Small airways obstruction and mortality: Findings from the UK Biobank.

BACKGROUND: Small airways obstruction (SAO) is common in general populations. It has been associated with respiratory symptoms, cardiometabolic diseases and progression to chronic obstructive pulmonary disease over time. Whether SAO predicts mortality is largely unknown. RESEARCH QUESTION: Is spirometry-defined SAO associated with increased mortality? METHODS: We analysed data from 252,877 adult participants, aged 40-69 at baseline, in the UK Biobank who had provided good quality spirometry measurements. We defined SAO as the ratio of the forced expiratory volume in three seconds to the forced expiratory volume in six seconds less than the lower limit of normal (FEV3/FEV6

Prevalence of dyspnea in general adult populations: A systematic review and meta-analysis.

INTRODUCTION: Dyspnea is a commonly described symptom in various chronic and acute conditions. Despite its frequency, relatively little is known about the prevalence and assessment of dyspnea in general populations. The aims of this review were: 1) to estimate the prevalence of dyspnea in general adult populations; 2) to identify associated factors; and 3) to identify used methods for dyspnea assessment. METHODS: A systematic literature search was conducted using MEDLINE/PubMed, Embase, CINAHL and JAMA network. Records were screened by two independent reviewers and quality was assessed by using the Joanna Briggs Institute checklist for risk of bias in prevalence studies. Multi-level meta-analysis was performed to estimate pooled prevalence. The protocol was registered on PROSPERO (CRD42021275499). RESULTS: Twenty original articles, all from studies in high-income countries, met the criteria for inclusion. Overall, their quality was good. Pooled prevalence of dyspnea in general adult populations based on 11 studies was 10% (95% CI 7, 15), but heterogeneity across studies was high. The most frequently reported risk factors were increasing age, female sex, higher BMI and respiratory or cardiac disease. The MRC or the modified MRC scale was the most used tool to assess dyspnea in general populations. CONCLUSIONS: Dyspnea is a common symptom in adults in high-income countries. However, the high heterogeneity across studies and the lack of data from low- and middle-income countries limit the generalizability of our findings. Therefore, more research is needed to unveil the prevalence of dyspnea and its main risk factors in general populations around the world.

Residential greenspace and lung function decline over 20 years in a prospective cohort: The ECRHS study.

BACKGROUND: The few studies that have examined associations between greenspace and lung function in adulthood have yielded conflicting results and none have examined whether the rate of lung function decline is affected. OBJECTIVE: We explored the association between residential greenspace and change in lung function over 20 years in 5559 adults from 22 centers in 11 countries participating in the population-based, international European Community Respiratory Health Survey. METHODS: Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were measured by spirometry when participants were approximately 35 (1990-1994), 44 (1999-2003), and 55 (2010-2014) years old. Greenness was assessed as the mean Normalized Difference Vegetation Index (NDVI) in 500 m, 300 m, and 100 m circular buffers around the residential addresses at the time of lung function measurement. Green spaces were defined as the presence of agricultural, natural, or urban green spaces in a circular 300 m buffer. Associations of these greenspace parameters with the rate of lung function change were assessed using adjusted linear mixed effects regression models with random intercepts for subjects nested within centers. Sensitivity analyses considered air pollution exposures. RESULTS: A 0.2-increase (average interquartile range) in NDVI in the 500 m buffer was consistently associated with a faster decline in FVC (-1.25 mL/year [95% confidence interval: -2.18 to -0.33]). These associations were especially pronounced in females and those living in areas with low PM10 levels. We found no consistent associations with FEV1 and the FEV1/FVC ratio. Residing near forests or urban green spaces was associated with a faster decline in FEV1, while agricultural land and forests were related to a greater decline in FVC. CONCLUSIONS: More residential greenspace was not associated with better lung function in middle-aged European adults. Instead, we observed slight but consistent declines in lung function parameters. The potentially detrimental association requires verification in future studies.

Body mass index and weight change are associated with adult lung function trajectories: the prospective ECRHS study.

BACKGROUND: Previous studies have reported an association between weight increase and excess lung function decline in young adults followed for short periods. We aimed to estimate lung function trajectories during adulthood from 20-year weight change profiles using data from the population-based European Community Respiratory Health Survey (ECRHS). METHODS: We included 3673 participants recruited at age 20-44 years with repeated measurements of weight and lung function (forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1)) in three study waves (1991-93, 1999-2003, 2010-14) until they were 39-67 years of age. We classified subjects into weight change profiles according to baseline body mass index (BMI) categories and weight change over 20 years. We estimated trajectories of lung function over time as a function of weight change profiles using population-averaged generalised estimating equations. RESULTS: In individuals with normal BMI, overweight and obesity at baseline, moderate (0.25-1 kg/year) and high weight gain (>1 kg/year) during follow-up were associated with accelerated FVC and FEV1 declines. Compared with participants with baseline normal BMI and stable weight (±0.25 kg/year), obese individuals with high weight gain during follow-up had -1011 mL (95% CI -1.259 to -763) lower estimated FVC at 65 years despite similar estimated FVC levels at 25 years. Obese individuals at baseline who lost weight (<-0.25 kg/year) exhibited an attenuation of FVC and FEV1 declines. We found no association between weight change profiles and FEV1/FVC decline. CONCLUSION: Moderate and high weight gain over 20 years was associated with accelerated lung function decline, while weight loss was related to its attenuation. Control of weight gain is important for maintaining good lung function in adult life.