Adiposity and Interstitial Lung Abnormalities in Community-Dwelling Adults: The MESA Cohort Study

Determinants of cough-related quality of life in interstitial lung diseases

BACKGROUND

Interstitial lung diseases (ILD) include a wide range of diseases impacting lung parenchyma and leading to fibrosis and architectural distortion. Chronic cough and dyspnea are common symptoms which affect the quality of life (QoL) in ILD patients. The mechanisms of cough in ILD patients are still unknown. The aim of this study was to prospectively investigate histological, radiological, and physiological determinants of cough-related QoL in ILD patients who underwent transbronchial lung cryobiopsy (TBLC).

METHODS

All patients (n = 111) filled in The Leicester Cough Questionnaire (LCQ) and The St George's Respiratory Questionnaire (SGRQ). They underwent lung function tests, forced vital capacity (FVC), forced vital expiratory volume in 1 s (FEV1), diffusion capacity to carbon monoxide (DLCO), high-resolution computed tomography (HRCT), and blood samples before diagnostic TBLC. Two experienced radiologists assessed the extents of following HRCT patterns: ground-glass opacities (GGO), honeycombing, reticulation, traction bronchiectasis, and emphysema. Histology of TBLC were re-analyzed by two experienced pulmonary pathologists and the presence of fibroblast foci, fibrosis, giant cells, granulomas, and honeycombing were recorded.

RESULTS

In the median multivariate regression analysis, BMI (-0.19; 95% CI -0.37- -0.014; p 0.035), GGO (-0.38; 95% CI -0.61- -0.15; p 0.001), granulomas (-3.21; 95% CI -6.12- -0.30; p 0.031), and current smoking (2.49; 95% CI 0.12-4.86; p 0.040) showed independent associations with LCQ total score. BMI (1.3; 95% CI 0.20-2.42; p 0.021) and DLCO (-0.51; 95% CI -0.85 - -0.16; p 0.004) showed independent association with SGRQ total score.

CONCLUSION

Determinants of cough-related QoL in ILD patients are multifactorial including physiological, radiological and histological parameters.

Prevalence and progression rate of interstitial lung abnormalities detected on thoracic CT: a systematic review and meta-analysis

OBJECTIVES

To estimate the pooled prevalence and progression rate of ILAs and identify the risk factors for radiological progression.

MATERIALS AND METHODS

An EMBASE and PubMed search was undertaken, identifying all studies meeting the inclusion criteria performed before May 10, 2023. Random effect models were used to estimate pooled prevalence, ILA progression rates, and odds ratio for radiological progression based on radiological subtype. Subgroup analyses were performed to compare the general and high-risk populations for lung cancer. The quality of the included studies was evaluated using the risk of bias assessment tool for non-randomized studies.

RESULTS

We analyzed 19 studies (241,541 patients) and 10 studies (1317 patients) for the pooled prevalence and progression rate of ILA, respectively. The pooled ILA prevalence was 9.7% (95% CI, 6.1-13.9%). The pooled prevalence was 6.8% (95% CI, 3.1-11.6%) and 7.1% (95% CI, 2.2-14.4%) in the general (six studies) and high-risk population for lung cancer (six studies), respectively. The pooled progression rate was 47.1% (95% CI, 29.1-65.5%). The pooled progression rate was 64.2% (95% CI, 45.0-81.2%, five studies) and 31.0% (95% CI, 8.2-60.5%, five studies) for longer (≥ 4.5 years) and shorter follow-up periods (< 4.5 years), respectively (p = 0.009). Fibrotic ILAs were significantly associated with a higher progression probability (combined OR, 5.55; 95% CI, 1.95-15.82).

CONCLUSIONS

The prevalence of ILAs was approximately 9.7%. Approximately half of the patients exhibited radiological progression, with the rate increasing over a longer follow-up period. Fibrotic ILA was a significant risk factor for radiological progression.

CLINICAL RELEVANCE STATEMENT

The prevalence of interstitial lung abnormalities (ILAs) is approximately 9.7%, with about half exhibiting progression; a longer follow-up duration and fibrotic ILAs are associated with a higher progression rate.

KEY POINTS

ILAs are increasingly recognized as important, but few population data are available. ILAs exhibited a pooled prevalence of 9.7% with a progression rate of 47.1%. Fibrotic ILAs were associated with increased progression likelihood.

Interstitial lung abnormality evaluated by an automated quantification system: prevalence and progression rate

BACKGROUND

Despite the importance of recognizing interstitial lung abnormalities, screening methods using computer-based quantitative analysis are not well developed, and studies on the subject with an Asian population are rare. We aimed to identify the prevalence and progression rate of interstitial lung abnormality evaluated by an automated quantification system in the Korean population.

METHODS

A total of 2,890 healthy participants in a health screening program (mean age: 49 years, men: 79.5%) with serial chest computed tomography images obtained at least 5 years apart were included. Quantitative lung fibrosis scores were measured on the chest images by an automated quantification system. Interstitial lung abnormalities were defined as a score ≥ 3, and progression as any score increased above baseline.

RESULTS

Interstitial lung abnormalities were identified in 251 participants (8.6%), who were older and had a higher body mass index. The prevalence increased with age. Quantification of the follow-up images (median interval: 6.5 years) showed that 23.5% (59/251) of participants initially diagnosed with interstitial lung abnormality exhibited progression, and 11% had developed abnormalities (290/2639). Older age, higher body mass index, and higher erythrocyte sedimentation rate were independent risk factors for progression or development. The interstitial lung abnormality group had worse survival on follow-up (5-year mortality: 3.4% vs. 1.5%; P = 0.010).

CONCLUSIONS

Interstitial lung abnormality could be identified in one-tenth of the participants, and a quarter of them showed progression. Older age, higher body mass index and higher erythrocyte sedimentation rate increased the risk of development or progression of interstitial lung abnormality.

Nonlinear associations between computed tomography-measures of adiposity and long pentraxin-3 in the Multi-Ethnic Study of Atherosclerosis

Objective

Long pentraxin-3 (PTX-3) is an acute phase protein associated with cardiovascular disease, lung injury, and mortality. We evaluated the association between computed tomography (CT)-measurements of adipose tissue and plasma levels of PTX-3.

Methods

We performed a cross-sectional analysis of community-dwelling adults enrolled in the multi-center Multiethnic Study of Atherosclerosis who underwent cardiac or abdominal CT and had available PTX-3 measurements.

Results

There was a U-shaped association between pericardial adipose tissue volume (PAT), abdominal visceral adipose tissue area (VAT), hepatic attenuation, and PTX-3 levels, with extremes of adiposity associated with greater PTX-3 levels. Using multivariable-adjusted piecewise regression models, among participants with low PAT, every 1% increase in PAT volume was associated with a 13.8% decrease in PTX-3 (95% confidence interval [CI] -21.6 to -6.0); among participants with high PAT, every 1% increase in PAT volume was associated with a 6.0% increase in PTX-3 (95% CI -0.4 to 12.5). Results were similar for abdominal VAT and hepatic attenuation.

Conclusions

In a cohort of community-dwelling adults, we demonstrated a "U-shaped" association between pericardial, abdominal visceral, and hepatic adiposity with PTX3 levels, suggesting that extreme adiposity is associated with greater circulating levels of PTX3. Further work is required to identify the mechanisms linking adiposity and PTX-3.

Ectopic and visceral fat deposition in aging, obesity, and idiopathic pulmonary fibrosis: an interconnected role

Idiopathic pulmonary fibrosis (IPF) is considered an age-related disease. Age-related changes, along with other factors such as obesity, hormonal imbalances, and various metabolic disorders, lead to ectopic fat deposition (EFD). This accumulation of fat outside of its normal storage sites is associated with detrimental effects such as lipotoxicity, oxidative stress, inflammation, and insulin resistance. This narrative review provides an overview of the connection between ectopic and visceral fat deposition in aging, obesity, and IPF. It also elucidates the mechanism by which ectopic fat deposition in the airways and lungs, pericardium, skeletal muscles, and pancreas contributes to lung injury and fibrosis in patients with IPF, directly or indirectly. Moreover, the review discusses the impact of EFD on the severity of the disease, quality of life, presence of comorbidities, and overall prognosis in IPF patients. The review provides detailed information on recent research regarding representative lipid-lowering drugs, hypoglycemic drugs, and lipid-targeting drugs in animal experiments and clinical studies. This may offer new therapeutic directions for patients with IPF.

Establishment and application of the BRP prognosis model for idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is the most common idiopathic interstitial lung disease. Clinical models to accurately evaluate the prognosis of IPF are currently lacking. This study aimed to construct an easy-to-use and robust prediction model for transplant-free survival (TFS) of IPF based on clinical and radiological information.

METHODS

A multicenter prognostic study was conducted involving 166 IPF patients who were followed up for 3 years. The end point of follow-up was death or lung transplantation. Clinical information, lung function tests, and chest computed tomography (CT) scans were collected. Body composition quantification on CT was performed using 3D Slicer software. Risk factors in blood routine examination-radiology-pulmonary function (BRP) were identified by Cox regression and utilized to construct the "BRP Prognosis Model". The performance of the BRP model and the gender-age-physiology variables (GAP) model was compared using time-ROC curves, calibration curves, and decision curve analysis (DCA). Furthermore, histopathology fibrosis scores in clinical specimens were compared between the different risk stratifications identified by the BRP model. The correlations among body composition, lung function, serum inflammatory factors, and profibrotic factors were analyzed.

RESULTS

Neutrophil percentage > 68.3%, pericardial adipose tissue (PAT) > 94.91 cm3, pectoralis muscle radiodensity (PMD) ≤ 36.24 HU, diffusing capacity of the lung for carbon monoxide/alveolar ventilation (DLCO/VA) ≤ 56.03%, and maximum vital capacity (VCmax) < 90.5% were identified as independent risk factors for poor TFS among patients with IPF. We constructed a BRP model, which showed superior accuracy, discrimination, and clinical practicability to the GAP model. Median TFS differed significantly among patients at different risk levels identified by the BRP model (low risk: TFS > 3 years; intermediate risk: TFS = 2-3 years; high risk: TFS ≈ 1 year). Patients with a high-risk stratification according to the BRP model had a higher fibrosis score on histopathology. Additionally, serum proinflammatory markers were positively correlated with visceral fat volume and infiltration.

CONCLUSIONS

In this study, the BRP prognostic model of IPF was successfully constructed and validated. Compared with the commonly used GAP model, the BRP model had better performance and generalization with easily obtainable indicators. The BRP model is suitable for clinical promotion.

Fibrotic-Like Pulmonary Radiographic Patterns Are Not Associated With Adverse Outcomes in COVID-19 Chronic Critical Illness

OBJECTIVES

Pulmonary fibrosis is a feared complication of COVID-19. To characterize the risks and outcomes associated with fibrotic-like radiographic abnormalities in patients with COVID-19-related acute respiratory distress syndrome (ARDS) and chronic critical illness.

DESIGN

Single-center prospective cohort study.

SETTING

We examined chest CT scans performed between ICU discharge and 30 days after hospital discharge using established methods to quantify nonfibrotic and fibrotic-like patterns.

PATIENTS

Adults hospitalized with COVID-19-related ARDS and chronic critical illness (> 21 d of mechanical ventilation, tracheostomy, and survival to ICU discharge) between March 2020 and May 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We tested associations of fibrotic-like patterns with clinical characteristics and biomarkers, and with time to mechanical ventilator liberation and 6-month survival, controlling for demographics, comorbidities, and COVID-19 therapies. A total of 141 of 616 adults (23%) with COVID-19-related ARDS developed chronic critical illness, and 64 of 141 (46%) had a chest CT a median (interquartile range) 66 days (42-82 d) after intubation. Fifty-five percent had fibrotic-like patterns characterized by reticulations and/or traction bronchiectasis. In adjusted analyses, interleukin-6 level on the day of intubation was associated with fibrotic-like patterns (odds ratio, 4.40 per quartile change; 95% CI, 1.90-10.1 per quartile change). Other inflammatory biomarkers, Sequential Organ Failure Assessment score, age, tidal volume, driving pressure, and ventilator days were not. Fibrotic-like patterns were not associated with longer time to mechanical ventilator liberation or worse 6-month survival.

CONCLUSIONS

Approximately half of adults with COVID-19-associated chronic critical illness have fibrotic-like patterns that are associated with higher interleukin-6 levels at intubation. Fibrotic-like patterns are not associated with longer time to liberation from mechanical ventilation or worse 6-month survival.

Linking Adiposity to Interstitial Lung Disease: The Role of the Dysfunctional Adipocyte and Inflammation

Adipose tissue has functions beyond its principal functions in energy storage, including endocrine and immune functions. When faced with a surplus of energy, the functions of adipose tissue expand by mechanisms that can be both adaptive and detrimental. These detrimental adipose tissue functions can alter normal hormonal signaling and promote local and systemic inflammation with wide-ranging consequences. Although the mechanisms by which adipose tissue triggers metabolic dysfunction and local inflammation have been well described, little is known about the relationship between adiposity and the pathogenesis of chronic lung conditions, such as interstitial lung disease (ILD). In this review, we detail the conditions and mechanisms by which adipose tissue becomes dysfunctional and relate this dysfunction to inflammatory changes observed in various forms of ILD. Finally, we review the existing basic and clinical science literature linking adiposity to ILD, highlighting the need for additional research on the mechanisms of adipocyte-mediated inflammation in ILD and its clinical implications.

High-Fat Diet Related Lung Fibrosis-Epigenetic Regulation Matters

Pulmonary fibrosis (PF) is an interstitial lung disease characterized by the destruction of the pulmonary parenchyma caused by excessive extracellular matrix deposition. Despite the well-known etiological factors such as senescence, aberrant epithelial cell and fibroblast activation, and chronic inflammation, PF has recently been recognized as a metabolic disease and abnormal lipid signature was observed both in serum and bronchoalveolar lavage fluid (BALF) of PF patients and mice PF model. Clinically, observational studies suggest a significant link between high-fat diet (HFD) and PF as manifested by high intake of saturated fatty acids (SFAs) and meat increases the risk of PF and mice lung fibrosis. However, the possible mechanisms between HFD and PF remain unclear. In the current review we emphasize the diversity effects of the epigenetic dysregulation induced by HFD on the fibrotic factors such as epithelial cell injury, abnormal fibroblast activation and chronic inflammation. Finally, we discuss the potential ways for patients to improve their conditions and emphasize the prospect of targeted therapy based on epigenetic regulation for scientific researchers or drug developers.

Interstitial Lung Disease in Primary Biliary Cholangitis: A Cohort Prospective Study

Interstitial lung disease (ILD) has been recognized as an extrahepatic manifestation ofprimary biliary cholangitis (PBC), althoughlimited data are available on its prevalence and clinical significance. Therefore, we evaluated the occurrence and clinical features of ILD in a cohort of PBC patients. Ninety-three individuals without concomitant rheumatic diseases were enrolled in our prospective cohort study. All patients underwent chest high-resolution computed tomography (HRCT). Liver-related and lung-related survival wereassessed. A lung-related outcome was defined as death from ILD complications; a liver-related outcome was defined as liver transplantation or death from liver cirrhosis complications. HRCT findings suggestive ofILD were detected in 38 patients (40.9%). A sarcoid-like pattern of PBC-associated ILD was the most frequent, followed by subclinical ILD and organizing pneumonia. Patients with ILD were less likely to have liver cirrhosis and liver-related symptoms and presented with higher serum immunoglobulin M(IgM) and M2 subtype antimitochondrial antibodies (AMA-M2) positivity rates. In a multivariate analysis, the absence of liver disease symptoms at the disease presentation (OR 11.509; 95% CI 1.210-109.421; p = 0.033), the presence of hepatic non-necrotizing epithelioid cell granulomas (OR 17.754; 95% CI 1.805-174.631; p = 0.014), higher serum IgM (OR 1.535; 95% CI 1.067-2.208; p = 0.020) and higher blood leukocyte count (OR 2.356; 95% CI 1.170-4.747; p = 0.016) were independent risk factors associated with ILD in PBC. More than a third of patients with ILD showed no respiratory symptoms, and only one ILD-related death occurred during a follow-up of 29.0 months (IQR 11.5; 38.0). Patients with ILD had better liver transplant-free survival.ILD in PBC had a benign course and was associated with a lower liver disease severity. PBC-associated ILD should be included in a list of differential diagnoses of ILD.

Lung CCR6-CXCR3- type 2 helper T cells as an indicator of progressive fibrosing interstitial lung diseases

Progressive fibrosing interstitial lung diseases (PF-ILDs) have a poor prognosis and may be resistant to corticosteroids and/or immunosuppressants, but antifibrotic therapies such as nintedanib and pirfenidone have been shown to slow the deterioration of lung function. The aim of this study was to identify the characteristic cellular profile of bronchoalveolar lavage fluid at diagnostic bronchoscopy for predicting PF-ILDs, defined as fibrotic diseases on chest high-resolution computed tomography with more than a 5% relative decline in the percent predicted value of forced vital capacity (FVC) over 6 months. The proportions of inflammatory cells, CCR6^-CXCR3^- T helper type 2 (Th2) cells among conventional CD4⁺ T cells in bronchoalveolar lavage fluid (BALF) and peripheral blood, were measured by flowcytometry. The proportion of lymphocytes in BALF was significantly higher in non-PF-ILD patients than in PF-ILD patients. The proportion of Th2 cells in BALF, but not in peripheral blood, was significantly higher in PF-ILD patients than in non-PF-ILD patients. Multivariate analysis showed that a greater population of Th2 cells in BALF was the only indicator for PF-ILDs. An increased proportion of Th2 cells in BALF is associated with greater deterioration of lung function in fibrotic interstitial lung diseases.

Contemporary Concise Review 2021: Interstitial lung disease

The last 2 years have presented previously unforeseen challenges in pulmonary medicine. Despite the significant impact of the SARS‐CoV‐2 pandemic on patients, clinicians and communities, advances in the care and understanding of interstitial lung disease (ILD) continued unabated. Recent studies have led to improved guidelines, better understanding of the role for antifibrotics in fibrosing ILDs, prognostic indicators and novel biomarkers. In this concise contemporary review, we summarize many of the important studies published in 2021, highlighting their relevance and impact to the management and knowledge of ILD.

Association of BMI and Change in Weight With Mortality in Patients With Fibrotic Interstitial Lung Disease

BACKGROUND

Mortality risk assessment in interstitial lung disease (ILD) is challenging. Our objective was to determine the prognostic significance of BMI and change in weight in the most common fibrotic ILD subtypes.

RESEARCH QUESTION

Could BMI and weight loss over time be reliable prognostic indicators in patients with fibrotic ILD?

STUDY DESIGN AND METHODS

This observational retrospective multicenter cohort study enrolled patients with fibrotic ILD from the six-center CAnadian REgistry for Pulmonary Fibrosis (CARE-PF, derivation) and the ILD registry at the University of California, San Francisco (UCSF, validation). Patients were subcategorized as underweight (BMI < 18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25-29.9), or obese (BMI > 30). Annual change in weight was calculated for all years of follow-up as the slope of best fit using the least square method based on every available measurement. Separate multivariable analyses evaluated the associations of BMI and change in weight with mortality, adjusting for common prognostic variables.

RESULTS

The derivation and validation cohorts included 1,786 and 1,779 patients, respectively. Compared with patients with normal BMI, mortality was highest in patients who were underweight (hazard ratio [HR], 3.19; 95% CI, 1.88-5.43; P < .001) and was lowest in those who were overweight (HR, 0.52; 95% CI, 0.36-0.75; P < .001) or obese (HR, 0.55; 95%CI, 0.37-0.83; P < .001) in the analysis adjusted for the ILD-GAP (gender, age, physiology) Index. Patients who had a weight loss of at least 2 kg within 1 year had increased risk of death in the subsequent year (HR, 1.41; 95% CI, 1.01-1.97; P = .04) after adjustment for the ILD-GAP Index and baseline BMI category, with a plateau in risk for patients with greater weight loss. Consistent results were observed in the validation cohort.

INTERPRETATION

Both BMI and weight loss are independently associated with 1-year mortality in fibrotic ILD. BMI and weight loss may be clinically useful prognostic indicators in fibrotic ILD.

Respiratory diseases and obesity: special phenotype or independent events: Review

A combination of factors, including Western European eating habits, physical inactivity and genetic predisposition, lead to a dramatic increase in adipose tissue mass. A special place is occupied by abdominal obesity, in which there is an accumulation of adipose tissue in the mesentery of the small intestine and the omentum. Developing in conditions of visceral obesity, insulin resistance, dyslipidemia and systemic inflammation are one of the key components of the pathogenesis of type 2 diabetes mellitus, cardiovascular diseases, non-alcoholic fatty liver and pancreas disease, polycystic ovary disease, some forms of cancer (breast cancer, endometrial cancer, colonic and direct intestines). At the same time, the pathogenetic role of adipose tissue is not limited to its participation in the formation of the cardiometabolic continuum and oncogenesis. The most important role of metabolically active fat in the pathogenesis of many respiratory diseases is known, including bronchial asthma, obstructive sleep apnea and pulmonary hypertension. This paper presents an overview of current data on immunological, pathophysiological and clinical features of the phenotype of the combination of respiratory diseases with overweight and obesity.

Interstitial lung abnormalities - current knowledge and future directions

Efforts to grasp the significance of radiologic changes similar to interstitial lung disease (ILD) in undiagnosed individuals have intensified in the recent decade. The term interstitial lung abnormalities (ILA) is an emerging definition of such changes, defined by visual examination of computed tomography scans. Substantial insights have been made in the origins and clinical consequences of these changes, as well as automated measures of early lung fibrosis, which will likely lead to increased recognition of early fibrotic lung changes among clinicians and researchers alike.

Interstitial lung abnormalities have an estimated prevalence of 7–10% in elderly populations. They correlate with many ILD risk factors, both epidemiologic and genetic. Additionally, histopathological similarities with IPF exist in those with ILA. While no established blood biomarker of ILA exists, several have been suggested. Distinct imaging patterns indicating advanced fibrosis correlate with worse clinical outcomes. ILA are also linked with adverse clinical outcomes such as increased mortality and risk of lung cancer.

Progression of ILA has been noted in a significant portion of those with ILA and is associated with many of the same features as ILD, including advanced fibrosis. Those with ILA progression are at risk of accelerated FVC decline and increased mortality. Radiologic changes resembling ILD have also been attained by automated measures. Such measures associate with some, but not all the same factors as ILA.

ILA and similar radiologic changes are in many ways analogous to ILD and likely represent a precursor of ILD in some cases. While warranting an evaluation for ILD, they are associated with poor clinical outcomes beyond possible ILD development and thus are by themselves a significant finding. Among the present objectives of this field are the stratification of patients with regards to progression and the discovery of biomarkers with predictive value for clinical outcomes.