From Differential DNA Methylation in COPD to Mitochondria: Regulation of AHRR Expression Affects Airway Epithelial Response to Cigarette Smoke.

Cigarette smoking causes hypomethylation of the gene Aryl Hydrocarbon Receptor Repressor (AHRR), which regulates detoxification and oxidative stress-responses. We investigated whether AHRR DNA methylation is related to chronic obstructive pulmonary disease (COPD) and studied its function in airway epithelial cells (AECs). The association with COPD was assessed in blood from never and current smokers with/without COPD, and in AECs from ex-smoking non-COPD controls and GOLD stage II-IV COPD patients cultured with/without cigarette smoke extract (CSE). The effect of CRISPR/Cas9-induced AHRR knockout on proliferation, CSE-induced mitochondrial membrane potential and apoptosis/necrosis in human bronchial epithelial 16HBE cells was studied. In blood, DNA methylation of AHRR at cg05575921 and cg21161138 was lower in smoking COPD subjects than smoking controls. In vitro, AHRR DNA methylation at these CpG-sites was lower in COPD-derived than control-derived AECs only upon CSE exposure. Upon AHRR knockout, we found a lower proliferation rate at baseline, stronger CSE-induced decrease in mitochondrial membrane potential, and higher CSE-induced late apoptosis/necroptosis. Together, our results show lower DNA methylation of AHRR upon smoking in COPD patients compared to non-COPD controls. Our data suggest that higher airway epithelial AHRR expression may lead to impaired cigarette smoke-induced mitochondrial dysfunction and apoptosis/necroptosis, potentially promoting unprogrammed/immunogenic cell death.

Changes in lung function in European adults born between 1884 and 1996 and implications for the diagnosis of lung disease: a cross-sectional analysis of ten population-based studies.

BACKGROUND: During the past century, socioeconomic and scientific advances have resulted in changes in the health and physique of European populations. Accompanying improvements in lung function, if unrecognised, could result in the misclassification of lung function measurements and misdiagnosis of lung diseases. We therefore investigated changes in population lung function with birth year across the past century, accounting for increasing population height, and examined how such changes might influence the interpretation of lung function measurements. METHODS: In our analyses of cross-sectional data from ten European population-based studies, we included individuals aged 20-94 years who were born between 1884 and 1996, regardless of previous respiratory diagnoses or symptoms. FEV1, forced vital capacity (FVC), height, weight, and smoking behaviour were measured between 1965 and 2016. We used meta-regression to investigate how FEV1 and FVC (adjusting for age, study, height, sex, smoking status, smoking pack-years, and weight) and the FEV1/FVC ratio (adjusting for age, study, sex, and smoking status) changed with birth year. Using estimates from these models, we graphically explored how mean lung function values would be expected to progressively deviate from predicted values. To substantiate our findings, we used linear regression to investigate how the FEV1 and FVC values predicted by 32 reference equations published between 1961 and 2015 changed with estimated birth year. FINDINGS: Across the ten included studies, we included 243 465 European participants (mean age 51·4 years, 95% CI 51·4-51·5) in our analysis, of whom 136 275 (56·0%) were female and 107 190 (44·0%) were male. After full adjustment, FEV1 increased by 4·8 mL/birth year (95% CI 2·6-7·0; p<0·0001) and FVC increased by 8·8 mL/birth year (5·7-12·0; p<0·0001). Birth year-related increases in the FEV1 and FVC values predicted by published reference equations corroborated these findings. This height-independent increase in FEV1 and FVC across the last century will have caused mean population values to progressively exceed previously predicted values. However, the population mean adjusted FEV1/FVC ratio decreased by 0·11 per 100 birth years (95% CI 0·09-0·14; p<0·0001). INTERPRETATION: If current diagnostic criteria remain unchanged, the identified shifts in European values will allow the easier fulfilment of diagnostic criteria for lung diseases such as chronic obstructive pulmonary disease, but the systematic underestimation of lung disease severity. FUNDING: The European Respiratory Society, AstraZeneca, Chiesi Farmaceutici, GlaxoSmithKline, Menarini, and Sanofi-Genzyme.

Risk of neuropsychiatric adverse events associated with varenicline treatment for smoking cessation among Dutch population: A sequence symmetry analysis.

PURPOSE: Varenicline is an effective treatment for smoking cessation. While clinical trials did not confirm a causal role, case reports suggested a possible link of varenicline with neuropsychiatric adverse drug events (NPAEs). This study aims to investigate the risk of NPAEs associated with varenicline initiation among the general population in a real-world setting. METHODS: We conducted a sequence symmetry analysis (SSA) based on the University of Groningen IADB.nl prescription database. We selected incident users of both varenicline and marker drugs for NPAEs, including depression, anxiety and sleep disorder within different time-intervals. Adjusted sequence ratios (aSR) were calculated for each time-interval. RESULTS: Within 365-days' time-interval 1066 patients were incident users of both varenicline and NPAE marker drugs. In total, 505 patients were prescribed varenicline before NPAE marker drugs and 561 vice versa (crude sequence ratio [cSR] 0.90, 95% CI: 0.80-1.02). After adjustments for trends in prescriptions, overall a null association was found (aSR 1.00, 95% CI: 0.89-1.13). Regarding specific NPAEs, no increased risks were found for depression nor anxiety within any time-interval. A small transient increased risk was found for sleep disorders, particularly in earlier time-intervals 3 and 6 months (aSRs 1.52, 95% CI: 1.10-2.11 and 1.45, 95% CI: 1.15-1.83, respectively). Subgroup and sensitivity analyses showed similar findings. CONCLUSIONS: Varenicline initiation was unlikely to be associated with an increased risk of taking anti-depressants nor anti-anxiety drugs. Yet a small, but statistically significant, transient association with drugs for sleep disorders was noticed, possibly associated with withdrawal symptoms caused by smoking cessation.

Psychosocial work factors and blood pressure among 63 800 employees from The Netherlands in the Lifelines Cohort Study.

OBJECTIVES: Previous studies on the association between psychosocial work factors and blood pressure mainly focused on specific occupations or populations and had limited sample sizes. We, therefore, investigated the associations between psychosocial work factors and blood pressure in a large general working population in the Netherlands. METHODS: We included 63 800 employees from the Netherlands, aged 18-65 years, with blood pressure measurements and a reliable job code at baseline. Psychosocial work factors (job strain, effort-reward imbalance (ERI) and emotional demands) in the current job were estimated with three recently developed psychosocial job exposure matrices. To examine the associations, regression analyses adjusted for covariates (age, sex, body mass index, education, monthly income, pack-years, smoking, alcohol consumption and antihypertensive medication (not included for hypertension)) were performed. RESULTS: Higher job strain was associated with higher systolic blood pressure (SBP) (B (regression coefficients) (95% CI) 2.14 (1.23 to 3.06)) and diastolic blood pressure (DBP) (B (95% CI) 1.26 (0.65 to 1.86)) and with higher odds of hypertension (OR (95% CI) 1.43 (1.17 to 1.74)). Higher ERI was associated with higher DBP (B (95% CI) 4.37 (3.05 to 5.68)), but not with SBP or hypertension. Higher emotional demands were associated with lower SBP (B (95% CI) -0.90 (-1.14 to -0.66)) and lower odds of hypertension ((OR) (95% CI) 0.91 (0.87 to 0.96)). CONCLUSIONS: In the general working population, employees in jobs with high job strain and ERI have higher blood pressure compared with employees with low job strain and ERI. Emotional demands at work are inversely associated with blood pressure.

Spirometric phenotypes from early childhood to young adulthood: a Chronic Airway Disease Early Stratification study.

BACKGROUND: The prevalences of obstructive and restrictive spirometric phenotypes, and their relation to early-life risk factors from childhood to young adulthood remain poorly understood. The aim was to explore these phenotypes and associations with well-known respiratory risk factors across ages and populations in European cohorts. METHODS: We studied 49 334 participants from 14 population-based cohorts in different age groups (≤10, >10-15, >15-20, >20-25 years, and overall, 5-25 years). The obstructive phenotype was defined as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) z-score less than the lower limit of normal (LLN), whereas the restrictive phenotype was defined as FEV1/FVC z-score ≥LLN, and FVC z-score

A Protective Role of FAM13A in Human Airway Epithelial Cells Upon Exposure to Cigarette Smoke Extract.

BACKGROUND: Chronic Obstructive Pulmonary Disease (COPD) is a progressive lung disease characterized by chronic inflammation upon inhalation of noxious particles, e.g., cigarette smoke. FAM13A is one of the genes often found to be associated with COPD, however its function in the pathophysiology of COPD is incompletely understood. We studied its role in airway epithelial barrier integrity and cigarette smoke-induced epithelial responses. MATERIALS AND METHODS: Protein level and localization of FAM13A was assessed with immunohistochemistry in lung tissue from COPD patients and non-COPD controls. In vitro, FAM13A expression was determined in the absence or presence of cigarette smoke extract (CSE) in primary airway epithelial cells (AECs) from COPD patients and controls by western blotting. FAM13A was overexpressed in cell line 16HBE14o- and its effect on barrier function was monitored real-time by electrical resistance. Expression of junctional protein E-cadherin and ß-catenin was assessed by western blotting. The secretion of neutrophil attractant CXCL8 upon CSE exposure was measured by ELISA. RESULTS: FAM13A was strongly expressed in airway epithelium, but significantly weaker in airways of COPD patients compared to non-COPD controls. In COPD-derived AECs, but not those of controls, FAM13A was significantly downregulated by CSE. 16HBE14o- cells overexpressing FAM13A built up epithelial resistance significantly more rapidly, which was accompanied by higher E-cadherin expression and reduced CSE-induced CXCL8 levels. CONCLUSION: Our data indicate that the expression of FAM13A is lower in airway epithelium of COPD patients compared to non-COPD controls. In addition, cigarette smoking selectively downregulates airway epithelial expression of FAM13A in COPD patients. This may have important consequences for the pathophysiology of COPD, as the more rapid build-up of epithelial resistance upon FAM13A overexpression suggests improved (re)constitution of barrier function. The reduced epithelial secretion of CXCL8 upon CSE-induced damage suggests that lower FAM13A expression upon cigarette smoking may facilitate epithelial-driven neutrophilia.

Neuropsychiatric safety of varenicline in the general and COPD population with and without psychiatric disorders: a retrospective cohort study in a real-world setting.

OBJECTIVES: To evaluate the real-world association between varenicline and neuropsychiatric adverse events (NPAEs) in general and chronic obstructive pulmonary disease (COPD) population with and without psychiatric disorders compared with nicotine replacement therapy (NRT) to strengthen the knowledge of varenicline safety. DESIGN: A retrospective cohort study. SETTING: Prescription database IADB.nl, the Netherlands. PARTICIPANTS: New users of varenicline or NRT among general (≥18 years) and COPD (≥40 years) population. Psychiatric subcohort was defined as people prescribed psychotropic medications (≥2) within 6 months before the index date. OUTCOME MEASURES: The incidence of NPAEs including depression, anxiety and insomnia, defined by new or naive prescriptions of related medications in IADB.nl within 24 weeks after the first treatment initiation of varenicline or NRT. RESULTS: For the general population in non-psychiatric cohort, the incidence of total NPAEs in varenicline (4480) and NRT (1970) groups was 10.5% and 12.6%, respectively (adjusted OR (aOR) 0.85, 95% CI 0.72 to 1.00). For the general population in psychiatric cohort, the incidence of total NPAEs was much higher, 75.3% and 78.5% for varenicline (1427) and NRT (1200) groups, respectively (aOR 0.82, 95% CI 0.68 to 0.99). For the COPD population (1598), there were no differences in the incidence of NPAEs between comparison groups in both the psychiatric cohort (aOR 0.97, 95% CI 0.66 to 1.44) and non-psychiatric cohort (aOR 0.81, 95% CI 0.54 to 1.20). Results from subgroup or sensitivity analyses also did not reveal increased risks of NPAEs but showed decreased risk of some subgroup NPAEs associated with varenicline. CONCLUSIONS: In contrast to the concerns of a possible increased risk of NPAEs among varenicline users, we found a relative decreased risk of total NPAEs in varenicline users of the general population in psychiatric or non-psychiatric cohorts compared with NRT and no difference for NPAEs between varenicline and NRT users in smaller population with COPD.

Prevalence, predictors, and outcomes of clonal hematopoiesis in individuals aged ≥80 years.

Clonal hematopoiesis (CH), characterized by a fraction of peripheral blood cells carrying an acquired genetic variant, emerges with age. Although in general CH is associated with increased mortality and morbidity, no higher risk of death was observed for individuals ≥80 years. Here, we investigated CH in 621 individuals aged ≥80 years from the population-based LifeLines cohort. Sensitive error-corrected sequencing of 27 driver genes at a variant allele frequency ≥1% revealed CH in the majority (62%) of individuals, independent of gender. The observed mutational spectrum was dominated by DNMT3A and TET2 variants, which frequently (29%) displayed multiple mutations per gene. In line with previous results in individuals ≥80 years, the overall presence of CH did not associate with a higher risk of death (hazard ratio, 0.91; 95% confidence interval, 0.70-1.18; P = .48). Being able to assess the causes of death, we observed no difference between individuals with or without CH, except for deaths related to hematological malignancies. Interestingly, comparison of mutational spectra confined to DNMT3A and TET2 vs spectra containing other mutated genes, showed a higher risk of death when mutations other than DNMT3A or TET2 were present (hazard ratio, 1.48; 95% confidence interval, 1.06-2.08; P = .025). Surprisingly, no association of CH with cardiovascular morbidity was found, irrespective of clone size. Further, CH associated with chronic obstructive pulmonary disease. Data on estimated exposure to DNA damaging toxicities (ie, smoking, a history of cancer [as a proxy for previous genotoxic therapy], and job-related pesticide exposure) showed an association with spliceosome and ASXL1 variants, but not with DNMT3A and TET2 variants.

Airborne occupational exposures and inflammatory biomarkers in the Lifelines cohort study.

INTRODUCTION: Inflammatory biomarkers are associated with negative health outcomes. In this study, we investigated the associations between airborne occupational exposures and levels and changes in inflammatory biomarkers. METHODS: We included 79 604 adults at baseline from the Lifelines cohort of which 48 403 (60.8%) subjects were followed for a median of 4.5 years. Airborne occupational exposures at the current or last-held job at baseline were estimated with the occupational asthma-specific job-exposure matrix. Both in cross-sectional and longitudinal analyses, we used linear regression models (adjusted for age, sex, education, monthly income, body mass index, smoking, pack-years, asthma and anti-inflammatory medication) to investigate the associations between airborne occupational exposures (allergens, reactive chemicals, pesticides and micro-organisms) and inflammatory biomarkers (C reactive protein (CRP), eosinophils and neutrophils). RESULTS: In the cross-sectional analyses, exposure to allergens, reactive chemicals and micro-organisms was associated with a lower (Log) CRP level (B(95% CI)=-0.05 (-0.08 to -0.02),-0.05(-0.08 to -0.02) and -0.09(-0.16 to -0.02), respectively). Likewise, exposure to allergens, reactive chemicals, pesticides and micro-organisms was associated with a lower (log) neutrophils count (-0.01 (-0.02 to -0.01), -0.01 (-0.02 to -0.01),-0.02 (-0.04 to -0.01) and -0.02(-0.03 to -0.01), respectively). No association between airborne occupational exposures and eosinophils count was found. In the longitudinal analyses, no association between airborne occupational exposures and changes in inflammatory biomarkers was found. CONCLUSIONS: At baseline, airborne occupational exposures are inversely associated with inflammation; no effect of occupational exposures on inflammation was found at follow-up. In the future studies, details of occupational exposures, such as duration of exposures and cumulative exposures, need to be included to investigate the airborne occupational exposures and inflammatory biomarkers.

Airborne Occupational Exposures and Lung Function in the Lifelines Cohort Study.

Rationale: The association between airborne occupational exposures and lung function level is inconsistent in the general population. Moreover, little is known about the association between occupational exposures and annual lung function decline.Objectives: We investigated the association between occupational exposures and lung function level and annual lung function decline in the population-based Lifelines cohort study.Methods: We included 55,631 adults with baseline spirometry and reliable job code-13,759 of these subjects were aged ≥30 years and underwent spirometry again after 4.5 years of follow-up. Occupational exposures in the current or last-held job at baseline were estimated with the ALOHA+ job-exposure matrix. Linear regression analyses adjusted for covariates were used to test the association between each occupational exposure-biological dust, mineral dust, gases and fumes, pesticides, solvents, and metals-and lung function level and annual lung function decline. Interactions were used to test effect modification by sex or smoking.Results: Exposures to biological dust, mineral dust, gases and fumes, insecticides, fungicides, and aromatic solvents were associated with a lower lung function level at baseline. The effects were larger in males and smokers compared with females and nonsmokers, respectively. However, no association between occupational exposures and the rate of annual lung function decline was found between baseline and follow-up.Conclusions: In this study, airborne occupational exposures are associated with lower lung function level but not with a faster lung function decline. These negative effects are more pronounced among males and smokers.

Maternal occupational exposure and congenital heart defects in offspring.

Objectives Congenital heart defects (CHD) are the most prevalent congenital anomalies. This study aims to examine the association between maternal occupational exposures to organic and mineral dust, solvents, pesticides, and metal dust and fumes and CHD in the offspring, assessing several subgroups of CHD. Methods For this case-control study, we examined 1174 cases with CHD from EUROCAT Northern Netherlands and 5602 controls without congenital anomalies from the Lifelines cohort study. Information on maternal jobs held early in pregnancy was collected via self-administered questionnaires, and job titles were linked to occupational exposures using a job exposure matrix. Results An association was found between organic dust exposure and coarctation of aorta [adjusted odds ratio (OR adj) 1.90, 95% confidence interval (CI) 1.01-3.59] and pulmonary (valve) stenosis in combination with ventricular septal defect (OR adj2.68, 95% CI 1.07-6.73). Mineral dust exposure was associated with increased risk of coarctation of aorta (OR adj2.94, 95% CI 1.21-7.13) and pulmonary valve stenosis (OR adj1.99, 95% CI 1.10-3.62). Exposure to metal dust and fumes was infrequent but was associated with CHD in general (OR adj2.40, 95% CI 1.09-5.30). Exposure to both mineral dust and metal dust and fumes was associated with septal defects (OR adj3.23, 95% CI 1.14-9.11). Any maternal occupational exposure was associated with a lower risk of aortic stenosis (OR adj0.32, 95% CI 0.11-0.94). Conclusions Women should take preventive measures or avoid exposure to mineral and organic dust as well as metal dust and fumes early in pregnancy as this could possibly affect foetal heart development.

Blood eosinophil level and lung function trajectories: cross-sectional and longitudinal studies in European cohorts.

BACKGROUND: Elevated blood eosinophils have been associated with lower lung function and are believed to be associated with accelerated lung function decline. METHOD: Blood eosinophils were measured in four cohorts: <45 years cohort within the Vlagtwedde-Vlaardingen (V&V) study, the Uppsala cohort of the European Community Respiratory Health Survey (ECRHS-Uppsala; <45 years), ≥45 years cohort within the V&V study, and the Rotterdam study (≥45 years). Blood eosinophils at baseline were classified as normal (<300 cells·µL-1) or elevated (≥300 cells·µL-1). Lung function was measured at baseline and follow-up with spirometry: forced expiratory volume in 1 s (FEV1), vital capacity (VC) and their ratio FEV1/VC. The association between blood eosinophils and lung function was tested cross-sectionally using linear regression and longitudinally using a mixed model, both adjusted for age, sex, height, pack-years smoking and smoking status. Stratified analyses were done for asthma. RESULTS: Elevated blood eosinophils were associated with lower FEV1 (regression coefficient -147 mL (95% CI -188 to -105 mL)), VC (-120 mL (-165 to -75 mL)) and FEV1/VC (-1.3% (-1.9% to -0.6%)) at baseline in the two <45 years cohorts, and with lower FEV1 (-70 mL (-112 to -27 mL)) and FEV1/VC (-1.8% (-2.6% to -1.0%)) in the two ≥45 years cohorts. Elevated blood eosinophils were associated with an accelerated decline in FEV1 (-5.5 mL·year-1 (95% CI -10.5 to -0.5 mL·year-1)) and VC (-6.4 mL·year-1 (-11.26 to -1.5 mL·year-1)) compared to normal blood eosinophils in the younger asthmatic subjects in the longitudinal studies. CONCLUSION: Elevated blood eosinophils are associated with lower lung function in the general population and with an accelerated lung function decline among asthmatic individuals.

Maternal occupational exposure to solvents and gastroschisis in offspring - National Birth Defects Prevention Study 1997-2011.

OBJECTIVES: The aim of this study was to assess the association between maternal occupational exposure to solvents and gastroschisis in offspring. METHODS: We used data from the National Birth Defects Prevention Study, a large population-based case-control study of major birth defects conducted in 10 US states from 1997 to 2011. Infants with gastroschisis were ascertained by active birth defects surveillance systems. Control infants without major birth defects were selected from vital records or birth hospital records. Self-reported maternal occupational histories were collected by telephone interview. Industrial hygienists reviewed this information to estimate exposure to aromatic, chlorinated and petroleum-based solvents from 1 month before conception through the first trimester of pregnancy. Cumulative exposure to solvents was estimated for the same period accounting for estimated exposure intensity and frequency, job duration and hours worked per week. ORs and 95% CIs were estimated to assess the association between exposure to any solvents or solvent classes, and gastroschisis risk. RESULTS: Among 879 cases and 7817 controls, the overall prevalence of periconceptional solvent exposure was 7.3% and 7.4%, respectively. Exposure to any solvent versus no exposure to solvents was not associated with gastroschisis after adjusting for maternal age (OR 1.00, 95% CI 0.75 to 1.32), nor was an association noted for solvent classes. There was no exposure-response relationship between estimated cumulative solvent exposure and gastroschisis after adjusting for maternal age. CONCLUSION: Our study found no association between maternal occupational solvent exposure and gastroschisis in offspring. Further research is needed to understand risk factors for gastroschisis.

DNA methylation is associated with lung function in never smokers.

BACKGROUND: Active smoking is the main risk factor for COPD. Here, epigenetic mechanisms may play a role, since cigarette smoking is associated with differential DNA methylation in whole blood. So far, it is unclear whether epigenetics also play a role in subjects with COPD who never smoked. Therefore, we aimed to identify differential DNA methylation associated with lung function in never smokers. METHODS: We determined epigenome-wide DNA methylation levels of 396,243 CpG-sites (Illumina 450 K) in blood of never smokers in four independent cohorts, LifeLines COPD&C (N = 903), LifeLines DEEP (N = 166), Rotterdam Study (RS)-III (N = 150) and RS-BIOS (N = 206). We meta-analyzed the cohort-specific methylation results to identify differentially methylated CpG-sites with FEV1/FVC. Expression Quantitative Trait Methylation (eQTM) analysis was performed in the Biobank-based Integrative Omics Studies (BIOS). RESULTS: A total of 36 CpG-sites were associated with FEV1/FVC in never smokers at p-value< 0.0001, but the meta-analysis did not reveal any epigenome-wide significant CpG-sites. Of interest, 35 of these 36 CpG-sites have not been associated with lung function before in studies including subjects irrespective of smoking history. Among the top hits were cg10012512, cg02885771, annotated to the gene LTV1 Ribosome Biogenesis factor (LTV1), and cg25105536, annotated to Kelch Like Family Member 32 (KLHL32). Moreover, a total of 11 eQTMS were identified. CONCLUSIONS: With the identification of 35 CpG-sites that are unique for never smokers, our study shows that DNA methylation is also associated with FEV1/FVC in subjects that never smoked and therefore not merely related to smoking.

Treatment-related mortality in children with cancer: Prevalence and risk factors.

AIM: Intensive treatment regimens have contributed to a marked increase in childhood cancer survival rates. Death due to treatment-related adverse effects becomes an increasingly important area to further improve overall survival. In this study, we examined 5-year survival in children with cancer to identify risk factors for treatment-related mortality (TRM). METHODS: All children (aged <18 years at diagnosis) diagnosed with cancer in 2 Dutch university hospitals between 2003 and 2013 were included, survival status was determined and causes of death were analysed. Various demographic and treatment factors were evaluated, for which a multivariable competing risks analysis was performed. RESULTS: A total of 1764 patients were included; overall 5-year survival was 78.6%. Of all 378 deaths, 81 (21.4%) were treatment-related, with infection being responsible for more than half of these deaths. Forty percent of TRM occurred in the first three months after initial diagnosis. Factors associated with TRM in the multivariable competing risks analysis were diagnosis of a haematological malignancy, age at diagnosis <1 year and receipt of allogeneic haematopoietic stem cell transplantation. In children suffering from haematological malignancies, TRM accounted for 56.3% of 103 deaths. CONCLUSION: Over one in five deaths in children with cancer death was related to treatment, mostly due to infection. In children suffering from a haematological malignancy, more children died due to their treatment than due to progression of their disease. To further increase overall survival, clinical and research focus should be placed on lowering TRM rates without compromising anti-tumour efficacy. The findings presented in this study might help identifying areas for improvement.

Occupational exposure to gases/fumes and mineral dust affect DNA methylation levels of genes regulating expression.

Many workers are daily exposed to occupational agents like gases/fumes, mineral dust or biological dust, which could induce adverse health effects. Epigenetic mechanisms, such as DNA methylation, have been suggested to play a role. We therefore aimed to identify differentially methylated regions (DMRs) upon occupational exposures in never-smokers and investigated if these DMRs associated with gene expression levels. To determine the effects of occupational exposures independent of smoking, 903 never-smokers of the LifeLines cohort study were included. We performed three genome-wide methylation analyses (Illumina 450 K), one per occupational exposure being gases/fumes, mineral dust and biological dust, using robust linear regression adjusted for appropriate confounders. DMRs were identified using comb-p in Python. Results were validated in the Rotterdam Study (233 never-smokers) and methylation-expression associations were assessed using Biobank-based Integrative Omics Study data (n = 2802). Of the total 21 significant DMRs, 14 DMRs were associated with gases/fumes and 7 with mineral dust. Three of these DMRs were associated with both exposures (RPLP1 and LINC02169 (2×)) and 11 DMRs were located within transcript start sites of gene expression regulating genes. We replicated two DMRs with gases/fumes (VTRNA2-1 and GNAS) and one with mineral dust (CCDC144NL). In addition, nine gases/fumes DMRs and six mineral dust DMRs significantly associated with gene expression levels. Our data suggest that occupational exposures may induce differential methylation of gene expression regulating genes and thereby may induce adverse health effects. Given the millions of workers that are exposed daily to occupational exposures, further studies on this epigenetic mechanism and health outcomes are warranted.

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

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 ß-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.

Genetic overlap of chronic obstructive pulmonary disease and cardiovascular disease-related traits: a large-scale genome-wide cross-trait analysis.

BACKGROUND: A growing number of studies clearly demonstrate a substantial association between chronic obstructive pulmonary disease (COPD) and cardiovascular diseases (CVD), although little is known about the shared genetics that contribute to this association. METHODS: We conducted a large-scale cross-trait genome-wide association study to investigate genetic overlap between COPD (Ncase = 12,550, Ncontrol = 46,368) from the International COPD Genetics Consortium and four primary cardiac traits: resting heart rate (RHR) (N = 458,969), high blood pressure (HBP) (Ncase = 144,793, Ncontrol = 313,761), coronary artery disease (CAD)(Ncase = 60,801, Ncontrol = 123,504), and stroke (Ncase = 40,585, Ncontrol = 406,111) from UK Biobank, CARDIoGRAMplusC4D Consortium, and International Stroke Genetics Consortium data. RESULTS: RHR and HBP had modest genetic correlation, and CAD had borderline evidence with COPD at a genome-wide level. We found evidence of local genetic correlation with particular regions of the genome. Cross-trait meta-analysis of COPD identified 21 loci jointly associated with RHR, 22 loci with HBP, and 3 loci with CAD. Functional analysis revealed that shared genes were enriched in smoking-related pathways and in cardiovascular, nervous, and immune system tissues. An examination of smoking-related genetic variants identified SNPs located in 15q25.1 region associated with cigarettes per day, with effects on RHR and CAD. A Mendelian randomization analysis showed a significant positive causal effect of COPD on RHR (causal estimate = 0.1374, P = 0.008). CONCLUSION: In a set of large-scale GWAS, we identify evidence of shared genetics between COPD and cardiac traits.

Limited overlap in significant hits between genome-wide association studies on two airflow obstruction definitions in the same population.

BACKGROUND: Airflow obstruction is a hallmark of chronic obstructive pulmonary disease (COPD), and is defined as either the ratio between forced expiratory volume in one second and forced vital capacity (FEV1/FVC) < 70% or < lower limit of normal (LLN). This study aimed to assess the overlap between genome-wide association studies (GWAS) on airflow obstruction using these two definitions in the same population stratified by smoking. METHODS: GWASes were performed in the LifeLines Cohort Study for both airflow obstruction definitions in never-smokers (NS = 5071) and ever-smokers (ES = 4855). The FEV1/FVC < 70% models were adjusted for sex, age, and height; FEV1/FVC < LLN models were not adjusted. Ever-smokers models were additionally adjusted for pack-years and current-smoking. The overlap in significantly associated SNPs between the two definitions and never/ever-smokers was assessed using several p-value thresholds. To quantify the agreement, the Pearson correlation coefficient was calculated between the p-values and ORs. Replication was performed in the Vlagtwedde-Vlaardingen study (NS = 432, ES = 823). The overlapping SNPs with p < 10- 4 were validated in the Vlagtwedde-Vlaardingen and Rotterdam Study cohorts (NS = 1966, ES = 3134) and analysed for expression quantitative trait loci (eQTL) in lung tissue (n = 1087). RESULTS: In the LifeLines cohort, 96% and 93% of the never- and ever-smokers were classified concordantly based on the two definitions. 26 and 29% of the investigated SNPs were overlapping at p < 0.05 in never- and ever-smokers, respectively. At p < 10- 4 the overlap was 4% and 6% respectively, which could be change findings as shown by simulation studies. The effect estimates of the SNPs of the two definitions correlated strongly, but the p-values showed more variation and correlated only moderately. Similar observations were made in the Vlagtwedde-Vlaardingen study. Two overlapping SNPs in never-smokers (NFYC and FABP7) had the same direction of effect in the validation cohorts and the NFYC SNP was an eQTL for NFYC-AS1. NFYC is a transcription factor that binds to several known COPD genes, and FABP7 may be involved in abnormal pulmonary development. CONCLUSIONS: The definition of airflow obstruction and the population under study may be important determinants of which SNPs are associated with airflow obstruction. The genes FABP7 and NFYC(-AS1) could play a role in airflow obstruction in never-smokers specifically.

Genetic landscape of chronic obstructive pulmonary disease identifies heterogeneous cell-type and phenotype associations.

Chronic obstructive pulmonary disease (COPD) is the leading cause of respiratory mortality worldwide. Genetic risk loci provide new insights into disease pathogenesis. We performed a genome-wide association study in 35,735 cases and 222,076 controls from the UK Biobank and additional studies from the International COPD Genetics Consortium. We identified 82 loci associated with P < 5 × 10-8; 47 of these were previously described in association with either COPD or population-based measures of lung function. Of the remaining 35 new loci, 13 were associated with lung function in 79,055 individuals from the SpiroMeta consortium. Using gene expression and regulation data, we identified functional enrichment of COPD risk loci in lung tissue, smooth muscle, and several lung cell types. We found 14 COPD loci shared with either asthma or pulmonary fibrosis. COPD genetic risk loci clustered into groups based on associations with quantitative imaging features and comorbidities. Our analyses provide further support for the genetic susceptibility and heterogeneity of COPD.