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Effect of Physical Activity, Smoking, and Sleep on Telomere Length: A Systematic Review of Observational and Intervention Studies. J Clin Med 2021; 11:jcm11010076. [PMID: 35011817 PMCID: PMC8745211 DOI: 10.3390/jcm11010076] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 12/14/2021] [Accepted: 12/21/2021] [Indexed: 12/12/2022] Open
Abstract
Aging is a risk factor for several pathologies, restricting one’s health span, and promoting chronic diseases (e.g., cardiovascular and neurodegenerative diseases), as well as cancer. Telomeres are regions of repetitive DNA located at chromosomal ends. Telomere length has been inversely associated with chronological age and has been considered, for a long time, a good biomarker of aging. Several lifestyle factors have been linked with telomere shortening or maintenance. However, the consistency of results is hampered by some methodological issues, including study design, sample size, measurement approaches, and population characteristics, among others. Therefore, we aimed to systematically review the current literature on the effects of three relevant lifestyle factors on telomere length in human adults: physical activity, smoking, and sleep. We conducted a qualitative systematic review of observational and intervention studies using the Preferred Reporting Item for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The systematic literature search covered articles published in MEDLINE and EMBASE databases (from 2010 to 2020). A total of 1400 studies were identified; 83 were included after quality control. Although fewer sedentary activities, optimal sleep habits, and non- or ex-smoker status have been associated with less telomere shortening, several methodological issues were detected, including the need for more targeted interventions and standardized protocols to better understand how physical activity and sleep can impact telomere length and aging. We discuss the main findings and current limitations to gain more insights into the influence of these lifestyle factors on the healthy aging process.
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Gao X, Zhang Y, Mons U, Brenner H. Leukocyte telomere length and epigenetic-based mortality risk score: associations with all-cause mortality among older adults. Epigenetics 2018; 13:846-857. [PMID: 30152726 DOI: 10.1080/15592294.2018.1514853] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Telomere length (TL) has been established as a biomarker of aging and aging-related health outcomes, but showed only a weak or inconsistent association with all-cause mortality in previous epidemiological studies. Recently, an epigenetic 'mortality risk score' (MS) based on whole blood DNA methylation at 10 mortality-related CpG sites has been demonstrated to be strongly related to all-cause mortality at the population level. This study aimed to address the association between TL and this MS, and to assess and compare their associations with all-cause mortality. The MS was derived from the DNA methylation profiles measured by Illumina Human Methylation450K Beadchip and TL was measured by quantitative PCR at baseline among 1517 participants aged 50-75 of the German ESTHER cohort study. In cross-sectional bi- and multivariable analyses, the MS was strongly associated and showed monotonic dose-response relationships with TL (p-values <0.05). However, only the MS but not TL was associated with all-cause mortality during a median follow-up of 12.5 years. After controlling for potential covariates and TL, hazard ratios (95% CI) for all-cause mortality for low, moderate and high levels of the MS defined by 1, 2-5 and >5 CpG sites with aberrant methylation were 2.24 (1.13-4.41), 3.31 (1.76-6.22) and 6.33 (3.22-12.41) compared to a MS of 0, respectively. Our investigation shows that the epigenetic-based MS is strongly associated with TL, a broadly accepted aging biomarker, and at the same time shows much stronger associations with all-cause mortality than the latter.
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Affiliation(s)
- Xu Gao
- a Division of Clinical Epidemiology and Aging Research , German Cancer Research Center (DKFZ) , Heidelberg , Germany
| | - Yan Zhang
- a Division of Clinical Epidemiology and Aging Research , German Cancer Research Center (DKFZ) , Heidelberg , Germany
| | - Ute Mons
- a Division of Clinical Epidemiology and Aging Research , German Cancer Research Center (DKFZ) , Heidelberg , Germany
| | - Hermann Brenner
- a Division of Clinical Epidemiology and Aging Research , German Cancer Research Center (DKFZ) , Heidelberg , Germany.,b Network Aging Research , University of Heidelberg , Heidelberg , Germany.,c Division of Preventive Oncology , German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT) , Heidelberg , Germany.,d German Cancer Consortium (DKTK) , German Cancer Research Center (DKFZ) , Heidelberg , Germany
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Bateson M, Nettle D. Why are there associations between telomere length and behaviour? Philos Trans R Soc Lond B Biol Sci 2018; 373:20160438. [PMID: 29335363 PMCID: PMC5784059 DOI: 10.1098/rstb.2016.0438] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2017] [Indexed: 12/30/2022] Open
Abstract
Individual differences in telomere length are associated with individual differences in behaviour in humans and birds. Within the human epidemiological literature this association is assumed to result from specific behaviour patterns causing changes in telomere dynamics. We argue that selective adoption-the hypothesis that individuals with short telomeres are more likely to adopt specific behaviours-is an alternative worthy of consideration. Selective adoption could occur either because telomere length directly affects behaviour or because behaviour and telomere length are both affected by a third variable, such as exposure to early-life adversity. We present differential predictions of the causation and selective adoption hypotheses and describe how these could be tested with longitudinal data on telomere length. Crucially, if behaviour is causal then it should be associated with differential rates of telomere attrition. Using smoking behaviour as an example, we show that the evidence that smoking accelerates the rate of telomere attrition within individuals is currently weak. We conclude that the selective adoption hypothesis for the association between behaviour and telomere length is both mechanistically plausible and, if anything, more compatible with existing empirical evidence than the hypothesis that behaviour is causal.This article is part of the theme issue 'Understanding diversity in telomere dynamics'.
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Affiliation(s)
- Melissa Bateson
- Centre for Behaviour and Evolution and Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Daniel Nettle
- Centre for Behaviour and Evolution and Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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Titus AJ, Gallimore RM, Salas LA, Christensen BC. Cell-type deconvolution from DNA methylation: a review of recent applications. Hum Mol Genet 2018; 26:R216-R224. [PMID: 28977446 PMCID: PMC5886462 DOI: 10.1093/hmg/ddx275] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 07/11/2017] [Indexed: 02/07/2023] Open
Abstract
Recent advances in cell-type deconvolution approaches are adding to our understanding of the biology underlying disease development and progression. DNA methylation (DNAm) can be used as a biomarker of cell types, and through deconvolution approaches, to infer underlying cell type proportions. Cell-type deconvolution algorithms have two main categories: reference-based and reference-free. Reference-based algorithms are supervised methods that determine the underlying composition of cell types within a sample by leveraging differentially methylated regions (DMRs) specific to cell type, identified from DNAm measures of purified cell populations. Reference-free algorithms are unsupervised methods for use when cell-type specific DMRs are not available, allowing scientists to estimate putative cellular proportions or control for potential confounding from cell type. Reference-based deconvolution is typically applied to blood samples and has potentiated our understanding of the relation between immune profiles and disease by allowing estimation of immune cell proportions from archival DNA. Bioinformatic analyses using DNAm to infer immune cell proportions, part of a new field known as Immunomethylomics, provides a new direction for consideration in epigenome wide association studies (EWAS).
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Affiliation(s)
- Alexander J Titus
- Program in Quantitative Biomedical Sciences.,Department of Epidemiology
| | | | | | - Brock C Christensen
- Department of Epidemiology.,Department of Molecular and Systems Biology.,Department of Community and Family Medicine, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755, USA
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Li S, Wong EM, Bui M, Nguyen TL, Joo JHE, Stone J, Dite GS, Giles GG, Saffery R, Southey MC, Hopper JL. Causal effect of smoking on DNA methylation in peripheral blood: a twin and family study. Clin Epigenetics 2018; 10:18. [PMID: 29456763 PMCID: PMC5810186 DOI: 10.1186/s13148-018-0452-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/01/2018] [Indexed: 11/10/2022] Open
Abstract
Background Smoking has been reported to be associated with peripheral blood DNA methylation, but the causal aspects of the association have rarely been investigated. We aimed to investigate the association and underlying causation between smoking and blood methylation. Methods The methylation profile of DNA from the peripheral blood, collected as dried blood spots stored on Guthrie cards, was measured for 479 Australian women including 66 monozygotic twin pairs, 66 dizygotic twin pairs, and 215 sisters of twins from 130 twin families using the Infinium HumanMethylation450K BeadChip array. Linear regression was used to estimate associations between methylation at ~ 410,000 cytosine-guanine dinucleotides (CpGs) and smoking status. A regression-based methodology for twins, Inference about Causation through Examination of Familial Confounding (ICE FALCON), was used to assess putative causation. Results At a 5% false discovery rate, 39 CpGs located at 27 loci, including previously reported AHRR, F2RL3, 2q37.1 and 6p21.33, were found to be differentially methylated across never, former and current smokers. For all 39 CpG sites, current smokers had the lowest methylation level. Our study provides the first replication for two previously reported CpG sites, cg06226150 (SLC2A4RG) and cg21733098 (12q24.32). From the ICE FALCON analysis with smoking status as the predictor and methylation score as the outcome, a woman’s methylation score was associated with her co-twin’s smoking status, and the association attenuated towards the null conditioning on her own smoking status, consistent with smoking status causing changes in methylation. To the contrary, using methylation score as the predictor and smoking status as the outcome, a woman’s smoking status was not associated with her co-twin’s methylation score, consistent with changes in methylation not causing smoking status. Conclusions For middle-aged women, peripheral blood DNA methylation at several genomic locations is associated with smoking. Our study suggests that smoking has a causal effect on peripheral blood DNA methylation, but not vice versa. Electronic supplementary material The online version of this article (10.1186/s13148-018-0452-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shuai Li
- 1Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, Victoria Australia
| | - Ee Ming Wong
- 2Genetic Epidemiology Laboratory, Department of Pathology, University of Melbourne, Parkville, Victoria Australia.,3Precision Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, Victoria Australia
| | - Minh Bui
- 1Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, Victoria Australia
| | - Tuong L Nguyen
- 1Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, Victoria Australia
| | - Ji-Hoon Eric Joo
- 2Genetic Epidemiology Laboratory, Department of Pathology, University of Melbourne, Parkville, Victoria Australia.,3Precision Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, Victoria Australia
| | - Jennifer Stone
- 4Centre for Genetic Origins of Health and Disease, Curtin University and the University of Western Australia, Perth, Western Australia Australia
| | - Gillian S Dite
- 1Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, Victoria Australia
| | - Graham G Giles
- 1Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, Victoria Australia.,5Cancer Epidemiology and Intelligence Division, Cancer Council Victoria, Melbourne, Victoria Australia
| | - Richard Saffery
- 6Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria Australia.,7Department of Paediatrics, University of Melbourne, Parkville, Victoria Australia
| | - Melissa C Southey
- 2Genetic Epidemiology Laboratory, Department of Pathology, University of Melbourne, Parkville, Victoria Australia.,3Precision Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, Victoria Australia
| | - John L Hopper
- 1Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, Victoria Australia
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Huang H, Ji Y, Zhang J, Su Z, Liu M, Tong J, Ge C, Chen T, Li J. Aberrant DNA methylation in radon and/or cigarette smoke-induced malignant transformation in BEAS-2B human lung cell line. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2017; 80:1321-1330. [PMID: 29048996 DOI: 10.1080/15287394.2017.1384156] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
It is well known that cigarette smoking (CS) and/or radon (Rn) induce malignant transformation in lung cells. To investigate the mechanisms underlying lung carcinogenesis induced by CS, Rn; or Rn followed by CS using BEAS-2B cell line derived from human bronchial epithelial cells. BEAS-2B cells were exposed to either Rn (20,000 Bq/m3) for 30 min or CS (20%) for 10 min or Rn followed by CS for 40 min. Global and gene-specific DNA methylation modifications were measured by microarray and methylation-specific polymerase chain reaction. Cell cycle and apoptosis were determined by flow cytometry, while soft agar colony formation was conducted to assess the characteristics of malignant transformation. Data demonstrated global hypomethylation as well as gene-specific DNA methylation alterations in all treatment groups compared to unexposed control cells. In addition, Rn and CS produced DNA hypermethylation of protein tyrosine phosphatase receptor type M and ectodysplasin A2 receptor, two genes related to malignant transformation. In all treatment conditions, cell proliferation and survival of malignant cells was increased, while apoptosis was initially first passage elevated but decreased at passages 5-15. Our results indicate that aberrant DNA methylation plays an important role in Rn- and/or CS-induced malignant transformation. In addition, BEAS-2B cell line may be used as an in vitro model to investigate mechanisms underlying malignant transformation induced by ambient environmental contaminants.
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Affiliation(s)
- Huanhuan Huang
- a Department of Toxicology, School of Public Health , Medical College of Soochow University , Suzhou , China
| | - Yahui Ji
- a Department of Toxicology, School of Public Health , Medical College of Soochow University , Suzhou , China
| | - Jiayu Zhang
- a Department of Toxicology, School of Public Health , Medical College of Soochow University , Suzhou , China
| | - Zhigang Su
- a Department of Toxicology, School of Public Health , Medical College of Soochow University , Suzhou , China
| | - Mingxing Liu
- a Department of Toxicology, School of Public Health , Medical College of Soochow University , Suzhou , China
| | | | - Cuicui Ge
- b School of Radiation Medicine and Protection , Medical College of Soochow University , Suzhou , China
| | - Tao Chen
- a Department of Toxicology, School of Public Health , Medical College of Soochow University , Suzhou , China
| | - Jianxiang Li
- a Department of Toxicology, School of Public Health , Medical College of Soochow University , Suzhou , China
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Cappa R, Theroux L, Brenton JN. Pediatric Multiple Sclerosis: Genes, Environment, and a Comprehensive Therapeutic Approach. Pediatr Neurol 2017; 75:17-28. [PMID: 28843454 DOI: 10.1016/j.pediatrneurol.2017.07.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 06/03/2017] [Accepted: 07/06/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND Pediatric multiple sclerosis is an increasingly recognized and studied disorder that accounts for 3% to 10% of all patients with multiple sclerosis. The risk for pediatric multiple sclerosis is thought to reflect a complex interplay between environmental and genetic risk factors. MAIN FINDINGS Environmental exposures, including sunlight (ultraviolet radiation, vitamin D levels), infections (Epstein-Barr virus), passive smoking, and obesity, have been identified as potential risk factors in youth. Genetic predisposition contributes to the risk of multiple sclerosis, and the major histocompatibility complex on chromosome 6 makes the single largest contribution to susceptibility to multiple sclerosis. With the use of large-scale genome-wide association studies, other non-major histocompatibility complex alleles have been identified as independent risk factors for the disease. The bridge between environment and genes likely lies in the study of epigenetic processes, which are environmentally-influenced mechanisms through which gene expression may be modified. CONCLUSIONS This article will review these topics to provide a framework for discussion of a comprehensive approach to counseling and ultimately treating the pediatric patient with multiple sclerosis.
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Affiliation(s)
- Ryan Cappa
- Department of Neurology, Division of Pediatric Neurology, University of Virginia, Charlottesville, Virginia
| | - Liana Theroux
- Department of Neurology, Division of Pediatric Neurology, University of Virginia, Charlottesville, Virginia
| | - J Nicholas Brenton
- Department of Neurology, Division of Pediatric Neurology, University of Virginia, Charlottesville, Virginia.
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Associations of Helicobacter pylori infection and chronic atrophic gastritis with accelerated epigenetic ageing in older adults. Br J Cancer 2017; 117:1211-1214. [PMID: 28898235 PMCID: PMC5674108 DOI: 10.1038/bjc.2017.314] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/03/2017] [Accepted: 08/18/2017] [Indexed: 12/20/2022] Open
Abstract
Background: Helicobacter pylori (HP) infection and chronic atrophic gastritis (CAG) have shown strong associations with the development of gastric cancer. This study aimed to examine whether both risk factors are associated with accelerated epigenetic ageing, as determined by the ‘DNA methylation age’, in a population-based study of older adults (n=1477). Methods: Serological measurements of HP antibodies and pepsinogen I and II for CAG definition were obtained by ELISA kits. Whole blood DNA methylation profiles were measured by Illumina Human Methylation450K Beadchip. DNA methylation ages were calculated by two algorithms proposed by Horvath and Hannum et al. Results: After adjusting for potential covariates in linear regression models, we found that HP infection, infection with virulent HP strains (CagA+) and severe CAG were significantly associated with an increase in DNA methylation age by ∼0.4, 0.6 and 1 year (all P-values <0.05), respectively. Conclusions: Our study indicates that both CagA+ HP infection and CAG go along with accelerated epigenetic ageing.
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Gao X, Gào X, Zhang Y, Breitling LP, Schöttker B, Brenner H. Associations of self-reported smoking, cotinine levels and epigenetic smoking indicators with oxidative stress among older adults: a population-based study. Eur J Epidemiol 2017; 32:443-456. [PMID: 28434075 DOI: 10.1007/s10654-017-0248-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/14/2017] [Indexed: 02/02/2023]
Abstract
Tobacco smoking and oxidative stress (OS) are both related to a wide spectrum of adverse age-related health outcomes, but their association is not yet well-established. We examined the associations of self-reported smoking indicators, serum cotinine levels and smoking-related DNA methylation biomarkers with two urinary proxy markers of OS, 8-isoprostane (8-iso) and 8-hydroxy-2'-deoxyguanosine (8-oxodG), in two independent subsets of older adults recruited in Germany (discovery set: n = 978, validation set: n = 531). We obtained DNA methylation profiles in whole blood samples by Illumina Human Methylation450K Beadchip and measured the urinary levels of both OS markers using commercial ELISA kits. After controlling for potential confounders, current smoking, cumulative smoking exposure (pack-years) and serum cotinine levels (ng/ml) were strongly associated with 8-iso levels (p values <0.0001, 0.004 and 0.001, respectively). Of 151 previously identified smoking-related CpG sites, 71 loci were associated with 8-iso levels after correction for multiple testing (FDR < 0.05) in the validation phase and were designated as loci related to 8-iso levels defined OS. In addition, serum cotinine levels, cumulative smoking exposure and a smoking index (SI) based on the 71 identified loci manifested monotonic associations with 8-iso levels. However, we did not observe any associations between these smoking indicators and 8-oxodG levels. In conclusion, this study suggests that smoking-related epigenetic alterations are closely correlated with smoking-induced OS. The identified CpG sites could potentially be prognostic epigenetic markers of OS and OS-related health outcomes. Our findings and the underlying mechanisms should be followed up in further, preferably longitudinal studies.
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Affiliation(s)
- Xu Gao
- Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany
| | - Xīn Gào
- Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany.,Network Aging Research, University of Heidelberg, Bergheimer Straße 20, 69115, Heidelberg, Germany
| | - Yan Zhang
- Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany
| | - Lutz Philipp Breitling
- Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany
| | - Ben Schöttker
- Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany.,Network Aging Research, University of Heidelberg, Bergheimer Straße 20, 69115, Heidelberg, Germany.,Institute of Health Care and Social Sciences, FOM University, Essen, Germany
| | - Hermann Brenner
- Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany. .,Network Aging Research, University of Heidelberg, Bergheimer Straße 20, 69115, Heidelberg, Germany. .,Division of Preventive Oncology, National Center for Tumor Diseases (NCT), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 460, 69120, Heidelberg, Germany. .,German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.
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Gao X, Thomsen H, Zhang Y, Breitling LP, Brenner H. The impact of methylation quantitative trait loci (mQTLs) on active smoking-related DNA methylation changes. Clin Epigenetics 2017; 9:87. [PMID: 28824732 PMCID: PMC5561570 DOI: 10.1186/s13148-017-0387-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/10/2017] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Methylation quantitative trait loci (mQTLs) are the genetic variants that may affect the DNA methylation patterns of CpG sites. However, their roles in influencing the disturbances of smoking-related epigenetic changes have not been well established. This study was conducted to address whether mQTLs exist in the vicinity of smoking-related CpG sites (± 50 kb) and to examine their associations with smoking exposure and all-cause mortality in older adults. RESULTS We obtained DNA methylation profiles in whole blood samples by Illumina Infinium Human Methylation 450 BeadChip array of two independent subsamples of the ESTHER study (discovery set, n = 581; validation set, n = 368) and their corresponding genotyping data using the Illumina Infinium OncoArray BeadChip. After correction for multiple testing (FDR), we successfully identified that 70 out of 151 previously reported smoking-related CpG sites were significantly associated with 192 SNPs within the 50 kb search window of each locus. The 192 mQTLs significantly influenced the active smoking-related DNA methylation changes, with percentage changes ranging from 0.01 to 18.96%, especially for the weakly/moderately smoking-related CpG sites. However, these identified mQTLs were not directly associated with active smoking exposure or all-cause mortality. CONCLUSIONS Our findings clearly demonstrated that if not dealt with properly, the mQTLs might impair the power of epigenetic-based models of smoking exposure to a certain extent. In addition, such genetic variants could be the key factor to distinguish between the heritable and smoking-induced impact on epigenome disparities. These mQTLs are of special importance when DNA methylation markers measured by Illumina Infinium assay are used for any comparative population studies related to smoking-related cancers and chronic diseases.
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Affiliation(s)
- Xu Gao
- 0000 0004 0492 0584grid.7497.dDivision of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
| | - Hauke Thomsen
- 0000 0004 0492 0584grid.7497.dDivision of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Yan Zhang
- 0000 0004 0492 0584grid.7497.dDivision of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
| | - Lutz Philipp Breitling
- 0000 0004 0492 0584grid.7497.dDivision of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
| | - Hermann Brenner
- 0000 0004 0492 0584grid.7497.dDivision of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
- 0000 0004 0492 0584grid.7497.dDivision of Preventive Oncology, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT), Im Neuenheimer Feld 460, 69120 Heidelberg, Germany
- 0000 0004 0492 0584grid.7497.dGerman Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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Gao X, Zhang Y, Saum KU, Schöttker B, Breitling LP, Brenner H. Tobacco smoking and smoking-related DNA methylation are associated with the development of frailty among older adults. Epigenetics 2016; 12:149-156. [PMID: 28001461 DOI: 10.1080/15592294.2016.1271855] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Tobacco smoking is a preventable environmental factor that contributes to a wide spectrum of age-related health outcomes; however, its association with the development of frailty is not yet well established. We examined the associations of self-reported smoking indicators, serum cotinine levels and smoking-related DNA methylation biomarkers with a quantitative frailty index (FI) in 2 independent subsets of older adults (age 50-75) recruited in Saarland, Germany in 2000 - 2002 (discovery set: n = 978, validation set: n = 531). We obtained DNA methylation profiles in whole blood samples by Illumina HumanMethylation450 BeadChip and calculated the FI according to the method of Mitnitski and Rockwood. Mixed linear regression models were implemented to assess the associations between smoking indicators and the FI. After controlling for potential covariates, current smoking, cumulative smoking exposure (pack-years), and time after smoking cessation (years) were significantly associated with the FI (P-value < 0.05). In the discovery panel, 17 out of 151 previously identified smoking-related CpG sites were associated with the FI after correction for multiple testing (FDR < 0.05). Nine of them survived in the validation phase and were designated as frailty-associated loci. A smoking index (SI) based on the 9 loci manifested a monotonic association with the FI. In conclusion, this study suggested that epigenetic alterations could play a role in smoking-associated development of frailty. The identified CpG sites have the potential to be prognostic biomarkers of frailty and frailty-related health outcomes. Our findings and the underlying mechanisms should be followed up in further, preferably longitudinal studies.
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Affiliation(s)
- Xu Gao
- a Division of Clinical Epidemiology and Aging Research , German Cancer Research Center (DKFZ) , Heidelberg , Germany
| | - Yan Zhang
- a Division of Clinical Epidemiology and Aging Research , German Cancer Research Center (DKFZ) , Heidelberg , Germany
| | - Kai-Uwe Saum
- a Division of Clinical Epidemiology and Aging Research , German Cancer Research Center (DKFZ) , Heidelberg , Germany
| | - Ben Schöttker
- a Division of Clinical Epidemiology and Aging Research , German Cancer Research Center (DKFZ) , Heidelberg , Germany.,b Network Aging Research , University of Heidelberg , Heidelberg , Germany
| | - Lutz Philipp Breitling
- a Division of Clinical Epidemiology and Aging Research , German Cancer Research Center (DKFZ) , Heidelberg , Germany
| | - Hermann Brenner
- a Division of Clinical Epidemiology and Aging Research , German Cancer Research Center (DKFZ) , Heidelberg , Germany.,b Network Aging Research , University of Heidelberg , Heidelberg , Germany.,c Division of Preventive Oncology , German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT) , Heidelberg , Germany.,d German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) , Heidelberg , Germany
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