Factors contributing to risks for pediatric asthma in rural Saskatchewan

Farm Exposures and Allergic Disease Among Children Living in a Rural Setting

OBJECTIVES

The purpose of this study was to examine the association between farm exposures and asthma and allergic disease in children while also highlighting the experiences of non-farm rural children.

METHODS

This was a cross-sectional analysis of data collected from across the province of Saskatchewan, Canada in 2014. Surveys were completed by parents of 2275 rural dwelling children (farm and non-farm) aged 0 to 17 years within 46 rural schools. Questionnaires were distributed through schools for parents to complete.

RESULTS

Asthma prevalence was 7.6%, of which 29.5% of cases were allergic. After adjustment for potential confounders, home location (farm vs non-farm) and other farm exposures were not associated with asthma and asthma phenotypes. Those who completed farm safety education were more likely to have asthma (11.7% vs. 6.7%; p = .001) compared to children without asthma. In sub-analyses among 6-12-year-old children, boys were more likely to have asthma (non-allergic) and use short-acting beta-agonists compared to girls. Doing farm work in the summer was associated with an increased risk of asthma [adjusted OR (aOR) = 1.71 (1.02-2.88); p = .041]. Doing routine chores with large animals was associated with an increased risk of asthma [aOR = 1.83 (1.07-3.15); p = .027] and allergic asthma [aOR = 2.37 (95%CI = 1.04-5.40); p = .04].

CONCLUSION

The present study showed that the prevalence of asthma and asthma phenotypes were similar between farm and non-farm rural children. There did not appear to be differential involvement in farming activities between those with and without asthma although those with asthma had more training suggesting possible attempts to mitigate harm from farm exposures.

Domestic Risk Factors for Atopic and non-Atopic Asthma in First Nations Children Living in Saskatchewan, Canada

Both allergic and non-allergic asthma phenotypes are thought to vary by specific housing and other indoor environmental conditions. This study evaluated risk factors for allergic asthma phenotypes in First Nation children, an understudied Canadian population with recognized increased respiratory morbidity. We conducted a cross-sectional survey with a clinical component to assess the respiratory health of 351 school-age children living on two rural reserve communities. Asthma was defined as parental report of physician diagnosed asthma or a report of wheeze in the past 12 months. Atopy was determined by a ≥ 3-mm wheal response to any of six respiratory allergens upon skin prick testing (SPT). Important domestic and personal characteristics evaluated included damp housing conditions, household heating, respiratory infections and passive smoking exposure. Asthma and atopy prevalence were 17.4% and 17.1%, respectively. Of those with asthma, 21.1% were atopic. We performed multivariate multinomial logistic regression modelling with three outcomes: non-atopic asthma, atopic asthma and no asthma for 280 children who underwent SPT. After adjusting for potential confounders, children with atopic asthma were more likely to be obese and to live in homes with either damage due to dampness (p < 0.05) or signs of mildew/mold (p = 0.06). Both natural gas home heating and a history of respiratory related infections were associated with non-atopic asthma (p < 0.01). Domestic risk factors for asthma appear to vary by atopic status in First Nations children. Determining asthma phenotypes could be useful in environmental management of asthma in this population.

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

OBJECTIVE

Although there are more studies showing higher asthma prevalence in urban rather than rural zones, few assessed asthma mortality by zone in children. The objective of this study is to compare asthma mortality rates (AMR) by zone of residence of Mexican children.

DESIGN

Using national death certificate and population projections data, AMR were compared in children aged 0 to 14 years by gender, age group, and zone of residence from 1999 to 2016. AMR trends were calculated using Joinpoint regression.

RESULTS

Of the 680 823 deaths, 2464 (0.36%) were due to asthma. Asthma mortality was higher in rural (0.65%) than urban (0.26%) zones, P < .0001. Whole period AMR median was also higher in rural vs urban zones (0.6 vs 0.3, respectively), P < .05. The average annual percent change (AAPC) of AMR for the whole period was -5.1 in all children with a higher percent decrease in rural vs urban zones (girls' AAPC = -6.3 vs -4.1, respectively and boys' AAPC = -4.8 vs -4.2, respectively). AMR decreased in children aged 0 to 4 from both zones (rural's AAPC: girls = -7.9, boys = -5.2; urban's AAPC: girls = -5.1, boys = -5.4), P < .05. No trend was found in children aged 5 to 14.

CONCLUSIONS

Asthma mortality in Mexican children is higher in rural than urban zones. The decrease of mortality over time in early childhood is reassuring. More research is needed to determine reasons for higher mortality in rural Mexico and for the lack of a favorable decreasing trend in children aged 5 to 14 from both zones.

Association of early daycare attendance with allergic disorders in children: a longitudinal national survey in Japan

The association between early daycare attendance and risk of allergic diseases remains inconclusive. Therefore, we examined the association among Japanese children on a long-term basis using a nationwide longitudinal survey data. We estimated the association between daycare attendance at age 6 or 18 months and allergy development using information on outpatient visits for atopic dermatitis (AD), food allergy (FA), and asthma and admission for asthma up to 12 years of age as a proxy for developing these diseases, with multilevel logistic regression. Early daycare attendance was associated with increased odds of AD at ages 2.5-3.5 years: the adjusted odds ratio (OR) was 1.34 [95% CI: 1.21, 1.47]. The association with FA was equivocal. The odds of asthma was increased before age 3.5 years and afterwards decreased: the adjusted ORs were 1.60 [1.44, 1.77] for ages 1.5-2.5 years and 0.77 [0.69, 0.87] for ages 5.5-7 years. The effect of early daycare attendance depends on the type of allergies.

Day-care center attendance and risk of Asthma-A systematic review

INTRODUCTION AND OBJECTIVES

Asthma and other wheezing disorders are common chronic health problems in childhood. We aim to evaluate whether the attendance by children under three years of age to day-care centers is a protector or risk factor in the development of recurrent wheezing or asthma in the following years of their lives.

METHODS

Systematic review of published cohort or cross-sectional studies, without any time limitation. We searched in PubMed, Cinhal, Cuiden and Scopus (EMBASE included). The quality of the studies was evaluated using the Newcastle-Ottawa Scale. Disagreements were solved by mutual consensus. Weighted odds ratio (ORs) were estimated using RevMan 5.3, following random effects models.

RESULTS

We selected 18 studies for qualitative analysis, nine cohort studies and nine cross-sectional studies. Day-care center attendance is associated with an increased risk of early recurrent wheezing (four studies; 50,619 subjects; adjusted OR 1.87 [1.21 to 2.88]; I² 91%) and asthma before the age of six (five studies; 5412 subjects; adjusted OR 1.59 [1.26 to 2.01]; I² 0%), but not later (five studies; 5538 subjects; adjusted OR 0.86 [0.55 to 1.32]; I² 76%).

CONCLUSIONS

Children attending day-care center during the first years of life have a higher risk of recurrent wheezing during the first three years and asthma before the age of six, but not later. This risk must be taken into account to inform parents in order to choose what kind of care children should have throughout infancy and to implement preventive measures to reduce its impact.

Lung function in relation to farm dwelling and farming activities in rural dwelling children

BACKGROUND AND OBJECTIVE

The relationship between farming exposures and pulmonary function in a rural paediatric population was evaluated.

METHODS

Baseline data collection records of the Saskatchewan Rural Health Study (SRHS), a population-based study, were used. A subset of children (6-14 years old) participated in clinical testing, including anthropometric measures and pulmonary function testing (PFT), using spirometry (n = 584). PFTs followed ATS criteria and all statistical analyses were controlled for age, sex and height.

RESULTS

Among clinical testing participants, 47.5% were females and 54.5% were farm dwelling. Of those living on farms, 77.5% were livestock farms. Mean percent predicted value (PPV) for forced expiratory volume in 1 s (FEV₁ ) and forced vital capacity (FVC) among children living on a farm were 104.8% and 105.4%, respectively. Mean PPV for FEV₁ and FVC among children not living on a farm were 102.7% and 101.4%, respectively. After adjustment, higher FEV₁ (=0.079, SE = 0.033, P = 0.03) and FVC (=0.110, SE = 0.039, P = 0.006) were seen among children living on a farm. A trend towards lower FEV₁ /FVC ratio (-0.013, SE = 0.008, P = 0.09) among children living on a farm was seen compared with children not living on a farm. Higher FVC and lower FEV₁ /FVC ratio were seen in children who regularly emptied grain bins (P < 0.05). Trends towards higher FEV₁ (P = 0.14) and FVC (P = 0.08) were also seen with children living on a farm in the first year of life. Since the majority of the population was Caucasian (91%), the results were not race-corrected.

CONCLUSION

We addressed the lack of knowledge regarding the association between lung function and rural exposures, and found that differences in lung function were seen between children living on a farm and not living on a farm in rural areas and certain farming activities, specifically emptying grain bins, where lung function was generally better in those living on a farm.

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

BACKGROUND

Asthma 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.

METHODS

In 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.

RESULTS

Of 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.

CONCLUSIONS

The 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.

The role of farm operational and rural environments as potential risk factors for pediatric asthma in rural Saskatchewan

BACKGROUND

Researchers have historically reported that farm children have a lower prevalence of asthma compared to more urban children. Potential explanations include theories surrounding differences in personal factors, access to health care, engagement in health risk behaviors, and differences in the environment.

OBJECTIVE

The aims of this study were to: (1) confirm whether the prevalence of asthma varies between farm and small town status among children living in Saskatchewan; (2) identify risk and protective factors for asthma, and use this information to infer which of the above theories is most explanatory for any observed geographic variations in pediatric asthma.

METHODS

Rural students (N = 2383, 42% participation rate) from the province of Saskatchewan participated in a 2011 cross-sectional study. Parents completed a survey that included questions about location of residence, respiratory symptoms, potential risk factors for respiratory disease, and exposures to farm activities. Multiple logistic regression was used to examine relations between respiratory outcomes (asthma, wheeze) with farm type and farm activities, while accounting for factors that may underlie such relations.

RESULTS

Asthma and wheeze prevalence did not differ by residential status. Living on a grain farm (OR = 0.64, 95% CI = 0.43-0.96), cleaning or playing in pens (OR = 0.69, 95% CI = 0.46-1.02), filling grain bins (OR = 0.56, 95% CI = 0.32-0.96), and riding horses (OR = 0.65, 95% CI = 0.40-1.05) were protective factors for ever diagnosis with asthma.

CONCLUSIONS

We identified a number of risk and protective factors for asthma and associated wheeze. This suggests the need to focus on specific environmental explanations to better understand previously observed associations between farm residential status and asthma.

Prevalence and determinants of atopy and allergic diseases among school-age children in rural Saskatchewan, Canada

BACKGROUND

There have been few investigations of farming-related activities or specific characteristics resulting in the associations between those exposures and atopic disease.

OBJECTIVE

To study the associations between farm-associated exposures and atopic diseases.

METHODS

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.

RESULTS

Of those who completed clinical testing, the prevalence of atopy was 19.4%, that of hay fever was 8.8%, and that of eczema was 27.4%. Based on skin prick testing, sensitization was highest for cat dander (8.6%) followed by local grasses (8.2%) and house dust mite (5.1%). After adjustment for potential confounders, home location (farm vs non-farm) was not associated with atopic status. However, livestock farming was protective against atopy (adjusted odds ratio 0.38, 95% confidence interval 0.17-0.88). In contrast, current residence on a farm was associated with an increase in the likelihood of hay fever in these children (adjusted odds ratio 3.68, 95% confidence interval 1.29-10.45). Also, regular farming activities in the past year were associated with an increased risk of hay fever.

CONCLUSION

In children, livestock exposure has a protective effect on skin prick test positivity, whereas farm living and activities increase the risk of hay fever.

Asthma incidence and risk factors in a national longitudinal sample of adolescent Canadians: a prospective cohort study

BACKGROUND

Estimates of asthma incidence and its possible determinants in adolescent populations have rarely been obtained using prospective designs. We sought to identify socio-demographic and other patterns in the incidence of asthma among Canadian adolescents and to examine possible behavioural and environmental determinants of asthma incidence using longitudinal analyses.

METHODS

We used data from the National Population Health Survey (NPHS), a nationally representative longitudinal survey of Canadians. All persons aged 12-18 years without asthma at baseline were followed up to a maximum of 12 years. The outcome was a reported diagnosis of asthma during the follow-up period. Analyses were weighted to the population and bootstrapping procedures were used to estimate variances.

RESULTS

Participants (n = 956) represented 2,038,890 adolescents of whom 293,450 (14.4%) developed asthma over the 21,274,890 person-years of follow-up. Overall, the incidence of asthma was 10.2 per 1000 person-years. In adjusted Cox regression analysis, being female (HR = 2.13, 95% CI = 1.26-3.62, p = 0.005) and being exposed to passive smoking (HR = 2.06, 95% CI = 1.27-3.34, p = 0.003) were associated with the development of asthma while no statistically significant associations were identified for rural residence, being overweight, and other health behaviours. There was also an apparent cohort effect among girls where girls who were older at baseline reported being diagnosed with asthma more over the follow-up than their younger counterparts. This was not observed among males.

CONCLUSIONS

Asthma prevention initiatives for adolescents should target girls and focus on smoking exposures. The role that differential diagnostic patterns play in these observations should be investigated to more accurately assess the incidence of asthma.

Obesity, diet, and activity in relation to asthma and wheeze among rural dwelling children and adolescents

AIMS AND OBJECTIVES

We investigated associations between weight status, activity level, and diet with asthma or wheeze as well as the interrelationship between these factors.

METHODS

We conducted a case-control study of 6-18-year olds from 2005 to 2007. Cases (n = 87) were subjects reporting episodes or breathing medication use along with doctor-diagnosed asthma or wheeze in the past 12 months. Controls were randomly selected (n = 208) and without asthma or wheeze. Data regarding health outcomes, diet, and activity were obtained from questionnaire. Objectively measured height and weight were collected.

RESULTS

In the adjusted analysis, there was a trend (P = 0.07) towards an increased risk of asthma or wheeze associated with high fast food and/or pop consumption. Among cases, a significantly lower proportion (66%) classified as overweight participated in hard exercise in ≥9 of the past 14 days compared to those who were not overweight (86%). This pattern was not seen among controls (76% participating in hard exercise versus 78%, resp.). However, based on perceived weight status by the parent, the patterns were similar regardless of case-control status.

CONCLUSIONS

Overweight status may negatively impact activity level among those with asthma or wheeze. Efforts should be made to encourage healthy food choices, and activity programming must consider the needs of overweight children with asthma.