Household concentrations and female and child exposures to air pollution in peri-urban sub-Saharan Africa: measurements from the CLEAN-Air(Africa) study.

BACKGROUND: Relatively clean cooking fuels such as liquefied petroleum gas (LPG) emit less fine particulate matter (PM2·5) and carbon monoxide (CO) than polluting fuels (eg, wood, charcoal). Yet, some clean cooking interventions have not achieved substantial exposure reductions. This study evaluates determinants of between-community variability in exposures to household air pollution (HAP) across sub-Saharan Africa. METHODS: In this measurement study, we recruited households cooking primarily with LPG or exclusively with wood or charcoal in peri-urban Cameroon, Ghana, and Kenya from previously surveyed households. In 2019-20, we conducted monitoring of 24 h PM2·5 and CO kitchen concentrations (n=256) and female cook (n=248) and child (n=124) exposures. PM2·5 measurements used gravimetric and light scattering methods. Stove use monitoring and surveys on cooking characteristics and ambient air pollution exposure (eg, walking time to main road) were also administered. FINDINGS: The mean PM2·5 kitchen concentration was five times higher among households cooking with charcoal than those using LPG in the Kenyan community (297 µg/m3, 95% CI 216-406, vs 61 µg/m3, 49-76), but only 4 µg/m3 higher in the Ghanaian community (56 µg/m3, 45-70, vs 52 µg/m3, 40-68). The mean CO kitchen concentration in charcoal-using households was double the WHO guideline (6·11 parts per million [ppm]) in the Kenyan community (15·81 ppm, 95% CI 8·71-28·72), but below the guideline in the Ghanaian setting (1·77 ppm, 1·04-2·99). In all communities, mean PM2·5 cook exposures only met the WHO interim-1 target (35 µg/m3) among LPG users staying indoors and living more than 10 min walk from a road. INTERPRETATION: Community-level variation in the relative difference in HAP exposures between LPG and polluting cooking fuel users in peri-urban sub-Saharan Africa might be attributed to differences in ambient air pollution levels. Thus, mitigation of indoor and outdoor PM2·5 sources will probably be critical for obtaining significant exposure reductions in rapidly urbanising settings of sub-Saharan Africa. FUNDING: UK National Institute for Health and Care Research.

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.

Incidence and impact of hospital-acquired complications in an internal medicine unit of a reference hospital in Cameroon: a prospective cohort study.

BACKGROUND: Hospital-acquired complications (HACs) contribute to increased morbidity, mortality and hospital costs. However, their burden is often overlooked in resource-limited settings. We sought to determine the incidence, risk factors and effects of HACs on direct medical costs. METHODS: This was a prospective cohort study conducted in the Internal Medicine inpatient ward of Douala General Hospital over 3 mo. Patients were examined daily from admission to discharge, transfer or death. Incidence of HACs was calculated and risk factors of HACs were determined using univariate and multivariate regression models. RESULTS: The cumulative incidence rate of HACs in 230 participants was 29.2/1000 patient-days. The incidence rate of infectious and non-infectious complications was 8.4/1000 and 20.9/1000 patient-days, respectively. The most common HAC was constipation (8.3/1000 patient-days). The most common infection was urinary tract infection (3.7/1000 patient-days). HIV infection and length of stay >8 d were significantly associated with the occurrence of HACs. Deep vein thrombosis was associated with the highest direct medical cost. CONCLUSION: The incidence of HACs is high in our setting and leads to increased length of hospital stays as well as greater direct medical costs. Thus, there is a need for effective preventive strategies.

Drivers of the Adoption and Exclusive Use of Clean Fuel for Cooking in Sub-Saharan Africa: Learnings and Policy Considerations from Cameroon.

Household air pollution (HAP) caused by the combustion of solid fuels for cooking and heating is responsible for almost 5% of the global burden of disease. In response, the World Health Organisation (WHO) has recommended the urgent need to scale the adoption of clean fuels, such as liquefied petroleum gas (LPG), in low and middle-income countries (LMICs). To understand the drivers of the adoption and exclusive use of LPG for cooking, we analysed representative survey data from 3343 peri-urban and rural households in Southwest Cameroon. Surveys used standardised tools to collect information on fuel use, socio-demographic and household characteristics and use of LPG for clean cooking. Most households reported LPG to be clean (95%) and efficient (88%), but many also perceived it to be expensive (69%) and unsafe (64%). Positive perceptions about LPG's safety (OR = 2.49, 95% CI = 2.04, 3.05), cooking speed (OR = 4.31, 95% CI = 2.62, 7.10), affordability (OR = 1.7, 95% CI = 1.38, 2.09), availability (OR = 2.17, 95% CI = 1.72, 2.73), and its ability to cook most dishes (OR = 3.79, 95% CI = 2.87, 5.01), were significantly associated with exclusive LPG use. Socio-economic status (higher education) and household wealth (higher income) were also associated with a greater likelihood of LPG adoption. Effective strategies to raise awareness around safe use of LPG and interventions to address financial barriers are needed to scale wider adoption and sustained use of LPG for clean cooking, displacing reliance on polluting solid fuels.

Questionnaires for Lung Health in Africa across the Life Course.

Respiratory infections remain a leading cause of morbidity and mortality in many low and middle-income countries but non-communicable disease rates are rising fast. Prevalence studies have been primarily symptom-focused, with tools developed in countries in the Global North such as the United States and the United Kingdom. Systematic study in sub-Saharan African populations is necessary to accurately reflect disease risk factors present in these populations. We present tools for such studies, developed as part of the International Multidisciplinary Programme to Address Lung Health and TB in Africa ('IMPALA'), which includes lay representatives. At a preliminary meeting, the adequacy and suitability of existing tools was discussed and a new questionnaire set proposed. Individual questionnaires were developed, and an expert panel considered content and criterion validity. Questionnaires underwent a cross-cultural adaptation process, incorporating translation and contextual 'sense-checking', through the use of pre-established lay focus groups in Malawi, before consensus-approval by project collaborators. The complete set of research questionnaires, providing information on lung health symptoms and a relevant range of potential risk factors for lung disease, is now available online. In developing the tools, cultural and contextual insights were important, as were translational considerations. The process benefitted from a foundation in expert knowledge, starting with validated tools and internationally respected research groups, and from a coordinated collaborative approach. We present and discuss a newly devised, contextually appropriate set of questionnaires for non-communicable lung disease research in Africa that are now available in open access for all to use.

Post-tuberculous lung function impairment in a tuberculosis reference clinic in Cameroon.

BACKGROUND: After completion of treatment, a proportion of pulmonary TB (pTB) patients experience lung function impairment which can influence their quality of life. This study aimed to determine the prevalence of lung function impairment in patients treated for pTB and investigate its associated factors. METHODS: A cross-sectional study was conducted in TB clinic of the Douala Laquintinie Hospital in Cameroon. Patients aged 15 and above who were treated for pTB between 2008 and 2012 were included in the study. Demographic data, respiratory symptoms prior TB diagnosis, comorbidities and chest radiography findings prior to TB treatment were collected. All participants underwent spirometric measurements. Airflow obstruction was defined as a post-bronchodilation FEV1/FVC <70% with FVC >80%, restrictive defects as an FEV1/FVC ratio of ≥70% with an FVC <80% predicted, and mixed defects as FVC of <80% predicted and an FEV1/FVC ratio of <70%. Lung function impairment was defined by the presence of at least one of these three abnormalities. Logistic regression analysis was employed to investigate risk factors of lung function impairment. RESULTS: Of a total of 269 participants included in the study, 146 (54.3%) were male. The median age of participants was 33 years. The median duration of symptoms before diagnosis of TB was 4 weeks [interquartile range (IQR) 3-8]. The prevalence of lung function impairment was 45.4% (95% CI 39-51). The multivariate analysis identified duration of symptoms [OR 1.08; 95% CI (1.01-1.15)] and fibrotic pattern [OR 3.54; 95% CI (1.40-8.95)] as independent risk factors for lung function impairment. CONCLUSION: Post-tuberculous pulmonary function impairment is frequent in Douala. Sensitization of patient with symptoms of pulmonary TB for an earlier visit to healthcare facilities could reduce the impact of pTB on lung function of patients.

Sensitization to common aeroallergens in a population of young adults in a sub-Saharan Africa setting: a cross-sectional study.

BACKGROUND: Sensitization to aeroallergens increases the risk of developing asthma or allergic rhinitis. Data on sensitization to airborne allergens in the general population in sub-Saharan Africa are lacking. The aim of this study was to determine the prevalence and determinants of sensitization to common aeroallergens in a population of young adults. METHODS: A cross-sectional study was conducted among students of the Faculty of Medicine and Pharmaceutical Sciences of the University of Douala between 1st February and 30th April 2014. We consecutively recruited all the students present in class or in hospital during our visit. They filled an anonymous questionnaire and underwent skin prick tests with common aeroallergens. A logistic regression model of the SPSS.20 software was used to investigate factors associated with sensitization to common aeroallergens. RESULTS: Of the 600 students included in the study, 305 (50.8 %) were female. The mean age of participants was 22.6 ± 2.7 years. The prevalence of sensitization to aeroallergens was 42.8 % (95 % CI 38.8-46.8). Dermatophagoides pteronyssimus (24.2 %), Dermatophagoides farinae (22.8 %), Blomia tropicalis (23.3 %) and Blatella germanica (15.2 %) were the most common allergens found. Allergic rhinitis, asthma symptoms and family atopy were independently associated to sensitization to common aeroallergens. CONCLUSION: A significant proportion of young adults are sensitized to common aeroallergens. Dust mites and cockroach should be included in the panel of aeroallergens in Cameroon.

Prevalence and determinants of cigarette smoking among college students: a cross-sectional study in Douala, Cameroon.

BACKGROUND: Tobacco is the most important avoidable risk for non communicable diseases. While tobacco consumption is stable or declining in developed countries, it is increasing in the developing world with a rate of 3.4 % per annum. The objective of this study was to estimate the prevalence and factors associated with cigarette smoking among college students. METHODS: A cross-sectional study was conducted from December 2012 to April 2013 in secondary schools in Douala, Cameroon. A self-administered questionnaire was used to collect sociodemographic data, smoking behavior and peer smoking among college students. Logistic regression analyses was employed to identify factors associated with cigarette smoking. RESULTS: Of a total of 2623 students included, 1579 (60.2 %) were female. The mean age of participants was 19.2 ± 2.53 years. The prevalence of current smoking was 11.2 % [95 % confidence interval (CI) 10 - 12], with 20 % in males and 5.3 % in females. Cigarette smoking was with significantly associated with friends smoking [Odds ratio (OR) 6.66; 95 % CI 4.69 - 9.45)], male gender (OR 3.61; 95 % CI 2.52 - 5.16), increase in age (OR 1.10; 1.03 - 1.17), parental smoking 1.69 (1.04 - 2.76), and attending general education (OR 1.85; 1.23 - 2.78). CONCLUSIONS: Cigarette smoking constitutes a significant health hazard in college students in Douala. Youth population and especially male students should be continuously targeted by preventive measures and sensitization campaigns against tobacco use. Parents should be aware on the influence of their smoking behavior on initiation of smoking in their children and should be encouraged to quit smoking.

Prevalence and determinants of excessive daytime sleepiness in hypertensive patients: a cross-sectional study in Douala, Cameroon.

OBJECTIVE: To determine the prevalence and determinants of excessive daytime sleepiness (EDS) among a group of sub-Saharan Africans living with hypertension. DESIGN: A cross-sectional study. SETTING: Cardiology outpatient unit of the Douala General Hospital in Cameroon. PARTICIPANTS: Patients aged 15 years and over, being followed for hypertension between 1st January and 31st July 2013. Patients with unstable heart failure, stroke and head trauma were excluded. MAIN OUTCOME MEASURE: EDS was the outcome of interest. It was defined as an Epworth sleeping scale greater or equal to 10. Logistic regression was used to identify factors associated with EDS. RESULTS: A total of 411 patients participated in this study, with a sex ratio (male/female) of 0.58 and a mean age of 55.56 years. No patient was underweight and the mean body mass index was 30 kg/m(2). Controlled blood pressure was found in 92 (22.4%) patients. The prevalence of EDS was 62.78% (95% CI 58.08 to 67.47). The factors independently associated with EDS were: type 2 diabetes (OR 2.51; 95% CI 1 to 6.29), obesity (OR 2.75; 95% CI 1.52 to 4.97), snoring (OR 7.92; 95% CI 4.43 to 14.15) and uncontrolled blood pressure (OR 4.34; 95% CI 2.24 to 8.40). CONCLUSIONS: A significant proportion of hypertensive patients suffer from EDS and present a high risk of sleep apnoea. Preventive measures targeted on weight loss, type 2 diabetes and snoring should be considered among these patients.

Sensitization to workplace respiratory allergens among bakery workers in Douala, Cameroon: a cross-sectional study.

BACKGROUND: Sensitization to flour or fungal alpha-amylase is a prerequisite for the development of respiratory allergy in bakers. The knowledge of occupational allergen sensitization among bakery workers will facilitate the implementation of preventive measures for respiratory allergies in bakeries. The objective of this study was to determine the prevalence and factors associated with sensitization to wheat flour and α-amylase in bakers in Douala. METHODS: A cross-sectional study was conducted in 42 of the 151 bakeries that are present in the city of Douala. Demographics, clinical data, as well as results of skin prick tests to wheat flour, α-amylase and common aeroallergens were collected from all participants. A logistic regression model of the SPSS.20 software was used to identify factors associated with sensitization to wheat flour and α-amylase. RESULTS: Of the 229 participants included in the study, 222 (96.9%) were male. The mean age was 36.3 ± 8.9 years. The prevalence of sensitization to flour and α-amylase were 16.6% and 8.3% respectively. After multivariate analysis, factors associated with sensitization to flour were work seniority and sensitization to storage mites while an age of 30 years and above was the only factor associated with sensitization to α-amylase. CONCLUSION: Bakers in Douala are at risk of sensitization to occupational allergens. The environmental hygiene in bakeries, health surveillance and the use of personal protective equipment could reduce the risk of respiratory allergies among bakers.

Effects of cooking fuel smoke on respiratory symptoms and lung function in semi-rural women in Cameroon.

BACKGROUND: Indoor air pollution is a major health problem in the developing world. In sub-Saharan Africa more than 90% of people rely on biomass to meet their domestic energy demands. Pollution from biomass fuel ranks 10th among preventable risk factors contributing to the global burden of diseases. OBJECTIVES: The present study aimed to determine the prevalence of respiratory symptoms and the factors associated with reduced lung function in a population of women exposed to cooking fuel smoke. METHODS: A cross-sectional study was conducted in a semi-rural area in Cameroon. We compared forced respiratory volume between women using wood (n = 145) and women using alternative sources of energy (n = 155) for cooking. RESULTS: Chronic bronchitis was found in 7·6% of the wood smoke group and 0·6% in the alternative fuels group. We observed two cases of airflow obstruction in the wood smoke group. Factors associated with lung function impairment were chronic bronchitis, use of wood as cooking fuel, age, and height. CONCLUSION: Respiratory symptoms and reduced lung function are more pronounced among women using wood as cooking fuel. Improved stoves technology should be developed to reduce the effects of wood smoke on respiratory health.

Prevalence and risk factors for allergic rhinitis in bakers in Douala, Cameroon.

OBJECTIVE: To determine the prevalence and risk factors of allergic rhinitis among bakers in Douala. DESIGN: A cross-sectional study; the logistic regression model was use to find the risk factors of allergic rhinitis. SETTING: The study was conducted in 42 bakeries randomly selected among a total of 151 bakeries in the city of Douala. PARTICIPANTS: All bakers who consented to participate in the study between 1 May and 31 July 2013. OUTCOME MEASURES: Allergic rhinitis was the outcome of interest. It was defined as the presence of the following symptoms: itchy nose, rhinorrhea, nasal obstruction and sneezing. RESULTS: During the study period, a total of 273 bakers were invited and 229 finally agreed to participate in this study. Males were the most represented gender with 222 (96.9%) participants. The mean age of the participants was 36.29±8.9 years. Smoking was found in 55 participants (24.5%). The symptoms of allergic rhinitis were observed in 24.5% of participants. Work related nasal symptoms were present in 15% of participants. Sensitisation to wheat flour and α-amylase was found in 16.6% and 8.3% of participants, respectively. The Prick test was positive for mites in 12.2% of participants. After multivariate analysis, sensitisation to flour (OR 3.95, 95% CI 1.85 to 8.47) and storage mites (OR 3.44, 95% CI 1.45 to 8.18) were the factors independently associated with symptoms of allergic rhinitis. CONCLUSIONS: Allergic rhinitis is frequent among bakers in Cameroon. Implementation of preventive measures against inhalation of airborne allergens in bakeries and clinical monitoring of bakers sensitised to wheat flour and mites could help to reduce the prevalence of allergic rhinitis among bakers.