Non-communicable airway disease and air pollution exposure in sub-Saharan Africa

Awokola, Babatunde (2023) Non-communicable airway disease and air pollution exposure in sub-Saharan Africa, Thesis (Doctoral), Liverpool School of Tropical Medicine.

Text B Awokola Non-Communicable Airway Disease Thesis_260424_Final.pdf - Accepted Version Restricted to Repository staff only until 7 February 2025. Download (8MB)

Abstract

Background: Non-communicable airway diseases are public health problems and a cause of premature mortality globally: chronic obstructive pulmonary disease (COPD) accounts for 3.2 million deaths while asthma causes 445,000 deaths annually. Over 90% of the world’s population are exposed to air pollution daily. These two important and interplaying issues unfortunately do not get the needed attention from many health systems. This PhD sought tcontribute to non-communicable disease (NCD) control in sub-Saharan Africa (sSA) by generating novel data in chronic airway disease in three West African countries, as well as ambient air pollution level data in eight countries across sSA.

Methodology: Overall approaches used were: (a) Systematic review and meta-analysis of 17,566 adults with COPD in sSA: Prevalence and risk factors, (b) Pilot case-control study of the air pollution exposure-PM2.5 , CO and exhaled CO of 50 adult asthma and COPD patients and 50 age and sex-matched controls in The Gambia, with comparison of the cases with those obtained from Benin Republic (35 adults) and Cameroon (13 adults), (c) Longitudinal ground level ambient fine particulate matter 2.5 microns or less (PM2.5) measurement from eight sSA countries over one year. Data entry and formatting was done using microsoft excel while data management and analysis was done with R-studio. Descriptive and inferential statistical methods were applied as needed. Mixed effects model meta-analysis, conditional regression for the cases and controls, linear regression conducted for risk factors, and longitudinal data analysis were the main statistical methods used.

Results: COPD pooled prevalence in sub-Saharan Africa is 8% (CI 6-11%). This increases with age and smoking exposure. The Odds ratio of current smoking versus never smoking on COPD prevalence is 2.20 (CI 1.62-2.99).
The mean annual PM2.5 levels in all the 15 urban sites across the eight sSA countries were higher than the World Health Organization (WHO) recommended annual limit of 5µg/m3. Diurnal variation was observed across all sites with two daily PM2.5 peaks at 6:00 and 18:00 local time. The main challenges of use of low-cost sensors for longitudinal particulate matter measurement were power issues, internet connectivity and SD memory card issues.
Chronic Airway Disease (CAD) patients in The Gambia are likely to present with poorly controlled asthma or COPD with at least moderate effect on the person, significant exposure to second hand smoke (26%), personal PM2.5, burning refuse and occupational dust when compared with controls. Air pollution exposure was similar among both cases and controls.
Across Benin, Cameroon and The Gambia, respondents were mainly urban dwellers (69%), mean age of 51.6±17.5 years, with cough, wheeze and shortness of breath being the commonest symptoms.
Asthma was the commonest presenting CAD. Eighteen percent of the cohort reported 5 or more exacerbations in the past year. Ever smoking was highest in Cameroon (23%). Median home PM2.5 and
home CO were highest in Benin (13.0 µg/m3 : IQR-112.3 & 1.65µg/m3 : IQR-1.4 respectively.

Implications: sSA adult COPD prevalence and passive smoking exposure makes tobacco cessation counselling and anti-tobacco policies paramount. Urban African cities high air pollutant levels should engender citizen science and influence clean air policy enforcement. Clean fuel alternatives such as LPG, biogas and briquettes should be made available in much of sSA.

Item Type:	Thesis (Doctoral)
Subjects:	WA Public Health > WA 30 Socioeconomic factors in public health (General) WA Public Health > Air pollution > WA 754 Pollution and pollutants (incl. tobacco pollution; passive smoking)
Repository link:	Item title Item URI Chronic obstructive pulmonary disease in sub-Saharan Africa https://archive.lstmed.ac.uk/20044 Measuring Air Quality for Advocacy in Africa (MA3): Feasibility and Practicality of Longitudinal Ambient PM2.5 Measurement Using Low-Cost Sensors https://archive.lstmed.ac.uk/15855 Longitudinal Ambient PM 2.5 Measurement at Fifteen Locations in Eight Sub-Saharan African Countries Using Low-Cost Sensors https://archive.lstmed.ac.uk/21367 Non-communicable airway disease and air pollution in three African Countries: Benin, Cameroon and The Gambia https://archive.lstmed.ac.uk/24448
Faculty: Department:	Clinical Sciences & International Health > Clinical Sciences Department
Depositing User:	Lynn Roberts-Maloney
Date Deposited:	16 May 2024 13:32
Last Modified:	04 Jun 2024 13:14
URI:	https://archive.lstmed.ac.uk/id/eprint/24571

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