Differences In Asthma Prevalence Research Articles

Impact of pollution and place of residence on atopic diseases among schoolchildren in Telemark County, Norway.

For estimation of the prevalence, degree of severity, and association with outdoor pollution, a questionnaire on asthma and other atopic diseases was distributed to the parents of 4666 7-13-year-olds, comprising all the children in 36 schools in Telemark County, Norway, including 37% of the schoolchildren in the county. The response rate was 94%. In a validity study employing clinical evaluations, the questionnaire-based diagnosis of asthma was found to have a sensitivity of 0.96 and a specificity of 0.88. The lifetime prevalence of asthma in Telemark was 9% (boys 11.3%, girls 6.6%; p < 0.001). There was no significant difference in the lifetime prevalence of asthma by pollution zone; 8.3% in heavily, 9.3% in moderately, and 9.2% in minimally polluted zones. The asthma prevalence was significantly higher (14.2%; p < 0.05) among boys in the coastal area of the county than in the mountainous area (8.9%). Both of these areas were in the minimal pollution zone. Of asthma cases, 67% were categorized as mild, 29% as moderate, and 4% as severe. The lifetime prevalence was 17.8% (boys 21.3%, girls 14.2%; p < 0.001) for allergic rhinitis, 13.2% (boys 11.4%, girls 15.2%; p < 0.001) for atopic eczema, and 29.6% (boys 31.7%, girls 27.4%; p < 0.01) for overall atopic disease (asthma, allergic rhinitis, eczema). These findings are not compatible with the hypothesis that outdoor pollution is associated with the lifetime prevalence of asthma in school-age children. The results also show that less than 0.5% of schoolchildren suffer from severe asthma.

No Association Found BetweenStrongyloidesInfestation and Asthma

It has been postulated that infestation with Strongyloides stercoralis is associated with asthma. We conducted a case-control study to determine whether the presence of parasites is associated with asthma. We undertook a retrospective analysis of 15,856 stool specimens received by our Parasitology Laboratory from January 1989 to December 1992. The diagnosis of asthma was secured by a chart review or a review of the computer diagnosis coding system. An association between asthma and Strongyloides was tested by calculating an odds ratio, as well as a Fisher's Exact Test to estimate the strength of the relationship. We also prospectively collected stool specimens for Strongyloides in asthmatics hospitalized for acute exacerbations of asthma from January 1992 to January 1993. Of 60 subjects with evidence of Strongyloides in a stool specimen, 6 were asthmatic. Of 203 stool-negative controls matched for age, sex, and ethnicity, 13 were asthmatic (odds ratio, 1:62; 95% confidence interval, 0.6-4.4; Fisher's Exact two-tailed, p = 0.39). Of 443 subjects admitted for acute exacerbations of asthma, stool specimens were analyzed for the presence of Strongyloides from 161, of which two were parasitized. These data suggest no statistically significant difference in prevalence of asthma among patients with Strongyloides infestation compared to those without parasitic infection. These results do not support the hypothesis that there is an association, either causal or protective, between Strongyloides infestation and asthma.

Environmental factors may explain differences in asthma prevalence

Environmental factors may explain differences in asthma prevalence

Racial inequalities in childhood asthma

Mortality and hospital admission rates for asthma are higher in Maoris and Pacific Islander children than in European children. These ethnic differences are not explained by ethnic differences in asthma prevalence, the characteristics of the disease or admission criteria. There are major ethnic differences in asthma drug management both in the community and at the time of discharge from hospital. In particular Polynesians were less likely to receive prophylactic therapy and this factor probably accounts for ethnic differences in mortality and admission rates. Possible explanations for the ethnic differences in medical management are discussed.

Ethnic differences in prevalence of asthma symptoms and bronchial hyperresponsiveness in New Zealand schoolchildren.

Maoris and Pacific Islanders in New Zealand have a higher asthma mortality and hospital admission rates than Europeans. To determine whether difference in asthma prevalence is the major factor underlying these differences in mortality, 2053 Auckland children aged 7-10 years (European 1084, Maori 509, Pacific Islander 460) were randomly sampled from school classes in the Auckland Urban Area, and studied by questionnaire (completed by parents) and histamine inhalation challenge to assess the provocative dose of histamine causing a 20% fall in FEV1 (PD20). Maoris had the highest prevalence rates of respiratory symptoms, and Europeans had rates similar to Pacific Islanders. For "any current wheeze" for example, the prevalence in Maoris was 22.2% compared with 16.1% and 16.3% in the Europeans and Pacific Islanders. The prevalence of diagnosed asthma was similar in the three groups. When bronchial hyperresponsiveness (defined as a PD20 less than or equal to 7.8 mumol histamine) was considered, Europeans had the highest rates (20%), followed by Maoris (13%), and then Pacific Islanders (8.7%). These differences were not accounted for by differences in socioeconomic status, rates of smoking in the home, age, gender, or height. It is concluded that differences in asthma prevalence do not satisfactorily explain the mortality and admission rate differences, although the higher symptom prevalence in the Maoris could be relevant to the higher mortality rate. Maori and Pacific Island children with symptoms of asthma were less likely to be taking prophylactic medication than European children. It is proposed that differences in management are important factors relevant to the increased mortality and morbidity from asthma in Polynesians.

Worldwide Differences in Asthma Prevalence and Mortality: Why is Asthma Mortality So Low in the USA?

Investigation of the differences in the drug treatment of asthma have little meaning unless the results can be related to differences in the prevalence, severity and mortality of the illness. Mortality figures for asthma are available for only some populations and, even if reliable, give little insight into the cause of death. Even less is known about the differences in prevalence and severity of the disease between populations. This article describes the prevalence of asthma and the mortality from asthma in some selected populations and discusses the possible reasons for the observed differences, Methods for obtaining more information about the prevalence of asthma, for documenting its severity and for identifying those at risk from death are suggested. Although asthma is defined as reversible narrowing of the airways, patients with severe disease frequently develop irreversible and progressive reduction in air-