Airflow limitation classified with the fixed ratio or the lower limit of normal and cause-specific mortality - A prospective study

BACKGROUND

There is controversy as to whether airflow limitation should be defined as forced expiratory volume in 1 s (FEV₁)/vital capacity (VC) < 0.7 or as FEV₁/VC< the lower limit of normal (LLN). The aim was to examine whether different definitions of airflow limitation differ in predicting mortality.

METHODS

Longitudinal prospective study of a national cohort of Swedish workers (199,408 men; 7988 women), aged 20-64 years with spirometry without bronchodilation at baseline followed from 1979 until death, or censorship at 2010. Airflow limitation (AL) by Global Obstructive Lung Disease criteria, AL_GOLD, was defined as FEV₁/VC < 0.7; AL_LLN as FEV₁/VC < LLN. All all-cause, COPD and cardiovascular disease mortality was analyzed among men and women in relation to AL_GOLD and AL_LLN, adjusted for age and smoking.

RESULTS

Among men, all-cause mortality risks were similar by airflow limitation criteria: AL_GOLD RR = 1.32, 95% CI 1.26-1.38; AL_LLN, RR = 1.37, 95% CI 1.31-1.44. The risk estimates were also similar by airflow limitation definition for cardiovascular mortality and for COPD mortality. Among women, all-cause mortality was also similar by airflow limitation criteria, but significantly higher as compared to men: AL_GOLD RR = 2.10, 95% CI 1.66-2.66; AL_LLN, RR = 2.09, 95% CI 1.66-2.62. Also cardiovascular and COPD mortality by airflow limitation criteria was significantly higher among women as compared to men.

CONCLUSIONS

Defined either as FEV₁/VC < 0.7 or as FEV₁/VC < LLN, airflow limitation predicted excess mortality risk of similar magnitude. Mortality in relation to airflow limitation was higher among women compared to men.

Off the Courts: Occupational “Tennis Leg”

Objective: Injury to the gastrocnemius muscle (tennis leg) is a presenting complaint often associated with athletic pursuits. Despite that label, this form of injury is likely to be common to a variety of salaried and nonsalaried pursuits beyond sports. Method: We describe the presentation and management of two cases of “tennis leg” injury occurring in an occupational rather than athletic setting and review the relevant medical literature. Results: Partial tears of the medial insertion of the gastrocnemius tendon were documented in both cases, in the first through magnetic resonance imaging and in the second by ultrasound. Conclusion: Rupture of the tendon to the medial head of the gastrocnemius, the so-called “tennis leg” injury, should be considered as potentially work-related trauma, rather than taken to be solely a sports injury.

Exposure to second-hand tobacco smoke and respiratory symptoms in non-smoking adults: cross-sectional data from the general population of Telemark, Norway

Background

In Norway, data on the association between second-hand tobacco smoke (SHS) exposure at home and respiratory symptoms in adults are limited.

Methods

We assessed the association between self-reported exposure to SHS and the prevalence of respiratory symptoms among never-smokers aged 16 to 50 years from the general population who were included in a cross-sectional population-based study in Telemark County, Norway. Logistic regression analysis was used to estimate the odds ratios of symptoms among 8850 never-smokers who provided an affirmative response to questions regarding SHS; 504 (5.7%) of these reported that they lived in a home with daily or occasional indoor smoking.

Results

Productive cough and nocturnal dyspnoea were statistically associated with daily SHS exposure (ORs 1.5 [95% CI 1.04–2.0] and 1.8 [1.2–2.7], respectively). In analyses stratified by gender, nocturnal dyspnoea was associated with SHS among women (OR 1.8 [1.1–3.1]), but not among men (OR 0.93 [0.49–1.8]). Symptoms were not associated with occasional SHS exposure in the entire group, but infrequent exposure among men only was associated with increased prevalence of chronic cough; (OR 1.6; [1.04–2.6]) and was negatively associated with wheeze; (OR 0.44 [0.21–0.92)].

Conclusions

Daily SHS exposure in private homes was associated with productive cough and nocturnal dyspnoea. Our results suggest that preventive measures may be needed to reduce the respiratory effects of SHS at home.

Trial registration

ClinicalTrials.gov Identifier: NCT02073708 Registered February 27. 2014.

Lung volumes identify an at-risk group in persons with prolonged secondhand tobacco smoke exposure but without overt airflow obstruction

Introduction

Exposure to secondhand smoke (SHS) is associated with occult obstructive lung disease as evident by abnormal airflow indices representing small airway disease despite having preserved spirometry (normal forced expiratory volume in 1 s-to-forced vital capacity ratio, FEV₁/FVC). The significance of lung volumes that reflect air trapping in the presence of preserved spirometry is unclear.

Methods

To investigate whether lung volumes representing air trapping could determine susceptibility to respiratory morbidity in people with SHS exposure but without spirometric chronic obstructive pulmonary disease, we examined a cohort of 256 subjects with prolonged occupational SHS exposure and preserved spirometry. We elicited symptom prevalence by structured questionnaires, examined functional capacity (maximum oxygen uptake, VO_2max) by exercise testing, and estimated associations of those outcomes with air trapping (plethysmography-measured residual volume-to-total lung capacity ratio, RV/TLC), and progressive air trapping with exertion (increase in fraction of tidal breathing that is flow limited on expiration during exercise (per cent of expiratory flow limitation, %EFL)).

Results

RV/TLC was within the predicted normal limits, but was highly variable spanning 22%±13% and 16%±8% across the increments of FEV₁/FVC and FEV₁, respectively. Respiratory complaints were prevalent (50.4%) with the most common symptom being ≥2 episodes of cough per year (44.5%). Higher RV/TLC was associated with higher OR of reporting respiratory symptoms (n=256; r²=0.03; p=0.011) and lower VO_2max (n=179; r²=0.47; p=0.013), and %EFL was negatively associated with VO_2max (n=32; r²=0.40; p=0.017).

Conclusions

In those at risk for obstruction due to SHS exposure but with preserved spirometry, higher RV/TLC identifies a subgroup with increased respiratory symptoms and lower exercise capacity.

Occupational exposures and 20-year incidence of COPD: the European Community Respiratory Health Survey

BACKGROUND

Occupational exposures have been associated with an increased risk of COPD. However, few studies have related objectively assessed occupational exposures to prospectively assessed incidence of COPD, using postbronchodilator lung function tests. Our objective was to examine the effect of occupational exposures on COPD incidence in the European Community Respiratory Health Survey.

METHODS

General population samples aged 20-44 were randomly selected in 1991-1993 and followed up 20 years later (2010-2012). Spirometry was performed at baseline and at follow-up, with incident COPD defined using a lower limit of normal criterion for postbronchodilator FEV1/FVC. Only participants without COPD and without current asthma at baseline were included. Coded job histories during follow-up were linked to a Job-Exposure Matrix, generating occupational exposure estimates to 12 categories of agents. Their association with COPD incidence was examined in log-binomial models fitted in a Bayesian framework.

FINDINGS

3343 participants fulfilled the inclusion criteria; 89 of them had COPD at follow-up (1.4 cases/1000 person-years). Participants exposed to biological dust had a higher incidence of COPD compared with those unexposed (relative risk (RR) 1.6, 95% CI 1.1 to 2.3), as did those exposed to gases and fumes (RR 1.5, 95% CI 1.0 to 2.2) and pesticides (RR 2.2, 95% CI 1.1 to 3.8). The combined population attributable fraction for these exposures was 21.0%.

INTERPRETATION

These results substantially strengthen the evidence base for occupational exposures as an important risk factor for COPD.

Improvement in patient-reported outcomes after lung transplantation is not impacted by the use of extracorporeal membrane oxygenation as a bridge to transplantation

OBJECTIVE

Extracorporeal membrane oxygenation (ECMO) is increasingly used as a bridge to lung transplantation. The impact of preoperative ECMO on health-related quality of life (HRQL) and depressive symptoms after lung transplantation remains unknown, however.

METHODS

In a single-center prospective cohort study, we assessed HRQL and depressive symptoms before and at 3, 6, and 12 months after lung transplantation using the Short Form 12 Physical and Mental Component Scores (SF12-PCS and SF12-MCS), Airway Questionnaire 20-Revised (AQ20R), EuroQol 5D (EQ5D), and Geriatric Depression Scale (GDS). Changes in HRQL were quantified by segmented linear mixed-effects models controlling for age, sex, diagnosis, preoperative forced expiratory volume in 1 second, 6-minute walk distance, and Lung Allocation Score. We compared changes in HRQL among subjects bridged with ECMO, subjects hospitalized but not on ECMO, and subjects called in for transplantation as outpatients.

RESULTS

Out of 189 subjects, 17 were bridged to transplantation with ECMO. In all groups, improvements in HRQL following lung transplantation exceeded the minimally clinically important difference using the SF12-PCS, AQ20R, EQ5D, and GDS. HRQL defined by SF12-MCS did not change after transplantation. Improvements were generally similar among the groups, except for EQ5D, which showed a trend toward less benefit in the outpatients, possibly due to their better HRQL before lung transplantation.

CONCLUSIONS

Subjects ill enough to require ECMO as a bridge to lung transplantation appear to achieve similar improvements in HRQL and depressive symptoms as those who do not. It is reassuring to both providers and patients that lung transplantation provides substantial improvements in HRQL, even for those patients who are critically ill in the run up to transplantation.

Impact of Rhinitis on Work Productivity: A Systematic Review

BACKGROUND

Allergic rhinitis (AR) is increasingly acknowledged as having a substantial socioeconomic impact associated with impaired work productivity, although available information remains fragmented.

OBJECTIVE

This systematic review summarizes recently available information to provide a quantitative estimate of the burden of AR on work productivity including lost work time (ie, absenteeism) and reduced performance while working (ie, presenteeism).

METHODS

A Medline search retrieved original studies from 2005 to 2015 pertaining to the impact of AR on work productivity. A pooled analysis of results was carried out with studies reporting data collected through the validated Work Productivity and Activity Impairment (WPAI) questionnaire.

RESULTS

The search identified 19 observational surveys and 9 interventional studies. Six studies reported economic evaluations. Pooled analysis of WPAI-based studies found an estimated 3.6% (95% confidence interval [CI], 2.4; 4.8%) missed work time and 35.9% (95% CI, 29.7; 42.1%) had impairment in at-work performance due to AR. Economic evaluations indicated that indirect costs associated with lost work productivity are the principal contributor to the total AR costs and result mainly from impaired presenteeism. The severity of AR symptoms was the most consistent disease-related factor associated with a greater impact of AR on work productivity, although ocular symptoms and sleep disturbances may independently affect work productivity. Overall, the pharmacologic treatment of AR showed a beneficial effect on work productivity.

CONCLUSIONS

This systematic review provides summary estimates of the magnitude of work productivity impairment due to AR and identifies its main determinant factors. This information may help guide both clinicians and health policy makers.

Incidence of and Risk Factors for Skin Cancer in Organ Transplant Recipients in the United States

Importance

Skin cancer is the most common malignancy occurring after organ transplantation. Although previous research has reported an increased risk of skin cancer in solid organ transplant recipients (OTRs), no study has estimated the posttransplant population-based incidence in the United States.

Objective

To determine the incidence and evaluate the risk factors for posttransplant skin cancer, including squamous cell carcinoma (SCC), melanoma (MM), and Merkel cell carcinoma (MCC) in a cohort of US OTRs receiving a primary organ transplant in 2003 or 2008.

Design, Setting, and Participants

This multicenter retrospective cohort study examined 10 649 adult recipients of a primary transplant performed at 26 centers across the United States in the Transplant Skin Cancer Network during 1 of 2 calendar years (either 2003 or 2008) identified through the Organ Procurement and Transplantation Network (OPTN) database. Recipients of all organs except intestine were included, and the follow-up periods were 5 and 10 years.

Main Outcomes and Measures

Incident skin cancer was determined through detailed medical record review. Data on predictors were obtained from the OPTN database. The incidence rates for posttransplant skin cancer overall and for SCC, MM, and MCC were calculated per 100 000 person-years. Potential risk factors for posttransplant skin cancer were tested using multivariate Cox regression analysis to yield adjusted hazard ratios (HR).

Results

Overall, 10 649 organ transplant recipients (mean [SD] age, 51 [12] years; 3873 women [36%] and 6776 men [64%]) contributed 59 923 years of follow-up. The incidence rates for posttransplant skin cancer was 1437 per 100 000 person-years. Specific subtype rates for SCC, MM, and MCC were 812, 75, and 2 per 100 000 person-years, respectively. Statistically significant risk factors for posttransplant skin cancer included pretransplant skin cancer (HR, 4.69; 95% CI, 3.26-6.73), male sex (HR, 1.56; 95% CI, 1.34-1.81), white race (HR, 9.04; 95% CI, 6.20-13.18), age at transplant 50 years or older (HR, 2.77; 95% CI, 2.20-3.48), and being transplanted in 2008 vs 2003 (HR, 1.53; 95% CI, 1.22-1.94).

Conclusions and Relevance

Posttransplant skin cancer is common, with elevated risk imparted by increased age, white race, male sex, and thoracic organ transplantation. A temporal cohort effect was present. Understanding the risk factors and trends in posttransplant skin cancer is fundamental to targeted screening and prevention in this population.

Effect of Lung Transplantation on Health-Related Quality of Life in the Era of the Lung Allocation Score: A U.S. Prospective Cohort Study

Under the U.S. Lung Allocation Score (LAS) system, older and sicker patients are prioritized for lung transplantation (LT). The impact of these changes on health-related quality of life (HRQL) after transplant has not been determined. In a single-center prospective cohort study from 2010 to 2016, we assessed HRQL before and repeatedly after LT for up to 3 years using the SF12-Physical and Mental Health, the respiratory-specific Airway Questionnaire 20-Revised, and the Euroqol 5D/Visual Analog Scale utility measures by multivariate linear mixed models jointly modeled with death. We also tested changes in LT-Valued Life Activities disability, BMI, allograft function, and 6-min walk test exercise capacity as predictors of HRQL change. Among 211 initial participants (92% of those eligible), LT improved HRQL by all 5 measures (p < 0.05) and all but SF12-Mental Health improved by threefold or greater than the minimally clinically important difference. Compared to younger participants, those aged ≥65 improved less in SF12-Physical and Mental Health (p < 0.01). Improvements in disability accounted for much of the HRQL improvement. In the LAS era, LT affords meaningful and durable HRQL improvements, mediated by amelioration of disability. Identifying factors limiting HRQL improvement in selected subgroups, especially those aged ≥65, are needed to maximize the net benefits of LT.

Fatigue and sleepiness determine respiratory quality of life among veterans evaluated for sleep apnea

Background

In those with symptoms indicative of obstructive sleep apnea (OSA), respiratory-specific health-related quality of life (HRQL) may be an important patient-centered outcome. The aim of this study was to assess the associations between sleepiness, fatigue, and impaired general and respiratory-specific HRQL among persons with suspected OSA.

Methods

We evaluated military veterans consecutively referred for suspected OSA with sleep studies yielding apnea-hypopnea index (AHI) values. They also completed the sleepiness (Epworth Sleepiness Scale [ESS]), and fatigue (Fatigue Severity Scale [FSS]) questionnaires, as well as two HRQL instruments (the generic Short-Form SF-12v2 yielding the Physical Component Scale [PCS] and the respiratory-specific Airways Questionnaire [AQ]-20R). Multiple linear regression tested the associations between ESS and FSS (standardized as Z scores for scaling comparability) with AQ-20R, accounting for AHI, SF-12v2-PCS and comorbid respiratory conditions other than OSA.

Results

We studied 1578 veterans (median age 61.1 [IQR 16.8] years; 93.9% males). Of these, 823 (52%) met AHI criteria for moderate to severe OSA (AHI ≥15/h). The majority reported excessive daytime sleepiness (53%; median ESS 11 [IQR 9]) or fatigue (61%; median FSS 42 [IQR 23]). The median AQ-20R was 4 [IQR 1–8]. Controlling for AHI, SF-12v2-PCS, respiratory co-morbid conditions, body mass index, and demographics, both ESS and FSS were significantly associated with poorer AQ-20R: for each; ESS, 1.6 points (95% CI 1.4–1.9), and for FSS, 2.5 points (95% CI, 2.3–2.7).

Conclusions

Greater daytime sleepiness and fatigue are associated with poorer respiratory-specific HRQL, over and above the effects of OSA, respiratory comorbidity, and generic physical HRQL.

Survival following lung transplantation for artificial stone silicosis relative to idiopathic pulmonary fibrosis

BACKGROUND

Silicosis is a progressive lung disease resulting from the inhalation of respirable crystalline silica. Lung transplantation is the only treatment for end-stage silicosis. The aim of this study was to analyze the survival experience following lung transplantation among patients with silicosis.

METHODS

We reviewed data for all patients who underwent lung transplantation for silicosis and a matched group undergoing lung transplantation for idiopathic pulmonary fibrosis (IPF) at a single medical center between March 2006 and the end of December 2013. Survival was followed through 2015.

RESULTS

A total of 17 lung transplantations were performed for silicosis among 342 lung transplantations (4.9%) during the study period. We observed non-statistically significant survival advantage (hazard ratio 0.6; 95%CI 0.24-1.55) for those undergoing lung transplantation for silicosis relative to IPF patients undergoing lung transplantation during the same period.

CONCLUSIONS

Within the limits of a small sample, survival in silicosis patients following lung transplantation was not reduced compared to IPF. Am. J. Ind. Med. 60:248-254, 2017. © 2017 Wiley Periodicals, Inc.

High-altitude alpine therapy and lung function in asthma: systematic review and meta-analysis

We used meta-analysis to measure the effect of high-altitude climate therapy (HACT) on lung function outcomes in asthma, and systematically searched PubMed, Embase and www.elibrary.ru for publications appearing from 1970 to mid-2015. We included studies carried out with children or adults with an exposure of up to 12 weeks at an altitude of ≥1500 m above sea level. Changes in forced expiratory volume in 1 s (FEV₁), FEV₁/vital capacity ratio or peak expiratory flow rate as the HACT intervention outcomes were analysed. We included data for 907 participants (age range 4–58 years) from 21 studies, altogether including 28 substrata based on asthma type or severity. Only three of 21 included studies had high quality, whereas 93% of substudies reported lung function improvement with an overall pooled standardised mean difference (SMD) of 0.53 (95% CI 0.43–0.62). The measured effect of HACT was greater in adults (SMD 0.75, 95% CI 0.63–0.88, n=14) than in children (SMD 0.24, 95% CI 0.09–0.38, n=14). Studies at altitude >2000 m above sea level yielded the same effect as those at lower altitude. Based on a cut-point of a 0.50 change in SMD to define a meaningful clinical difference, HACT appears to have efficacy as an intervention. This extent of benefit appears to be limited to adults with asthma.

High-altitude alpine therapy may be an effective intervention to improve lung function in patients with asthmahttp://ow.ly/u3i23008vU5

Obesity and Functioning Among Individuals with Chronic Obstructive Pulmonary Disease (COPD)

In COPD, body composition studies have focused primarily on low BMI. We examined obesity (BMI ≥ 30 kg/m(2)) as a risk factor for poor function and longitudinal functional decline. Data from a longitudinal cohort of adults with COPD (n = 1096) and an age- and sex-matched comparison group collected in two in-person visits ∼49 months apart were analyzed. Two measures of functioning were examined: six-minute walk distance (6MWD) and Short Physical Performance Battery (SPPB). Multivariate regression analyses examined relationships of obesity with functioning. Secondary analyses stratified by GOLD classification (GOLD-0/1, GOLD-2, GOLD-3/4). Obesity (53% of COPD cohort) was associated cross-sectionally with 6MWD and SPPB in COPD, and only with 6MWD in the comparison group. Obesity predicted significant functional decline in 6MWD for individuals with COPD (odds ratio (OR) for decline [95% CI] 1.8 [1.1, 2.9]), but not the comparison group. Secondary analyses revealed that the risk of decline was significant only in those with more severe COPD (GOLD 3/4, OR = 2.3 [1.0, 5.4]). Obesity was highly prevalent and was associated with poor function concurrently and with subsequent decline in 6MWD in COPD. Obesity in COPD should be considered a risk not only for more co-morbidities and greater health care use, but also for functional decline.

Frailty Phenotypes, Disability, and Outcomes in Adult Candidates for Lung Transplantation

RATIONALE

Frailty is associated with morbidity and mortality in abdominal organ transplantation but has not been examined in lung transplantation.

OBJECTIVES

To examine the construct and predictive validity of frailty phenotypes in lung transplant candidates.

METHODS

In a multicenter prospective cohort, we measured frailty with the Fried Frailty Phenotype (FFP) and Short Physical Performance Battery (SPPB). We evaluated construct validity through comparisons with conceptually related factors. In a nested case-control study of frail and nonfrail subjects, we measured serum IL-6, tumor necrosis factor receptor 1, insulin-like growth factor I, and leptin. We estimated the association between frailty and disability using the Lung Transplant Valued Life Activities disability scale. We estimated the association between frailty and risk of delisting or death before transplant using multivariate logistic and Cox models, respectively.

MEASUREMENTS AND MAIN RESULTS

Of 395 subjects, 354 completed FFP assessments and 262 completed SPPB assessments; 28% were frail by FFP (95% confidence interval [CI], 24-33%) and 10% based on the SPPB (95% CI, 7-14%). By either measure, frailty correlated more strongly with exercise capacity and grip strength than with lung function. Frail subjects tended to have higher plasma IL-6 and tumor necrosis factor receptor 1 and lower insulin-like growth factor I and leptin. Frailty by either measure was associated with greater disability. After adjusting for age, sex, diagnosis, and transplant center, both FFP and SPPB were associated with increased risk of delisting or death before lung transplant. For every 1-point worsening in score, hazard ratios were 1.30 (95% CI, 1.01-1.67) for FFP and 1.53 (95% CI, 1.19-1.59) for SPPB.

CONCLUSIONS

Frailty is prevalent among lung transplant candidates and is independently associated with greater disability and an increased risk of delisting or death.

"Acute" silicosis at the 1930 Johannesburg Conference on silicosis and in its aftermath: Controversies over a distinct entity later recognized as silicoproteinosis

BACKGROUND

Very rapidly progressive "acute silicosis" was observed prior to the 1930 International Labour Office Conference on silicosis, but its clinical significance and pathologic relationship to classic silica caused pneumoconiosis were not settled.

METHODS

Textual analysis of the 1930 Conference proceedings identified data relevant to rapidly progressive silicosis. Standard bibliographic searches identified relevant biomedical literature dating from before and after the Conference.

RESULTS

The 1930 Johannesburg Conference contained descriptions of acute silicosis, especially in the abrasive powders industry, but acute silica-related lung disease did not conform to a three-stage disease model in which tuberculosis supra-infection caused advanced disease, a model accepted at the Conference. Over following decades, additional reports appeared of rapidly progressive silicosis, unrelated to tuberculosis. Pulmonary alveolar proteinosis was identified only in 1958.

CONCLUSIONS

Adoption by the 1930 Johannesburg Conference of a classification scheme into which acute rapidly progressive disease unrelated to tuberculosis fitted poorly may have impeded the understanding of acute silicosis and its importance.

Fungal contamination of the respiratory tract and associated respiratory impairment among sawmill workers in India

Wood processing workers are exposed to wood-associated microbiological contaminants, including fungi. Our aim was to study the potential association between sputum fungus and adverse respiratory effects in such workers. In a group of sawmill workers, we administered a respiratory questionnaire, performed lung function testing and quantified the proportions of leukocytes in spontaneously expectorated sputum samples. We identified fungal species by DNA sequencing. Of 54 sawmill workers, 19 yielded fungal positive sputum samples (mean age 42.5±10.4 years) and 35 were negative for fungus (mean age 36.9±5.2 years). The fungus was identified as Candida sp. in all samples. Those with fungal-positive sputum, compared to others, reported more cough (26% versus 63%) and haemoptysis (6% versus 37%) (both p<0.05), manifested reduced forced midexpiratory flow rates (FEF_25-75%) (82.3±4.5 versus 69.2±9.9% predicted, p<0.001), and had higher sputum eosinophil counts (median 9.25 versus 3.25%, p<0.01). Reduction of FEF_25-75% was associated both with fungus detection in sputum (-12.7%, 95% CI-8.5- -16.9%) and sputum eosinophils (-2.1% per 1% increase in eosinophils, 95% CI -1.5- -2.8%) (both p<0.001). In sawmill workers, Candida sp. detectable in sputum was associated with respiratory symptoms, sputum eosinophilia and reduced FEF_25-75%.

Prospective risk of rheumatologic disease associated with occupational exposure in a cohort of male construction workers

BACKGROUND

The association between occupational exposure and autoimmune disease is well recognized for silica, and suspected for other inhalants. We used a large cohort to estimate the risks of rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, and dermatomyositis associated with silica and other occupational exposures.

METHODS

We analyzed data for male Swedish construction industry employees. Exposure was defined by a job-exposure matrix for silica and for other inorganic dusts; those with other job-exposure matrix exposures but not to either of the 2 inorganic dust categories were excluded. National hospital treatment data were linked for International Classification of Diseases, 10(th) Revision-coded diagnoses of rheumatoid arthritis (seronegative and positive), systemic lupus erythematosus, systemic sclerosis, and dermatomyositis. The 2 occupational exposures were tested as independent predictors of prospective hospital-based treatment for these diagnoses using age-adjusted Poisson multivariable regression analyses to calculate relative risk (RR).

RESULTS

We analyzed hospital-based treatment data (1997 through 2010) for 240,983 men aged 30 to 84 years. There were 713 incident cases of rheumatoid arthritis (467 seropositive, 195 seronegative, 51 not classified) and 128 cases combined for systemic lupus erythematosus, systemic sclerosis, and dermatomyositis. Adjusted for smoking and age, the 2 occupational exposures (silica and other inorganic dusts) were each associated with increased risk of rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, and dermatomyositis combined: RR 1.39 (95% confidence interval [CI], 1.17-1.64) and RR 1.31 (95% CI, 1.11-1.53), respectively. Among ever smokers, both silica and other inorganic dust exposure were associated with increased risk of rheumatoid arthritis (RRs 1.36; 95% CI, 1.11-1.68 and 1.42; 95% CI, 1.17-1.73, respectively), while among never smokers, neither exposure was associated with statistically significant increased risk of rheumatoid arthritis.

CONCLUSION

This analysis reaffirms the link between occupational silica and a range of autoimmune diseases, while also suggesting that other inorganic dusts may also impart excess risk of such disease.

Is Smoking a Predictor for Acute Mountain Sickness? Findings From a Meta-Analysis

AIM

Studies of the potential association between cigarette smoking and acute mountain sickness (AMS) have reached contradictory conclusions. Our aim was to perform a meta-analysis of studies across a range of populations to ascertain better the true relationship between cigarette smoking and AMS.

MATERIALS AND METHODS

We used the PRISMA protocol to identify and screen eligible studies of smoking and AMS. Databases including Pubmed and Google Scholar were searched, using the terms "smoking" and "acute mountain sickness." We conducted a meta-analysis of the selected studies in order to evaluate causal inference, evaluate potential biases, and investigate possible sources of heterogeneity across studies.

RESULTS

We identified 3907 publications, of which 29 were eligible for inclusion by reporting smoking status and AMS. Of these, eight publications were excluded because they were duplicative or were lacking quantitative data. The 21 studies analyzed included 16 566 subjects. These fell into two groups: occupational/military (n = 8) or volunteers/trekkers/mixed (n = 13). Study heterogeneity was high (X (2) = 55.5, P < .001). Smoking was not statistically associated with increased risk of AMS: pooled OR = 0.88 (95% CI = 0.74-1.05). Stratification yielded similar risk estimates among the occupational/military studies versus all others and studies at relatively higher and lower altitudes.

CONCLUSIONS

Overall, smoking was not statistically significantly associated with AMS: there is no consistent effect of cigarette smoking acting as either a protective factor against or a risk factor for AMS.

IMPLICATIONS

This is the first quantitative assessment of published studies on smoking and AMS, which shows smoking to be neither a risk, nor protective. Studies specifically focusing on smoking as a risk factor, should guide further research on this issue. Although all smokers should be strongly advised to quit, studies on risk factors for AMS focusing on other exposures could shed light on the full range of risks for AMS.

Lung transplantation for hypersensitivity pneumonitis

BACKGROUND

Hypersensitivity pneumonitis (HP) is an inhaled antigen-mediated interstitial lung disease (ILD). Advanced disease may necessitate the need for lung transplantation. There are no published studies addressing lung transplant outcomes in HP. We characterized HP outcomes compared with referents undergoing lung transplantation for idiopathic pulmonary fibrosis (IPF).

METHODS

To identify HP cases, we reviewed records for all ILD lung transplantation cases at our institution from 2000 to 2013. We compared clinical characteristics, survival, and acute and chronic rejection for lung transplant recipients with HP to referents with IPF. We also reviewed diagnoses of HP discovered only by explant pathology and looked for evidence of recurrent HP after transplant. Survival was compared using Kaplan-Meier methods and Cox proportional hazard modeling.

RESULTS

We analyzed 31 subjects with HP and 91 with IPF among 183 cases undergoing lung transplantation for ILD. Survival at 1, 3, and 5 years after lung transplant in HP compared with IPF was 96%, 89%, and 89% vs 86%, 67%, and 49%, respectively. Subjects with HP manifested a reduced adjusted risk for death compared with subjects with IPF (hazard ratio, 0.25; 95% CI, 0.08-0.74; P = .013). Of the 31 cases, the diagnosis of HP was unexpectedly made at explant in five (16%). Two subjects developed recurrent HP in their allografts.

CONCLUSIONS

Overall, subjects with HP have excellent medium-term survival after lung transplantation and, relative to IPF, a reduced risk for death. HP may be initially discovered only by review of the explant pathology. Notably, HP may recur in the allograft.

Occupational exposures are associated with worse morbidity in patients with chronic obstructive pulmonary disease

RATIONALE

Links between occupational exposures and morbidity in individuals with established chronic obstructive pulmonary disease (COPD) remain unclear.

OBJECTIVES

To determine the impact of occupational exposures on COPD morbidity.

METHODS

A job exposure matrix (JEM) determined occupational exposure likelihood based on longest job in current/former smokers (n = 1,075) recruited as part of the Subpopulations and Intermediate Outcomes in COPD Study, of whom 721 had established COPD. Bivariate and multivariate linear regression models estimated the association of occupational exposure with COPD, and among those with established disease, the occupational exposure associations with 6-minute-walk distance (6MWD), the Modified Medical Research Council Dyspnea Scale (mMRC), the COPD Assessment Test (CAT), St. George's Respiratory Questionnaire (SGRQ), 12-item Short-Form Physical Component (SF-12), and COPD exacerbations requiring health care utilization, adjusting for demographics, current smoking status, and cumulative pack-years.

MEASUREMENTS AND MAIN RESULTS

An intermediate/high risk of occupational exposure by JEM was found in 38% of participants. In multivariate analysis, those with job exposures had higher odds of COPD (odds ratio, 1.44; 95% confidence interval, 1.04-1.97). Among those with COPD, job exposures were associated with shorter 6MWDs (-26.0 m; P = 0.006); worse scores for mMRC (0.23; P = 0.004), CAT (1.8; P = 0.003), SGRQ (4.5; P = 0.003), and SF-12 Physical (-3.3; P < 0.0001); and greater odds of exacerbation requiring health care utilization (odds ratio, 1.55; P = 0.03).

CONCLUSIONS

Accounting for smoking, occupational exposure was associated with COPD risk and, for those with established disease, shorter walk distance, greater breathlessness, worse quality of life, and increased exacerbation risk. Clinicians should obtain occupational histories from patients with COPD because work-related exposures may influence disease burden.