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1.  Genome-wide association study identifies five loci associated with lung function 
Repapi, Emmanouela | Sayers, Ian | Wain, Louise V | Burton, Paul R | Johnson, Toby | Obeidat, Ma’en | Zhao, Jing Hua | Ramasamy, Adaikalavan | Zhai, Guangju | Vitart, Veronique | Huffman, Jennifer E | Igl, Wilmar | Albrecht, Eva | Deloukas, Panos | Henderson, John | Granell, Raquel | McArdle, Wendy L | Rudnicka, Alicja R | Barroso, Inês | Loos, Ruth J F | Wareham, Nicholas J | Mustelin, Linda | Rantanen, Taina | Surakka, Ida | Imboden, Medea | Wichmann, H Erich | Grkovic, Ivica | Jankovic, Stipan | Zgaga, Lina | Hartikainen, Anna-Liisa | Peltonen, Leena | Gyllensten, Ulf | Johansson, Åsa | Zaboli, Ghazal | Campbell, Harry | Wild, Sarah H | Wilson, James F | Gläser, Sven | Homuth, Georg | Völzke, Henry | Mangino, Massimo | Soranzo, Nicole | Spector, Tim D | Polašek, Ozren | Rudan, Igor | Wright, Alan F | Heliövaara, Markku | Ripatti, Samuli | Pouta, Anneli | Naluai, Åsa Torinsson | Olin, Anna-Carin | Torén, Kjell | Cooper, Matthew N | James, Alan L | Palmer, Lyle J | Hingorani, Aroon D | Wannamethee, S Goya | Whincup, Peter H | Smith, George Davey | Ebrahim, Shah | McKeever, Tricia M | Pavord, Ian D | MacLeod, Andrew K | Morris, Andrew D | Porteous, David J | Cooper, Cyrus | Dennison, Elaine | Shaheen, Seif | Karrasch, Stefan | Schnabel, Eva | Schulz, Holger | Grallert, Harald | Bouatia-Naji, Nabila | Delplanque, Jérôme | Froguel, Philippe | Blakey, John D | Britton, John R | Morris, Richard W | Holloway, John W | Lawlor, Debbie A | Hui, Jennie | Nyberg, Fredrik | Jarvelin, Marjo-Riitta | Jackson, Cathy | Kähönen, Mika | Kaprio, Jaakko | Probst-Hensch, Nicole M | Koch, Beate | Hayward, Caroline | Evans, David M | Elliott, Paul | Strachan, David P | Hall, Ian P | Tobin, Martin D
Nature genetics  2009;42(1):36-44.
Pulmonary function measures are heritable traits that predict morbidity and mortality and define chronic obstructive pulmonary disease (COPD). We tested genome-wide association with forced expiratory volume in 1 s (FEV1) and the ratio of FEV1 to forced vital capacity (FVC) in the SpiroMeta consortium (n = 20,288 individuals of European ancestry). We conducted a meta-analysis of top signals with data from direct genotyping (n ≤ 32,184 additional individuals) and in silico summary association data from the CHARGE Consortium (n = 21,209) and the Health 2000 survey (n ≤ 883). We confirmed the reported locus at 4q31 and identified associations with FEV1 or FEV1/FVC and common variants at five additional loci: 2q35 in TNS1 (P = 1.11 × 10−12), 4q24 in GSTCD (2.18 × 10−23), 5q33 in HTR4 (P = 4.29 × 10−9), 6p21 in AGER (P = 3.07 × 10−15) and 15q23 in THSD4 (P = 7.24 × 10−15). mRNA analyses showed expression of TNS1, GSTCD, AGER, HTR4 and THSD4 in human lung tissue. These associations offer mechanistic insight into pulmonary function regulation and indicate potential targets for interventions to alleviate respiratory disease.
doi:10.1038/ng.501
PMCID: PMC2862965  PMID: 20010834
2.  Genome-wide association study identifies TH1 pathway genes associated with lung function in asthmatic patients 
Background
Recent meta-analyses of genome-wide association studies in general populations of European descent have identified 28 loci for lung function.
Objective
We sought to identify novel lung function loci specifically for asthma and to confirm lung function loci identified in general populations.
Methods
Genome-wide association studies of lung function (percent predicted FEV1 [ppFEV1], percent predicted forced vital capacity, and FEV1/forced vital capacity ratio) were performed in 4 white populations of European descent (n = 1544), followed by meta-analyses.
Results
Seven of 28 previously identified lung function loci (HHIP, FAM13A, THSD4, GSTCD, NOTCH4-AGER, RARB, and ZNF323) identified in general populations were confirmed at single nucleotide polymorphism (SNP) levels (P < .05). Four of 32 loci (IL12A, IL12RB1, STAT4, and IRF2) associated with ppFEV1 (P < 10−4) belong to the TH1 or IL-12 cytokine family pathway. By using a linear additive model, these 4 TH1 pathway SNPs cumulatively explained 2.9% to 7.8% of the variance in ppFEV1 values in 4 populations (P = 3 × 10−11). Genetic scores of these 4 SNPs were associated with ppFEV1 values (P = 2 × 10−7) and the American Thoracic Society severe asthma classification (P = .005) in the Severe Asthma Research Program population. TH2 pathway genes (IL13, TSLP, IL33, and IL1RL1) conferring asthma susceptibility were not associated with lung function.
Conclusion
Genes involved in airway structure/remodeling are associated with lung function in both general populations and asthmatic subjects. TH1 pathway genes involved in anti-virus/bacterial infection and inflammation modify lung function in asthmatic subjects. Genes associated with lung function that might affect asthma severity are distinct from those genes associated with asthma susceptibility.
doi:10.1016/j.jaci.2013.01.051
PMCID: PMC3746327  PMID: 23541324
Lung function; FEV1; asthma; TH1; IL12A; IL12RB1; STAT4; IRF2
3.  A Genome-Wide Association Study in Chronic Obstructive Pulmonary Disease (COPD): Identification of Two Major Susceptibility Loci 
PLoS Genetics  2009;5(3):e1000421.
There is considerable variability in the susceptibility of smokers to develop chronic obstructive pulmonary disease (COPD). The only known genetic risk factor is severe deficiency of α1-antitrypsin, which is present in 1–2% of individuals with COPD. We conducted a genome-wide association study (GWAS) in a homogenous case-control cohort from Bergen, Norway (823 COPD cases and 810 smoking controls) and evaluated the top 100 single nucleotide polymorphisms (SNPs) in the family-based International COPD Genetics Network (ICGN; 1891 Caucasian individuals from 606 pedigrees) study. The polymorphisms that showed replication were further evaluated in 389 subjects from the US National Emphysema Treatment Trial (NETT) and 472 controls from the Normative Aging Study (NAS) and then in a fourth cohort of 949 individuals from 127 extended pedigrees from the Boston Early-Onset COPD population. Logistic regression models with adjustments of covariates were used to analyze the case-control populations. Family-based association analyses were conducted for a diagnosis of COPD and lung function in the family populations. Two SNPs at the α-nicotinic acetylcholine receptor (CHRNA 3/5) locus were identified in the genome-wide association study. They showed unambiguous replication in the ICGN family-based analysis and in the NETT case-control analysis with combined p-values of 1.48×10−10, (rs8034191) and 5.74×10−10 (rs1051730). Furthermore, these SNPs were significantly associated with lung function in both the ICGN and Boston Early-Onset COPD populations. The C allele of the rs8034191 SNP was estimated to have a population attributable risk for COPD of 12.2%. The association of hedgehog interacting protein (HHIP) locus on chromosome 4 was also consistently replicated, but did not reach genome-wide significance levels. Genome-wide significant association of the HHIP locus with lung function was identified in the Framingham Heart study (Wilk et al., companion article in this issue of PLoS Genetics; doi:10.1371/journal.pgen.1000429). The CHRNA 3/5 and the HHIP loci make a significant contribution to the risk of COPD. CHRNA3/5 is the same locus that has been implicated in the risk of lung cancer.
Author Summary
There is considerable variability in the susceptibility of smokers to develop chronic obstructive pulmonary disease (COPD), which is a heritable multi-factorial trait. Identifying the genetic determinants of COPD risk will have tremendous public health importance. This study describes the first genome-wide association study (GWAS) in COPD. We conducted a GWAS in a homogenous case-control cohort from Norway and evaluated the top 100 single nucleotide polymorphisms in the family-based International COPD Genetics Network. The polymorphisms that showed replication were further evaluated in subjects from the US National Emphysema Treatment Trial and controls from the Normative Aging Study and then in a fourth cohort of extended pedigrees from the Boston Early-Onset COPD population. Two polymorphisms in the α-nicotinic acetylcholine receptor 3/5 locus on chromosome 15 showed unambiguous evidence of association with COPD. This locus has previously been implicated in both smoking behavior and risk of lung cancer, suggesting the possibility of multiple functional polymorphisms in the region or a single polymorphism with wide phenotypic consequences. The hedgehog interacting protein (HHIP) locus on chromosome 4, which is associated with COPD, is also a significant risk locus for COPD.
doi:10.1371/journal.pgen.1000421
PMCID: PMC2650282  PMID: 19300482
4.  Meta-analyses of genome-wide association studies identify multiple novel loci associated with pulmonary function 
Nature genetics  2009;42(1):45-52.
Measurements of lung function by spirometry are heritable traits that reflect respiratory health and predict morbidity and mortality. We meta-analyzed genome-wide association studies for two clinically important measures, forced expiratory volume in the first second (FEV1) and its ratio to forced vital capacity (FEV1/FVC), an indicator of airflow obstruction. This meta-analysis included 20,890 participants of European ancestry from four CHARGE consortium studies: Atherosclerosis Risk in Communities (ARIC), Cardiovascular Health Study (CHS), Framingham Heart Study (FHS), and Rotterdam Study (RS). We identified eight loci associated with FEV1/FVC (HHIP, GPR126, ADAM19, AGER-PPT2, FAM13A, PTCH1, PID1, and HTR4) and one locus associated with FEV1 (INTS12-GSTCD-NPNT) at or near genome-wide significance (P<5×10−8) in CHARGE; all but 3 loci (FAM13A, PTCH1, and PID1) replicated with the SpiroMeta consortium. Our findings of novel loci influencing pulmonary function may offer insights into chronic lung disease pathogenesis.
doi:10.1038/ng.500
PMCID: PMC2832852  PMID: 20010835
5.  A Genome-Wide Association Study of Pulmonary Function Measures in the Framingham Heart Study 
PLoS Genetics  2009;5(3):e1000429.
The ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC) is a measure used to diagnose airflow obstruction and is highly heritable. We performed a genome-wide association study in 7,691 Framingham Heart Study participants to identify single-nucleotide polymorphisms (SNPs) associated with the FEV1/FVC ratio, analyzed as a percent of the predicted value. Identified SNPs were examined in an independent set of 835 Family Heart Study participants enriched for airflow obstruction. Four SNPs in tight linkage disequilibrium on chromosome 4q31 were associated with the percent predicted FEV1/FVC ratio with p-values of genome-wide significance in the Framingham sample (best p-value = 3.6e-09). One of the four chromosome 4q31 SNPs (rs13147758; p-value 2.3e-08 in Framingham) was genotyped in the Family Heart Study and produced evidence of association with the same phenotype, percent predicted FEV1/FVC (p-value = 2.0e-04). The effect estimates for association in the Framingham and Family Heart studies were in the same direction, with the minor allele (G) associated with higher FEV1/FVC ratio levels. Results from the Family Heart Study demonstrated that the association extended to FEV1 and dichotomous airflow obstruction phenotypes, particularly among smokers. The SNP rs13147758 was associated with the percent predicted FEV1/FVC ratio in independent samples from the Framingham and Family Heart Studies producing a combined p-value of 8.3e-11, and this region of chromosome 4 around 145.68 megabases was associated with COPD in three additional populations reported in the accompanying manuscript. The associated SNPs do not lie within a gene transcript but are near the hedgehog-interacting protein (HHIP) gene and several expressed sequence tags cloned from fetal lung. Though it is unclear what gene or regulatory effect explains the association, the region warrants further investigation.
Author Summary
Cigarette smoking is the primary risk factor for impaired lung function, yet only 20% of smokers develop chronic obstructive pulmonary disease (COPD). This observation, along with family studies of lung function and COPD, suggests that genetic factors influence susceptibility to cigarette smoke. We examined the relationship between common genetic variants and measures of lung function in a sample of 7,691 participants from the Framingham Heart Study and confirmed our observations in 835 participants from the Family Heart Study selected to include cases of airflow obstruction. We identified a variant on chromosome 4 that was strongly associated with FEV1/FVC in the Framingham Study and confirmed the association in the Family Heart Study. The accompanying manuscript identified the same region to be associated with COPD. Several interesting genes are present in the region that we identified, including a gene (HHIP) interacting with a biological pathway involved in lung development, but it is not yet clear which gene in the region explains the association. Our results identified a region of chromosome 4 that warrants further study to understand the genetic effects influencing lung function.
doi:10.1371/journal.pgen.1000429
PMCID: PMC2652834  PMID: 19300500
6.  Loci Identified by Genome-wide Association Studies Influence Different Disease-related Phenotypes in Chronic Obstructive Pulmonary Disease 
Rationale: Genome-wide association studies have shown significant associations between variants near hedgehog interacting protein HHIP, FAM13A, and cholinergic nicotinic acetylcholine receptor CHRNA3/5 with increased risk of chronic obstructive pulmonary disease (COPD) in smokers; however, the disease mechanisms behind these associations are not well understood.
Objectives: To identify the association between replicated loci and COPD-related phenotypes in well-characterized patient populations.
Methods: The relationship between these three loci and COPD-related phenotypes was assessed in the Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-point (ECLIPSE) cohort. The results were validated in the family-based International COPD Genetics Network (ICGN).
Measurements and Main Results: The CHRNA3/5 locus was significantly associated with pack-years of smoking (P = 0.002 and 3 × 10−4), emphysema assessed by a radiologist using high-resolution computed tomography (P = 2 × 10−4 and 4.8 × 10−5), and airflow obstruction (P = 0.004 and 1.8 × 10−5) in the ECLIPSE and ICGN populations, respectively. However, variants in the IREB2 gene were only significantly associated with FEV1. The HHIP locus was not associated with smoking intensity but was associated with FEV1/FVC (P = 1.9 × 10−4 and 0.004 in the ECLIPSE and ICGN populations). The HHIP locus was also associated with fat-free body mass (P = 0.007) and with both retrospectively (P = 0.015) and prospectively (P = 0.024) collected COPD exacerbations in the ECLIPSE cohort. Single-nucleotide polymorphisms in the FAM13A locus were associated with lung function.
Conclusions: The CHRNA3/5 locus was associated with increased smoking intensity and emphysema in individuals with COPD, whereas the HHIP and FAM13A loci were not associated with smoking intensity. The HHIP locus was associated with the systemic components of COPD and with the frequency of COPD exacerbations. FAM13A locus was associated with lung function.
doi:10.1164/rccm.201002-0151OC
PMCID: PMC3029936  PMID: 20656943
COPD exacerbations; nicotine addiction; high-resolution CT; genetic association analysis; emphysema
7.  Identification of a chronic obstructive pulmonary disease genetic determinant that regulates HHIP 
Human Molecular Genetics  2011;21(6):1325-1335.
Multiple intergenic single-nucleotide polymorphisms (SNPs) near hedgehog interacting protein (HHIP) on chromosome 4q31 have been strongly associated with pulmonary function levels and moderate-to-severe chronic obstructive pulmonary disease (COPD). However, whether the effects of variants in this region are related to HHIP or another gene has not been proven. We confirmed genetic association of SNPs in the 4q31 COPD genome-wide association study (GWAS) region in a Polish cohort containing severe COPD cases and healthy smoking controls (P = 0.001 to 0.002). We found that HHIP expression at both mRNA and protein levels is reduced in COPD lung tissues. We identified a genomic region located ∼85 kb upstream of HHIP which contains a subset of associated SNPs, interacts with the HHIP promoter through a chromatin loop and functions as an HHIP enhancer. The COPD risk haplotype of two SNPs within this enhancer region (rs6537296A and rs1542725C) was associated with statistically significant reductions in HHIP promoter activity. Moreover, rs1542725 demonstrates differential binding to the transcription factor Sp3; the COPD-associated allele exhibits increased Sp3 binding, which is consistent with Sp3's usual function as a transcriptional repressor. Thus, increased Sp3 binding at a functional SNP within the chromosome 4q31 COPD GWAS locus leads to reduced HHIP expression and increased susceptibility to COPD through distal transcriptional regulation. Together, our findings reveal one mechanism through which SNPs upstream of the HHIP gene modulate the expression of HHIP and functionally implicate reduced HHIP gene expression in the pathogenesis of COPD.
doi:10.1093/hmg/ddr569
PMCID: PMC3284120  PMID: 22140090
8.  The Association of Genome-Wide Significant Spirometric Loci with Chronic Obstructive Pulmonary Disease Susceptibility 
Two recent metaanalyses of genome-wide association studies conducted by the CHARGE and SpiroMeta consortia identified novel loci yielding evidence of association at or near genome-wide significance (GWS) with FEV1 and FEV1/FVC. We hypothesized that a subset of these markers would also be associated with chronic obstructive pulmonary disease (COPD) susceptibility. Thirty-two single-nucleotide polymorphisms (SNPs) in or near 17 genes in 11 previously identified GWS spirometric genomic regions were tested for association with COPD status in four COPD case-control study samples (NETT/NAS, the Norway case-control study, ECLIPSE, and the first 1,000 subjects in COPDGene; total sample size, 3,456 cases and 1,906 controls). In addition to testing the 32 spirometric GWS SNPs, we tested a dense panel of imputed HapMap2 SNP markers from the 17 genes located near the 32 GWS SNPs and in a set of 21 well studied COPD candidate genes. Of the previously identified GWS spirometric genomic regions, three loci harbored SNPs associated with COPD susceptibility at a 5% false discovery rate: the 4q24 locus including FLJ20184/INTS12/GSTCD/NPNT, the 6p21 locus including AGER and PPT2, and the 5q33 locus including ADAM19. In conclusion, markers previously associated at or near GWS with spirometric measures were tested for association with COPD status in data from four COPD case-control studies, and three loci showed evidence of association with COPD susceptibility at a 5% false discovery rate.
doi:10.1165/rcmb.2011-0055OC
PMCID: PMC3262664  PMID: 21659657
9.  GSTCD and INTS12 Regulation and Expression in the Human Lung 
PLoS ONE  2013;8(9):e74630.
Genome-Wide Association Study (GWAS) meta-analyses have identified a strong association signal for lung function, which maps to a region on 4q24 containing two oppositely transcribed genes: glutathione S-transferase, C-terminal domain containing (GSTCD) and integrator complex subunit 12 (INTS12). Both genes were found to be expressed in a range of human airway cell types. The promoter regions and transcription start sites were determined in mRNA from human lung and a novel splice variant was identified for each gene. We obtained the following evidence for GSTCD and INTS12 co-regulation and expression: (i) correlated mRNA expression was observed both via Q-PCR and in a lung expression quantitative trait loci (eQTL) study, (ii) induction of both GSTCD and INTS12 mRNA expression in human airway smooth muscle cells was seen in response to TGFβ1, (iii) a lung eQTL study revealed that both GSTCD and INTS12 mRNA levels positively correlate with percent predicted FEV1, and (iv) FEV1 GWAS associated SNPs in 4q24 were found to act as an eQTL for INTS12 in a number of tissues. In fixed sections of human lung tissue, GSTCD protein expression was ubiquitous, whereas INTS12 expression was predominantly in epithelial cells and pneumocytes. During human fetal lung development, GSTCD protein expression was observed to be highest at the earlier pseudoglandular stage (10-12 weeks) compared with the later canalicular stage (17-19 weeks), whereas INTS12 expression levels did not alter throughout these stages. Knowledge of the transcriptional and translational regulation and expression of GSTCD and INTS12 provides important insights into the potential role of these genes in determining lung function. Future work is warranted to fully define the functions of INTS12 and GSTCD.
doi:10.1371/journal.pone.0074630
PMCID: PMC3776747  PMID: 24058608
10.  Refining Susceptibility Loci of Chronic Obstructive Pulmonary Disease with Lung eqtls 
PLoS ONE  2013;8(7):e70220.
Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of mortality worldwide. Recent genome-wide association studies (GWAS) have identified robust susceptibility loci associated with COPD. However, the mechanisms mediating the risk conferred by these loci remain to be found. The goal of this study was to identify causal genes/variants within susceptibility loci associated with COPD. In the discovery cohort, genome-wide gene expression profiles of 500 non-tumor lung specimens were obtained from patients undergoing lung surgery. Blood-DNA from the same patients were genotyped for 1,2 million SNPs. Following genotyping and gene expression quality control filters, 409 samples were analyzed. Lung expression quantitative trait loci (eQTLs) were identified and overlaid onto three COPD susceptibility loci derived from GWAS; 4q31 (HHIP), 4q22 (FAM13A), and 19q13 (RAB4B, EGLN2, MIA, CYP2A6). Significant eQTLs were replicated in two independent datasets (n = 363 and 339). SNPs previously associated with COPD and lung function on 4q31 (rs1828591, rs13118928) were associated with the mRNA expression of HHIP. An association between mRNA expression level of FAM13A and SNP rs2045517 was detected at 4q22, but did not reach statistical significance. At 19q13, significant eQTLs were detected with EGLN2. In summary, this study supports HHIP, FAM13A, and EGLN2 as the most likely causal COPD genes on 4q31, 4q22, and 19q13, respectively. Strong lung eQTL SNPs identified in this study will need to be tested for association with COPD in case-control studies. Further functional studies will also be needed to understand the role of genes regulated by disease-related variants in COPD.
doi:10.1371/journal.pone.0070220
PMCID: PMC3728203  PMID: 23936167
11.  CHRNA3/5, IREB2, and ADCY2 Are Associated with Severe Chronic Obstructive Pulmonary Disease in Poland 
We examined the association between single-nucleotide polymorphisms (SNPs) previously associated with chronic obstructive pulmonary disease (COPD) and/or lung function with COPD and COPD-related phenotypes in a novel cohort of patients with severe to very severe COPD. We examined 315 cases of COPD and 330 Caucasian control smokers from Poland. We included three SNPs previously associated with COPD: rs7671167 (FAM13A), rs13180 (IREB2), and rs8034191 (CHRNA 3/5), and four SNPs associated with lung function in a genome-wide association study of general population samples: rs2070600 (AGER), rs11134242 (ADCY2), rs4316710 (THSD4), and rs17096090 (INTS12). We tested for associations with severe COPD and COPD-related phenotypes, including lung function, smoking behavior, and body mass index. Subjects with COPD were older (average age 62 versus 58 years, P < 0.01), with more pack-years of smoking (45 versus 33 pack-years, P < 0.01). CHRNA3/5 (odds ratio [OR], 1.89; 95% confidence interval [CI], 1.5–2.4; P = 7.4 × 10−7), IREB2 (OR, 0.69; 95% CI, 0.5–0.9; P = 3.4 × 10−3), and ADCY2 (OR, 1.35; 95% CI, 1.1–1.7; P = 0.01) demonstrated significant associations with COPD. FAM13A (OR, 0.8; 95% CI, 0.7–1.0; P = 0.11) approached statistical significance. FAM13A and ADCY2 also demonstrated a significant association with lung function. Thus, in severe to very severe COPD, we demonstrate a replication of association between two SNPs previously associated with COPD (CHRNA3/5 and IREB2), as well as an association with COPD of one locus initially associated with lung function (ADCY2).
doi:10.1165/rcmb.2012-0011OC
PMCID: PMC3423462  PMID: 22461431
chronic obstructive pulmonary disease; genetic association analysis; lung function; smoking; nicotine addiction
12.  Long-Term Oxygen Therapy for Patients With Chronic Obstructive Pulmonary Disease (COPD) 
Executive Summary
In July 2010, the Medical Advisory Secretariat (MAS) began work on a Chronic Obstructive Pulmonary Disease (COPD) evidentiary framework, an evidence-based review of the literature surrounding treatment strategies for patients with COPD. This project emerged from a request by the Health System Strategy Division of the Ministry of Health and Long-Term Care that MAS provide them with an evidentiary platform on the effectiveness and cost-effectiveness of COPD interventions.
After an initial review of health technology assessments and systematic reviews of COPD literature, and consultation with experts, MAS identified the following topics for analysis: vaccinations (influenza and pneumococcal), smoking cessation, multidisciplinary care, pulmonary rehabilitation, long-term oxygen therapy, noninvasive positive pressure ventilation for acute and chronic respiratory failure, hospital-at-home for acute exacerbations of COPD, and telehealth (including telemonitoring and telephone support). Evidence-based analyses were prepared for each of these topics. For each technology, an economic analysis was also completed where appropriate. In addition, a review of the qualitative literature on patient, caregiver, and provider perspectives on living and dying with COPD was conducted, as were reviews of the qualitative literature on each of the technologies included in these analyses.
The Chronic Obstructive Pulmonary Disease Mega-Analysis series is made up of the following reports, which can be publicly accessed at the MAS website at: http://www.hqontario.ca/en/mas/mas_ohtas_mn.html.
Chronic Obstructive Pulmonary Disease (COPD) Evidentiary Framework
Influenza and Pneumococcal Vaccinations for Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Smoking Cessation for Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Community-Based Multidisciplinary Care for Patients With Stable Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Pulmonary Rehabilitation for Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Long-term Oxygen Therapy for Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Noninvasive Positive Pressure Ventilation for Acute Respiratory Failure Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Noninvasive Positive Pressure Ventilation for Chronic Respiratory Failure Patients With Stable Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Hospital-at-Home Programs for Patients With Acute Exacerbations of Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Home Telehealth for Patients With Chronic Obstructive Pulmonary Disease (COPD): An Evidence-Based Analysis
Cost-Effectiveness of Interventions for Chronic Obstructive Pulmonary Disease Using an Ontario Policy Model
Experiences of Living and Dying With COPD: A Systematic Review and Synthesis of the Qualitative Empirical Literature
For more information on the qualitative review, please contact Mita Giacomini at: http://fhs.mcmaster.ca/ceb/faculty member_giacomini.htm.
For more information on the economic analysis, please visit the PATH website: http://www.path-hta.ca/About-Us/Contact-Us.aspx.
The Toronto Health Economics and Technology Assessment (THETA) collaborative has produced an associated report on patient preference for mechanical ventilation. For more information, please visit the THETA website: http://theta.utoronto.ca/static/contact.
Objective
The objective of this health technology assessment was to determine the effectiveness, cost-effectiveness, and safety of long-term oxygen therapy (LTOT) for chronic obstructive pulmonary disease (COPD).
Clinical Need: Condition and Target Population
Oxygen therapy is used in patients with COPD with hypoxemia, or very low blood oxygen levels, because they may have difficulty obtaining sufficient oxygen from inspired air.
Technology
Long-term oxygen therapy is extended use of oxygen. Oxygen therapy is delivered as a gas from an oxygen source. Different oxygen sources are: 1) oxygen concentrators, electrical units delivering oxygen converted from room air; 2) liquid oxygen systems, which deliver gaseous oxygen stored as liquid in a tank; and 3) oxygen cylinders, which contain compressed gaseous oxygen. All are available in portable versions. Oxygen is breathed in through a nasal cannula or through a mask covering the mouth and nose. The treating clinician determines the flow rate, duration of use, method of administration, and oxygen source according to individual patient needs. Two landmark randomized controlled trials (RCTs) of patients with COPD established the role of LTOT in COPD. Questions regarding the use of LTOT, however, still remain.
Research Question
What is the effectiveness, cost-effectiveness, and safety of LTOT compared with no LTOT in patients with COPD, who are stratified by severity of hypoxemia?
Research Methods
Literature Search
Search Strategy
A literature search was performed on September 8, 2010 using OVID MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, CINAHL, the Cochrane Library, and INAHTA for studies published from January 1, 2007 to September 8, 2010.
A single clinical epidemiologist reviewed the abstracts, obtained full-text articles for studies meeting the eligibility criteria, and examined reference lists for additional relevant studies not identified through the literature search. A second clinical epidemiologist and then a group of epidemiologists reviewed articles with an unknown eligibility until consensus was established.
Inclusion Criteria
patients with mild, moderate, or severe hypoxemia;
English-language articles published between January 1, 2007 and September 8, 2010;
journal articles reporting on effectiveness, cost-effectiveness, or safety for the comparison of interest;
clearly described study design and methods;
health technology assessments, systematic reviews, RCTs, or prospective cohort observational studies;
any type of observational study for the evaluation of safety.
Exclusion Criteria
no hypoxemia
non-English papers
animal or in vitro studies
case reports, case series, or case-case studies
studies comparing different oxygen therapy regimens
studies on nocturnal oxygen therapy
studies on short-burst, palliative, or ambulatory oxygen (supplemental oxygen during exercise or activities of daily living)
Outcomes of Interest
mortality/survival
hospitalizations
readmissions
forced expiratory volume in 1 second (FEV1)
forced vital capacity (FVC)
FEV1/FVC
pulmonary hypertension
arterial partial pressure of oxygen (PaO2)
arterial partial pressure of carbon dioxide (PaCO2)
end-exercise dyspnea score
endurance time
health-related quality of life
Note: Outcomes of interest were formulated according to existing studies, with arterial pressure of oxygen and carbon dioxide as surrogate outcomes.
Summary of Findings
Conclusions
Based on low quality of evidence, LTOT (~ 15 hours/day) decreases all-cause mortality in patients with COPD who have severe hypoxemia (PaO2 ~ 50 mm Hg) and heart failure.
The effect for all-cause mortality had borderline statistical significance when the control group was no LTOT: one study.
Based on low quality of evidence, there is no beneficial effect of LTOT on all-cause mortality at 3 and 7 years in patients with COPD who have mild-to-moderate hypoxemia (PaO2 ~ 59-65 mm Hg)1
Based on very low quality of evidence, there is some suggestion that LTOT may have a beneficial effect over time on FEV1 and PaCO2 in patients with COPD who have severe hypoxemia and heart failure: improved methods are needed.
Based on very low quality of evidence, there is no beneficial effect of LTOT on lung function or exercise factors in patients with COPD who have mild-to-moderate hypoxemia, whether survivors or nonsurvivors are assessed.
Based on low to very low quality of evidence, LTOT does not prevent readmissions in patients with COPD who have severe hypoxemia. Limited data suggest LTOT increases the risk of hospitalizations.
Limited work has been performed evaluating the safety of LTOT by severity of hypoxemia.
Based on low to very low quality of evidence, LTOT may have a beneficial effect over time on health-related quality of life in patients with COPD who have severe hypoxemia. Limited work using disease-specific instruments has been performed.
Ethical constraints of not providing LTOT to eligible patients with COPD prohibit future studies from examining LTOT outcomes in an ideal way.
PMCID: PMC3384376  PMID: 23074435
13.  Lower FEV1 in non-COPD, nonasthmatic subjects: association with smoking, annual decline in FEV1, total IgE levels, and TSLP genotypes 
Few studies have investigated the significance of decreased FEV1 in non-COPD, nonasthmatic healthy subjects. We hypothesized that a lower FEV1 in these subjects is a potential marker of an increased susceptibility to obstructive lung disease such as asthma and COPD. This was a cross-sectional analysis of 1505 Japanese adults. We divided the population of healthy adults with no respiratory diseases whose FEV1/FVC ratio was ≥70% (n = 1369) into 2 groups according to their prebronchodilator FEV1 (% predicted) measurements: <80% (n = 217) and ≥80% (n = 1152). We compared clinical data – including gender, age, smoking habits, total IgE levels, and annual decline of FEV1 – between these 2 groups. In addition, as our group recently found that TSLP variants are associated with asthma and reduced lung function, we assessed whether TSLP single nucleotide polymorphisms (SNPs) were associated with baseline lung function in non-COPD, nonasthmatic healthy subjects (n = 1368). Although about half of the subjects with lower FEV1 had never smoked, smoking was the main risk factor for the decreased FEV1 in non-COPD, nonasthmatic subjects. However, the subjects with lower FEV1 had a significantly higher annual decline in FEV1 independent of smoking status. Airflow obstruction was associated with increased levels of total serum IgE (P = 0.029) and with 2 functional TSLP SNPs (corrected P = 0.027–0.058 for FEV1% predicted, corrected P = 0.015–0.033 for FEV1/FVC). This study highlights the importance of early recognition of a decreased FEV1 in healthy subjects without evident pulmonary diseases because it predicts a rapid decline in FEV1 irrespective of smoking status. Our series of studies identified TSLP variants as a potential susceptibility locus to asthma and to lower lung function in non-COPD, nonasthmatic healthy subjects, which may support the contention that genetic determinants of lung function influence susceptibility to asthma.
doi:10.2147/COPD.S16383
PMCID: PMC3064418  PMID: 21468164
airflow obstruction; asthma; chronic obstructive pulmonary disease; pulmonary function test; thymic stromal lymphopoietin
14.  MMP12, Lung Function, and COPD in High-Risk Populations 
The New England journal of medicine  2009;361(27):2599-2608.
BACKGROUND
Genetic variants influencing lung function in children and adults may ultimately lead to the development of chronic obstructive pulmonary disease (COPD), particularly in high-risk groups.
METHODS
We tested for an association between single-nucleotide polymorphisms (SNPs) in the gene encoding matrix metalloproteinase 12 (MMP12) and a measure of lung function (prebronchodilator forced expiratory volume in 1 second [FEV1]) in more than 8300 subjects in seven cohorts that included children and adults. Within the Normative Aging Study (NAS), a cohort of initially healthy adult men, we tested for an association between SNPs that were associated with FEV1 and the time to the onset of COPD. We then examined the relationship between MMP12 SNPs and COPD in two cohorts of adults with COPD or at risk for COPD.
RESULTS
The minor allele (G) of a functional variant in the promoter region of MMP12 (rs2276109 [−82A→G]) was positively associated with FEV1 in a combined analysis of children with asthma and adult former and current smokers in all cohorts (P=2×10−6). This allele was also associated with a reduced risk of the onset of COPD in the NAS cohort (hazard ratio, 0.65; 95% confidence interval [CI], 0.46 to 0.92; P = 0.02) and with a reduced risk of COPD in a cohort of smokers (odds ratio, 0.63; 95% CI, 0.45 to 0.88; P = 0.005) and among participants in a family-based study of early-onset COPD (P = 0.006).
CONCLUSIONS
The minor allele of a SNP in MMP12 (rs2276109) is associated with a positive effect on lung function in children with asthma and in adults who smoke. This allele is also associated with a reduced risk of COPD in adult smokers.
doi:10.1056/NEJMoa0904006
PMCID: PMC2904064  PMID: 20018959
15.  Genome-Wide Association Studies Identify CHRNA5/3 and HTR4 in the Development of Airflow Obstruction 
Wilk, Jemma B. | Shrine, Nick R. G. | Loehr, Laura R. | Zhao, Jing Hua | Manichaikul, Ani | Lopez, Lorna M. | Smith, Albert Vernon | Heckbert, Susan R. | Smolonska, Joanna | Tang, Wenbo | Loth, Daan W. | Curjuric, Ivan | Hui, Jennie | Cho, Michael H. | Latourelle, Jeanne C. | Henry, Amanda P. | Aldrich, Melinda | Bakke, Per | Beaty, Terri H. | Bentley, Amy R. | Borecki, Ingrid B. | Brusselle, Guy G. | Burkart, Kristin M. | Chen, Ting-hsu | Couper, David | Crapo, James D. | Davies, Gail | Dupuis, Josée | Franceschini, Nora | Gulsvik, Amund | Hancock, Dana B. | Harris, Tamara B. | Hofman, Albert | Imboden, Medea | James, Alan L. | Khaw, Kay-Tee | Lahousse, Lies | Launer, Lenore J. | Litonjua, Augusto | Liu, Yongmei | Lohman, Kurt K. | Lomas, David A. | Lumley, Thomas | Marciante, Kristin D. | McArdle, Wendy L. | Meibohm, Bernd | Morrison, Alanna C. | Musk, Arthur W. | Myers, Richard H. | North, Kari E. | Postma, Dirkje S. | Psaty, Bruce M. | Rich, Stephen S. | Rivadeneira, Fernando | Rochat, Thierry | Rotter, Jerome I. | Artigas, María Soler | Starr, John M. | Uitterlinden, André G. | Wareham, Nicholas J. | Wijmenga, Cisca | Zanen, Pieter | Province, Michael A. | Silverman, Edwin K. | Deary, Ian J. | Palmer, Lyle J. | Cassano, Patricia A. | Gudnason, Vilmundur | Barr, R. Graham | Loos, Ruth J. F. | Strachan, David P. | London, Stephanie J. | Boezen, H. Marike | Probst-Hensch, Nicole | Gharib, Sina A. | Hall, Ian P. | O’Connor, George T. | Tobin, Martin D. | Stricker, Bruno H.
Rationale: Genome-wide association studies (GWAS) have identified loci influencing lung function, but fewer genes influencing chronic obstructive pulmonary disease (COPD) are known.
Objectives: Perform meta-analyses of GWAS for airflow obstruction, a key pathophysiologic characteristic of COPD assessed by spirometry, in population-based cohorts examining all participants, ever smokers, never smokers, asthma-free participants, and more severe cases.
Methods: Fifteen cohorts were studied for discovery (3,368 affected; 29,507 unaffected), and a population-based family study and a meta-analysis of case-control studies were used for replication and regional follow-up (3,837 cases; 4,479 control subjects). Airflow obstruction was defined as FEV1 and its ratio to FVC (FEV1/FVC) both less than their respective lower limits of normal as determined by published reference equations.
Measurements and Main Results: The discovery meta-analyses identified one region on chromosome 15q25.1 meeting genome-wide significance in ever smokers that includes AGPHD1, IREB2, and CHRNA5/CHRNA3 genes. The region was also modestly associated among never smokers. Gene expression studies confirmed the presence of CHRNA5/3 in lung, airway smooth muscle, and bronchial epithelial cells. A single-nucleotide polymorphism in HTR4, a gene previously related to FEV1/FVC, achieved genome-wide statistical significance in combined meta-analysis. Top single-nucleotide polymorphisms in ADAM19, RARB, PPAP2B, and ADAMTS19 were nominally replicated in the COPD meta-analysis.
Conclusions: These results suggest an important role for the CHRNA5/3 region as a genetic risk factor for airflow obstruction that may be independent of smoking and implicate the HTR4 gene in the etiology of airflow obstruction.
doi:10.1164/rccm.201202-0366OC
PMCID: PMC3480517  PMID: 22837378
chronic obstructive pulmonary disease; single-nucleotide polymorphism; genes
16.  Lung Function and Incidence of Chronic Obstructive Pulmonary Disease after Improved Cooking Fuels and Kitchen Ventilation: A 9-Year Prospective Cohort Study 
PLoS Medicine  2014;11(3):e1001621.
Pixin Ran, Nanshan Zhong, and colleagues report that cleaner cooking fuels and improved ventilation were associated with better lung function and reduced COPD among a cohort of villagers in Southern China.
Please see later in the article for the Editors' Summary
Background
Biomass smoke is associated with the risk of chronic obstructive pulmonary disease (COPD), but few studies have elaborated approaches to reduce the risk of COPD from biomass burning. The purpose of this study was to determine whether improved cooking fuels and ventilation have effects on pulmonary function and the incidence of COPD.
Methods and Findings
A 9-y prospective cohort study was conducted among 996 eligible participants aged at least 40 y from November 1, 2002, through November 30, 2011, in 12 villages in southern China. Interventions were implemented starting in 2002 to improve kitchen ventilation (by providing support and instruction for improving biomass stoves or installing exhaust fans) and to promote the use of clean fuels (i.e., biogas) instead of biomass for cooking (by providing support and instruction for installing household biogas digesters); questionnaire interviews and spirometry tests were performed in 2005, 2008, and 2011. That the interventions improved air quality was confirmed via measurements of indoor air pollutants (i.e., SO2, CO, CO2, NO2, and particulate matter with an aerodynamic diameter of 10 µm or less) in a randomly selected subset of the participants' homes. Annual declines in lung function and COPD incidence were compared between those who took up one, both, or neither of the interventions.
Use of clean fuels and improved ventilation were associated with a reduced decline in forced expiratory volume in 1 s (FEV1): decline in FEV1 was reduced by 12 ml/y (95% CI, 4 to 20 ml/y) and 13 ml/y (95% CI, 4 to 23 ml/y) in those who used clean fuels and improved ventilation, respectively, compared to those who took up neither intervention, after adjustment for confounders. The combined improvements of use of clean fuels and improved ventilation had the greatest favorable effects on the decline in FEV1, with a slowing of 16 ml/y (95% CI, 9 to 23 ml/y). The longer the duration of improved fuel use and ventilation, the greater the benefits in slowing the decline of FEV1 (p<0.05). The reduction in the risk of COPD was unequivocal after the fuel and ventilation improvements, with an odds ratio of 0.28 (95% CI, 0.11 to 0.73) for both improvements.
Conclusions
Replacing biomass with biogas for cooking and improving kitchen ventilation are associated with a reduced decline in FEV1 and risk of COPD.
Trial Registration
Chinese Clinical Trial Register ChiCTR-OCH-12002398
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Nearly 3 billion people in developing countries heat their homes and cook by burning biomass—wood, crop waste, and animal dung—in open fires and leaky stoves. Burning biomass this way releases pollutants into the home that impair lung function and that are responsible for more than a million deaths from chronic obstructive pulmonary disease (COPD) every year. COPD is a group of diseases that interfere with breathing. Normally, air is breathed in through the nose or mouth and travels down the windpipe into two bronchial tubes (airways) in the lungs. These tubes branch into smaller tubes (bronchioles) that end in bunches of tiny air sacs (alveoli). Oxygen in the air passes through the thin walls of these sacs into small blood vessels and is taken to the heart for circulation round the body. The two main types of COPD—chronic bronchitis (long-term irritation and swelling of the bronchial tubes) and emphysema (damage to the walls of the alveoli)—make it hard for people to breathe. Most people with COPD have both chronic bronchitis and emphysema, both of which are caused by long-term exposure to cigarette smoke, indoor air pollution, and other lung irritants. Symptoms of COPD include breathlessness during exercise and a persistent cough that produces large amounts of phlegm (mucus). There is no cure for COPD, but drugs and oxygen therapy can relieve its symptoms, and avoiding lung irritants can slow disease progression.
Why Was This Study Done?
Exposure to indoor air pollution has been associated with impaired lung function and COPD in several studies. However, few studies have assessed the long-term effects on lung function and on the incidence of COPD (the proportion of a population that develops COPD each year) of replacing biomass with biogas (a clean fuel produced by bacterial digestion of biodegradable materials) for cooking and heating, or of improving kitchen ventilation during cooking. Here, the researchers undertook a nine-year prospective cohort study in rural southern China to investigate whether these interventions are associated with any effects on lung function and on the incidence of COPD. A prospective cohort study enrolls a group of people, determines their characteristics at baseline, and follows them over time to see whether specific characteristic are associated with specific outcomes.
What Did the Researchers Do and Find?
The researchers offered nearly 1,000 people living in 12 villages in southern China access to biogas and to improved kitchen ventilation. All the participants, who adopted these interventions according to personal preferences, completed a questionnaire about their smoking habits and occupational exposure to pollutants and had their lung function measured using a spirometry test at the start and end of the study. Some participants also completed a questionnaire and had their lung function measured three and six years into the study. Finally, the researchers measured levels of indoor air pollution in a randomly selected subset of homes at the end of the study to confirm that the interventions had reduced indoor air pollution. Compared with non-use, the use of clean fuels and of improved ventilation were both associated with a reduction in the decline in lung function over time after adjusting for known characteristics that affect lung function, such as smoking. The use of both interventions reduced the decline in lung function more markedly than either intervention alone, and the benefits of using the interventions increased with length of use. Notably, the combined use of both interventions reduced the risk of COPD occurrence among the study participants.
What Do These Findings Mean?
These findings suggest that, among people living in rural southern China, the combined interventions of use of biogas instead of biomass and improved kitchen ventilation were associated with a reduced decline in lung function over time and with a reduced risk of COPD. Because participants were not randomly allocated to intervention groups, the people who adopted the interventions may have shared other unknown characteristics (confounders) that affected their lung function (for example, having a healthier lifestyle). Thus, it is not possible to conclude that either intervention actually caused a reduction in the decline in lung function. Nevertheless, these findings suggest that the use of biogas as a substitute for biomass for cooking and heating and improvements in kitchen ventilation might lead to a reduction in the global burden of COPD associated with biomass smoke.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001621.
The US National Heart, Lung, and Blood Institute provides detailed information for the public about COPD
The US Centers for Disease Control and Prevention provides information about COPD and links to other resources (in English and Spanish)
The UK National Health Service Choices website provides information for patients and carers about COPD, personal stories, and links to other resources
The British Lung Foundation, a not-for-profit organization, provides information about COPD in several languages
The Global Initiative for Chronic Obstructive Lung Disease works to improve prevention and treatment of COPD around the world
The World Health Organization provides information about all aspects of indoor air pollution and health (in English, French, and Spanish)
MedlinePlus provides links to other information about COPD (in English and Spanish)
doi:10.1371/journal.pmed.1001621
PMCID: PMC3965383  PMID: 24667834
17.  Individual and Cumulative Effects of GWAS Susceptibility Loci in Lung Cancer: Associations after Sub-Phenotyping for COPD 
PLoS ONE  2011;6(2):e16476.
Epidemiological studies show that approximately 20–30% of chronic smokers develop chronic obstructive pulmonary disease (COPD) while 10–15% develop lung cancer. COPD pre-exists lung cancer in 50–90% of cases and has a heritability of 40–77%, much greater than for lung cancer with heritability of 15–25%. These data suggest that smokers susceptible to COPD may also be susceptible to lung cancer. This study examines the association of several overlapping chromosomal loci, recently implicated by GWA studies in COPD, lung function and lung cancer, in (n = 1400) subjects sub-phenotyped for the presence of COPD and matched for smoking exposure. Using this approach we show; the 15q25 locus confers susceptibility to lung cancer and COPD, the 4q31 and 4q22 loci both confer a reduced risk to both COPD and lung cancer, the 6p21 locus confers susceptibility to lung cancer in smokers with pre-existing COPD, the 5p15 and 1q23 loci both confer susceptibility to lung cancer in those with no pre-existing COPD. We also show the 5q33 locus, previously associated with reduced FEV1, appears to confer susceptibility to both COPD and lung cancer. The 6p21 locus previously linked to reduced FEV1 is associated with COPD only. Larger studies will be needed to distinguish whether these COPD-related effects may reflect, in part, associations specific to different lung cancer histology. We demonstrate that when the “risk genotypes” derived from the univariate analysis are incorporated into an algorithm with clinical variables, independently associated with lung cancer in multivariate analysis, modest discrimination is possible on receiver operator curve analysis (AUC = 0.70). We suggest that genetic susceptibility to lung cancer includes genes conferring susceptibility to COPD and that sub-phenotyping with spirometry is critical to identifying genes underlying the development of lung cancer.
doi:10.1371/journal.pone.0016476
PMCID: PMC3033394  PMID: 21304900
18.  Whole Exome Re-Sequencing Implicates CCDC38 and Cilia Structure and Function in Resistance to Smoking Related Airflow Obstruction 
PLoS Genetics  2014;10(5):e1004314.
Chronic obstructive pulmonary disease (COPD) is a leading cause of global morbidity and mortality and, whilst smoking remains the single most important risk factor, COPD risk is heritable. Of 26 independent genomic regions showing association with lung function in genome-wide association studies, eleven have been reported to show association with airflow obstruction. Although the main risk factor for COPD is smoking, some individuals are observed to have a high forced expired volume in 1 second (FEV1) despite many years of heavy smoking. We hypothesised that these “resistant smokers” may harbour variants which protect against lung function decline caused by smoking and provide insight into the genetic determinants of lung health. We undertook whole exome re-sequencing of 100 heavy smokers who had healthy lung function given their age, sex, height and smoking history and applied three complementary approaches to explore the genetic architecture of smoking resistance. Firstly, we identified novel functional variants in the “resistant smokers” and looked for enrichment of these novel variants within biological pathways. Secondly, we undertook association testing of all exonic variants individually with two independent control sets. Thirdly, we undertook gene-based association testing of all exonic variants. Our strongest signal of association with smoking resistance for a non-synonymous SNP was for rs10859974 (P = 2.34×10−4) in CCDC38, a gene which has previously been reported to show association with FEV1/FVC, and we demonstrate moderate expression of CCDC38 in bronchial epithelial cells. We identified an enrichment of novel putatively functional variants in genes related to cilia structure and function in resistant smokers. Ciliary function abnormalities are known to be associated with both smoking and reduced mucociliary clearance in patients with COPD. We suggest that genetic influences on the development or function of cilia in the bronchial epithelium may affect growth of cilia or the extent of damage caused by tobacco smoke.
Author Summary
Very large genome-wide association studies in general population cohorts have successfully identified at least 26 genes or gene regions associated with lung function and a number of these also show association with chronic obstructive pulmonary disease (COPD). However, these findings explain a small proportion of the heritability of lung function. Although the main risk factor for COPD is smoking, some individuals have normal or good lung function despite many years of heavy smoking. We hypothesised that studying these individuals might tell us more about the genetics of lung health. Re-sequencing of exomes, where all of the variation in the protein-coding portion of the genome can be measured, is a recent approach for the study of low frequency and rare variants. We undertook re-sequencing of the exomes of “resistant smokers” and used publicly available exome data for comparisons. Our findings implicate CCDC38, a gene which has previously shown association with lung function in the general population, and genes involved in cilia structure and lung function as having a role in resistance to smoking.
doi:10.1371/journal.pgen.1004314
PMCID: PMC4006731  PMID: 24786987
19.  PLAUR polymorphisms and lung function in UK smokers 
BMC Medical Genetics  2009;10:112.
Background
We have previously identified Urokinase Plasminogen Activator Receptor (PLAUR) as an asthma susceptibility gene. In the current study we tested the hypothesis that PLAUR single nucleotide polymorphisms (SNPs) determine baseline lung function and contribute to the development of Chronic Obstructive Pulmonary Disease (COPD) in smokers.
Methods
25 PLAUR SNPs were genotyped in COPD subjects and individuals with smoking history (n = 992). Linear regression was used to determine the effects of polymorphism on baseline lung function (FEV1, FEV1/FVC) in all smokers. Genotype frequencies were compared in spirometry defined smoking controls (n = 176) versus COPD cases (n = 599) and COPD severity (GOLD stratification) using logistic regression.
Results
Five SNPs showed a significant association (p < 0.01) with baseline lung function; rs2302524(Lys220Arg) and rs2283628(intron 3) were associated with lower and higher FEV1 respectively. rs740587(-22346), rs11668247(-20040) and rs344779(-3666) in the 5'region were associated with increased FEV1/FVC ratio. rs740587 was also protective for COPD susceptibility and rs11668247 was protective for COPD severity although no allele dose relationship was apparent. Interestingly, several of these associations were driven by male smokers not females.
Conclusion
This study provides tentative evidence that the asthma associated gene PLAUR also influences baseline lung function in smokers. However the case-control analyses do not support the conclusion that PLAUR is a major COPD susceptibility gene in smokers. PLAUR is a key serine protease receptor involved in the generation of plasmin and has been implicated in airway remodelling.
doi:10.1186/1471-2350-10-112
PMCID: PMC2784766  PMID: 19878584
20.  Up-to-date on mortality in COPD - report from the OLIN COPD study 
Background
The poor recognition and related underdiagnosis of COPD contributes to an underestimation of mortality in subjects with COPD. Data derived from population studies can advance our understanding of the true burden of COPD. The objective of this report was to evaluate the impact of COPD on mortality and its predictors in a cohort of subjects with and without COPD recruited during the twenty first century.
Methods
All subjects with COPD (n = 993) defined according to the GOLD spirometric criteria, FEV1/FVC < 0.70, and gender- and age-matched subjects without airway obstruction, non-COPD (n = 993), were identified in a clinical follow-up survey of the Obstructive Lung Disease in Northern Sweden (OLIN) Studies cohorts in 2002-2004. Mortality was observed until the end of year 2007. Baseline data from examination at recruitment were used in the risk factor analyses; age, smoking status, lung function (FEV1 % predicted) and reported heart disease.
Results
The mortality was significantly higher among subjects with COPD, 10.9%, compared to subjects without COPD, 5.8% (p < 0.001). Mortality was associated with higher age, being a current smoker, male gender, and COPD. Replacing COPD with FEV1 % predicted in the multivariate model resulted in the decreasing level of FEV1 being a significant risk factor for death, while heart disease was not a significant risk factor for death in any of the models.
Conclusions
In this cohort COPD and decreased FEV1 were significant risk factors for death when adjusted for age, gender, smoking habits and reported heart disease.
doi:10.1186/1471-2466-12-1
PMCID: PMC3276412  PMID: 22230685
21.  Adam33 polymorphisms are associated with COPD and lung function in long-term tobacco smokers 
Respiratory Research  2009;10(1):21.
Background
Variation in ADAM33 has been shown to be important in the development of asthma and altered lung function. This relationship however, has not been investigated in the population susceptible to COPD; long term tobacco smokers. We evaluated the association between polymorphisms in ADAM33 gene with COPD and lung function in long term tobacco smokers.
Methods
Caucasian subjects, at least 50 year old, who smoked ≥ 20 pack-years (n = 880) were genotyped for 25 single nucleotide polymorphisms (SNPs) in ADAM33. COPD was defined as an FEV1/FVC ratio < 70% and percent-predicted (pp)FEV1 < 75% (n = 287). The control group had an FEV1/FVC ratio ≥ 70% and ppFEV1 ≥ 80% (n = 311) despite ≥ 20 pack years of smoking. Logistic and linear regressions were used for the analysis. Age, sex, and smoking status were considered as potential confounders.
Results
Five SNPs in ADAM33 were associated with COPD (Q-1, intronic: p < 0.003; S1, Ile → Val: p < 0.003; S2, Gly → Gly: p < 0.04; V-1 intronic: p < 0.002; V4, in 3' untranslated region: p < 0.007). Q-1, S1 and V-1 were also associated with ppFEV1, FEV1/FVC ratio and ppFEF25–75 (p values 0.001 – 0.02). S2 was associated with FEV1/FVC ratio (p < 0.05). The association between S1 and residual volume revealed a trend toward significance (p value < 0.07). Linkage disequilibrium and haplotype analyses suggested that S1 had the strongest degree of association with COPD and pulmonary function abnormalities.
Conclusion
Five SNPs in ADAM33 were associated with COPD and lung function in long-term smokers. Functional studies will be needed to evaluate the biologic significance of these polymorphisms in the pathogenesis of COPD.
doi:10.1186/1465-9921-10-21
PMCID: PMC2664793  PMID: 19284602
22.  Decorin and TGF-β1 polymorphisms and development of COPD in a general population 
Respiratory Research  2006;7(1):89.
Background
Decorin, an extracellular matrix (ECM) proteoglycan, and TGF-β1 are both involved in lung ECM turnover. Decorin and TGF-β1 expression are decreased respectively increased in COPD lung tissue. Interestingly, they act as each other's feedback regulator. We investigated whether single nucleotide polymorphisms (SNPs) in decorin and TGF-β1 underlie accelerated decline in FEV1 and development of COPD in the general population.
Methods
We genotyped 1390 subjects from the Vlagtwedde/Vlaardingen cohort. Lung function was measured every 3 years for a period of 25 years. We tested whether five SNPs in decorin (3'UTR and four intron SNPs) and three SNPs in TGF-β1 (3'UTR rs6957, C-509T rs1800469 and Leu10Pro rs1982073), and their haplotypes, were associated with COPD (last survey GOLD stage = II). Linear mixed effects models were used to analyze genotype associations with FEV1 decline.
Results
We found a significantly higher prevalence of carriers of the minor allele of the TGF-β1 rs6957 SNP (p = 0.001) in subjects with COPD. Additionally, we found a significantly lower prevalence of the haplotype with the major allele of rs6957 and minor alleles for rs1800469 and rs1982073 SNPs in TGF-β1 in subjects with COPD (p = 0.030), indicating that this association is due to the rs6957 SNP. TGF-β1 SNPs were not associated with FEV1 decline. SNPs in decorin, and haplotypes constructed of both TGF-β1 and decorin SNPs were not associated with development of COPD or with FEV1 decline.
Conclusion
Our study shows for the first time that SNPs in decorin on its own or in interaction with SNPs in TGF-β1 do not underlie the disturbed balance in expression between these genes in COPD. TGF-β1 SNPs are associated with COPD, yet not with accelerated FEV1 decline in the general population.
doi:10.1186/1465-9921-7-89
PMCID: PMC1539000  PMID: 16780585
23.  Tomographic and functional findings in severe COPD: comparison between the wood smoke-related and smoking-related disease *  
OBJECTIVE:
Wood smoke exposure is a risk factor for COPD. For a given degree of airway obstruction, the reduction in DLCO is smaller in individuals with wood smoke-related COPD than in those with smoking-related COPD, suggesting that there is less emphysema in the former. The objective of this study was to compare HRCT findings between women with wood smoke-related COPD and women with smoking-related COPD.
METHODS:
Twenty-two women with severe COPD (FEV1/FVC ratio < 70% and FEV1 < 50%) were divided into two groups: those with wood smoke-related COPD (n = 12) and those with smoking-related COPD (n = 10). The two groups were compared regarding emphysema scores and airway involvement (as determined by HRCT); and functional abnormalities-spirometry results, DLCO, alveolar volume (VA), the DLCO/VA ratio, lung volumes, and specific airway resistance (sRaw).
RESULTS:
There were no significant differences between the two groups in terms of FEV1, sRaw, or lung hyperinflation. Decreases in DLCO and in the DLCO/VA ratio were greater in the smoking-related COPD group subjects, who also had higher emphysema scores, in comparison with the wood smoke-related COPD group subjects. In the wood smoke-related COPD group, HRCT scans showed no significant emphysema, the main findings being peribronchial thickening, bronchial dilation, and subsegmental atelectasis.
CONCLUSIONS:
Female patients with severe wood smoke-related COPD do not appear to develop emphysema, although they do show severe airway involvement. The reduction in DLCO and VA, with a normal DLCO/VA ratio, is probably due to severe bronchial obstruction and incomplete mixing of inspired gas during the determination of single-breath DLCO.
doi:10.1590/S1806-37132013000200005
PMCID: PMC4075823  PMID: 23670499
Pulmonary disease, chronic obstructive; Tomography; Air pollution; Biomass; Smoke; Respiratory function tests
24.  Lung function and blood markers of nutritional status in non-COPD aging men with smoking history: A cross-sectional study 
Purpose:
Cigarette smoking and advanced age are well known as risk factors for chronic obstructive pulmonary disease (COPD), and nutritional abnormalities are important in patients with COPD. However, little is known about the nutritional status in non-COPD aging men with smoking history. We therefore investigated whether reduced lung function is associated with lower blood markers of nutritional status in those men.
Subjects and methods:
This association was examined in a cross-sectional study of 65 Japanese male current or former smokers aged 50 to 80 years: 48 without COPD (non-COPD group), divided into tertiles according to forced expiratory volume in one second as percent of forced vital capacity (FEV1/FVC), and 17 with COPD (COPD group).
Results:
After adjustment for potential confounders, lower FEV1/FVC was significantly associated with lower red blood cell count (RBCc), hemoglobin, and total protein (TP); not with total energy intake. The difference in adjusted RBCc and TP among the non-COPD group tertiles was greater than that between the bottom tertile in the non-COPD group and the COPD group.
Conclusion:
In non-COPD aging men with smoking history, trends toward reduced nutritional status and anemia may independently emerge in blood components along with decreased lung function even before COPD onset.
PMCID: PMC2921691  PMID: 20714377
anemia; chronic obstructive pulmonary disease; lung function; nutritional assessment; nutritional status; smoking
25.  Variants in the 15q24/25 Locus Associate with Lung Function Decline in Active Smokers 
PLoS ONE  2013;8(1):e53219.
Genetic variation in nicotinic acetylcholine receptor subunit genes (nAChRs) is associated with lung function level and chronic obstructive pulmonary disease (COPD). It is unknown whether these variants also predispose to an accelerated lung function decline. We investigated the association of nAChR susceptibility variants with lung function decline and COPD severity. The rs1051730 and rs8034191 variants were genotyped in a population-based cohort of 1,226 heavy smokers (COPACETIC) and in an independent cohort of 883 heavy smokers, of which 653 with COPD of varying severity (LEUVEN). Participants underwent pulmonary function tests at baseline. Lung function decline was assessed over a median follow-up of 3 years in COPACETIC. Current smokers homozygous for the rs1051730 A-allele or rs8034191 G-allele had significantly greater FEV1/FVC decline than homozygous carriers of wild-type alleles (3.3% and 4.3%, p = 0.026 and p = 0.009, respectively). In the LEUVEN cohort, rs1051730 AA-carriers and rs8034191 GG-carriers had a two-fold increased risk to suffer from COPD GOLD IV (OR 2.29, 95% confidence interval [CI] = 1.11–4.75; p = 0.025 and OR = 2.42, 95% [CI] = 1.18–4.95; p = 0.016, respectively). The same risk alleles conferred, respectively, a five- and four-fold increased risk to be referred for lung transplantation because of end-stage COPD (OR = 5.0, 95% [CI] = 1.68–14.89; p = 0.004 and OR = 4.06, 95% [CI] = 1.39–11.88; p = 0.010). In Europeans, variants in nAChRs associate with an accelerated lung function decline in current smokers and with clinically relevant COPD.
doi:10.1371/journal.pone.0053219
PMCID: PMC3548843  PMID: 23349703

Results 1-25 (953343)