Chronic airflow obstruction and ambient particulate air pollution.

Smoking is the most well-established cause of chronic airflow obstruction (CAO) but particulate air pollution and poverty have also been implicated. We regressed sex-specific prevalence of CAO from 41 Burden of Obstructive Lung Disease study sites against smoking prevalence from the same study, the gross national income per capita and the local annual mean level of ambient particulate matter (PM2.5) using negative binomial regression. The prevalence of CAO was not independently associated with PM2.5 but was strongly associated with smoking and was also associated with poverty. Strengthening tobacco control and improved understanding of the link between CAO and poverty should be prioritised.

Domestic solid fuel combustion in an adult population in Nigeria: A cross sectional analysis of association with respiratory symptoms, quality of life and lung function.

BACKGROUND AND OBJECTIVES: We examined the association of respiratory symptoms, health status, and lung function with the use of solid fuel (wood, charcoal, coal or crop residue) for cooking or heating in a predominantly non-smoking population. METHODS: Using the protocol of the Burden of Obstructive Lung Diseases (BOLD) initiative, we collected representative population data using questionnaires and spirometry tests. We categorized solid fuel use into 'never user', 'ex user' and 'current user' based on responses to the survey. We developed regression models to evaluate the relation between use of solid fuel and the prevalence of respiratory symptoms, quality of life and lung function adjusting for confounding variables. RESULTS: Out of 1147 respondents with complete information on domestic fuel type, 33% were 'never-users', 19% were 'ex-users' while 48% reported current use of solid fuel for domestic cooking and/or indoor heating. Compared with never-users, current solid fuel users were more likely to report cough (OR: 1.7, 95% CI: 1.0, 2.9), cough or phlegm (OR: 1.6, 95% CI: 1.0, 2.5) and the association was stronger among women (OR: 3.0, 95% CI: 1.3, 7.1 and OR: 2.3, 95% CI: 1.1, 5.2, respectively). Current solid fuel users also had lower mental health status (coefficient: ?1.5, 95% CI: ?2.8, - 0.2) compared with the group of never-users. Current or previous domestic use of solid fuels for cooking or heating was not associated with higher prevalence of chronic airflow obstruction (FEV1/FVC < LLN). CONCLUSIONS: Using solid fuel for domestic cooking or heating was associated with a higher risk of cough or phlegm and a lower mental quality of life. However we found no significant effect in the prevalence of chronic airflow obstruction in Ife, Nigeria.

Prevalence and burden of chronic bronchitis symptoms: results from the BOLD study.

We studied the prevalence, burden and potential risk factors for chronic bronchitis symptoms in the Burden of Obstructive Lung Disease study.Representative population-based samples of adults aged ≥40 years were selected in participating sites. Participants completed questionnaires and spirometry. Chronic bronchitis symptoms were defined as chronic cough and phlegm on most days for ≥3 months each year for ≥2 years.Data from 24 855 subjects from 33 sites in 29 countries were analysed. There were significant differences in the prevalence of self-reported symptoms meeting our definition of chronic bronchitis across sites, from 10.8% in Lexington (KY, USA), to 0% in Ile-Ife (Nigeria) and Blantyre (Malawi). Older age, less education, current smoking, occupational exposure to fumes, self-reported diagnosis of asthma or lung cancer and family history of chronic lung disease were all associated with increased risk of chronic bronchitis. Chronic bronchitis symptoms were associated with worse lung function, more dyspnoea, increased risk of respiratory exacerbations and reduced quality of life, independent of the presence of other lung diseases.The prevalence of chronic bronchitis symptoms varied widely across the studied sites. Chronic bronchitis symptoms were associated with significant burden both in individuals with chronic airflow obstruction and those with normal lung function.

Unemployment in chronic airflow obstruction around the world: results from the BOLD study.

We aimed to examine associations between chronic airflow obstruction (CAO) and unemployment across the world.Cross-sectional data from 26 sites in the Burden of Obstructive Lung Disease (BOLD) study were used to analyse effects of CAO on unemployment. Odds ratios for unemployment in subjects aged 40-65 years were estimated using a multilevel mixed-effects generalised linear model with study site as random effect. Site-by-site heterogeneity was assessed using individual participant data meta-analyses.Out of 18 710 participants, 11.3% had CAO. The ratio of unemployed subjects with CAO divided by subjects without CAO showed large site discrepancies, although these were no longer significant after adjusting for age, sex, smoking and education. The site-adjusted odds ratio (95% CI) for unemployment was 1.79 (1.41-2.27) for CAO cases, decreasing to 1.43 (1.14-1.79) after adjusting for sociodemographic factors, comorbidities and forced vital capacity. Of other covariates that were associated with unemployment, age and education were important risk factors in high-income sites (4.02 (3.53-4.57) and 3.86 (2.80-5.30), respectively), while female sex was important in low- to middle-income sites (3.23 (2.66-3.91)).In the global BOLD study, CAO was associated with increased levels of unemployment, even after adjusting for sociodemographic factors, comorbidities and lung function.

Reduced Forced Vital Capacity in an African Population. Prevalence and Risk Factors.

RATIONALE: Black Africans have reduced FVC compared with white persons, but the prevalence and determinants of reduced values are not well understood. OBJECTIVES: To evaluate the prevalence and factors leading to reduced FVC in a Nigerian population and to examine current theories regarding the determinants of this difference. METHODS: We studied the ventilatory function of 883 adults aged 40 years or older participating in the Burden of Obstructive Lung Disease Study in Ile-Ife, Nigeria. Respondents completed pre- and post-bronchodilator spirometry test and provided information on their smoking history, respiratory symptoms, risk factors, and diagnoses, including anthropometric details. We used standard categories to define body mass index as either underweight, normal, overweight, or obese. We defined reduced FVC as a post-bronchodilator FVC below the lower limit of normal using National Health and Nutrition Examination Survey (NHANES) equations, Global Lung Function Initiative 2012 equations, and local reference equations based on nonsmoking study participants without a respiratory diagnosis. We fit multivariate linear regression models to FVC as a continuous measure, adjusting for age, sex, height, and other confounders. RESULTS: The prevalence of reduced FVC was 70.4% for men and 72.8% for women when using NHANES values for white Americans, 17.8% for men and 14.4% for women using NHANES equations for African Americans, and 15.5% for men and 20.5% for women using the Global Lung Function Initiative 2012 equations. Using the equations derived from nonsmoking respondents in the survey without a respiratory diagnosis, the prevalence of reduced FVC was less than 4% for both men and women. FVC was lower in participants who had less than 7 years of education (FVC, -96 ml; 95% confidence interval [CI], -172 to -19), were underweight (FVC, -269 ml; 95% CI, -464 to -73), were overweight (FVC, -132 ml; 95% CI, -219 to -46), and were obese (FVC, -222 ml; 95% CI, -332 to -112). CONCLUSIONS: There is a wide variation in the prevalence of reduced FVC based on the reference standard used. This variation is not satisfactorily explained by factors thought to affect FVC within individual populations. However, the prevalence strongly associates with both education level and body mass index in this population, regardless of the specific standard used.

Chronic Airflow Obstruction in a Black African Population: Results of BOLD Study, Ile-Ife, Nigeria.

Global estimates suggest that Chronic Obstructive Pulmonary Disease (COPD) is emerging as a leading cause of death in developing countries but there are few spirometry-based general population data on its prevalence and risk factors in sub-Saharan Africa. We used the Burden of Obstructive Lung Disease (BOLD) protocol to select a representative sample of adults aged 40 years and above in Ile-Ife, Nigeria. All the participants underwent spirometry and provided information on smoking history, biomass and occupational exposures as well as diagnosed respiratory diseases and symptoms. Chronic Airflow Obstruction (CAO) was defined as the ratio of post-bronchodilator (BD) one second Forced Expiratory Volume (FEV1) to Forced Vital Capacity (FVC) below the lower limit of normal (LLN) of the population distribution for FEV1/FVC. The overall prevalence of obstruction (post-BD FEV1/FVC < LLN) was 7.7% (2.7% above LLN) using Global Lung Function Initiative (GLI) equations. It was associated with few respiratory symptoms; 0.3% reported a previous doctor-diagnosed chronic bronchitis, emphysema or COPD. Independent predictors included a lack of education (OR 2.5, 95% CI: 1.0, 6.4) and a diagnosis of either TB (OR 23.4, 95% CI: 2.0, 278.6) or asthma (OR 35.4, 95%CI: 4.9, 255.8). There was no association with the use of firewood or coal for cooking or heating. The vast majority of this population (89%) are never smokers. We conclude that the prevalence of CAO is low in Ile-Ife, Nigeria and unrelated to biomass exposure. The key independent predictors are poor education, and previous diagnosis of tuberculosis or asthma.

HIV Associated Chronic Obstructive Pulmonary Disease in Nigeria.

OBJECTIVE: To determine the prevalence and risk factors for chronic obstructive pulmonary disease (COPD) among HIV-infected adults in Nigeria. DESIGN: Cross-sectional study. METHODS: HIV-infected adults aged ≥ 30 years with no acute ailments accessing care at the antiretroviral therapy clinic of Jos University Teaching Hospital were enrolled consecutively. Participants were interviewed to obtain pertinent demographic and clinical information, including exposure to risk factors for COPD. Post-bronchodilator spirometry was carried out. HIV related information was retrieved from the clinic medical records. COPD case-definition was based on the Global Initiative for Obstructive Lung Disease (GOLD) criteria using post-bronchodilator FEV1/FVC <0.7. COPD prevalence was also calculated using the lower limit of normal for FEV1/FVC criteria (LLN) from the European Respiratory Society normative equation. Factors associated with COPD were determined using logistic regression models. RESULTS: Study population comprised 356 HIV infected adults with mean age of 44.5 (standard deviation, 7.1) years and 59% were female. The mean time elapsed since HIV diagnosis was 7.0 (SD, 2.6) years and 97.5% of the respondents were on stable ART with virologic suppression present in 67.2%. Prevalence of COPD were 15.4% (95% confidence interval [CI] 11.7-19.2), 12.07% (95% CI 8.67-15.48), 22.19% (95% CI 18.16-26.83) using GOLD, ERS LLN and GLI LLN diagnostic criteria respectively. In multivariate analyses adjusting for gender, exposure to cigarette smoke or biomass, history of pulmonary tuberculosis, use of antiretroviral therapy, current CD4 T-cell count and HIV RNA, only age > 50 years was independently associated with COPD with OR 3.4; 95% CI 1.42-8.17 when compared to ages 30-40 years. CONCLUSION: HIV-associated COPD is common in our population of HIV patients.