Lies Lahousse

Genome-Wide Association Studies Identify CHRNA5/3 and HTR4 in the Development of Airflow Obstruction

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 FEV(1) and its ratio to FVC (FEV(1)/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 FEV(1)/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.

Chronic obstructive pulmonary disease and lipid core carotid artery plaques in the elderly: the Rotterdam Study.

RATIONALE Chronic obstructive pulmonary disease (COPD) is an independent risk factor for ischemic stroke and the risk increases with severity of airflow limitation. Even though vulnerable carotid artery plaque components, such as intraplaque hemorrhage and lipid core, place persons at high risk for ischemic events, the plaque composition in patients with COPD has never been explored. OBJECTIVES To investigate the prevalence of carotid wall thickening, the different carotid artery plaque components, and their relationship with severity of airflow limitation in elderly patients with COPD. METHODS This cross-sectional analysis was part of the Rotterdam Study, a prospective population-based cohort study performed in subjects aged 55 years and older. Diagnosis of COPD was confirmed by spirometry. Participants with carotid wall intima-media thickness greater than or equal to 2.5 mm on ultrasonography underwent high-resolution magnetic resonance imaging for characterization of carotid plaques. Data were analyzed using logistic regression. MEASUREMENTS AND MAIN RESULTS COPD cases (n = 253) had a twofold increased risk (odds ratio, 2.0; 95% confidence interval, 1.44-2.85; P < 0.0001) of presentation with carotid wall thickening on ultrasonography compared with control subjects with a normal lung function (n = 920). Moreover, the risk increased significantly with severity of airflow limitation. On magnetic resonance imaging, vulnerable lipid core plaques were more frequent in COPD cases than in control subjects (odds ratio, 2.1; 95% confidence interval, 1.25-3.69; P = 0.0058). CONCLUSIONS Carotid artery wall thickening is more prevalent in patients with COPD than in control subjects. In elderly subjects with carotid wall thickening, COPD is an independent predictor for the presence of a lipid core, and therefore of vulnerable plaques.

Genetic loci associated with chronic obstructive pulmonary disease overlap with loci for lung function and pulmonary fibrosis

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality worldwide. We performed a genetic association study in 15,256 cases and 47,936 controls, with replication of select top results (P < 5 × 10−6) in 9,498 cases and 9,748 controls. In the combined meta-analysis, we identified 22 loci associated at genome-wide significance, including 13 new associations with COPD. Nine of these 13 loci have been associated with lung function in general population samples, while 4 (EEFSEC, DSP, MTCL1, and SFTPD) are new. We noted two loci shared with pulmonary fibrosis (FAM13A and DSP) but that had opposite risk alleles for COPD. None of our loci overlapped with genome-wide associations for asthma, although one locus has been implicated in joint susceptibility to asthma and obesity. We also identified genetic correlation between COPD and asthma. Our findings highlight new loci associated with COPD, demonstrate the importance of specific loci associated with lung function to COPD, and identify potential regions of genetic overlap between COPD and other respiratory diseases.

Chronic obstructive pulmonary disease and sudden cardiac death: the Rotterdam study

AIMS Both sudden cardiac death (SCD) and chronic obstructive pulmonary disease (COPD) are common conditions in the elderly. Previous studies have identified an association between COPD and cardiovascular disease, and with SCD in specific patient groups. Our aim was to investigate whether there is an association between COPD and SCD in the general population. METHODS AND RESULTS The Rotterdam study is a population-based cohort study among 14 926 subjects aged 45 years and older with up to 24 years of follow-up. Analyses were performed with a (time dependent) Cox proportional hazard model adjusted for age, sex, and smoking. Of the 13 471 persons included in the analysis; 1615 had a diagnosis of COPD and there were 551 cases of SCD. Chronic obstructive pulmonary disease was associated with an increased risk of SCD (age- and sex-adjusted hazard ratio, HR, 1.34, 95% CI 1.06-1.70). The risk particularly increased in the period 2000 days (5.48 years) after the diagnosis of COPD (age- and sex-adjusted HR 2.12, 95% CI 1.60-2.82) and increased further to a more than three-fold higher risk in COPD subjects with frequent exacerbations during this period (age- and sex-adjusted HR 3.58, 95% CI 2.35-5.44). Analyses restricted to persons without prevalent myocardial infarction or heart failure yielded similar results. CONCLUSION Chronic obstructive pulmonary disease is associated with an increased risk for SCD. The risk especially increases in persons with frequent exacerbations 5 years after the diagnosis of COPD. This risk indicator could provide new directions for better-targeted actions to prevent SCD.

Chronic obstructive pulmonary disease and cerebral Microbleeds the Rotterdam study

RATIONALE Chronic obstructive pulmonary disease (COPD) is a common, complex multisystem disease in the elderly with multiple comorbidities that significantly impact morbidity and mortality. Although cerebral small-vessel disease is an important cause of cognitive decline and age-related disability, it is a poorly investigated potential systemic manifestation of patients with COPD. OBJECTIVES To examine whether COPD relates to the development and location of cerebral microbleeds, a novel marker of cerebral small-vessel disease. METHODS Cross-sectional and longitudinal analyses were part of the Rotterdam Study, a prospective population-based cohort study in subjects aged greater than or equal to 55 years. Diagnosis of COPD was confirmed by spirometry. Cerebral microbleeds were detected using high-resolution magnetic resonance imaging (MRI). MEASUREMENTS AND MAIN RESULTS Subjects with COPD (n = 165) had a higher prevalence of cerebral microbleeds compared with subjects with normal lung function (n = 645) independent of age, sex, smoking status, atherosclerotic macroangiopathy, antithrombotic use, total cholesterol, triglycerides, and serum creatinin (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.15-2.47; P = 0.007). Regarding the specific microbleed location, subjects with COPD had a significantly higher prevalence of microbleeds in deep or infratentorial locations (OR, 3.3; 95% CI, 1.97-5.53; P < 0.001), which increased with severity of airflow limitation and are suggestive of hypertensive or arteriolosclerotic microangiopathy. Furthermore, in longitudinal analysis restricted to subjects without microbleed at baseline, COPD was an independent predictor of incident cerebral microbleeds in deep or infratentorial locations (OR, 7.1; 95% CI, 2.1-24.5; P = 0.002). CONCLUSIONS Our findings are compatible with COPD causing an increased risk of the development of cerebral microbleeds in deep or infratentorial locations.

Large-Scale Genome-Wide Association Studies and Meta-Analyses of Longitudinal Change in Adult Lung Function

Background Genome-wide association studies (GWAS) have identified numerous loci influencing cross-sectional lung function, but less is known about genes influencing longitudinal change in lung function. Methods We performed GWAS of the rate of change in forced expiratory volume in the first second (FEV1) in 14 longitudinal, population-based cohort studies comprising 27,249 adults of European ancestry using linear mixed effects model and combined cohort-specific results using fixed effect meta-analysis to identify novel genetic loci associated with longitudinal change in lung function. Gene expression analyses were subsequently performed for identified genetic loci. As a secondary aim, we estimated the mean rate of decline in FEV1 by smoking pattern, irrespective of genotypes, across these 14 studies using meta-analysis. Results The overall meta-analysis produced suggestive evidence for association at the novel IL16/STARD5/TMC3 locus on chromosome 15 (P  =  5.71 × 10-7). In addition, meta-analysis using the five cohorts with ≥3 FEV1 measurements per participant identified the novel ME3 locus on chromosome 11 (P  =  2.18 × 10-8) at genome-wide significance. Neither locus was associated with FEV1 decline in two additional cohort studies. We confirmed gene expression of IL16, STARD5, and ME3 in multiple lung tissues. Publicly available microarray data confirmed differential expression of all three genes in lung samples from COPD patients compared with controls. Irrespective of genotypes, the combined estimate for FEV1 decline was 26.9, 29.2 and 35.7 mL/year in never, former, and persistent smokers, respectively. Conclusions In this large-scale GWAS, we identified two novel genetic loci in association with the rate of change in FEV1 that harbor candidate genes with biologically plausible functional links to lung function.

Cardiac effects of current treatments of chronic obstructive pulmonary disease

We review the cardiac safety of the drugs available at present for the maintenance treatment of chronic obstructive pulmonary disease (COPD) in stable disease, focusing on inhaled long-acting muscarinic antagonists (LAMA) and long-acting β2 agonists (LABA), used either as a monotherapy or as a fixed-dose combination. We report the difficulties of, and pitfalls in, the investigation of the safety of drug treatments in COPD, which is hampered by the so-called COPD trial paradox: on the one hand, COPD is defined as a systemic disease and is frequently associated with comorbidities (especially cardiovascular comorbidities), which have an important effect on the prognosis of individual patients; on the other hand, patients with COPD and cardiovascular or other coexisting illnesses are often excluded from participation in randomised controlled clinical trials. In these trials, inhaled long-acting bronchodilators, both LAMA or LABA, or both, seem to be safe when used in the appropriate dose in adherent patients with COPD without uncontrolled cardiovascular disease or other notable comorbidities. However, the cardiac safety of LAMA and LABA is less evident when used inappropriately (eg, overdosing) or in patients with COPD and substantial cardiovascular disease, prolonged QTc interval, or polypharmacy. Potential warnings about rare cardiac events caused by COPD treatment from meta-analyses and observational studies need to be confirmed in high quality large randomised controlled trials. Finally, we briefly cover the cardiac safety issues of chronic oral drug treatments for COPD, encompassing theophylline, phosphodiesterase inhibitors, and macrolides.

Chronic Obstructive Pulmonary Disease and the Risk of Stroke. The Rotterdam Study

RATIONALE Worldwide, chronic obstructive pulmonary disease (COPD) and stroke are leading causes of death. Increasing evidence suggests an association between both diseases, either caused by an increased atherosclerosis risk in patients with COPD or as a consequence of shared risk factors between stroke and COPD. OBJECTIVES To examine the associations between COPD and subtypes of stroke in the general population and to explore the role of cardiovascular risk factors and exacerbations on these associations. METHODS Within the prospective population-based Rotterdam Study, we followed 13,115 participants without history of stroke for occurrence of stroke. Follow up started in 1990 to 2008 and ended in 2012. COPD was related to stroke using a time-dependent Cox proportional hazard model. MEASUREMENTS AND MAIN RESULTS COPD was diagnosed in 1,566 participants. During 126,347 person-years, 1,250 participants suffered a stroke, of which 701 were ischemic and 107 hemorrhagic. Adjusted for age, age squared, and sex, COPD was significantly associated with all stroke (hazard ratio [HR], 1.20; 95% confidence interval, 1.00-1.43), ischemic stroke (HR, 1.27; 1.02-1.59), and hemorrhagic stroke (HR, 1.70; 1.01-2.84). Adjusting for cardiovascular risk factors gave similar effect sizes. In contrast, additional adjusting for smoking attenuated the effect sizes: HR, 1.09 (0.91-1.31) for all stroke; HR, 1.13 (0.91-1.42) for ischemic stroke; and HR 1.53 (0.91-2.59) for hemorrhagic stroke. After an acute severe exacerbation, subjects with COPD had a 6.66-fold (2.42-18.20) increased risk of stroke. CONCLUSIONS Our cohort study demonstrated a higher risk of both ischemic and hemorrhagic stroke in subjects with COPD and revealed the importance of smoking as a shared risk factor.

Chronic obstructive pulmonary disease and cerebrovascular disease: A comprehensive review

Along with the aging population, the public health burden of cerebrovascular disease is increasing. Cerebral small vessel disease and accumulation of brain pathology associate with cognitive decline and can lead to clinical outcomes, such as stroke and dementia. Chronic Obstructive Pulmonary Disease (COPD) is a common respiratory disease among elderly. The quality of life and prognosis of patients with COPD is greatly determined by the presence of comorbidities including stroke and cognitive impairment. Despite the clinical relevance of cerebral small vessel disease, stroke and (vascular) cognitive impairment in patients with COPD, literature is scarce and underlying mechanisms are unknown. The aim of the present review is therefore to summarize current scientific knowledge, to provide a better understanding of the interplay between COPD and the aging brain and to define remaining knowledge gaps. This narrative review article 1) overviews the epidemiology of cerebral small vessel disease, stroke and cognitive impairment in patients with COPD; 2) discusses potential underlying mechanisms including aging, smoking, systemic inflammation, vasculopathy, hypoxia and genetic susceptibility; and 3) highlights areas requiring further research.

Gait patterns in COPD: the Rotterdam Study

Gait disturbances in patients with chronic obstructive pulmonary disease (COPD) may lead to disability and falls. As studies assessing gait kinematics in COPD are sparse, we investigated associations of COPD with various gait domains and explored a potential link with falling. Gait was measured within the prospective, population-based Rotterdam Study (age ≥55 years) using an electronic walkway and summarised into seven gait domains: Rhythm, Variability, Phases, Pace, Tandem, Turning and Base of Support. Rhythm is a temporal gait aspect that includes cadence and reflects how quickly steps are taken. Persons with COPD (n=196) exhibited worse Rhythm (−0.21 sd, 95% CI −0.36– −0.06 sd) compared with persons with normal lung function (n=898), independent of age, sex, height, education, smoking or analgesic use, especially when dyspnoea and severe airflow limitation or frequent exacerbations (Global Initiative for Chronic Obstructive Lung Disease group D: −0.83 sd, 95% CI −1.25– −0.41 sd) were present. A lower forced expiratory volume in 1 s was associated with worse Rhythm and Pace, including lower cadence and gait velocity, respectively. Importantly, fallers with COPD had significantly worse Rhythm than nonfallers with COPD. This study demonstrates that persons with COPD exhibit worse Rhythm, especially fallers with COPD. The degree of Rhythm deterioration was associated with the degree of airflow limitation, symptoms and frequency of exacerbations. This study comprehensively investigates, in a large, population-based cohort, the gait pattern in COPD http://ow.ly/HQbc3