Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Jul 4;54(1):1900457.
doi: 10.1183/13993003.00457-2019. Print 2019 Jul.

Epigenome-wide association study of lung function level and its change

Affiliations

Epigenome-wide association study of lung function level and its change

Medea Imboden et al. Eur Respir J. .

Abstract

Previous reports link differential DNA methylation (DNAme) to environmental exposures that are associated with lung function. Direct evidence on lung function DNAme is, however, limited. We undertook an agnostic epigenome-wide association study (EWAS) on pre-bronchodilation lung function and its change in adults.In a discovery-replication EWAS design, DNAme in blood and spirometry were measured twice, 6-15 years apart, in the same participants of three adult population-based discovery cohorts (n=2043). Associated DNAme markers (p<5×10-7) were tested in seven replication cohorts (adult: n=3327; childhood: n=420). Technical bias-adjusted residuals of a regression of the normalised absolute β-values on control probe-derived principle components were regressed on level and change of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and their ratio (FEV1/FVC) in the covariate-adjusted discovery EWAS. Inverse-variance-weighted meta-analyses were performed on results from discovery and replication samples in all participants and never-smokers.EWAS signals were enriched for smoking-related DNAme. We replicated 57 lung function DNAme markers in adult, but not childhood samples, all previously associated with smoking. Markers not previously associated with smoking failed replication. cg05575921 (AHRR (aryl hydrocarbon receptor repressor)) showed the statistically most significant association with cross-sectional lung function (FEV1/FVC: pdiscovery=3.96×10-21 and pcombined=7.22×10-50). A score combining 10 DNAme markers previously reported to mediate the effect of smoking on lung function was associated with lung function (FEV1/FVC: p=2.65×10-20).Our results reveal that lung function-associated methylation signals in adults are predominantly smoking related, and possibly of clinical utility in identifying poor lung function and accelerated decline. Larger studies with more repeat time-points are needed to identify lung function DNAme in never-smokers and in children.

PubMed Disclaimer

Conflict of interest statement

Conflict of interest: M. Imboden has nothing to disclose. Conflict of interest: M. Wielscher has nothing to disclose. Conflict of interest: F.I. Rezwan has nothing to disclose. Conflict of interest: A.F.S. Amaral has nothing to disclose. Conflict of interest: E. Schaffner has nothing to disclose. Conflict of interest: A. Jeong has nothing to disclose. Conflict of interest: A. Beckmeyer-Borowko has nothing to disclose. Conflict of interest: S.E. Harris reports grants from Medical Research Council, Biotechnology and Biological Sciences Research Council, Age UK and The Wellcome Trust, during the conduct of the study. Conflict of interest: J.M. Starr has nothing to disclose. Conflict of interest: I.J. Deary reports grants from Age UK and Medical Research Council, during the conduct of the study. Conflict of interest: C. Flexeder has nothing to disclose. Conflict of interest: M. Waldenberger has nothing to disclose. Conflict of interest: A. Peters has nothing to disclose. Conflict of interest: H. Schulz reports grants from German Federal Ministry of Education and Research (BMBF), during the conduct of the study. Conflict of interest: S. Chen has nothing to disclose. Conflict of interest: S.K. Sunny has nothing to disclose. Conflict of interest: W.J.J. Karmaus has nothing to disclose. Conflict of interest: Y. Jiang has nothing to disclose. Conflict of interest: G. Erhart has nothing to disclose. Conflict of interest: F. Kronenberg has nothing to disclose. Conflict of interest: R. Arathimos has nothing to disclose. Conflict of interest: G.C. Sharp has nothing to disclose. Conflict of interest: A.J. Henderson reports grants from Medical Research Council and Wellcome Trust, during the conduct of the study. Conflict of interest: Y. Fu has nothing to disclose. Conflict of interest: P. Piirilä has nothing to disclose. Conflict of interest: K.H. Pietiläinen has nothing to disclose. Conflict of interest: M. Ollikainen has nothing to disclose. Conflict of interest: A. Johansson has nothing to disclose. Conflict of interest: U. Gyllensten has nothing to disclose. Conflict of interest: M de Vries has nothing to disclose. Conflict of interest: D.A. van der Plaat has nothing to disclose. Conflict of interest: K. de Jong has nothing to disclose. Conflict of interest: H.M. Boezen has nothing to disclose. Conflict of interest: I.P. Hall reports grants from GSK and Boehringer Ingelheim, outside the submitted work. Conflict of interest: M.D. Tobin reports grants from Pfizer and GSK, outside the submitted work. Conflict of interest: M-R. Jarvelin has nothing to disclose. Conflict of interest: J.W. Holloway reports grants from European Union and National Institutes of Health, during the conduct of the study. Conflict of interest: D. Jarvis reports grants from European Union, Medical Research Council and Asthma UK, during the conduct of the study. Conflict of interest: N.M. Probst-Hensch has nothing to disclose.

Figures

FIGURE 1
FIGURE 1
Flow of the multilevel discovery design of the epigenome-wide association study (EWAS) on lung function parameters: forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC. DNAme1: DNA methylation at time-point 1; DNAme2: DNA methylation at time-point 2. #: base model (Mbase) EWAS was covariate adjusted for age, age squared, height, squared deviation from the mean of height, sex and interaction terms of age, age squared, height and squared deviation of height with sex, education (low, medium and high), body mass index, spirometer type, study centre, and cell composition. : smoking model EWAS (Msmok) additionally adjusted for smoking covariates: history of smoking intensity as pack-years smoked up to the time-point of data collection for regressions and for smoking status (current smoker, ex-smoker and never-smoker). EWAS longitudinally predicting the change in lung function (EWASpredict) was additionally adjusted for lung function at time-point 1.
FIGURE 2
FIGURE 2
a, b) Effect of ageing on the associations between DNA methylation (DNAme) and lung function: quantile–quantile plots of the cross-sectional covariate-adjusted discovery epigenome-wide association study (EWAS) (Mbase#) on forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) at a) time-point 1 and b) time-point 2, all participants. Increase in numbers of signals with ageing. For FEV1/FVC, we identified 21 CpGs at time-point 2 compared with three CpGs at time-point 1 to be statistically significant. Meta-analyses were performed without genomic control (for time-point 1 inflation factor λ=1.15 and for time-point 2 inflation factor λ=1.14). For analogous figure for cross-sectional associations with FEV1 and FVC, see supplementary figure S2. c, d) Effect of smoking adjustment on the associations between DNAme and lung function: quantile–quantile plots of c) the repeat cross-sectional covariate-adjusted discovery EWAS (Mbase#; inflation factor λ=1.13) and d) additionally smoking adjusted (Msmok; inflation factor λ=1.05), all participants. Decrease in numbers of signals after smoking adjustment. #: base model (Mbase) EWAS was covariate adjusted for age, age squared, height, squared deviation from the mean of height, sex and interaction terms of age, age squared, height and squared deviation of height with sex, education (low, medium and high), body mass index, spirometer type, study centre, and cell composition. : smoking-adjusted model (Msmok): covariates applied for Mbase and additionally smoking status and pack-years smoked.
FIGURE 3
FIGURE 3
a) Manhattan and b) quantile–quantile plots of the covariate-adjusted prediction# epigenome-wide association study (EWAS) (Mbase) on forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC), all participants. Meta-analysis of the prediction association was performed without genomic control (inflation factor λ=0.95). For analogous figure for associations with change in FEV1 and FVC, see supplementary figure S4. #: predictive associations of DNA methylation at first time-point with change in lung function during follow-up. : base model (Mbase) EWAS was covariate adjusted for age, age squared, height, FEV1/FVC at time-point 1, squared deviation from the mean of height, sex and interaction terms of age, age squared, height and squared deviation of height with sex, education (low, medium and high), body mass index, spirometer type, study centre, and cell composition.
FIGURE 4
FIGURE 4
Forest plots of cohort-specific results and meta-analyses of the association of the mediation smoking index (Mediation-SI) with forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) and change in FEV1/FVC in a, b) ever-smokers and c, d) never-smokers in the discovery cohorts: a, c) time-point 2 and b, d) prediction. Associations run applying base model adjustment (Mbase#). #: base model (Mbase) epigenome-wide association study was covariate adjusted for age, age squared, height, squared deviation from the mean of height, sex and interaction terms of age, age squared, height and squared deviation of height with sex, education (low, medium and high), body mass index, spirometer type, study centre, and cell composition. Prediction models were additionally adjusted for FEV1/FVC at time-point 1.
FIGURE 5
FIGURE 5
Distribution and association# of a) mediation smoking index (Mediation-SI) and b) self-reported smoking history (pack-years) with forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) with 95% confidence intervals (shaded). Box plots of a) Mediation-SI (median (range) 0.3 (−1.7–5.2)) and b) pack-years (median (range) 2.0 (0–145.9)) in all participants of SAPALDIA are shown at the top of each panel. Red dotted lines indicate box plot interquartile range (IQR) borders. Whiskers indicate 1.5 IQR of the lower and upper quartile; outliers are indicated. For analogous figures for associations of Mediation-SI with FEV1 and FVC, see supplementary figures S6 and S7, respectively. #: associations were adjusted for the base model (Mbase): age, age squared, height, squared deviation from the mean of height, sex and interaction terms of age, age squared, height and squared deviation of height with sex, education (low, medium and high), body mass index, spirometer type, study centre, and cell composition. : Mediation-SI can be constructed for all participants irrespective of their smoking status. The Mbase-adjusted model explained 17.5% of the variance in the outcome. The Mbase-adjusted model additionally adjusted for the Mediation-SI explained 19.6% of the FEV1/FVC variance (total adjusted R2=0.196) of which 2.8% of the variance was specifically explained by the Mediation-SI variable. This was comparable to the variance explained by the Mbase-adjusted model additionally adjusted for pack-years and smoking status corresponding to the Msmok model (R2=0.198, and with 1.6% of the variance specifically explained by the pack-years variable). Model including both smoking adjustments (Msmok and additionally Mediation-SI) explained 20.1% of the FEV1/FVC variance.
FIGURE 6
FIGURE 6
Distribution of adjusted mediation smoking index (Mediation-SI) in SAPALDIA at time-point 2. a) Smoking status: adjusted for age, sex and education. Never-smokers (n=395), ex-smokers (n=356) and current smokers (n=211). b) Years since quitting: adjusted for age, sex, education, pack-years and cigarettes per day. Ex-smokers (n=356). c) Pack-years: adjusted for age, sex, education and cigarettes per day. Current smokers (n=211). d) Cigarettes per day: adjusted for age, sex, education and pack-years. Current smokers (n=211). Data are presented as median with interquartile range (IQR) (boxes) and 1.5 IQR of the lower and upper quartile (whiskers); outliers are indicated.

Comment in

References

    1. Klimentidis YC, Vazquez AI, de Los Campos G, et al. . Heritability of pulmonary function estimated from pedigree and whole-genome markers. Front Genet 2013; 4: 174. - PMC - PubMed
    1. Joehanes R, Just AC, Marioni RE, et al. . Epigenetic signatures of cigarette smoking. Circ Cardiovasc Genet 2016; 9: 436–447. - PMC - PubMed
    1. Gao X, Jia M, Zhang Y, et al. . DNA methylation changes of whole blood cells in response to active smoking exposure in adults: a systematic review of DNA methylation studies. Clin Epigenetics 2015; 7: 113. - PMC - PubMed
    1. de Vries M, van der Plaat DA, Nedeljkovic I, et al. . From blood to lung tissue: effect of cigarette smoke on DNA methylation and lung function. Respir Res 2018; 19: 212. - PMC - PubMed
    1. Machin M, Amaral AF, Wielscher M, et al. . Systematic review of lung function and COPD with peripheral blood DNA methylation in population based studies. BMC Pulm Med 2017; 17: 54. - PMC - PubMed

Publication types