Prevalence of obstructive lung disease in an African country using definitions from different international guidelines: a community based cross-sectional survey.

BACKGROUND: Obstructive lung disease (OLD), a major global public health problem, has been less investigated in African countries. We assessed the prevalence and determinants of OLD in Yaounde (the capital city of Cameroon), using internationally agreed definitions. METHODS: Participants were adults (age >19 years) screened during a community-based survey between December 2013 and April 2014. Air flow limitation (AFL) was based on a pre-bronchodilator forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) below the lower limit of normal (LLN, AFL-LLN). Chronic obstructive pulmonary disease (COPD) was based on post-bronchodilator FEV1/FVC ratio < LLN (COPD-LLN). RESULTS: Of the 1287 subjects included, 51.9% were female, 9.3% were current smokers and their mean age was 34.4 ± 12.8 years. Forty-nine (3.8%, 95% CI 2.8-4.9%) participants had AFL-LLN. Thirty-one subjects had COPD-LLN; giving a prevalence of COPD-LLN of (2.4%, 95% CI 1.6-3.3%). In multivariable analysis, male gender (AOR 2.42; 95% CI 1.12-5.20) and lifetime wheezing (AOR 2.88; 95% CI 1.06-7.81) were the determinants of COPD-LLN. Otherwise, male sex (AOR 1.93, 95% CI 1.00-3.73), age 40-59 years (AOR 1.99, 95% CI 1.04-3.81) and lifetime wheezing (AOR 2.65, 95% CI 1.13-6.20) remained as independent determinants of AFL-LLN. CONCLUSIONS: Obstructive lung disease based on more accurate definitions was relatively infrequent in this population. It is important to sensitize the medical staff and the general public about this condition which should be actively investigated in individuals aged 40 years and above.

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.

Perennial aeroallergens sensitisation and risk of asthma in African children and adolescents: a case-control study.

OBJECTIVES: The distribution and impact of various aeroallergens on asthma occurrence vary across regions. We investigated the association between sensitisation to perennial aeroallergens and asthma risk in children and adolescents in Yaounde, Cameroon. METHODS: This was a case-control study involving children and adolescents with asthma (cases) vs. non-allergic counterparts (controls). Children/adolescents with doctor-diagnosed asthma were included over a period of 30 months, and controls were selected from the community through random sampling. Logistic regression models were used to relate perennial aeroallergens sensitisation with asthma. RESULTS: The asthma and control groups included, respectively, 151 and 372 participants, with no sex ratio difference. The mean age (standard deviation) was 11.9 (4.4) years in cases and 11.3 (3.7) years in controls. The prevalence of sensitisation to any aeroallergen (cases vs. controls) was 76.8% (116/151) and 32.3% (120/372), p < 0.001. Sensitisation to mites was found in 104 (68.9%) cases vs. 56 (15.1%) controls, p < 0.001. In multivariable analysis, sensitisation to Alternaria alternata, Blattella germanica and dander (cat and dog) was not associated with asthma. However, sensitisation to mites was significantly associated with asthma. Odds ratios (95% CI) for sensitisation to Dermatophagoides pteronyssinus, Dermatophagoides farinae and Blomia tropicalis in relation with asthma were 7.28 (3.75-14.15), 2.65 (1.27-5.45) and 3.23 (1.68-6.21), respectively. CONCLUSIONS: Sensitisation to mites was the main perennial allergenic factor associated with asthma in children and adolescents in this setting. This has application for the selection of patients with asthma who could benefit from the control of exposure to mites and specific immunotherapy.