Association between lung function and dyspnoea and its variation in the multinational Burden of Obstructive Lung Disease (BOLD) study.

BACKGROUND: Dyspnoea is a common symptom of respiratory disease. However, data on its prevalence in general populations and its association with lung function are limited and are mainly from high-income countries. The aims of this study were to estimate the prevalence of dyspnoea across several world regions, and to investigate the association of dyspnoea with lung function. METHODS: Dyspnoea was assessed, and lung function measured in 25,806 adult participants of the multinational Burden of Obstructive Lung Disease study. Dyspnoea was defined as ≥2 on the modified Medical Research Council (mMRC) dyspnoea scale. The prevalence of dyspnoea was estimated for each of the study sites and compared across countries and world regions. Multivariable logistic regression was used to assess the association of dyspnoea with lung function in each site. Results were then pooled using random-effects meta-analysis. RESULTS: The prevalence of dyspnoea varied widely across sites without a clear geographical pattern. The mean prevalence of dyspnoea was 13.7 % (SD=8.2 %), ranging from 0 % in Mysore (India) to 28.8 % in Nampicuan-Talugtug (Philippines). Dyspnoea was strongly associated with both spirometry restriction (FVC

Indoor air quality and its relationship with cluster type in urban Pakistani households.

OBJECTIVE: To assess the levels and predictors of formaldehyde, nitrogen dioxide (NO2), carbon monoxide (CO) and fine particulate matter with diameter less than 2.5 µm (PM2.5) in Karachi, Pakistan.METHODS: A total of 1629 households were selected through multistage cluster sampling in a community-based cross-sectional survey. Formaldehyde, NO2 and CO levels were measured using YesAir Indoor air monitor and for PM2.5, UCB-PATS (University of California Berkeley Particle and Temperature Sensor) was used. Clusters were classified either as planned (areas of planned housing) or unplanned (informal settlements).RESULTS: We found the median concentrations to be as follows: formaldehyde, 0.03 ppm (IQR 0.00-0.090); CO, 0.00 ppm (IQR 0.00-1.00); NO2, 0 ppm (IQR 0.00-0.00) and PM2.5, 0.278 mg/m³ (IQR 0.162-0.526). We found a significant association of the upper quartiles of formaldehyde and PM2.5 levels with type of cluster. The risk of obtaining formaldehyde and PM2.5 levels in the upper quartile was higher in unplanned clusters than in planned clusters (adjusted odds ratio [aOR] 33.0, 95% CI 4.02-271.5 and aOR 0.10, 95% CI 0.001-0.16, respectively). No significant association was observed between levels of CO and cluster type (aOR 0.84, 95%CI 0.62-1.14).CONCLUSION: This study reports high levels of indoor air pollutants in Karachi, with considerable variation across planned vs. unplanned clusters.

Prevalence of and risk factors for respiratory symptoms in an adult urban population.

OBJECTIVE: To determine prevalence of and risk factors for respiratory symptoms in an adult urban Pakistani population.METHODS: We conducted a multi-stage, community-based, cross-sectional survey from May 2014 to August 2015, comprising 1629 adults from 75 random clusters in Karachi using questionnaire-based interviews.RESULTS: Around 60% of participants were females and 43% belonged to the >37 years age group. At least one respiratory symptom was reported by 37.5% of participants. Breathlessness was the most common symptom (25.2%, 95%CI 23.1-27.3), followed by acute wheeze (10.1%, 95%CI 8.7-11.7). Multivariable models revealed that males and those aged >37 years were more likely to report acute and chronic phlegm and bronchitis, and breathlessness. Participants with a higher level of education were less likely to report acute and chronic cough. Participants with >5 years pack-years of smoking were more likely to report acute and chronic cough and breathlessness. Other risk factors included passive smoking, regular use of air conditioning and mosquito coils, wet spots and mould in the house, and exposure to dusty jobs.CONCLUSION: We found breathlessness to be the most prevalent respiratory symptom and identified various risk factors for respiratory symptoms.