A scoping review of asthma and machine learning.

OBJECTIVE: The objective of this study was to determine the extent of machine learning (ML) application in asthma research and to identify research gaps while mapping the existing literature. DATA SOURCES: We conducted a scoping review. PubMed, ProQuest, and Embase Scopus databases were searched with an end date of September 18, 2020. STUDY SELECTION: DistillerSR was used for data management. Inclusion criteria were an asthma focus, human participants, ML techniques, and written in English. Exclusion criteria were abstract only, simulation-based, not human based, or were reviews or commentaries. Descriptive statistics were presented. RESULTS: A total of 6,317 potential articles were found. After removing duplicates, and reviewing the titles and abstracts, 102 articles were included for the full text analysis. Asthma episode prediction (24.5%), asthma phenotype classification (16.7%), and genetic profiling of asthma (12.7%) were the top three study topics. Cohort (52.9%), cross-sectional (20.6%), and case-control studies (11.8%) were the study designs most frequently used. Regarding the ML techniques, 34.3% of the studies used more than one technique. Neural networks, clustering, and random forests were the most common ML techniques used where they were used in 20.6%, 18.6%, and 17.6% of studies, respectively. Very few studies considered location of residence (i.e. urban or rural status). CONCLUSIONS: The use of ML in asthma studies has been increasing with most of this focused on the three major topics (>50%). Future research using ML could focus on gaps such as a broader range of study topics and focus on its use in additional populations (e.g. location of residence).Supplemental data for this article is available online at http://dx.doi.org/ .

Personal and early life factors associated with new-onset asthma, remission, and persistence of asthma in a 2-year follow-up of schoolchildren.

OBJECTIVE: The natural course of childhood asthma, after its onset, is characterized by periods of persistence, relapse and remission. To investigate personal and early life factors associated with new-onset asthma, persistence and remission among children. METHODS: The study was conducted in the province of Saskatchewan, Canada. Children in grades Kindergarten to Grade 8 (ages 5-14 years) participated in a cross-sectional study in 2013. In 2015, we approached those who gave consent in 2013 to be re-contacted, creating a prospective cohort. Data were collected using questionnaires in both years. Participants in 2013 who also had data in 2015 (25%: n = 324/1,348) had their asthma status reclassified and longitudinal descriptors were applied: "no asthma", "new-onset asthma", "persistent" or "remission". Personal and early life factors associations with asthma outcomes in 2015 were evaluated. RESULTS: Among those without asthma in 2013 (n = 245), the incidence of new-onset asthma in 2015 was 7.2%. Among those with asthma in 2013 (n = 79), 47.1% had remission and 52.9% had persistent asthma in 2015. Parental history of asthma (adjusted odds ratio (aOR): 4.99; 95% confidence interval (CI): 1.88-28.27), early life respiratory infection (aOR: 1.92; 95%CI: 1.47-7.88), early life allergy [aOR: 6.39; 95%CI: 1.34-30.58) and early life infection (aOR: 4.99; 95%CI: 1.19-20.93) were associated with new onset asthma. Similarly, while parental history of asthma (aOR: 1.13; 95%CI: 0.29-4.34), early life respiratory infection (aOR: 2.71; 95%CI: 0.70-10.45), and early life ear infection (aOR: 1.34; 95%CI: 0.36-5.05) were also positively association with persistent asthma, the associations were not statistically significant. CONCLUSION: Parental history of asthma, early life respiratory infection and allergy might not only influence the onset of childhood asthma but also be associated with asthma persistence.

Effects of tumor necrosis factor (TNF) gene polymorphisms on the association between smoking and lung function among workers in swine operations.

Workers in swine operations may be at increased risk of developing respiratory problems. These respiratory conditions are more prevalent among workers who are smokers. Tumor necrosis factor (TNF) genes play an important role in human immune responses to various respiratory hazards. This study aimed to investigate whether polymorphisms in TNF genes might alter the effects of smoking on lung function among workers in swine operations. Three hundred and seventy-four full-time workers from large swine operations and 411 non-farming rural dwellers in Saskatchewan were included in this study. Information on demographic and lifestyle characteristics, pulmonary function, and blood samples were obtained. Multiple linear regression analyses were used in the statistical analysis. Three promoter polymorphisms (rs1799724, rs361525, and rs1800629) in the TNF gene were investigated. Only the interaction term between smoking status and rs1799724 was significant in the multiple regression models. Among workers with the rs1799724 polymorphism (TT+TC), current smokers exhibited significantly lower lung function than nonsmokers. These associations were not observed among workers with the wild-type (CC). These findings were not observed among non-farming rural dwellers. Data demonstrated the possible involvement of TNF gene in (1) development of adverse respiratory conditions among workers who are smokers, (2) importance of smoking cessation among workers, especially those with polymorphisms in the TNF gene, and (3) potential implications in treatment, screening, and prevention.

Are Dietary Factors Associated with Lung Function in Canadian Adults?

Purpose: The purpose of this study was to explore the impact of dietary factors and biomarkers on lung function among Canadian adults (18-79 years). Methods: Our data source was the Canadian Health Measures Survey Cycle-3, which included 3397 adults. The household and clinic questionnaires and physical measures were used to assess individual dietary factors, modified Mediterranean Diet Scores, and biomarkers. Results: The overall mean percent predicted values for FVC and FEV1 were 97% and 95%, respectively. While somewhat inconsistent between outcomes, higher lung function was associated with bean, grain, milk, fruit, and vegetable consumption, whereas lower lung function was associated with egg and potato consumption. Among the biomarkers, vitamin D, chloride, total serum protein, and red blood cell folate were associated with higher lung function, whereas C-reactive protein and vitamin B12 was associated with lower lung function. Conclusion: Our study provides support for an association between some dietary factors and lung function, though not entirely consistent between a specific dietary factor and the outcomes studied (FVC, FEV1, FVC/FEV1, and FEF25%-75%). The associations between a specific biomarker and lung function were more consistent (i.e., observed with a larger number of lung function outcomes) than were the dietary factors.

Asthma diagnosis among children along an urban-rural gradient.

OBJECTIVE: Studies have reported lower asthma prevalence in rural compared to urban areas. While environmental factors have mostly been implicated for these differences, the lower asthma prevalence could also be linked to asthma under-diagnosis in rural children. We investigate if rural children experience under-diagnosis of asthma more compared to urban children. METHODS: In 2013, we conducted a cross-sectional survey of schoolchildren across an urban-rural gradient in Saskatchewan, Canada. The participants formed sampling frame for future studies. In 2015, we approached those who gave consent in 2013 for further testing, repeated the survey, and conducted clinical testing. Based on survey responses, children were classified into "no asthma," "at-risk-for-asthma," and "diagnosed asthma." We then classified asthma status as either "no asthma" or "probable asthma" based on a validated asthma algorithm. RESULTS: The study population of 335 schoolchildren (aged 7-17 years) comprised of 73.4% from large urban, 13.7% from small urban, and 12.8% from rural areas. Proportion with report of physician-diagnosed asthma was 28.5% (Large urban), 34.8% (Small urban), and 20.9% (Rural). Mean percent predicted FEV1 and FEF25%-75% were lower in rural compared to small urban and large urban children (p < 0.05). Among those not classified as with "diagnosed asthma" by the survey, the algorithm further identified presence of asthma in 5.5% large urban, 8.1% small urban, and 18.8% rural children (p = 0.03). CONCLUSION: The study revealed evidence of asthma underdiagnosis in rural areas and further supports the use of objective measures in addition to symptoms history when investigating asthma across urban-rural gradients.

The association between endotoxin in house dust with atopy and exercise-induced bronchospasm in children with asthma.

BACKGROUND: Studies have reported protective and adverse associations between microbial exposure and childhood asthma. However, among children with asthma the relationships between endotoxin and exercise-induced bronchospasm (EIB) is less clear. OBJECTIVE: We investigated the association between exposure to endotoxin in house dust with atopy and EIB in children with asthma. METHODS: A cross-sectional survey was conducted among schoolchildren (aged 7-17 years) in the province of Saskatchewan, Canada. A subpopulation with asthma (n = 116) were identified from 335 participants using a validated asthma algorithm. We determined atopy among the asthma subpopulation by skin prick testing (SPT) while EIB was evaluated using exercise challenge testing (ECT). Dust samples were collected from mattress and play area floors, and endotoxin was measured in dust extracts. Logistic regression analyses were used to explore associations between endotoxin with atopy and EIB. RESULTS: Among the 116 children with asthma, 99 completed SPT and all had completed ECT. Of these, 71/99 (71.7%) were atopic and 26/116 (22.4%) had EIB. Exposure to high play area endotoxin concentration [adjusted odds ratio (aOR) = 0.15, 95% CI: 0.03-0.85] and load (aOR = 0.11, 95% CI: 0.02-0.73) were negatively associated with atopy. In contrast, EIB was positively associated with high mattress endotoxin concentration (aOR = 6.01, 95% CI: 1.20-30.13). CONCLUSION: Indoor microbial endotoxin exposure has varied associations with atopy and exercise-induced bronchospasm among children with asthma.

Gender-specific associations between polymorphisms in the Toll-like receptor (TLR) genes and lung function among workers in swine operations.

Workers in swine operations are exposed to dust, bacteria, and virus, and are at increased risk of respiratory problems. Toll-like receptors (TLR) play an important role in human immune responses to respiratory hazards. Worker gender and age may significantly modify the involvement of TLR in the etiology of these respiratory outcomes. The aim of this study was to investigate whether modification effects of worker gender and age altered associations between polymorphisms in the TLR genes and lung function. This study included 374 full-time workers from large swine operations from Saskatchewan. Information on demography, lifestyle, pulmonary function,  and blood samples were obtained. Multiple linear regression and decision tree model were used in the analysis. Among females aged <45.8 years, workers with polymorphisms of rs4696480 in the TLR2 gene exhibited markedly better lung function than workers with wild-type. These associations were not observed among female workers aged ≥45.8 years and males. Among males, workers with polymorphisms of rs187084 in the TLR9 gene displayed significantly lower lung function than those with wild-type. This male-specific association was not dependent on worker age. This is the first study to report gender-specific correlations between lung function and polymorphisms of TLR genes, and modification effects of worker age on these associations, suggesting the importance of considering gender and age in genetic association studies of airway diseases due to exposure of high concentration of respiratory hazards.

Prevalence, risk factors, and clinical outcomes of atopic and nonatopic asthma among rural children.

BACKGROUND: 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. OBJECTIVE: To compare atopic and nonatopic asthma in rural children with regard to risk factors and clinical outcomes. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

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.

Determinants of excessive daytime sleepiness in two First Nation communities.

BACKGROUND: Excessive daytime sleepiness may be determined by a number of factors including personal characteristics, co-morbidities and socio-economic conditions. In this study we identified factors associated with excessive daytime sleepiness in 2 First Nation communities in rural Saskatchewan. METHODS: Data for this study were from a 2012-13 baseline assessment of the First Nations Lung Health Project, in collaboration between two Cree First Nation reserve communities in Saskatchewan and researchers at the University of Saskatchewan. Community research assistants conducted the assessments in two stages. In the first stage, brochures describing the purpose and nature of the project were distributed on a house by house basis. In the second stage, all individuals age 17 years and older not attending school in the participating communities were invited to the local health care center to participate in interviewer-administered questionnaires and clinical assessments. Excessive daytime sleepiness was defined as Epworth Sleepiness Scale score > 10. RESULTS: Of 874 persons studied, 829 had valid Epworth Sleepiness Scale scores. Of these, 91(11.0%) had excessive daytime sleepiness; 12.4% in women and 9.6% in men. Multivariate logistic regression analysis indicated that respiratory comorbidities, environmental exposures and loud snoring were significantly associated with excessive daytime sleepiness. CONCLUSIONS: Excessive daytime sleepiness in First Nations peoples living on reserves in rural Saskatchewan is associated with factors related to respiratory co-morbidities, conditions of poverty, and loud snoring.

Prevalence and associated risk factors of chronic bronchitis in First Nations people.

BACKGROUND: Inadequate housing, low family income, household smoking, personal smoking status, and poor schooling are some of the conditions that have been significantly associated with the prevalence and incidence of chronic bronchitis. The aim of the current study was to determine the prevalence of chronic bronchitis (CB) and associated risk factors among First Nations people. METHODS: An interviewer-administered survey was conducted as part of the First Nations Lung Health Project in 2012 and 2013 with 874 individuals from 406 households in two First Nations communities located in the province of Saskatchewan, Canada. The questionnaire collected information on individual and contextual determinants of health and a history of ever diagnosed with CB (outcome variable) from the two communities participating in the First Nations Lung Health Project. Clustering effect within households was adjusted using Generalized Estimating Equations. RESULTS: The prevalence of CB was 8.9% and 6.8% among residents (18 years and older) of community A and community B respectively and was not significantly different. CB prevalence was positively associated with odour or musty smell of mildew/mould in the house [OR adj (95% CI) = 2.33 (1.21, 4.50)], allergy to house dust [3.49 (1.75, 6.97)], an air conditioner in home [2.33 (1.18, 4.24)], and increasing age [0.99 (0.33, 2.95), 4.26 (1.74, 10.41), 6.08 (2.58, 14.33)]. An interaction exposure to environmental tobacco smoke in the house*body mass index showed that exposure to household smoke increased the risk of CB for overweight and obese participants (borderline). Some of the variables of interest were not significantly associated with the prevalence of CB in multivariable analysis, possibly due to small numbers. CONCLUSIONS: Our results suggest that significant determinants of CB were: increasing age; odour or musty smell of mildew/mould in the house; allergy to house dust; and, body mass index. Modifiable risk factors identified were: (i) community level-housing conditions (such as mould or mildew in home, exposure to environmental tobacco smoke in house); and, (ii) policy level-remediation of mould, and obesity. TRIAL REGISTRATION: Not applicable.

Early farm residency and prevalence of asthma and hay fever in adults.

BACKGROUND: Asthma and hay fever have been found to be both positively and negatively associated with farming lifestyles in adulthood. Lack of congruency may depend upon early life exposure. OBJECTIVE: To assess the importance of different periods of farm residency for asthma and hay fever in an adult Canadian population. METHODS: We conducted a questionnaire survey in rural Saskatchewan, Canada. We assessed a history of asthma and hay fever with five categories of farm residency that were mutually exclusive: first year of life only, currently living on a farm, both first year of life and currently living on a farm, other farm living, and no farm living. Generalized estimating equations were used to adjust for clustering effects of adults within households. RESULTS: Of the 7148 responding, 30.6% had an early farm living experience only, 34.4% had both early and current farm living experiences, while 17.4% had never lived on a farm. The overall prevalence of ever asthma and hay fever was 8.6% and 12.3%, respectively, and was higher in women. Sex modified the associations between ever asthma and hay fever with farm residency variables whereby women had a decreased risk for both asthma [adjusted odds ratio (ORadj): 0.67, 95% confidence interval (CI):0.47-0.96] and hay fever (ORadj: 0.60, 95% CI: 0.44-0.83) with an early farm exposure only. Men currently living on a farm without an early farm exposure had an increased risk for ever asthma (ORadj: 1.82, 95% CI: 1.02-3.24). CONCLUSION: Farm residency in the first year of life shows a protective effect for adult asthma and hay fever that appears to differ by sex.

Income adequacy and education associated with the prevalence of obesity in rural Saskatchewan, Canada.

BACKGROUND: Obesity is prevalent in rural communities in Canada, however little is known about the social determinants of health and obesity in rural populations. Socioeconomic status has been found to be inversely associated with the risk of obesity in developed countries. This study investigated the relationship between income adequacy, education and obesity in a rural setting. METHODS: The study used data from 5391 adults aged 18-69 who participated in the Saskatchewan Rural Health Study in 2010. Participants completed a survey that included questions about location of residence, body weight, height, and socio-demographic and behavioral factors. Obesity was defined as body mass index being ≥ 30 kg/m(2). Logistic regression using generalized estimating equation was conducted to assess the associations of income adequacy and education level with the prevalence of obesity taking covariates into consideration. RESULTS: Approximately a third of the participants were obese and the prevalence of obesity was similar for men and women. The prevalence of obesity was significantly higher for rural residents not living on farm compared with those living on farm (p < 0.05). After adjustment for potential confounders, the risk of obesity was increased for those with ≤ 12 years of education compared with those with > 12 years of education (aOR: 1.18; 95% CI: 1.05-1.34). Low income adequacy was significantly associated with an increased risk of obesity but only among those not living on farm (aOR: 1.80; 95% CI: 1.16-2.79). CONCLUSIONS: Home location was associated with obesity prevalence in rural Saskatchewan and modified the influence of income adequacy, but not the influence of education, on obesity. Adults not living on farm had an increased risk of obesity and showed a significant impact of income adequacy on obesity.

Do discrimination, residential school attendance and cultural disruption add to individual-level diabetes risk among Aboriginal people in Canada?

BACKGROUND: Aboriginal peoples in Canada (First Nations, Metis and Inuit) are experiencing an epidemic of diabetes and its complications but little is known about the influence of factors attributed to colonization. The purpose of this study was to investigate the possible role of discrimination, residential school attendance and cultural disruption on diabetes occurrence among First Nations adults. METHODS: This 2012/13 cross sectional survey was conducted in two Saskatchewan First Nations communities comprising 580 households and 1570 adults. In addition to self-reported diabetes, interviewer-administered questionnaires collected information on possible diabetes determinants including widely recognized (e.g. age, sex, lifestyle, social determinants) and colonization-related factors. Clustering effect within households was adjusted using Generalized Estimating Equations. RESULTS: Responses were obtained from 874 (55.7 %) men and women aged 18 and older living in 406 (70.0 %) households. Diabetes prevalence was 15.8 % among women and 9.7 % among men. In the final models, increasing age and adiposity were significant risk factors for diabetes (e.g. OR 8.72 [95 % CI 4.62; 16.46] for those 50+, and OR 8.97 [95 % CI 3.58; 22.52] for BMI 30+) as was spending most time on-reserve. Residential school attendance and cultural disruption were not predictive of diabetes at an individual level but those experiencing the most discrimination had a lower prevalence of diabetes compared to those who experienced little discrimination (2.4 % versus 13.6 %; OR 0.11 [95 % CI 0.02; 0.50]). Those experiencing the most discrimination were significantly more likely to be married and to have higher incomes. CONCLUSIONS: Known diabetes risk factors were important determinants of diabetes among First Nations people, but residential school attendance and cultural disruption were not predictive of diabetes on an individual level. In contrast, those experiencing the highest levels of discrimination had a low prevalence of diabetes. Although the reasons underlying this latter finding are unclear, it appears to relate to increased engagement with society off-reserve which may lead to an improvement in the social determinants of health. While this may have physical health benefits for First Nations people due to improved socio-economic status and other undefined influences, our findings suggest that this comes at a high emotional price.

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.

Perceptions Related to Death in Adolescents and Their Parents During the Management of Type 1 Diabetes: A Thematic Analysis.

BACKGROUND: Type 1 diabetes (T1D) is associated with an increased risk of premature death compared to those without T1D, yet perceptions of dying have not been well studied. The purpose of this secondary analysis of existing data was to explore the fears of adolescents with T1D and their parents related to the possibility of death due to T1D. METHOD: A reflexive thematic analysis was used to examine data from interviews conducted with adolescents with T1D and their parents who participated in a primary grounded theory study of interdependence in T1D management. FINDINGS: Three themes were generated from the data including: (1) Facing the Reality of Death, (2) Fearing Highs and Lows, and (3) Finding a Way through Fears. Participants indicated they see death as a consequence of failing to optimally manage T1D. CONCLUSION: Additional investigation is needed to explore the fear of death in adolescents with T1D and any fear their parents may have of their adolescents' mortality.

Sleep Efficiency and Sleep Onset Latency in One Saskatchewan First Nation.

BACKGROUND: Sleep efficiency and sleep onset latency are two measures that can be used to assess sleep quality. Factors that are related to sleep quality include age, sex, sociodemographic factors, and physical and mental health status. This study examines factors related to sleep efficiency and sleep onset latency in one First Nation in Saskatchewan, Canada. METHODS: A baseline survey of the First Nations Sleep Health project was completed between 2018 and 2019 in collaboration with two Cree First Nations. One-night actigraphy evaluations were completed within one of the two First Nations. Objective actigraphy evaluations included sleep efficiency and sleep onset latency. A total of 167 individuals participated, and of these, 156 observations were available for analysis. Statistical analysis was conducted using logistic and linear regression models. RESULTS: More females (61%) than males participated in the actigraphy study, with the mean age being higher for females (39.6 years) than males (35.0 years). The mean sleep efficiency was 83.38%, and the mean sleep onset latency was 20.74 (SD = 27.25) minutes. Age, chronic pain, ever having high blood pressure, and smoking inside the house were associated with an increased risk of poor sleep efficiency in the multiple logistic regression model. Age, chronic pain, ever having anxiety, heart-related illness, and smoking inside the house were associated with longer sleep onset latency in the multiple linear regression model. CONCLUSIONS: Sleep efficiency and sleep onset latency were associated with physical and environmental factors in this First Nation.

Association of Toll-like receptor 2 gene polymorphisms with lung function in workers in swine operations.

BACKGROUND: Workers in swine operations are exposed to indoor dusts and gases and are at increased risk of respiratory problems. Toll-like receptor (TLR) 2 recognizes ligands from gram-positive bacteria, whereas TLR4 responds to endotoxin from gram-negative bacteria. OBJECTIVE: To investigate the effects of TLR2 and TLR4 polymorphisms on lung function in workers from swine operations and nonfarming rural dwellers. METHODS: A total of 374 full-time workers from large swine operations and 411 nonfarming rural dwellers from Saskatchewan were included. Information on demography, lifestyle, and occupation, lung function measurements, and blood samples for genotyping were obtained from the participants. Multiple regression analysis and Bonferroni correction were used in the statistical analysis. RESULTS: Workers with TLR2-16933T/A polymorphism (AA) had significantly greater mean values of lung function than workers with wild-type genotypes (AT+TT) after controlling for potential confounders (forced expiratory volume in 1 second, 3.7 vs 3.5 L; P=.009; forced expiratory flow between 25% and 75%, 3.7 vs 3.3 L; P=.003; predicted forced expiratory volume in 1 second; 100.3% vs 95.6%; P=.005; forced expiratory flow between 25% and 75%, 92.4% vs 83.4%; P=.009). These results were also observed for TLR2Arg677Trp polymorphism among the workers. No such significant differences were observed among nonfarming rural dwellers. For Asp299Gly and Thr399Ile polymorphisms in the TLR4 gene, no significant differences were observed in the mean lung function values between the polymorphic and wild-type groups in both workers and rural dwellers. CONCLUSION: Our study is the first, to our knowledge, to report protective effects of TLR2 polymorphisms on lung function among workers in swine operations and raises the possibility that TLR2 polymorphisms are protective of airway disease in individuals exposed to gram-positive organisms in the inhaled airborne dust.