GWAS of depression.\n\nDiscussionWe found no evidence that HLA alleles, which play a major role in the genetic susceptibility to autoimmune diseases, or C4 haplotypes, which are strongly associated with schizophrenia, confer risk for depression. These results indicate that autoimmune diseases and depression do not share common risk loci of moderate or large effect in the MHC.

genetics↗

bioRxiv2018

Phenome-wide investigation of health outcomes associated with genetic predisposition to loneliness

AO_SCPLOWBSTRACTC_SCPLOWHumans are social animals that experience intense suffering when they perceive a lack of social connection. Modern societies are experiencing an epidemic of loneliness. While the experience of loneliness is universally human, some people report experiencing greater loneliness than others. Loneliness is more strongly associated with mortality than obesity, emphasizing the need to understand the nature of the relationship between loneliness and health. While it is intuitive that circumstantial factors such as marital status and age influence loneliness, there is also compelling evidence of a genetic predisposition towards loneliness. To better understand the genetic architecture of loneliness and its relationship with associated outcomes, we conducted a genome-wide association (GWAS) meta-analysis of loneliness (N=475,661), report 12 associated loci (two novel) and significant genetic correlations with 34 other complex traits. The polygenic basis for loneliness was significantly enriched for evolutionary constrained genes and genes expressed in specific brain tissues: (frontal) cortex, cerebellum, anterior cingulate cortex, and substantia nigra. We built polygenic scores based on this GWAS meta-analysis to explore the genetic association between loneliness and health outcomes in an independent sample of 18,498 individuals for whom electronic health records were available. A genetic predisposition towards loneliness predicted cardiovascular, psychiatric, and metabolic disorders, and triglycerides and high-density lipoproteins. Mendelian randomization analyses showed evidence of a causal, increasing, effect of body fat on loneliness, and a similar weaker causal effect of BMI. Our results provide a framework for ongoing studies of the genetic basis of loneliness and its role in mental and physical health.

genetics↗

bioRxiv2018

Levels of histidine-rich glycoprotein in human blood predict accelerated aging

1.Despite recognizing aging as risk factor of human diseases, little is still known about the molecular traits of biological age and mortality risk. To identify age-associated proteins circulating human blood, we screened 156 subjects aged 50-92 years using an exploratory and multiplexed affinity proteomics approach. We corroborated the top age-associated protein profile (adjusted P < 0.001) in eight additional study sets (N = 4,044 individuals), and confirmed a consistent age-associated increase (P = 6.61 x 10-6) by meta-analysis. Applying antibody validation determined circulating histidine-rich glycoprotein (HRG) as the target, and we observed that sequence variants influenced the antibodies ability to bind to the protein. Profiles of circulating HRG were associated to several clinical traits and predicted the risk of mortality during a follow-up period of 8.5 years (IQR = 7.7-9.3 years) after blood sampling (HR = 1.25 per SD; 95% CI = 1.12-1.39; P = 7.41 x 10-5). In conclusion, our affinity proteomics analysis found associations between the molecular traits of circulating HRG with age and all-cause mortality. This suggests that the profiles of multi-purpose protein HRG could serve as an accessible indicator of physiological processes related to aging.

epidemiology↗

bioRxiv2017

The Anorexia Nervosa Genetics Initiative: Overview and Methods

BackgroundGenetic factors contribute to anorexia nervosa (AN); and the first genome-wide significant locus has been identified. We describe methods and procedures for the Anorexia Nervosa Genetics Initiative (ANGI), an international collaboration designed to rapidly recruit 13000 individuals with AN as well as ancestrally matched controls. We present sample characteristics and the utility of an online eating disorder diagnostic questionnaire suitable for large-scale genetic and population research.\n\nMethodsANGI recruited from the United States (US), Australia/New Zealand (ANZ), Sweden (SE), and Denmark (DK). Recruitment was via national registers (SE, DK); treatment centers (US, ANZ, SE, DK); and social and traditional media (US, ANZ, SE). All cases had a lifetime AN diagnosis based on DSM-IV or ICD-10 criteria (excluding amenorrhea). Recruited controls had no lifetime history of disordered eating behaviors. To assess the positive and negative predictive validity of the online eating disorder questionnaire (ED100K-v1), 109 women also completed the Structured Clinical Interview for DSM-IV (SCID), Module H.\n\nResultsBlood samples and clinical information were collected from 13,364 individuals with lifetime AN and from controls. Online diagnostic phenotyping was effective and efficient; the validity of the questionnaire was acceptable.\n\nConclusionsOur multipronged recruitment approach was highly effective for rapid recruitment and can be used as a model for efforts by other groups. High online presence of individuals with AN rendered the Internet/social media a remarkably effective recruitment tool in some countries. ANGI has substantially augmented Psychiatric Genomics Consortium AN sample collection. ANGI is a registered clinical trial: clinicaltrials.gov NCT01916538; https://clinicaltrials.gov/ct2/show/NCT01916538?cond=Anorexia+Nervosa&draw=1&rank=3.

genetics↗

bioRxiv2017

A frailty index for UK Biobank participants

BackgroundFrailty indices (FIs) measure variation in health between aging individuals. Researching FIs in resources with large-scale genetic and phenotypic data will provide insights into the causes and consequences of frailty. Thus, we aimed to develop an FI using UK Biobank data, a cohort study of 500,000 middle-aged and older adults.\n\nMethodsAn FI was calculated using 49 self-reported questionnaire items on traits covering health, presence of diseases and disabilities, and mental wellbeing, according to standard protocol. We used multiple imputation to derive FI values for the entire eligible sample in the presence of missing item data (N =500,336). To validate the measure, we assessed associations of the FI with age, sex, and risk of all-cause mortality (follow-up [≤] 9.7 years) using linear and Cox proportional hazards regression models.\n\nResultsMean FI in the cohort was 0.125 (standard deviation = 0.075), and there was a curvilinear trend towards higher values in older participants. FI values were also marginally higher on average in women than men. In survival models, 10% higher baseline frailty (i.e. a 0.1 FI increment) was associated with higher risk of death (hazard ratio (HR) = 1.65; 95% confidence interval: 1.62, 1.68). Associations were stronger in younger participants than in old, and in men compared to women (HRs: 1.72 vs. 1.56, respectively).\n\nConclusionsThe FI is a valid measure of frailty in UK Biobank. The cohorts data are open-access for researchers to use, and we provide script for deriving this tool to facilitate future studies on frailty.

epidemiology↗

bioRxiv2017

Epigenetic influences on aging: a longitudinal genome-wide methylation study in old Swedish twins

Age-related changes in DNA methylation have been observed in many cross-sectional studies, but longitudinal evidence is still very limited. Here, we aimed to characterize longitudinal age-related methylation patterns (Illumina HumanMethylation450 array) using 1011 blood samples collected from 385 old Swedish twins (mean age of 69 at baseline) up to five times over 20 years. We identified 1316 age-associated methylation sites (p<1.3x10-7) using a longitudinal epigenome-wide association study design. We measured how estimated cellular compositions changed with age and how much they confounded the age effect. We validated the results in two independent longitudinal cohorts, where 118 CpGs were replicated in PIVUS (p<3.9x10-5) and 594 were replicated in LBC (p<5.1x10-5). Functional annotation of age-associated CpGs showed enrichment in CCCTC-binding factor (CTCF) and other unannotated transcription factor binding sites. We further investigated genetic influences on methylation (methylation quantitative trait loci) and found no interaction between age and genetic effects in the 1316 age-associated CpGs. Moreover, in the same CpGs, methylation differences within twin pairs increased over time, where monozygotic twins had smaller intra-pair differences than dizygotic twins. We show that age-related methylation changes persist in a longitudinal perspective, and are fairly stable across cohorts. Moreover, the changes are under genetic influence, although this effect is independent of age. In addition, inter-individual methylation variations increase over time, especially in age-associated CpGs, indicating the increase of environmental contributions on DNA methylation with age.

genetics↗

bioRxiv2017

The frailty index is associated with the need for care in an aging Swedish population

BackgroundThe Rockwood frailty index (FI) has proven a valid predictor of mortality, institutionalization and requirement for health services. However, little is known about the relationship between the FI and the need for care - an indication of dependency. To this end, we ascertained the associations between the FI and the need for current and future care.\n\nMethodsA Rockwood-based FI was tested for association with the current need for care and care needs in the future during a 23-year follow-up in the Swedish Adoption/Twin Study of Aging (n=1477; 623 men, 854 women; aged 29-95 years at baseline). Need for care was defined as receiving help at least once a week in daily routines. Age, sex, education, living alone, smoking status and body mass index were considered as covariates.\n\nResultsThe FI was independently associated with current need for care (OR=1.27 for accumulation of one deficit, 95%CI 1.20-1.34) and future need for care (HR=1.12 for accumulation of one deficit, 95%CI 1.08-1.15). Co-twin control analyses confirmed the results; the pair member currently needing care had higher median FI levels compared to their co-twin not needing care, and the pair member having higher baseline FI had shorter median time to the onset of future care need compared to their co-twin with lower FI.\n\nConclusionsThe FI is a determinant of current care needs and predictive of care needs in the future. The FI may thus represent a risk indicator for dependency and offer an amenable target for preventive measures.

epidemiology↗

bioRxiv2017

Frailty index as a predictor of all-cause and cause-specific mortality in a Swedish population-based cohort

BackgroundFrailty is a complex manifestation of aging and associated with increased risk of mortality and poor health outcomes. Younger individuals (under 65 years) typically have low levels of frailty and are less-studied in this respect. Also, the relationship between the Rockwood frailty index (FI) and cause-specific mortality in community settings is understudied.\n\nMethodsWe created and validated a 42-item Rockwood-based FI in The Swedish Adoption/Twin Study of Aging (n=1477; 623 men, 854 women; aged 29-95 years) and analyzed its association with all-cause and cause-specific mortality in up to 30-years of follow-up. Deaths due to cardiovascular disease (CVD), cancer, dementia and other causes were considered as competing risks.\n\nResultsOur FI demonstrated construct validity as its associations with age, sex and mortality were similar to the existing literature. The FI was independently associated with increased risk for all-cause mortality in younger (<65 years; HR per increase in one deficit 1.11, 95%CI 1.07-1.17) and older ([≥]65 years; HR 1.07, 95%CI 1.04-1.10) women and in younger men (HR 1.05, 95%CI 1.01-1.10). In cause-specific mortality analysis, the FI was strongly predictive of CVD mortality in women (HR per increase in one deficit 1.13, 95%CI 1.09-1.17), whereas in men the risk was restricted to deaths from other causes (HR 1.07, 95%CI 1.01-1.13).\n\nConclusionsThe FI showed good predictive value for all-cause mortality especially in the younger group. The FI predicted CVD mortality risk in women, whereas in men it captured vulnerability to death from various causes.

epidemiology↗

bioRxiv2017

An epigenome-wide association study of educational attainment (n = 10,767)

The epigenome has been shown to be influenced by biological factors, such as disease status, and environmental factors, such as smoking, alcohol consumption, and body mass index. Although there is a widespread perception that environmental influences on the epigenome are pervasive and profound, there has been little evidence to date in humans with respect to environmental factors that are biologically distal. Here, we provide evidence on the associations between epigenetic modifications--in our case, CpG methylation--and educational attainment (EA), a biologically distal environmental factor that is arguably among of the most important life-shaping experiences for individuals. Specifically, we report the results of an epigenome-wide association study meta-analysis of EA based on data from 27 cohort studies with a total of 10,767 individuals. While we find that 9 CpG probes are significantly associated with EA, only two remain associated when we restrict the sample to never-smokers. These two are known to be strongly associated with maternal smoking during pregnancy, and thus their association with EA could be due to correlation between EA and maternal smoking. Moreover, their effect sizes on EA are far smaller than the known associations between CpG probes and biologically proximal environmental factors. Two analyses that combine the effects of many probes--polygenic methylation score and epigenetic-clock analyses--both suggest small associations with EA. If our findings regarding EA can be generalized to other biologically distal environmental factors, then they cast doubt on the hypothesis that such factors have large effects on the epigenome.

genetics↗