Differences in respiratory symptoms and pulmonary function in children in 2 Saskatchewan communities

doi:10.1016/S1081-1206(10)61710-3

Annals of Allergy, Asthma & Immunology

Volume 92, Issue 1, January 2004, Pages 52-59

https://doi.org/10.1016/S1081-1206(10)61710-3 Get rights and content

Background

Asthma prevalence is known to vary among different geographical regions both nationally and internationally. However, there is limited understanding of the nature of differences within geographical regions.

Objective

To evaluate the prevalence of asthma in 2 prairie communities and differences in the patterns of respiratory symptoms between the communities.

Methods

A cross-sectional questionnaire survey was sent through schools in Estevan and Swift Current, Saskatchewan, to parents of 2,231 children in grades 1 to 6. Asthma prevalence was determined by questionnaire report of physician-diagnosed asthma. Pulmonary function tests (PFTs) using spirometry were conducted in children in grades 1 to 4. To evaluate respiratory morbidity without the use of a diagnostic label, similar comparisons were made between communities for respiratory symptoms.

Results

The overall response rate to the survey questionnaire was 91.3%. The prevalence ofever asthma in Estevan was 21.4% (95% confidence interval [CI], 20.1%–22.7%) compared with 16.2% (95% CI, 15.1%–17.3%) in Swift Current. A higher proportion of girls in Estevan (19.7%; 95% CI, 17.9%–21.5%) compared with girls in Swift Current (12.5%; 95% CI, 11.1%–13.9%) reported a history of asthma. There was no difference found between towns for boys. These findings were supported by findings for respiratory symptoms, including wheeze and cough. For both boys and girls, the forced expiratory flow at 25% to 75% of forced vital capacity and the ratio of forced expiratory volume in 1 second to forced vital capacity were lower in Estevan compared with Swift Current.

Conclusions

Differences in the distribution of childhood asthma can be found within regions. These results are strengthened by PFTs and cannot be fully explained by diagnostic biases.

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Citation Excerpt :
In Skopje, written consent was required for each completed survey to be included in the study. Surveys were based on standardized questionnaires including the ISAAC questionnaire [6], American Thoracic Society Children's Respiratory Disease questionnaire [17], and questionnaires used previously in Canadian lung studies [18–20]. Investigators from each location had some discretion on which questions to include in order to maximize practicality and issues of local importance.
There is variation in childhood asthma between countries with typically higher prevalence in “Westernized” nations. We compared asthma, respiratory symptoms, and medication prevalence in Eastern and Central European regions and Canada.
We conducted a cross-sectional survey study of children (5–15 years) from one urban centre in each of Canada, Belarus, Poland, Republic of Georgia (Adjara), Republic of Macedonia, and Ukraine. Surveys were distributed through randomly selected schools to parents (2013–2015).
The prevalence of asthma differed by country from 20.6% in Canada to 1.5% in Ukraine (p < 0.001). This association remained after confounder adjustment. Except for Canada (58.7%) and Poland (42.5%), less than 10% of children with a history of wheeze had a diagnosis of asthma. Regardless of country, more than 50% of children with a diagnosis of asthma used breathing medications in the past year. Finally, except for Georgia (12.1%), all countries had a prevalence of ever wheeze above 20% (23.8% in Poland to 30.9% in Macedonia).
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Citation Excerpt :
Surveys were distributed through schools to parents for self-completion. These surveys were based on standardized questionnaires, such as the International Study of Allergy and Asthma in Childhood (ISAAC) questionnaire,19 American Thoracic Society Children's Respiratory Disease questionnaire,20 and questionnaires used previously in other lung studies.21,22 Information was collected on lung and general health, indoor environment, health behaviors, and sociodemographics.
Because of time and cost constraints, objective classification of atopic and nonatopic asthma has been limited in large epidemiologic studies. However, as we try to better understand exposure-outcome associations and ensure appropriate treatment of asthma, it is important to focus on phenotype-defined asthma classification.
To compare atopic and nonatopic asthma in rural children with regard to risk factors and clinical outcomes.
We conducted a cross-sectional study in rural Saskatchewan, Canada, in 2011. Parents of 6- to 14-year-old children completed a health and exposure survey. Skin prick tests were completed in a subsample of 529 children. Asthma was based physician diagnosis. Asthma status was defined as no asthma, nonatopic asthma, and atopic asthma.
Asthma prevalence was 14.7% of which 32.1% of cases were atopic. After adjustment, early respiratory illness and a family history of asthma were predictors of childhood asthma, regardless of atopic status (P < .05). Being overweight and having a dog in the home were associated with an increased risk of nonatopic asthma (P < .05). A mother with a history of smoking increased the risk of atopic asthma (P = .01). Compared with those with nonatopic asthma, in the past 12 months, children with atopic asthma were more likely to report a sneezy, runny, or blocked nose or have shortness of breath (odds ratio >2), whereas those with nonatopic asthma were more likely to have parents who missed work (odd ratio >3). Those with nonatopic asthma had significantly lower forced expiratory volume in 1 second compared w2ith those with atopic asthma.
Exposures may contribute differentially to atopic and nonatopic asthma and result in differential clinical presentation or burden. The study of these characteristics is important for etiologic understanding and management decisions.
Prevalence and determinants of atopy and allergic diseases among school-age children in rural Saskatchewan, Canada
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There have been few investigations of farming-related activities or specific characteristics resulting in the associations between those exposures and atopic disease.
To study the associations between farm-associated exposures and atopic diseases.
As part of a longitudinal study of lung health in rural residents, a cross-sectional baseline study was conducted in rural Saskatchewan, Canada. This included an initial survey phase followed by a clinical testing phase. A subsample of 584 children (grades 1–8) completed skin prick testing to assess atopic status. Atopy was defined as a positive reaction to any of 6 allergens (local grasses, wheat dust, cat dander, house dust mite, Alternaria species, or Cladosporium species) of at least 3 mm compared with the negative control.
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In children, livestock exposure has a protective effect on skin prick test positivity, whereas farm living and activities increase the risk of hay fever.
Factors contributing to risks for pediatric asthma in rural Saskatchewan
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Citation Excerpt :
The 2003 study questionnaire included items describing demographics, current and previous asthma and asthma-like symptoms, related atopic diseases, other illnesses, home environments, lifestyle factors, and family factors. Asthma and wheeze were defined based on past operational definitions proposed by Rennie and colleagues,16 using data from the 2,000 Estevan study. These definitions were similar to those used in other epidemiological studies of childhood asthma16,19 and have shown relatively good agreement with other measures of lung health, including physician diagnosis, other questionnaires, and physiological measures.19
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School children (n = 842, ages 6–13; participation rate = 72.0%) were involved in a 2003 cross-sectional study. Their parents completed a lung health survey that included questions about asthma, asthma-like symptoms, and potential determinants of asthma (demographic, environmental, health risk behaviors). Participating children were classified into farm dwellers (live on farm or acreage) and small town dwellers. Multiple logistic regression was used to investigate the association between asthma and wheeze with demographic, environmental, and behavioral exposures with simultaneous adjustment for confounders.
Asthma and wheeze prevalence was not significantly different between farm and small town areas (current asthma: 16% vs 13%, respectively; current wheeze: 27% vs 21%, respectively) and followed consistent patterns. Factors associated with diagnosed asthma were dampness (odds ratio [OR] = 1.85; 95% confidence interval [CI] = 1.08–3.17), with enrollment in daycare found to be protective (OR = 0.53; 95% CI = 0.33–0.85). Being obese or overweight was associated with wheeze (OR = 1.77; 95% CI = 1.06–2.97).
Given the differences between areas and the associations between environmental risk factors and obesity with asthma and wheeze, the study findings support environment and health risk behavior explanations for the observed geographic variations.
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2011, Annals of Allergy, Asthma and Immunology
Citation Excerpt :
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Cross-sectional data from 4,726 Canadian youth (grades 6–10) were collected during the 2001–02 Health Behaviour in School-Aged Children survey. Geographic region was categorized as metro (urbanized), non-metro but adjacent to metro, and rural. Asthma was defined via self-report of doctors' diagnoses and at least 1 of: (1) asthma symptoms or (2) a health care visit for asthma in the past year. Health behaviors (diet and physical activity) as well as obesity were also assessed.
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Different wheeze phenotypes have been identified, primarily in preschool children.
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View all citing articles on Scopus

: This work was funded by the Lung Association of Saskatchewan, the South East Health District of Saskatchewan, and the South Central Health District of Saskatchewan. Dr. Cockcroft is the Ferguson Professor of Respiratory Medicine of the SLA.

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ORIGINAL ARTICLESDifferences in respiratory symptoms and pulmonary function in children in 2 Saskatchewan communities

Background

Objective

Methods

Results

Conclusions

Surveillance for Asthma-United States, 1960–1995

MMWR CDC Surveill Summ.

Changes in asthma prevalence: two surveys 15 years apart

Arch Dis Child.

Worldwide variations in the prevalence of asthma symptoms: the International Study of Asthma and Allergies in Childhood (ISAAC)

Eur Respir J.

Self-reported prevalence of asthma symptoms in children in Australia, England, Germany and New Zealand: an international comparison using the ISAAC protocol

Eur Respir J.

Childhood Asthma in Sentinel Units: Report of the Student Lung Health Study Results 1995–1996

Prevalence of childhood asthma across Canada

Int J Epidemiol.

Worldwide variation in prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema: ISAAC

Lancet.

Asthma and allergies among children in West and East Germany: a comparison between Munster and Greifswald using the ISAAC phase I protocol

Eur Respir J.

The epidemiology of childhood asthma in Red Deer and Medicine Hat, Alberta

Can Respir J.

Prevalence and severity of childhood asthma and allergic sensitisation in seven climatic regions of New South Wales

Med J Aust.

Epidemiology standardization project

Am Rev Respir Dis.

Influence of environmental tobacco smoke on asthma in nonallergic and allergic children

Epidemiology.

Distance to health care and the prevalence of asthma in school age children

J Agric Saf Health.

Standardization of spirometry—1987 update

Am J Respir Crit Care Med.

Percentiles for Body Mass Index

Lung function testing: selection of reference values and interpretive strategies

Am Rev Respir Dis.

ORIGINAL ARTICLES
Differences in respiratory symptoms and pulmonary function in children in 2 Saskatchewan communities