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CT measurement of body composition may improve lung transplant candidate selection. We assessed whether skeletal muscle adipose deposition on abdominal and thigh CT scans was associated with 6 min walk distance (6MWD) and wait-list survival in lung transplant candidates. Each ½-SD decrease in abdominal muscle attenuation (indicating greater lipid content) was associated with 14 m decrease in 6MWD (95% CI −20 to −8) and 20% increased risk of death or delisting (95% CI 10% to 40%). Each ½-standard deviation decrease in thigh muscle attenuation was associated with 15 m decrease in 6MWD (95% CI −21 to −10). CT imaging may improve candidate risk stratification.

Background Adults with interstitial lung disease (ILD) often have serologic evidence of autoimmunity of uncertain significance without overt autoimmune disease. We examined associations of rheumatoid arthritis (RA)-associated antibodies with subclinical ILD in community-dwelling adults. Methods We measured serum rheumatoid factor (RF) and anticyclic citrullinated peptide antibody (anti-CCP) and high attenuation areas (HAAs; CT attenuation values between −600 and −250 Hounsfield units) on cardiac CT in 6736 community-dwelling US adults enrolled in the Multi-Ethnic Study of Atherosclerosis. We measured interstitial lung abnormalities (ILAs) in 2907 full-lung CTs at 9.5-year median follow-up. We used generalised linear and additive models to examine associations between autoantibodies and both HAA and ILA, and tested for effect modification by smoking. Results In adjusted models, HAA increased by 0.49% (95% CI 0.11% to 0.86%) per doubling of RF IgM and by 0.95% (95% CI 0.50% to 1.40%) per RF IgA doubling. ILA prevalence increased by 11% (95% CI 3% to 20%) per RF IgA doubling. Smoking modified the associations of both RF IgM and anti-CCP with both HAA and ILA (interaction p values varied from 0.01 to 0.09). Among ever smokers, HAA increased by 0.81% (95% CI 0.33% to 1.30%) and ILA prevalence increased by 14% (95% CI 5% to 24%,) per RF IgM doubling; and HAA increased by 1.31% (95% CI 0.45% to 2.18%) and ILA prevalence increased by 13% (95% CI 2% to 24%) per anti-CCP doubling. Among never smokers, no meaningful associations were detected. Conclusions RA-related autoimmunity is associated with both quantitative and qualitative subclinical ILD phenotypes on CT, particularly among ever smokers.

Background Second-hand smoke (SHS) exposure has been linked to the development of and morbidity from lung disease. We sought to advance understanding of the impact of SHS on health-related outcomes in individuals with COPD. Methods Among the participants with COPD in SPIROMICS, recent SHS exposure was quantified as (1) hours of reported exposure in the past week or (2) reported living with a smoker. We performed adjusted regression for SHS with outcomes, testing for interactions with gender, race, smoking and obesity. Results Of the 1580 participants with COPD, 20% reported living with a smoker and 27% reported exposure in the past week. Living with a smoker was associated with worse St George9s Respiratory Questionnaire score (SGRQ, β 3.10; 95% CI 0.99 to 5.21), COPD Assessment Test score (β 1.43; 95% CI 0.52 to 2.35) and increased risk for severe exacerbations (OR 1.51, 95% CI 1.04 to 2.17). SHS exposure in the past week was associated with worse SGRQ (β 2.52; 95% CI 0.47 to 4.58), nocturnal symptoms (OR 1.58; 95% CI 1.19 to 2.10), wheezing (OR 1.34; 95% CI 1.02 to 1.77), chronic productive cough (OR 1.77; 95% CI 1.33 to 2.35) and difficulty with cough and sputum (Ease of Cough and Sputum scale, β 0.84; 95% CI 0.42 to 1.25). SHS was associated with increased airway wall thickness on CT but not emphysema. Active smokers, obese individuals and individuals with less severe airflow obstruction also had higher susceptibility to SHS for some outcomes. Conclusion Individuals with COPD, including active smokers, have significant SHS exposure, associated with worse outcomes and airway wall thickness. Active smokers and obese individuals may have worse outcomes associated with SHS. Trial registration number NCT01969344 (clinicaltrials.gov).

Subpopulations and Intermediate Outcomes in COPD Study (SPIROMICS) is a multicentre observational study of chronic obstructive pulmonary disease (COPD) designed to guide future development of therapies for COPD by providing robust criteria for subclassifying COPD participants into groups most likely to benefit from a given therapy during a clinical trial, and identifying biomarkers/phenotypes that can be used as intermediate outcomes to reliably predict clinical benefit during therapeutic trials. The goal is to enrol 3200 participants in four strata. Participants undergo a baseline visit and three annual follow-up examinations, with quarterly telephone calls. Adjudication of exacerbations and mortality will be undertaken.

We investigated associations of plasma lipoproteins with subclinical interstitial lung disease (ILD) by measuring high attenuation areas (HAA: lung voxels between −600 and −250 Hounsfield units) in 6700 adults and serum MMP-7 and SP-A in 1216 adults age 45–84 without clinical cardiovascular disease in Multi-Ethnic Study of Atherosclerosis. In cross-sectional analyses, each SD decrement in high density lipoprotein cholesterol (HDL-C) was associated with a 2.12% HAA increment (95% CI 1.44% to 2.79%), a 3.53% MMP-7 increment (95% CI 0.93% to 6.07%) and a 6.37% SP-A increment (95% CI 1.35% to 11.13%), independent of demographics, smoking and inflammatory biomarkers. These findings support a novel hypothesis that HDL-C might influence subclinical lung injury and extracellular matrix remodelling.

The value of quantitative CT (QCT) to identify chronic obstructive pulmonary disease (COPD) phenotypes is increasingly appreciated. The authors hypothesised that QCT-defined emphysema and airway abnormalities relate to St George's Respiratory Questionnaire (SGRQ) and Body-Mass Index, Airflow Obstruction, Dyspnea and Exercise Capacity Index (BODE).1200 COPDGene subjects meeting Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for COPD with QCT analysis were included. Total lung emphysema was measured using the density mask technique with a -950 Hounsfield unit threshold. An automated programme measured mean wall thickness (WT), wall area percentage (WA%) and 10 mm lumenal perimeter (pi10) in six segmental bronchi. Separate multivariate analyses examined the relative influence of airway measures and emphysema on SGRQ and BODE.In separate models predicting SGRQ score, a 1 unit SD increase in each airway measure predicted higher SGRQ scores (for WT, 1.90 points higher, p=0.002; for WA%, 1.52 points higher, p=0.02; for pi10, 2.83 points higher p0.001). The comparable increase in SGRQ for a 1 unit SD increase in emphysema percentage in these models was relatively weaker, significant only in the pi10 model (for emphysema percentage, 1.45 points higher, p=0.01). In separate models predicting BODE, a 1 unit SD increase in each airway measure predicted higher BODE scores (for WT, 1.07-fold increase, p0.001; for WA%, 1.20-fold increase, p0.001; for pi10, 1.16-fold increase, p0.001). In these models, emphysema more strongly influenced BODE (range 1.24-1.26-fold increase, p0.001).Emphysema and airway disease both relate to clinically important parameters. The relative influence of airway disease is greater for SGRQ; the relative influence of emphysema is greater for BODE.

Background Emphysema on CT is a risk factor for all-cause mortality in persons with and without airflow obstruction; however, causes of death associated with emphysema remain uncertain, particularly in the general population. Aims To test associations between quantitatively assessed emphysema on CT and cause of death in persons with and without a substantial smoking history. Methods The Multi-Ethnic Study of Atherosclerosis recruited 6814 participants, aged 45–84 years and without clinical cardiovascular disease, in 2000–2002. Per cent emphysema was defined on cardiac CT as per cent of lung voxels less than −950 Hounsfield units; emphysema on CT was defined as per cent emphysema above the upper limit of normal. Cause of death was classified by administrative codes. Proportional-hazards models were adjusted for age, race/ethnicity, gender, body mass index, smoking status, pack-years, coronary artery calcium, site and education. Additional adjustment for lung function was made in a subset with spirometry from 2004 to 2006. Results There were 1091 deaths over 12 years median follow-up. Emphysema on CT was strongly associated with increased mortality due to respiratory diseases (adjusted HR 2.94, 95% CI 1.68 to 5.15), particularly chronic lower respiratory diseases (adjusted HR 9.54, 95% CI 4.70 to 19.35), and lung cancer (adjusted HR 1.84, 95% CI 1.09 to 3.12), but not cardiovascular disease. Associations persisted among participants with fewer than 10 pack-years and those without physician-diagnosed respiratory disease, and were similar after adjustment for airflow measures and in persons without airflow limitation. Conclusions Quantitatively assessed emphysema on CT is associated with greater respiratory disease and lung cancer mortality, even among persons without traditional risk factors.

BackgroundThere is notable heterogeneity in the clinical presentation of patients with COPD. To characterise this heterogeneity, we sought to identify subgroups of smokers by applying cluster analysis to data from the COPDGene study.MethodsWe applied a clustering method, k-means, to data from 10 192 smokers in the COPDGene study. After splitting the sample into a training and validation set, we evaluated three sets of input features across a range of k (user-specified number of clusters). Stable solutions were tested for association with four COPD-related measures and five genetic variants previously associated with COPD at genome-wide significance. The results were confirmed in the validation set.FindingsWe identified four clusters that can be characterised as (1) relatively resistant smokers (ie, no/mild obstruction and minimal emphysema despite heavy smoking), (2) mild upper zone emphysema-predominant, (3) airway disease-predominant and (4) severe emphysema. All clusters are strongly associated with COPD-related clinical characteristics, including exacerbations and dyspnoea (p

Dr Young and Ms. Hopkins1 suggest that the lack of a confirmation of the ‘Hispanic paradox’ for lung phenotypes in the Multi-Ethnic Study of Atherosclerosis (MESA) Lung Study could be due to differences in the distribution of Hispanic subgroups and lower smoking exposure in MESA compared to the study by Bruse et al. 2 As suggested, we repeated our analyses stratifying the Hispanic group into those of Mexican and non-Mexican origin and found similar results to initial findings. In a sensitivity analysis including only those Hispanic-Americans who identified Mexico as their country of origin, we again found that among both women and men, genetic ancestry did …

SPIROMICS is a multi-center observational study of chronic obstructive pulmonary disease (COPD) designed to guide future development of therapies for COPD by 1) providing robust criteria for sub-classifying COPD participants into groups most likely to benefit from a given therapy during a clinical trial, thereby improving the chances of successful outcome; and 2) identifying biomarkers/phenotypes that can be used as intermediate outcomes to reliably predict clinical benefit during therapeutic trials, thus reducing costs. The goal is to enroll 3,200 participants in four strata: severe COPD, mild/moderate COPD, smokers without airflow obstruction and non-smoking controls. Participants undergo a baseline visit including morphometric measures, spirometry, six-minute walk, an inspiratory and expiratory chest CT, and a set of standardized questionnaires. Biospecimens, including plasma, serum, DNA, urine and induced sputum, are collected and stored. There are three annual follow-up examinations, with quarterly telephone calls to assess for exacerbations, hospitalizations and mortality. Bronchoscopy is being performed in a subset of participants and a subset of COPD patients will be assessed during exacerbations. Adjudication of exacerbations and mortality will be undertaken. SPIROMICS is designed so that sub-studies and ancillary studies testing additional hypotheses can be added.

We have read with interest Nakano and colleague's thoughtful comments1 on Smith et al 2 and are pleased to offer the following observations. We believe that a key strength of our paper is that it defines a rigorous sampling strategy to compare airways from matched hierarchical positions within the tracheobronchial tree with control for the known hierarchical gradient in airway dimensions.3 Nakano et al are correct to point out that hierarchical sampling by generation number results in grouping of airways from multiple anatomic locations (eg, segmental and lobar airways); conversely, hierarchical sampling by anatomic location results in grouping of airways from multiple generations.4 It is for this reason that we reported both sampling approaches (tables 2 …

Background Acetaminophen has been associated with asthma and is in part metabolised via the glutathione pathway. Inner-city minority children have high asthma morbidity and a relatively high frequency of a minor allele variant in the glutathione S transferase Pi gene (GSTP1). We hypothesised that prenatal acetaminophen exposure would predict wheeze at age 5years in an inner-city minority cohort and examined whether this association was modified by common polymorphisms in genes related to the glutathione pathway. Methods An ongoing population-based birth cohort study of Dominican Republic and African-American children in New York prospectively assessed the use of analgesics during pregnancy and current wheeze at age 5years in 301 children. Genotyping was conducted for GST polymorphisms. Binomial regression was used to adjust for potential confounders including postnatal acetaminophen use. Results 34% of mothers reported acetaminophen use during pregnancy and 27% of children had current wheeze at 5years. Prenatal exposure to acetaminophen predicted current wheeze (multivariate relative risk 1.71; 95% CI 1.20 to 2.42; p¼0.003), and the risk increased monotonically with increasing number of days of prenatal acetaminophen exposure (p trend

We thank Bokov and Delclaux for their thoughtful comments1 on our paper2 and offer the following comments. The homothety factor, as defined by Bokov and Delclaux,1 describes a structural aspect of the airway tree not directly addressed in our study, which we agree is important and likely also influences airflow in asthma and COPD. However, we believe the suggestion that the two factors, tracheal area and homothety factor, alone characterise the whole bronchial tree omits important structural characteristics, such as …