MCP-1-2518 (A>G) polymorphism and asthma risk: a pilot case-control study in Cameroon.

Introduction: there is little data on the genetic determinants of asthma in Cameroon and sub-Saharan Africa, yet the involvement of genetics in the pathogenesis of this disease has been reported in the literature for several years. This study aims to investigate the possible role of MCP-1 2518 for the risk of asthma in Cameroonians. Methods: we performed a case-control study on 30 volunteers suffering from asthma, matched by aged and sex to 30 healthy subjects. We determine the polymorphism of MCP-1 2518 using restriction fragment length polymorphism following Polymerase Chain Reaction (RFLP-PCR). Fisher exact test was used to compare proportions, with a threshold of significance set at 0.05. Results: the average age of cases was 21±10 years with 17 (56.7%) females. The distribution of the MCP-1-2518 (A>G) gene polymorphism in people with asthma was as follows: 3 for AA, 5 for GG, and 22 for AG. The minor G allele was predominant (90%) in people with asthma. It was significantly associated with asthma whether the genotype was heterozygous AG or homozygous GG (p<0.01). Conclusion: MCP-1-2518 (A>G) shows an association with asthma in our sample. Future larger studies evaluating several polymorphisms are needed to describe the genetic determinants of asthma in Cameroon and sub-Saharan Africa.

Evaluation of factors affecting adherence to asthma controller therapy in chest clinics in a sub-Saharan African setting: a cross-sectional study.

BACKGROUND: Adherence to controller therapy in asthma is a major concern during the management of the disease. OBJECTIVE: To determine the adherence rate and identify the predictors of low adherence to asthma controller therapy. METHODS: A cross-sectional study including asthma patients was conducted from November 1, 2012 to May 31, 2013 in 4 chest clinics in Cameroon. The adherence to asthma treatment was rated using Morisky Medication Adherence Scale. A multivariate logistic regression analysis was performed for the identification of factors associated with adherence to asthma treatment. RESULTS: Among the 201 asthma patients included, 133 (66.2%) were female. The mean age of participants was 41.2 years. Sixty-one (30.3%) of the patients did not visit the chest physician during the last year prior to the study. Asthma was well controlled in 118 patients (58.7%). The prevalence of low adherence rate to asthma controller therapy was 44.8% and the absence of any chest specialist visit within the last 12 months was the only factor associated with the low adherence rate to asthma treatment (OR 5.57 ; 95% CI 2.84-10.93). CONCLUSION: The adherence rate to asthma controller therapy in Cameroon is low and it could be improved if scheduled visits are respected by patients.

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 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.

Prevalence of asthma and allergic rhinitis among adults in Yaounde, Cameroon.

BACKGROUND: Population-based estimates of asthma and allergic rhinitis in sub-Saharan African adults are lacking. We assessed the prevalence and determinants of asthma and allergic rhinitis in urban adult Cameroonians. METHODS: A community-based survey was conducted from December 2013 to April 2014 among adults aged 19 years and above (N = 2,304, 57.3% women), selected through multilevel stratified random sampling across all districts of Yaounde (Capital city). Internationally validated questionnaires were used to investigate the presence of allergic diseases. Logistic regressions were employed to investigate the determinants of allergic conditions. RESULTS: Prevalence rates were 2.7% (95% CI: 2.1-3.4) for asthma-ever, 6.9% (5.9-7.9) for lifetime wheezing, 2.9% (92.2-3.6) for current wheezing and 11.4% (10.1-12.7) for self-reported lifetime allergic rhinitis; while 240 (10.4%) participants reported current symptoms of allergic rhinitis, and 125 (5.4%) had allergic rhino-conjunctivitis. The prevalence of current asthma medication use and self-reported asthma attack was 0.8 (0.4-1.2) and 1 (0.6-1.4) respectively. Multivariable adjusted determinants of current wheezing were signs of atopic eczema [2.91 (1.09-7.74)] and signs of allergic rhinitis [3.24 (1.83-5.71)]. Age group 31-40 years [0.27(0.09-0.78), p = 0.016] was an independent protective factor for wheezing. Determinants of current rhinitis symptoms were active smoking [2.20 (1.37-3.54), p<0.001], signs of atopic eczema [2.84 (1.48-5.46)] and current wheezing [3.02 (1.70-5.39)]. CONCLUSION: Prevalence rates for asthma and allergic rhinitis among adults in this population were at the lower tails of those reported in other regions of the world. Beside the classical interrelation between allergic diseases found in this study, active smoking was an independent determinant of allergic rhinitis symptoms. Nationwide surveys are needed to investigate regional variations.

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.

Sensitisation to Blattella germanica among adults with asthma in Yaounde, Cameroon: a cross-sectional study.

BACKGROUND: German cockroach or Blattella germanica is commonly found in homes across the inter-tropical region. The contribution of sensitisation to Blattella germanica in people with asthma in sub-Saharan Africa has not received attention. The aim of this study was to assess the prevalence and investigate the predicting factors of sensitisation to Blattella germanica in patients with asthma in Yaounde, Cameroon. METHODS: This was a cross-sectional study conducted between January 2012 and June 2013. All patients (aged 15 years and above) with asthma, receiving care at the Yaounde Jamot Hospital and the CEDIMER medical practice during the study period and who had received a prick skin testing for perennial aeroallergens were included in the study. RESULTS: The final sample comprised 184 patients including 123 (66.8%) women. The median age (25th-75th percentiles) was 38 (24-54) years. Prick skin test for Blattella germanica was positive in 47 (25.5%) patients. Sensitisation to Blattella germanica was associated with a sensitisation to mite in 41 (87.2%) patients, a sensitisation to Alternaria in 18 (38.3%) patients, and a sensitisation to cat or dog dander in 7 (14.9%) patients. Independent predicting factors of a sensitisation to Blattella germanica were the sensitisation to Blomia tropicalis [adjusted odd ratio (95% confidence interval) 4.10 (1.67-10.04), p = 0.002] and sensitisation to Alternaria [3.67 (1.53-7.46), p = 0.003]. CONCLUSIONS: Sensitisation to Blattella germanica is present in about a quarter of adult patients with asthma in Yaounde. Sensitisation to Alternaria and Blomia tropicalis appears to be a powerful predicting factor of sensitisation to Blattella germanica in this setting.

Clinical significance of low forced expiratory flow between 25% and 75% of vital capacity following treated pulmonary tuberculosis: a cross-sectional study.

OBJECTIVES: The aim of this study was to assess the prevalence and determinants of post-tuberculosis chronic respiratory signs, as well as the clinical impact of a low forced expiratory flow between 25% and 75% (FEF25-75%) in a group of individuals previously treated successfully for pulmonary tuberculosis. DESIGN: This was a cross-sectional study involving individuals in their post-tuberculosis treatment period. They all underwent a spirometry following the 2005 criteria of the American Thoracic Society/European Respiratory Society. Distal airflow obstruction (DAO) was defined by an FEF25-75% <65% and a ratio forced expiratory volume during the first second (FEV1)/forced vital capacity (FVC) ≥ 0.70. Logistic regression models were used to investigate the determinants of persisting respiratory symptoms following antituberculous treatment. SETTING: This study was carried out in the tuberculosis diagnosis and treatment centre at Yaounde Jamot Hospital, which serves as a referral centre for tuberculosis and respiratory diseases for the capital city of Cameroon (Yaounde) and surrounding areas. PARTICIPANTS: All consecutive patients in their post-tuberculosis treatment period were consecutively enrolled between November 2012 and April 2013. RESULTS: Of the 177 patients included, 101 (57.1%) were men, whose median age (25th-75th centiles) was 32 (24-45.5) years. At least one chronic respiratory sign was present in 110 (62.1%) participants and DAO was found in 67 (62.9%). Independent determinants of persisting respiratory signs were the duration of symptoms prior to tuberculosis diagnosis higher than 12 weeks (adjusted OR 2.91; 95% CI 1.12 to 7.60, p=0.029) and presence of DAO (2.22; 1.13 to 4.38, p=0.021). CONCLUSIONS: FEF25-75%<65% is useful for the assessment and diagnosis of post-tuberculous DAO. Mass education targeting early diagnosis of pulmonary tuberculosis can potentially reduce the prevalence of post-tuberculosis respiratory signs and distal airflow obstruction.

Protease mutations in HIV-1 non-B strains infecting drug-naive villagers in Cameroon.

To describe the presence of protease inhibitor (PI) resistance-associated mutations and subtype distribution in drug-naive villagers of six provinces of Cameroon, we sequenced the protease (PR) gene (297 bp) of 128 viruses. Secondary PI resistance-associated mutations were identified at five sites: L10I/V (16%), K20R (8%), M36I (98%), L63P (13%), and V77I (6%). No primary mutation in the PR was identified. Of the 128 specimens analyzed, subtypes A (11%), C(2%), D (6%), F2 (3%), G (6%), H (0.8%), J (6%), and CRF02_AG (60%) were identified. The mutations identified were not characteristic to any particular subtype. The absence of primary mutations, in addition to the few secondary mutations, gives good perspectives for PI treatment interventions in these rural areas.