Joint effect of long-term exposure to ambient air pollution on the prevalence of chronic obstructive pulmonary disease using the Korea National Health and Nutrition Examination Survey 2010-2019

BACKGROUND

Little is known about the relationship between long-term joint exposure to mixtures of air pollutants and the prevalence of chronic obstructive pulmonary disease (COPD). We aimed to assess the joint impact of long-term exposure to ambient air pollution on the prevalence of COPD in Korea, especially in areas with high levels of air pollution.

METHODS

We included 22,387 participants who underwent spirometry tests in 2010-2019. The community multiscale air quality model was used to estimate the levels of ambient air pollution at residential addresses. The average exposure over the 5 years before the examination date was used to calculate the concentrations of air pollution. Forced expiratory volume in 1 s and forced vital capacity were used to define restrictive lung disease, COPD, and moderate-to-severe COPD. Quantile-based g-computation models were used to assess the joint impact of air pollution on COPD prevalence.

RESULTS

A total of 2535 cases of restrictive lung disease, 2787 cases of COPD, and 1399 cases of moderate-to-severe COPD were identified. In the individual pollutant model, long-term exposure was significantly associated with both restrictive lung disease and COPD. In the mixture pollutant model, the odds ratios (ORs, 95% confidence intervals) for restrictive lung disease increased with each quartile increment in the 1- to 5-year average mixtures: 1.14 (1.02-1.28, 1 year), 1.25 (1.11-1.41, 2 years), 1.26 (1.11-1.42, 3 years), 1.32 (1.16-1.51, 4 years), and 1.37 (1.19-1.58, 5 years), respectively. The increase in ORs of restrictive lung disease accelerated over time. By contrast, the ORs of COPD showed a decreasing trend over time.

CONCLUSIONS

Long-term exposure to air pollutants, both individually and jointly, was associated with an increased risk of developing COPD, particularly restrictive lung disease. Our findings highlight the importance of comprehensively assessing exposure to various air pollutants in relation to COPD.

[Shrinking lung syndrome in systemic lupus erythematosus: A study of 9 patients]

INTRODUCTION

Shrinking lung syndrome (SLS) is a rare manifestation of systemic lupus erythematosus. Our aim was to describe the clinical, radiological, and functional characteristics of a cohort with SLS and its evolution over time.

METHODS

A retrospective study was conducted between 2009 and 2018. Demographic, clinical, functional, radiological, and treatment data were collected.

RESULTS

Out of a total of 225 patients, 11 presented with SLS (prevalence of 4.8%). Two patients were excluded. The mean age was 39.33±16 years, and 6 were female. The main symptoms were dyspnea and pleuritic pain. The mean forced vital capacity was 49%, total lung capacity was 60%, carbon monoxide diffusing capacity was 66%, carbon monoxide transference factor was 128%, maximal inspiratory pressure was 66%, and maximal expiratory pressure was 82%. All patients received corticosteroids. After a median follow-up of 19 months, 4 cases showed improvement, and 4 cases remained stable.

CONCLUSIONS

SLS should be considered in every lupus patient with unexplained dyspnea. Although it often shows improvement, many cases experience persistent deterioration despite treatment.

Surgical release of the chest wall skin and fascia for sclerodermatous graft versus host disease causing restrictive lung disease: A case report

INTRODUCTION

Graft versus host disease (GVHD) remains a significant source of morbidity and mortality in the setting of allogeneic stem cell transplantation. Skin involvement is reported to be as high as 70-95 % in this group with GVHD and the severity of the involvement varies widely. Surgical management of complications of severe cutaneous GVHD is uncommon and is rarely mentioned as a treatment option.

CASE PRESENTATION

We present a case of severe sclerodermatous skin changes restricting chest expansion and exercise tolerance to the point of limiting basic activities of daily life. A 54-year-old male presents with severe restrictive lung disease from sclerodermatous graft versus host disease (GVHD) after stem cell transplant for Chronic Myeloid Leukaemia (CML). He experienced limited symptomatic relief from maximal medical therapy and photochemotherapy, and subsequently underwent a skin release and split skin grafting of his chest and abdomen in an effort to improve exercise tolerance and quality of life.

CLINICAL DISCUSSION

Despite an initial improvement in functioning, the patient's spirometry and lung function continued to decline with time, possibly suggesting that he did not gain a sustained benefit from surgical release of his cutaneous GVHD.

CONCLUSION

While delineating between disease progression and surgical outcome is difficult in this case, the patient would argue that by delaying or reducing further decline in function, the surgical release procedures led to improved quality of life in subsequent years. However further research is required to establish a clear role for surgery in the treatment of refractory cutaneous GVHD.

Nonsurgical hypoparathyroidism is associated with skeletal muscle dysfunction and restrictive lung disease

CONTEXT

Systematic assessment of skeletal muscle function is lacking in patients with nonsurgical hypoparathyroidism (HP). Whether muscle dysfunction involves respiratory muscles and results in restrictive lung disease (RLD) is not studied.

OBJECTIVE

To assess skeletal muscle and pulmonary functions in patients with HP.

DESIGN

Observational case-control study.

METHODS

Thirty patients with HP (mean age 37.7 years, 60% males) and age, sex, and body mass index-matched forty healthy-controls were assessed for skeletal muscle function by hand-grip strength, short physical performance battery (SPPB) test, dual-energy x-ray absorptiometry, and electromyography. Pulmonary function was assessed by spirometry, body plethysmography, diffusion lung capacity for carbon monoxide and diaphragmatic ultrasound.

RESULTS

Patients with HP had lower serum calcium (2.25±0.15 vs 2.4±0.12 mmol/L, p<0.001), serum magnesium [median (interquartile-range) 0.74 (0.69-0.82) vs 0.78 (0.69-0.90) mmol/L, p=0.04], hand-grip strength (18.08±8.36 vs 22.90±7.77 kg, p=0.01) and composite SPPB score (9.5 [7-10] vs 12 [12-12], p< 0.001) compared to healthy-controls. Electromyographic evidence of myopathy was seen in 23% (5 of 22) patients with HP, but in none of the controls (p=0.08). The prevalence of RLD was higher in the HP cohort compared to that in controls (24% vs 0%, p=0.01). Diaphragmatic excursion (4.22±1.38 vs 5.18±1.53 cm, p=0.01) and thickness (3.79±1.18 vs 4.28±0.94 mm, p=0.05) on deep inspiration were reduced in patients with HP.

CONCLUSION

Detailed testing of patients with HP without overt muscle and lung diseases revealed significant impairment in parameters of skeletal muscle function. Myopathy and RLD were observed in a considerable proportion of patients with HP.

Elevated markers of DNA damage and senescence are associated with the progression of albuminuria and restrictive lung disease in patients with type 2 diabetes

BACKGROUND

This study was conducted to investigate the cascade involving DNA damage, senescence, and senescence-associated secretory phenotype (SASP) in experimental diabetes and in a four-year follow-up study in patients with pre-diabetes and type 2 diabetes.

METHODS

Kidney, lung, and liver were studied in 4 months diabetic db/db mice and age-matched controls for the presence of DNA damage and fibrosis. DNA damage (comet-tail-length and ɤH2Ax-positivity in white blood cells), urinary p21-excretion, and plasma IL-6 and TGF-β1 were determined from 115 healthy participants, 34 patients with pre-diabetes and 221 with type 2 diabetes. Urinary albumin-creatinine-ratio, lung function, and transient elastography of the liver were performed in a prospective follow-up study over 4 years.

FINDINGS

db/db mice showed an increased nuclear ɤH2AX signal in all tissues as compared to the background control. Markers for DNA damage, senescence, and SASP were increased in patients with diabetes. The presence of nephropathy, restrictive lung disease (RLD), and increased liver stiffness was in a cross-sectional design associated with increased markers for DNA damage, senescence, and SASP. The progression of nephropathy over 4 years was predicted by increased DNA damage, senescence, and SASP, while the progression of RLD was associated with increased DNA damage and IL-6 only. The progression of liver stiffness was not associated with any of these parameters. HbA1c was not predictive for progression.

INTERPRETATION

In db/db mice, the cascade of DNA damage is associated with diabetes-related complications. In patients with diabetes, the progression of complications in the kidney and lung is predicted by markers reflecting DNA damage, and senescence-triggered organ fibrosis.

FUNDING

This work was supported by the German Research Foundation (DFG) in the CRC 1118 and CRC 1158, by the GRK DIAMICOM, by the German Center for Diabetes Research (DZD e.V.), and by the Ministry of Science, Research and the Arts, Baden-Württemberg (Kompetenznetzwerk Präventivmedizin).

Thoracic insufficiency syndrome: Approaches to assessment and management

Thoracic insufficiency syndrome (TIS) was described in 2003 as the inability of the thorax to support normal respiration or lung growth. TIS includes a broad and disparate group of typically degenerative thoracospinal conditions. Although TIS arises due to a heterogeneous group of disorders and thus its incidence is not well quantified, general approaches to management and treatment exist. Evolving imaging techniques and measurements of health-related quality of life augment tests of pulmonary function to quantify disease burden, longitudinally and pre- and post-intervention. Intervention is primarily via growth-sparing surgery, for which several device options exist, to preserve vertical growth prior to a definitive spinal fusion at skeletal maturity.

Influence of chest wall conformation on spirometry parameters and outcome in mild-to-moderate idiopathic pulmonary fibrosis

Extrinsic causes of restrictive lung syndrome in idiopathic pulmonary fibrosis (IPF) patients have been poorly investigated. We aimed to investigate the influence of the anterior chest wall deformity, noninvasively assessed by modified Haller index (MHI), on spirometry parameters and outcome in a consecutive population of patients with mild-to-moderate IPF. Sixty consecutive IPF patients (73.8 ± 6.6 years, 45 males) were included in this retrospective study. All patients underwent physical examination, spirometry, blood tests, conventional transthoracic echocardiography and MHI assessment (chest transverse diameter over the distance between sternum and spine) at basal evaluation. During follow-up, we evaluated the composite endpoint of (1) pulmonary or cardiovascular hospitalizations and (2) all-cause mortality. IPF patients with concave-shaped chest wall (MHI > 2.5) (36.7% of total) and those with normal chest shape (MHI ≤ 2.5) (63.3%) were separately analyzed. In comparison to IPF patients with MHI ≤ 2.5, those with MHI > 2.5: were less likely to be men and smokers; had a more severe restrictive pattern; had significantly smaller cardiac chamber dimensions and significantly higher systolic pulmonary artery pressure (51.9 ± 15.1 vs 42.4 ± 14.3 mmHg, p = 0.02). Mean follow-up time was 2.5 ± 1.4 years. During follow-up, 13 deaths and 16 pulmonary or cardiovascular hospitalizations were detected. At multivariate Cox regression analysis, concave-shaped chest wall (MHI > 2.5) (HR 4.55, 95% CI 1.02-20.4), increased C-reactive protein (HR 1.68, 95% CI 1.08-2.61) and absence of beta-blocker therapy (HR 0.13, 95% CI 0.01-0.26) were independently associated to the investigated outcome. MHI assessment and implementation may help the clinician to identify, among IPF patients, those with poorer prognosis over a medium-term follow-up.

Environmental-level exposure to metals and metal-mixtures associated with spirometry-defined lung disease in American Indian adults: Evidence from the Strong Heart Study

BACKGROUND

American Indians have a higher burden of chronic lung disease compared to the US average. Several metals are known to induce chronic lung disease at high exposure levels; however, less is known about the role of environmental-level metal exposure. We investigated respiratory effects of exposure to single metals and metal-mixtures in American Indians who participated in the Strong Heart Study.

METHODS

We included 2077 participants with data on 6 metals (As, Cd, Mo, Se, W, Zn) measured from baseline urine samples (1989-1991) and who underwent spirometry testing at follow-up (1993-1995). We used generalized linear regression to assess associations of single metals with spirometry-defined measures of airflow limitation and restrictive ventilatory pattern, and continuous spirometry. We used Bayesian Kernel Machine Regression to investigate the joint effects of the metal-mixture. Sensitivity analyses included stratifying by smoking status and diabetes.

RESULTS

Participants were 40% male, with median age 55 years. 21% had spirometry-defined airflow limitation, and 14% had a restrictive ventilatory pattern. In individual metal analyses, Cd was associated with higher odds of airflow limitation and lower FEV1 and FEV1/FVC. Mo was associated with higher odds of restrictive ventilatory pattern and lower FVC. Metal-mixtures analyses confirmed these models. In smoking stratified analyses, the overall metal-mixture was linearly and positively associated with airflow limitation among non-smokers; Cd was the strongest contributor. For restrictive ventilatory pattern, the association with the overall metal-mixture was strong and linear among participants with diabetes and markedly attenuated among participants without diabetes. Among those with diabetes, Mo and Zn were the major contributors.

CONCLUSIONS

Environmental-level exposure to several metals was associated with higher odds of spirometry-defined lung disease in an American Indian population. Exposure to multiple metals, including Cd and Mo, may have an under-recognized adverse role on the respiratory system.

Performance and Interpretation of Office Spirometry

Pulmonary function testing (PFT) is an important component of the evaluation, monitoring, and management of patients with suspected or established lung disease. Spirometry is easily accomplished in the primary care office setting; determination of lung volumes and diffusion capacity is performed in a pulmonary laboratory. Spirometry evaluates vital capacity of the lungs and expiratory flow rates and provides both numeric data and a graphic depiction of respiratory air flow. Characteristic patterns in spirometry-derived data allow the clinician to identify potential lung disease, as well as establish relative reversibility of airflow abnormalities.

COVID-19 in advanced Duchenne/Becker muscular dystrophy patients

Duchenne muscular dystrophy (DMD) is the most common childhood muscular dystrophy. As a result of progressive muscle weakness, pulmonary function decreases during the second decade of life and lung disease contributes significantly to morbidity and mortality in these patients. Corticosteroids are the current standard of care for patients with DMD, despite known adverse effects such as obesity and immunosuppression. Over the past year (2020), the novel coronavirus (COVID-19/SARS-CoV2) outbreak has caused a global pandemic. Restrictive lung disease due to low lung volumes, chronic immunosuppressive treatment with corticosteroids, and obesity are potential risk factors that may contribute to a more severe course of the disease. Out of 116 Duchenne/Becker muscular dystrophy patients treated in our tertiary neuromuscular center, six patients with DMD and one with advanced Becker muscular dystrophy were found to be positive for COVID-19 infection. Two of the DMD patients were admitted for hospitalization, of whom one was dependent on daily nocturnal non-invasive ventilation. All patients recovered without complications despite obesity, steroid treatment and severe restrictive lung disease.

Pulmonary Manifestations of Endocrine and Metabolic Diseases in Children

Advances in technology, methodology, and deep phenotyping are increasingly driving the understanding of the pathologic basis of disease. Improvements in patient identification and treatment are impacting survival. This is true in endocrinology and inborn errors of metabolism, where disease-modifying therapies are developing. Inherent to this evolution is the increasing awareness of the respiratory manifestations of these rare diseases. This review updates clinicians, stratifying diseases spirometerically; pulmonary hypertension and diseases with a predisposition to recurrent pulmonary infection are discussed. This division is artificial; many diseases have multiple pathologic effects on respiration. This review does not cover the impact of obesity.

The evolution of pulmonary function in childhood onset Mucopolysaccharidosis type I

Respiratory outcomes in Mucopolysaccharidosis Type I (MPS I), have mainly focused on upper airway obstruction, with the evolution of the restrictive lung disease being poorly documented. We report the long-term pulmonary function outcomes and examine the potential factors affecting these in 2 cohorts of MPS I patients, those who have undergone Haematopoietic Stem Cell Transplantation (HSCT) and those treated with Enzyme Replacement Therapy (ERT). The results were stratified using the American Thoracic Society (ATS) guidelines. 66 patients, capable of adequately performing testing, were identified by a retrospective case note review, 46 transplanted (45 Hurler, 1 Non-Hurler) and 20 having ERT (17 Non-Hurler and 3 Hurler diagnosed too late for HSCT). 5 patients died; 4 in the ERT group including the 3 Hurler patients. Overall 14% of patients required respiratory support (non-invasive ventilation (NIV) or supplemental oxygen)) at the end of follow up. Median length of follow-up was 12.2 (range = 4.9-32) years post HSCT and 14.34 (range = 3.89-20.4) years on ERT. All patients had restrictive lung disease. Cobb angle and male sex were significantly associated with more severe outcomes in the HSCT cohort, with 49% having severe to very severe disease. In the 17 Non-Hurler ERT treated patients there was no variable predictive of severity of disease with 59% having severe to very severe disease. During the course of follow up 67% of the HSCT cohort had no change or improved pulmonary function as did 52% of the ERT patients. However, direct comparison between therapeutic modalities was not possible. This initial evidence would suggest that a degree of restrictive lung disease is present in all treated paediatrically diagnosed MPS I and is still a significant cause of morbidity, though further stratification incorporating diffusing capacity for carbon monoxide (DLCO) is needed.

Post-Tuberculosis Lung Disease: Clinical Review of an Under-Recognised Global Challenge

An estimated 58 million people have survived tuberculosis since 2000, yet many of them will suffer from post-tuberculosis lung disease (PTLD). PTLD results from a complex interplay between organism, host, and environmental factors and affects long-term respiratory health. PTLD is an overlapping spectrum of disorders that affects large and small airways (bronchiectasis and obstructive lung disease), lung parenchyma, pulmonary vasculature, and pleura and may be complicated by co-infection and haemoptysis. People affected by PTLD have shortened life expectancy and increased risk of recurrent tuberculosis, but predictors of long-term outcomes are not known. No data are available on PTLD in children and on impact throughout the life course. Risk-factors for PTLD include multiple episodes of tuberculosis, drug-resistant tuberculosis, delays in diagnosis, and possibly smoking. Due to a lack of controlled trials in this population, no evidence-based recommendations for the investigation and management of PTLD are currently available. Empirical expert opinion advocates pulmonary rehabilitation, smoking cessation, and vaccinations (pneumococcal and influenza). Exacerbations in PTLD remain both poorly understood and under-recognised. Among people with PTLD, the probability of tuberculosis recurrence must be balanced against other causes of symptom worsening. Unnecessary courses of repeated empiric anti-tuberculosis chemotherapy should be avoided. PTLD is an important contributor to the global burden of chronic lung disease. Advocacy is needed to increase recognition for PTLD and its associated economic, social, and psychological consequences and to better understand how PTLD sequelae could be mitigated. Research is urgently needed to inform policy to guide clinical decision-making and preventative strategies for PTLD.

Interstitial lung disease and diabetes

Diabetes mellitus (DM) is a chronic metabolic disease and its prevalence has been steadily increasing all over the world. DM and its associated micro and macrovascular complications result in significant morbidity and mortality. The microvascular complications are usually manifested as retinopathy, neuropathy, nephropathy and macrovascular complications generally affect the cardiovascular system. In addition to these complications, DM also affects the lungs because of its rich vascularity and abundance in connective tissue (collagen and elastin). DM has been found to cause microvascular complications and proliferation of extracellular connective tissue in the lungs, leading to decline in lung function in a restrictive pattern. Interstitial lung disease (ILD) includes a diverse group of disease conditions characterized by different degrees of inflammation and fibrosis in the pulmonary parenchyma. Idiopathic pulmonary fibrosis (IPF) is one of the common type of idiopathic interstitial pneumonia with a high mortality rate. IPF is characterized by chronic progressive fibrosis leading to progressive respiratory failure. In this review we focus on lung as the target organ in DM and the association of DM and ILD with special emphasis on IPF.

Effect of Ruxolitinib on Lung Function after Allogeneic Stem Cell Transplantation

Ruxolitinib, a selective Janus kinase (JAK)1/2 inhibitor, has recently been proposed for steroid-refractory chronic graft-versus host disease (cGVHD) after allogeneic hematopoietic stem cell transplantation (HSCT), particularly in severe skin cGVHD. Lung function impairment is common in severe skin cGVHD through concomitant bronchiolitis obliterans syndrome (BOS) or restrictive lung disease (RLD) from skin sclerosis. To date, no treatment has shown a benefit on lung function in this context. We retrospectively assessed the effect of ruxolitinib on lung function in a cohort of 70 patients diagnosed with sclerotic-type skin cGVHD between March 2015 and April 2018. Among these patients, 36 received ruxolitinib. To handle confounding by indication bias, exposure groups were matched on the propensity score to receive ruxolitinib, incorporating age, myeloablative conditioning, total body irradiation, BOS, forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and tobacco use at the time of cohort entry, as well as the time from transplantation. The 1:1 matching used a greedy-matching algorithm with replacement, with a caliper of 0.10. FVC and FEV₁ trajectories during follow-up were compared in the matched samples, using linear mixed-effects models. The median duration of follow-up of the 46 matched patients was 58 months (interquartile range, 32 to 84 months). Ten patients had an RLD (6 exposed, 4 unexposed), and 13 patients were diagnosed with BOS (8 exposed, 5 unexposed). FEV₁ decreased significantly over time independent of exposure to ruxolitinib (P < .0001). The FEV₁ trajectory was similar in the exposed patients and the unexposed patients (P = .11). In conclusion, ruxolitinib administration did not demonstrate any improvement in the course of respiratory function in allogeneic HSCT recipients with sclerotic-type skin cGVHD.

Restrictive spirometric pattern and true pulmonary restriction in a general population sample aged 50 - 64 years

Background

There is low diagnostic accuracy of the proxy restrictive spirometric pattern (RSP) to identify true pulmonary restriction. This knowledge is based on patients referred for spirometry and total lung volume determination by plethysmograpy, single breath nitrogen washout technique or gas dilution and selected controls. There is, however, a lack of data from general populations analyzing whether RSP is a valid proxy for true pulmonary restriction. We have validated RSP in relation to true pulmonary restriction in a general population where we have access to measurements of total lung capacity (TLC) and spirometry.

Methods

The data was from the Swedish CArdioPulmonary bioImage Study (SCAPIS Pilot), a general population-based study, comprising 983 adults aged 50–64. All subjects answered a respiratory questionnaire. Forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) were obtained before and after bronchodilation. TLC and residual volume (RV) was recorded using a body plethysmograph. All lung function values are generally expressed as percent predicted (% predicted) or in relation to lower limits of normal (LLN). True pulmonary restriction was defined as TLC < LLN₅ defined as a Z score < − 1.645, i e the fifth percentile. RSP was defined as FEV₁/FVC ≥ LLN and FVC < LLN after bronchodilation. Specificity, sensitivity, positive and negative likelihood ratios were calculated, and 95% confidence intervals (CIs) were calculated.

Results

The prevalence of true pulmonary restriction was 5.4%, and the prevalence of RSP was 3.4%. The sensitivity of RSP to identify true pulmonary restriction was 0.34 (0.20–0.46), the corresponding specificity was 0.98 (0.97–0.99), and the positive likelihood ratio was 21.1 (11.3–39.4) and the negative likelihood ratio was 0.67 (0.55–0.81).

Conclusions

RSP has low accuracy for identifying true pulmonary restriction. The results support previous observations that RSP is useful for ruling out true pulmonary restriction.

Association Between Sarcopenic Obesity and Pulmonary Function in Korean Elderly: Results from the Korean National Health and Nutrition Examination Survey

Although body composition is related to lung function, few studies have reported the effects of sarcopenic obesity on lung function. Thus, the aim of this study was to investigate the associations between lung function and sarcopenia in the presence and in the absence of obesity. We analyzed nationally representative data of 3044 adults aged > 60 years as collated by the 'Korean National Health and Nutrition Examination Survey 2014-2016. Subjects were classified into four groups: non-sarcopenic non-obese (S-O-), non-sarcopenic obese (S-O+), sarcopenic non-obese (S+O-), and sarcopenic obese (S+O+) according to handgrip strength (GS) and body mass index (BMI). GS was found to be positively associated with forced volume vital capacity (FVC). The S+O+ group had significantly lower FVC values than the S-O- group. Subjects in the S+O+ group were more likely to have restrictive lung disease than those in the S-O- group (odds ratios [ORs] 2.81, 95% confidence interval [CI] 1.72-4.59), and the ORs of restrictive lung disease in S+O+ group were higher than in the S-O+ or S+O- groups. These results were consistent after stratifying by sex and age (61-70 and 71-80). FEV1/FVC ratios (a marker for obstructive lung disease) were not significantly different between S+O+ and S-O- groups. Sarcopenic obesity is associated with a higher risk of restrictive lung disease in Korean elderly.

Lung function and cardiovascular disease: A link

The relationship between lung and heart diseases has long been recognized, with necropsy studies demonstrating silent myocardial infarctions or coronary artery calcification in patients with advanced emphysema as the death cause. Improvements in non-invasive techniques and epidemiologic approaches established that lung and cardiovascular diseases frequently coexist in mid and late life. Even among those without diagnosed lung disease, lower than expected forced vital capacity, forced expiratory volume in 1 s, and their ratio each portend greater risk of developing cardiovascular risk factors including hypertension, obesity, and metabolic syndrome, and for incident cardiovascular diseases including left heart failure, atrial fibrillation and stroke. Greater longitudinal declines in these spirometric measures are further associated with cardiovascular morbidity and mortality. While obstructive ventilatory patterns are more common, restrictive ventilatory patterns seem to demonstrate an independent and more robust association with cardiovascular diseases such as heart failure. These subclinical alterations in pulmonary function also relate to subclinical abnormalities of cardiac structure and function. Although the biologic pathways linking pulmonary and cardiovascular dysfunction are not clear, chronic systemic inflammation appears to be one important underlying pathophysiologic link. Despite the growing evidence of lung dysfunction as a cardiovascular risk factor, spirometric evaluation is still underutilized in clinical practice, particularly among cardiac patients, and optimal therapeutic and preventive strategies are still unclear. In this review, we address the current knowledge and controversies regarding the links between lung function and cardiovascular disease.

A Meta-analysis of Arsenic Exposure and Lung Function: Is There Evidence of Restrictive or Obstructive Lung Disease?

PURPOSE OF REVIEW

Hundreds of millions of people worldwide are exposed to arsenic via contaminated water. The goal of this study was to identify whether arsenic-associated lung function deficits resemble obstructive- or restrictive-like lung disease, in order to help illuminate a mechanistic pathway and identify at-risk populations.

RECENT FINDINGS

We recently published a qualitative systematic review outlining the body of research on arsenic and non-malignant respiratory outcomes. Evidence from several populations, at different life stages, and at different levels of exposure showed consistent associations of arsenic exposure with chronic lung disease mortality, respiratory symptoms, and lower lung function levels. The published review, however, only conducted a broad qualitative description of the published studies without considering specific spirometry patterns, without conducting a meta-analysis, and without evaluating the dose-response relationship. We searched PubMed and Embase for studies on environmental arsenic exposure and lung function. We performed a meta-analysis using inverse-variance-weighted random effects models to summarize adjusted effect estimates for arsenic and forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC ratio. Across nine studies, median water arsenic levels ranged from 23 to 860 μg/L. The pooled estimated mean difference (MD) comparing the highest category of arsenic exposure (ranging from > 11 to > 800 μg/L) versus the lowest (ranging from < 10 to < 100 μg/L) for each study for FEV₁ was - 42 mL (95% confidence interval (CI) - 70, - 16) and for FVC was - 50 mL (95% CI - 63, - 37). Three studies reported effect estimates for FEV₁/FVC, for which there was no evidence of an association; the pooled estimated MD was 0.01 (95% CI - 0.005, 0.024). This review supports that arsenic is associated with restrictive impairments based on inverse associations between arsenic and FEV₁ and FVC, but not with FEV₁/FVC. Future studies should confirm whether low-level arsenic exposure is a restrictive lung disease risk factor in order to identify at-risk populations in the USA.

Interstitial lung diseases in dogs and cats part I: The idiopathic interstitial pneumonias

Interstitial lung diseases (ILDs), also called diffuse parenchymal lung diseases, are a large heterogenous group of non-infectious, non-neoplastic disorders characterized by varied patterns of inflammation and fibrosis (Travis et al., 2002). In humans, accurate classification of interstitial lung diseases (ILDs) requires multidisciplinary collaboration between clinicians, radiologists and pathologists. The same is likely to be true for canine and feline ILDs; however, this collaborative approach is rarely taken, leading to a paucity of knowledge of ILDs in small animal species. A proposed classification scheme of canine and feline ILDs, modified from a human classification scheme, consists of three major groups: idiopathic interstitial pneumonias (IIPs), ILDs secondary to known causes, and miscellaneous ILDs (Travis et al., 2002). The focus of this review is on the IIPs in dogs and cats. A framework of what is known about the major IIPs in humans will be used to draw parallels when relevant to the canine and feline species. Differences will also be highlighted. When available from the veterinary literature, clinical presentation, diagnostic results, treatment and/or prognosis will be reported. The review underscores that to advance in our knowledge of veterinary IIPs and other ILDs, clinicopathologic features, advanced imaging and histopathology must be carefully integrated and larger groups of animals studied.

Clinical-pathological correlations in three patients with fibrodysplasia ossificans progressiva

OBJECTIVE

Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare genetic disorder in which heterotopic bone forms in the soft tissues. This often occurs in response to injury or inflammation, leading to joint immobilization and significant disability. There are currently no definitive treatment options for this devastating disease. Although the most dramatic phenotype in FOP is the episodic and progressive heterotopic ossification, patients report a number of symptoms that affect other organ systems. Post-mortem examination of FOP patients may contribute to our understanding of the underlying pathophysiology and complications of this disease. Here, we present the autopsy findings from three patients with FOP.

FINDINGS

Autopsy findings in two of the three patients confirmed that the cause of death was cardiorespiratory failure in the setting of severe thoracic insufficiency from heterotopic ossification. Both of these patients also had evidence of right ventricular dilatation likely secondary to thoracic insufficiency. The third patient died from complications of a traumatic head injury after a fall but also had post-mortem evidence of thoracic insufficiency syndrome. All three patients had extensive, widespread heterotopic ossification and joint deformities consistent with FOP. There was extensive ossification of the spinal ligament in these patients, which may contribute to cervical spine rigidity. One patient was diagnosed post-mortem with a brainstem malformation. No additional significant abnormalities were noted in the other organ systems. Finally, we also demonstrate that cadaveric skin fibroblasts can be isolated for use as a potential source for future in vitro cell culture studies.

CONCLUSIONS

This autopsy case series provides valuable information about the underlying complications of FOP and contributes significantly to our knowledge of this rare yet debilitating disorder. Thoracic insufficiency syndrome, right heart dysfunction, widespread heterotopic ossification, spinal ligament ossification, and CNS malformations were clearly evident; however, most other non-bone tissues appeared to be spared from gross malformations. Finally, the ability to isolate live cells from cadaveric skin is an important technique that will facilitate future studies, particularly as induced pluripotent stem cells and other cell-based technologies evolve. This case series highlights the importance of post-mortem examinations and their contribution to our current knowledge of disease pathophysiology and comorbidities.

The weighty issue of obesity in paediatric respiratory medicine

Some have observed that developed world is fat and getting fatter. This is even extending into the developing world, and it is important to appreciate that the consequences of childhood obesity last into adulthood and are associated with premature death. From the paediatric respiratory perspective, the deposition of excess adipose tissue in the thoraco-abdominal region begins early in life and is believed to alter diaphragm mobility and chest wall expansion, reduce lung compliance, and result in a rapid shallow breathing pattern with an increased work of breathing and reduction in maximum ventilatory capacity. This results in respiratory symptoms of exertional dyspnoea related to deconditioning which may present as exercise limitation, leading to confusion with common lung diseases such as asthma. The manifestations of the increasingly prevalent problems of overweight and obesity in young people and their interaction with common conditions of asthma and obstructive sleep apnoea will be discussed.

Disruption of the Hepcidin/Ferroportin Regulatory System Causes Pulmonary Iron Overload and Restrictive Lung Disease

Emerging evidence suggests that pulmonary iron accumulation is implicated in a spectrum of chronic lung diseases. However, the mechanism(s) involved in pulmonary iron deposition and its role in the in vivo pathogenesis of lung diseases remains unknown. Here we show that a point mutation in the murine ferroportin gene, which causes hereditary hemochromatosis type 4 (Slc40a1^C326S), increases iron levels in alveolar macrophages, epithelial cells lining the conducting airways and lung parenchyma, and in vascular smooth muscle cells. Pulmonary iron overload is associated with oxidative stress, restrictive lung disease with decreased total lung capacity and reduced blood oxygen saturation in homozygous Slc40a1^C326S/C326S mice compared to wild-type controls. These findings implicate iron in lung pathology, which is so far not considered a classical iron-related disorder.

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Ferroportin resistance to hepcidin binding leads to pulmonary iron overload.

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Lung iron accumulation is restricted to specific cell types.

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Iron overload causes restrictive lung disease and decreased blood oxygen saturation.

Pulmonary iron accumulation is associated with a wide spectrum of lung diseases, such as chronic obstructive pulmonary disease and cystic fibrosis. Impaired lung function was further reported in patients with thalassemia major, a disease hallmarked by transfusional iron overload. So far, the mechanism(s) leading to pulmonary iron deposition and its role in disease onset and progression are still unknown. Our study shows that in a murine disease model, in which the control of systemic iron homeostasis is disrupted, iron accumulates in the lung and correlates with oxidative stress, restrictive lung disease and decreased blood oxygen saturation. These findings implicate iron overload in lung pathology, which is not considered a classical iron-related disorder.

Anesthetic Management of the Adult Patient with Concomitant Cardiac and Pulmonary Disease

Several common diseases of the cardiac and pulmonary systems and the interactions of the two in disease and anesthetic management are discussed. Management of these disease processes in isolation is reviewed and how the management of one organ system impacts another is then explored. For example, in a patient with acute lung injury and right heart failure, lung-protective ventilation may directly conflict with strategies to minimize right heart afterload. Such challenging clinical scenarios require appreciation of each disease entity, their appropriate management, and the balance between competing priorities.

Determinants of Restrictive Spirometric Pattern in a Sub-Saharan Urban Setting: A Cross-sectional Population-based Study

Background

Restrictive spirometric pattern is a risk factor for all-cause and cause-specific mortality.

Objective

We assessed the prevalence of restrictive pattern and investigated its determinants in a major sub-Saharan Africa city.

Methods

Participants were adults (≥ 19 years) who took part in a population-based survey in Yaounde (Cameroon) between December 2013 and April 2014. Restrictive pattern was based on a FVC below the lower limit of the normal (LLN) and a ratio forced expiratory volume in one second (FEV1)/FVC ≥ LLN (LLN-based restrictive pattern) or a FVC <80% and FEV1/FVC ≥ LLN (fixed cut-off based restrictive pattern). Determinants were investigated by logistic regressions.

Results

In all, 1003 participants [514 (51.2%) women] with a mean age of 33.7 years were included. The prevalence of restrictive pattern was 18.8% (95%CI: 16.6-21.2) based on LLN and 15.0% (13.0-17.2) based on fixed cut-off. LLN-based restrictive pattern was mild in 148 (78.3%) subjects, moderate in 35 (18.5%) and severe in 6 (3.2%). Determinants of LLN-based restrictive pattern were age ≥ 60 years [adjusted odds ratio 2.90 (95%CI 1.46-5.77), p=0.002), history of pulmonary tuberculosis [3.81(1.42-10.20), p=0.008], prevalent heart diseases [3.81 (1.20-12.12), p=0.024] and underweight [5.15(1.30-20.39), p=0.020]. Determinants were largely similar with slightly different effect sizes for fixed cut-off based restrictive pattern.

Conclusion

Restrictive pattern was very frequent in this city.

Clinical implications

These results enhance the needs to increase the efforts to prevent and control tuberculosis, cardiovascular diseases and underweight in this setting.

Scoliosis and the impact in neuromuscular disease

Scoliosis can alter respiratory mechanics by changing the orientation of the muscles and joints of the respiratory system and in severe forms can put a patient at risk of severe respiratory morbidity or respiratory failure. However, perhaps the most important factor in determining the pulmonary morbidity in scoliosis is the balance between the "load" or altered respiratory mechanics and the "pump" or the respiratory muscle strength. Therefore, scoliosis in patients with neuromuscular disease will both lead to increased "load" and a weakened "pump", an exceptionally unfortunate combination. While progressive neuromuscular disease by its nature does not respond favorably to attempts to improve respiratory muscle strength, the natural approach of early proactive management of the "load" and in the case of scoliosis a variety of different strategies have been tried with variable short term and long term results. Figuring this out requires both an understanding of the underlying pathophysiology of a particular neuromuscular condition and the available options for and timing of surgical intervention.

Sleep in patients with restrictive lung disease

Restrictive lung disease leads to ventilatory defects and diffusion impairments. These changes may contribute to abnormal nocturnal pathophysiology, including sleep architecture disruption and impaired ventilation and oxygenation. Patients with restrictive lung disease may suffer significant daytime fatigue and dysfunction. Hypercarbia and hypoxemia during sleep may impact progression of lung disease and related symptoms. Little is known about the impact of treatment of sleep disruption on sleep quality and overall prognosis in restrictive lung disease. This review discusses the pathophysiology of sleep and comorbid sleep disorders in restrictive lung diseases including interstitial lung disease, neuromuscular disease, and obesity hypoventilation syndrome.

Predictors of early lung function in patients with congenital diaphragmatic hernia

PURPOSE

Long-term pulmonary outcomes of congenital diaphragmatic hernia (CDH) have demonstrated airflow obstruction in later childhood. We examined pulmonary function data to assess what factors predict lung function in the first three years of life in children with CDH.

METHODS

This was a retrospective study of patients treated for CDH who underwent infant pulmonary function testing (IPFT) between 2006 and 2012. IPFT was performed using the raised volume rapid thoracoabdominal compression technique and plethysmography.

RESULTS

Twenty-nine neonates with CDH had IPFTs in the first 3years of life. Their mean predicted survival using the CDH Study Group equation was 63%±4%. Fourteen infants (48%) required extracorporeal membrane oxygenation (ECMO). The mean age at IPFT was 85.1±5weeks. Airflow obstruction was the most common abnormality, seen in 14 subjects. 12 subjects had air trapping, and 9 demonstrated restrictive disease. ECMO (p=0.002), days on the ventilator (p=0.028), and days on oxygen (p=0.023) were associated with restrictive lung disease.

CONCLUSION

Despite following a group of patients with severe CDH, lung function revealed mild deficits in the first three years of life. Clinical markers of increased severity (ECMO, ventilator days, and prolonged oxygen use) are correlated with reduced lung function.

Patients with chronic pulmonary disease

Chronic pulmonary disease is common among the surgical population and the importance of a thorough and detailed preoperative assessment is monumental for minimizing morbidity and mortality and reducing the risk of perioperative pulmonary complications. These comorbidities contribute to pulmonary postoperative complications, including atelectasis, pneumonia, and respiratory failure, and can predict long-term mortality. The important aspects of the preoperative assessment for patients with chronic pulmonary disease, and the value of preoperative testing and smoking cessation, are discussed. Specifically discussed are preoperative pulmonary assessment and management of patients with chronic obstructive pulmonary disease, asthma, restrictive lung disease, obstructive sleep apnea, and obesity.

Assessment of bronchodilator response in various spirometric patterns

BACKGROUND

Spirometry is a physiologic test that measures the volume of air an individual inhales or exhales and the rate at which the volume is changed as a function of time. Bronchodilator response, as a beneficial test for diagnosis of bronchial responsiveness is measured using the percent change from baseline and absolute changes in forced expiratory volume in 1 second and/or forced vital capacity. In this study we aimed to assess the increase in spirometric parameters in patients with symptoms of asthma regardless of spirometric pattern.

MATERIALS AND METHODS

In this cross-sectional study bronchodilator test was performed in individuals with dyspnea, cough or wheezing and the mean increase in various spirometric parameters was measured and compared among individuals with different spirometric patterns.

RESULTS

Among all individuals 24.5% responded to bronchodilator. Forced expiratory volume in 1 second was the parameter with the most frequent response to bronchodilator. Patients with mixed pattern had the highest frequency of response to bronchodilator. Response to bronchodilator was more than 50% in most mid flow volumes.

CONCLUSION

Some patients with symptoms of asthma may show restrictive or mixed pattern in spirometry which may respond to bronchodilator administration.