Prevalence of asthma in Rhodesian Africans

Prevalence and determinants of current asthma in Cameroon

INTRODUCTION

The prevalence of asthma varies from one country to another due to differences in ethnicity, socio-economics status, environmental and climatic risk factors. The aim of this study was to determine the prevalence and determinants of current asthma in Cameroonian adults.

MATERIAL AND METHODS

Data from 4 cross-sectional community-based studies from 2014 to 2018 were analyzed. Participants aged 19 years and above were selected through multilevel stratified random sampling methods across 2 urban areas, 2 semi-urban areas and 1 rural area. Current asthma was defined as "wheezing in the last 12 months in a subject with self-reported asthma or having used drugs for asthma treatment". Logistic regression was used to investigate the determinants of current asthma.

RESULTS

A total of 10,707 adults [median age (interquartile range)=36 (26-52) years, 44.5% of men] were definitively enrolled in the study. The overall prevalence [95% confidence interval (CI)] of current asthma was 3.9% (3.5-4.3)%. Determinants [odd's ratio (OR), (95%CI)] of current asthma were: Sudanese ethnicity [1.9(1.4-2.7)], rural area [1.5(1.1-2.1)], urban area [1.6(1.2-2.2)], past history of pneumonia [1.9(1.1-3.4)], allergic rhino-conjunctivitis [6.5(4.7-8.9)], atopic eczema [2.3(1.5-3.6)], body mass index (BMI)≥40kg/m² [1.9(1.0-3.4)] and BMI<18kg/m² [1.8(1.2-2.9)].

CONCLUSION

The prevalence of current asthma is close to the low value of the Sub-Saharan African range. Sudanese ethnicity, rural area, urban area, history of pneumonia, allergic disease, severe obesity and underweight were determinants of current asthma in Cameroon. More research is surely warranted to understand the mechanisms underlying the association of asthma with Sudanese ethnicity.

Socio-epidemiological Aspects of Respiratory Allergic Diseases in Southern Africa

The prevalence of respiratory allergic diseases has been increasing in Southern Africa both in urban and in rural environments. Various factors may contribute toward this situation, namely, exposure to aeroallergens, such as grass pollens and house dust mites. However, other irritant environmental triggers, such as exposure to tobacco smoke and certain indoor and outdoor fumes, may also play a relevant part. Furthermore, certain parasitic and mycobacterial infections may act as allergic disease risk modifiers, although such an influence should be confirmed. Finally, certain cultural and socioeconomic factors may also influence accessibility to healthcare and adherence to treatment of these diseases.

Prevalence of symptoms of asthma, rhinitis and eczema in 13- to 14-year-old children in Africa: the International Study of Asthma and Allergies in Childhood Phase III

Phase I of the International Study of Asthma and Allergies in Childhood has provided valuable information regarding international prevalence patterns and potential risk factors in the development of asthma, allergic rhinoconjunctivitis and eczema. However, in Phase I, only six African countries were involved (Algeria, Tunisia, Morocco, Kenya, South Africa and Ethiopia). Phase III, conducted 5-6 years later, enrolled 22 centres in 16 countries including the majority of the centres involved in Phase I and new centres in Morocco, Tunisia, Democratic Republic of Congo, Togo, Sudan, Cameroon, Gabon, Reunion Island and South Africa. There were considerable variations between the various centres of Africa in the prevalence of the main symptoms of the three conditions: wheeze (4.0-21.5%), allergic rhinoconjunctivitis (7.2-27.3%) and eczema (4.7-23.0%). There was a large variation both between countries and between centres in the same country. Several centres, including Cape Town (20.3%), Polokwane (18.0%), Reunion Island (21.5%), Brazzaville (19.9%), Nairobi (18.0%), Urban Ivory Coast (19.3%) and Conakry (18.6%) showed relatively high asthma symptom prevalences, similar to those in western Europe. There were also a number of centres showing high symptom prevalences for allergic rhinoconjunctivitis (Cape Town, Reunion Island, Brazzaville, Eldoret, Urban Ivory Coast, Conakry, Casablanca, Wilays of Algiers, Sousse and Eldoret) and eczema (Brazzaville, Eldoret, Addis Ababa, Urban Ivory Coast, Conakry, Marrakech and Casablanca).

International union against tuberculosis and lung disease (IUATLD): initiatives in non-tuberculous lung disease

IUATLD initiatives in non-tuberculous lung disease developed in the late 1970s, coincident with improving tuberculosis control, and have targeted acute respiratory infections in children and chronic airways disease in adults and in children. The focus has been on methodology and the tools required to document the distribution and determinants of disease, and is illustrated in data gathered in African populations. Instruments developed include a simplified method of measuring bronchial hyper-reactivity and an asthma questionnaire Non-standard methods of questionnaire administration have also been validated, methods which are appropriate for use in the burgeoning urban communities and workforces of sub-Saharan Africa made up of rural migrants from different tribes and language groups. In addition, a review of reference values available for interpreting lung function in sub-Saharan African populations indicates a need to take into account a secular trend over the last two decades towards higher spirometric values. In the published data from Africa, not inconsiderable between-country differences are evident in the prevalence of chronic bronchitis in adults and of asthma in children. In addition, rates for childhood asthma were consistently higher in urban vs rural communities, with environmental factors playing an important role as well as being locally specific. Not only does the burden of morbidity attributable to both the chronic airway diseases reviewed justify past IUATLD initiatives in non-tuberculous lung disease, but it also argues that future initiatives should focus on investigating between- and within-country differences using a standardized methodology, with a view to identifying local environmental determinants susceptible to intervention and control. Curbing tobacco use is clearly important, not only to benefit the health of adult smokers for whom the ill-health consequences have long been recognized, but, and more important, to protect the health of children, born and unborn, with whom they share the environment.

Prevalence of asthma among Emirates school children

The aim of this study was to determine the prevalence of asthma among United Arab Emirates school children aged 6-14 years. A cross-sectional study of 850 school children living in both urban and rural areas (average age 9.36 +/- 2.11 years, 46.8% boys and 53.2% girls) was conducted using self-administered questionnaires between October 1992 and May 1993. The population sample had a high prevalence rate of diagnosed asthma (13.6%), breathlessness or tightness in chest (9.7%), allergic rhinitis (22.9%), and nocturnal cough (8.9%). Allergic rhinitis was the most frequently seen respiratory illness when compared to other respiratory symptoms. The frequency of asthma, allergic rhinitis and eczema among parents reflected the same pattern as that seen in the children. Prevalence rate of asthma was not significantly higher in fathers (5.9%) than in mothers (5.3%). The differences between the sexes were not significant in any of the age group studied for any of the allergic conditions, except for diagnosed asthma in which the prevalence rate in males was significantly higher than that in females. On the whole, the prevalence rate of all the conditions increased with age. But the frequency of allergic rhinitis symptoms was significantly higher in mothers (16%) than in fathers (10.8%). These results are consistent with those obtained in neighbouring gulf countries and are higher than those of some developed countries, but the differences are not statistically significant.

Prevalence of asthma and risk factors among Chinese, Malay, and Indian adults in Singapore

BACKGROUND

The prevalence and morbidity of asthma vary greatly among different ethnic communities and geographical locations, but the roles of environmental and genetic factors are not fully understood. The differences in prevalence of adult asthma among Chinese, Malay, and Indian ethnic groups in Singapore were examined, and the extent to which these could be explained by personal and environmental factors were investigated.

METHODS

A stratified disproportionate random sample (n = 2868) of Chinese (n = 1018), Malays (n = 967), and Indians (n = 883) of both sexes was drawn from households in five public housing estates, and an interviewer administered questionnaire was used to determine cumulative and current prevalence of "physician diagnosed asthma" (symptoms with a physician diagnosis of asthma).

RESULTS

Lifetime cumulative prevalence (standardised to the general population) of "physician diagnosed asthma" was 4.7% in men and 4.3% in women; 12 month period prevalences were 2.4% and 2.0%, respectively. Cumulative prevalence of asthma was significantly higher in Indians (6.6%) and Malays (6.0%) than in Chinese (3.0%); period prevalences of asthma were 4.5% in Indians, 3.3% in Malays, and 0.9% in Chinese. Ownership of cats or dogs was more frequent in Malays (15.4%) and Indians (11.2%) than in Chinese (8.8%). Rugs and carpets were also more frequently used by Malays (52.2%) and Indians (40.7%) than by Chinese (8.9%). Current smoking prevalences were higher in Malays (27.3%) than in Indians (19.4%) and Chinese (23.0%). Malays and Indians did not have higher rates of atopy (11.1% and 15.2%, respectively) than Chinese (15.4%). Adjustment for these factors in multivariate analyses reduced the greater odds of asthma in Malays and Indians, but not to a significant extent.

CONCLUSIONS

There are ethnic differences in the prevalence of asthma in Singapore which are not entirely explained by differences in smoking, atopy, or other risk factors. Other unmeasured environmental factors or genetic influences are likely to account for residual differences in the prevalence of asthma.

Asthma patterns in Saudi Arabian children

In a study of 2006 school children living in two urban areas of the Kingdom of Saudi Arabia, we used a questionnaire to collect details of age, sex, areas of residence, occupation, education, social class, parental history of asthma and information relating to parental smoking habit. The relative importance of these factors on the likelihood of children having bronchial asthma was assessed using a linear modelling analysis. The extent to which these factors affected the severity of bronchial asthma was also examined. A number of statistically significant associations between bronchial asthma and 'breathlessness' (P less than 0.0087), 'Father smoker' (P less than 0.0001), 'usually cough' (P less than 0.0001), 'pets' (P less than 0.0067) and 'Family history of allergy' (P less than 0.007), were found.

Prevalence rates of asthma in developing countries and their comparison with those in Europe and North America

Prevalence rates for asthma in various parts of the world are different and this cannot be entirely explained by differences in methodology. Low prevalence rates are found in third world countries, particularly marked for children. The reasons for these differences are obscure but are largely environmental. Some suggestions are made herein about their nature.