Childhood asthma, asthma severity indicators, and related conditions along an urban-rural gradient: a cross-sectional study

Abstract

BackgroundAsthma prevalence is generally lower in rural locations with some indication of an urban-rural gradient. However, among children with asthma, certain rural exposures thought to protect against the development of asthma could aggravate the condition. We examined childhood asthma prevalence and related conditions along an urban-rural gradient and also examined the characteristics of those with asthma along the urban-rural gradient.MethodsIn 2013 we completed a cross-sectional survey of 3509 children aged 5–14 years living in various population densities of Saskatchewan, Canada. Location of dwelling was identified as belonging to one of the following population densities: large urban region (approximately 200,000), small urban (approximately 35,000), or rural (small town of <1,500 or farm dweller). Physician-diagnosed asthma and asthma-related symptoms were ascertained from responses in the parental-completed questionnaires.ResultsOf the study population, 69% lived in a large urban region, 11% lived in a small urban centre and 20% were rural dwellers. Overall, asthma prevalence was 19.6% with differences in asthma prevalence with differences between locations (large urban = 20.7%; small urban = 21.5%; rural = 15.1%; p = 0.003). After adjustment for potential confounders, the association between location of dwelling and asthma remained significant. Despite a lower prevalence of asthma in the rural area, the prevalence and risk of ever wheeze and having more than 3 wheezing episodes in the past 12 months among those who reported asthma, was higher in rural locations after adjustment for potential confounders.ConclusionsThe results of this study support the evidence of a difference in childhood asthma prevalence between urban and rural locations and that once a child has asthma, certain rural exposures may aggravate the disease.

Rural to urban migration contributes to the high burden of asthma in the urban area

“…It is possible that limited health resources in rural areas led subjects with moderate‐severe asthma to migrate to urban centers. This possibility is in line with a recent evidence of lower prevalence but more severe asthma symptoms among subjects living in rural areas . The other possible explanation is that rural‐urban migrants with asthma are more susceptible than urban‐born subjects to get worse airway inflammation and asthma symptoms when exposed to environmental hazards in urban centers.…”

“…This possibility is in line with a recent evidence of lower prevalence but more severe asthma symptoms among subjects living in rural areas. 15 The other possible explanation is that rural-urban migrants with asthma are more susceptible than urban-born subjects to get worse airway inflammation and asthma symptoms when exposed to environmental hazards in urban centers. However, the latter hypothesis is not coherent with the current concept that the rural environment exposes subjects to immunomodulatory stimuli that downregulate the immune response, prevents airway inflammation and exacerbation of asthma.…”

Risk factors for asthma among schoolchildren who participated in a case-control study in urban Uganda

“…Asthma is estimated to affect more than 235 million people globally, and is the most common non-communicable condition among children (1). In Africa, the prevalence of asthma appears to be increasing (2)(3)(4)(5)(6), particularly in urban areas (3,7), but the causes of this increase are not fully understood. Moreover, asthma has various phenotypes which may have different aetiologies (8), and risk factors appear to vary internationally, and to differ between high-income countries (HICs) and low-and-middle income countries (LMICs) (9).…”

Asthma mortality among Mexican children: Rural and urban comparison and trends, 1999‐2016

“…Higher asthma prevalence in urban compared with rural settings, 3–5 have been shown in studies in children and adolescents. Other studies found higher prevalence in rural zones 6 and still others showed no difference between farm and nonfarm rural dwellers 7 or between farm and small‐town zones 8 .…”

“…Higher asthma prevalence in urban compared with rural settings, [3][4][5] have been shown in studies in children and adolescents.…”