Chandima Karunanayake

The Saskatchewan rural health study: an application of a population health framework to understand respiratory health outcomes

BackgroundRespiratory disease can impose a significant burden on the health of rural populations. The Saskatchewan Rural Health Study (SRHS) is a new large prospective cohort study of ages 6 and over currently being conducted in farming and non-farming communities to evaluate potential health determinants associated with respiratory outcomes in rural populations. In this article, we describe the rationale and methodology for the adult component.The study is being conducted over 5 years (2009–15) in two phases, baseline and longitudinal. The baseline survey consists of two components, adults and children. The adult component consists of a questionnaire-based evaluation of individual and contextual factors of importance to respiratory health in two sub populations (a Farm Cohort and a Small Town Cohort) of rural families in Saskatchewan Rural Municipalities (RMs). Clinical studies of lung function and allergy tests are being conducted on selected sub-samples of the two cohorts based on the positive response to the last question on the baseline questionnaire: “Would you be willing to be contacted about having breathing and/or allergy tests at a nearby location?”. We adopted existing population health theory to evaluate individual factors, contextual factors, and principal covariates on the outcomes of chronic bronchitis, chronic obstructive pulmonary disease, asthma and obstructive sleep apnea.FindingsOf the RMs selected to participate, 32 (89%) out of 36 RMs and 15 (94%) out of 16 small towns within the RMs agreed to participate. Using the mail out survey method developed by Dillman, we obtained completed questionnaires from 4264 households (8261 individuals). We obtained lung function measurements on 1609 adults, allergy skin test information on 1615 adults; both measurements were available on 1549 adults. We observed differences between farm and non-farm rural residents with respect to individual, contextual factors and covariates.DiscussionThere are differences between farm and non-farm rural residents with respect to individual and contextual factors and other variables of importance. The findings of the SRHS will improve knowledge of respiratory disease etiology, assist in the development and targeting of prevention programs, and in planning health services with farm and small town populations.

Prevalence, risk factors and co-morbidities of diabetes among adults in rural Saskatchewan: the influence of farm residence and agriculture-related exposures

BackgroundAlthough rural Canadians are reported to have higher rates of diabetes than others, little is known about the relative influence of known versus agriculture-related risk factors. The purpose of this research was to carry out a comprehensive study of prevalence, risk factors and co-morbidities of diabetes among adults in rural Saskatchewan and to determine possible differences between those living on and off farms.MethodsIn 2010, we conducted a baseline mail-out survey (Saskatchewan Rural Health Study) of 11,982 households located in the province′s four agricultural quadrants. In addition to self-reported physician-diagnosed diabetes, the questionnaire collected information from farm and small town cohorts on possible diabetes determinants including lifestyle, family history, early life factors and environmental/agricultural-related exposures. Clustering effect within households was adjusted using Generalized Estimating Equations approach.ResultsResponses were obtained from 4624 (42%) households comprising 8208 males and females aged 18 years or older and 7847 self-described Caucasian participants (7708 with complete information). The overall age-standardized diabetes prevalence for the latter was 6.35% but people whose primary residence was on farms had significantly lower diabetes prevalence than those living in non-farm locations (5.11% versus 7.33% respectively; p<0.0001). Diabetes risk increased with age and affected almost 17% of those older than 65 (OR 2.57; CI′ 1.63, 4.04 compared to those aged 18–45). Other known independent risk factors included family history of diabetes (OR 2.50 [CI′s 1.94, 3.23] if father; OR 3.11 [CI′s 2.44, 3.98] if mother), obesity (OR 2.66; CI′s 1.86, 3.78), as well as lower socioeconomic status, minimal/no alcohol intake and smoking. The most original finding was that exposure to insecticides conferred an increased risk for diabetes among males (OR 1.83; CI′s 1.15, 2.91). Finally, the co-morbidities with the strongest independent association with diabetes were heart disease and hypertension.ConclusionsWhile known diabetes risk factors are important determinants of diabetes in the agricultural zones of Saskatchewan, on-farm residence is protective and appears related to increased outdoor activities. In contrast, we have now shown for the first time that exposure to insecticides is an independent risk factor for diabetes among men in rural Canada.

Prevalence of High Epworth Sleepiness Scale scores in a rural population

BACKGROUND Increased daytime sleepiness is an important symptom of obstructive sleep apnea (OSA). OSA is frequently underdiagnosed, and the Epworth Sleepiness Scale (ESS) can be a useful tool in alerting physicians to a potential problem involving OSA. OBJECTIVE To measure the prevalence and determinants of daytime sleepiness measured using the ESS in a rural community population. METHODS A community survey was conducted to examine the risk factors associated with ESS in a rural population in 154 households comprising 283 adults. Questionnaire information was obtained regarding physical factors, social factors, general medical history, family medical history, ESS score, and self-reported height and weight. Multivariable binary logistic regression analysis based on the generalized estimating equations approach to account for clustering within households was used to predict the relationship between a binary ESS score outcome (normal or abnormal) and a set of explanatory variables. RESULTS The population included 140 men (49.5%) and 143 women (50.5%) with an age range of 18 to 97 years (mean [± SD] 52.0±14.9 years). The data showed that 79.2% of the study participants had an ESS score in the normal range (0 to 10) and 20.8% had an ESS score >10, which is considered to be abnormal or high sleepiness. Multivariable regression analysis revealed that obesity was significantly associated with an abnormal or high sleepiness score on the ESS (OR 3.40 [95% CI 1.31 to 8.80). CONCLUSION High levels of sleepiness in this population were common. Obesity was an important risk factor for high ESS score.

Hodgkin Lymphoma and Pesticides Exposure in Men: A Canadian Case-Control Study

ABSTRACT The objective of this study was to investigate the putative associations of specific pesticides with Hodgkin lymphoma. A population-based, case-control study of Hodgkin lymphoma was conducted among males in six regions of Canada. Data were collected by a mailed questionnaire followed by a telephone interview to obtain detailed exposures data for those reporting ≥10 hours per year of pesticide exposure. Conditional logistic regression was used to fit statisticalmodels. Comparisons of 316 Hodgkin lymphoma cases and 1506 controls identified several factors as predictors for increased Hodgkin lymphoma risk: family history of cancer, exposure to the insecticide chlorpyrifos [OR (95% CI) = 1.19 (1.03, 1.37)], and previous diagnosis of acne or shingles. The increased risk of developing Hodgkin lymphoma detected among Canadian men who used chlorpyrifos must be interpreted cautiously; however the strength of its association indicates that it requires investigation in other populations.

Multiple Myeloma and Exposure to Pesticides: A Canadian Case-Control Study

ABSTRACT The objective of this study was to investigate the putative associations of specific pesticides with multiple myeloma. A matched, population-based, case-control study was conducted among men residing in six Canadian provinces (Quebec, Ontario, Manitoba, Saskatchewan, Alberta, and British Columbia). Data were collected on 342 multiple myelome cases and 1506 age and province of residence matched controls. Data were collected by mailed questionnaires to capture demographic characteristics, antecedent medical history, detailed lifetime occupational history, smoking history, family history of cancer, and exposure to broadly characterized pesticides at home, work, and practicing hobbies. Details of pesticide exposures were collected by telephone interview for those who reported 10 hours or more per year of exposure. Exposure to pesticides grouped into major chemical classes resulted in increased risk being detected only for carbamate insecticides [odds ratio (OR) and 95% confidence interval (CI) 1.90 (1.11, 3.27) adjusted for potential confounders]. An exposure to fungicide captan [2.35 (1.03, 5.35)] was positively associated with the incidence of multiple myeloma. While an exposure to carbaryl [1.89 (0.98, 3.67)] was associated with the incidence of multiple myelome with borderline significance. The authors further suggest that certain pesticide exposures may have a role in multiple myeloma etiology, and identify specific factors warranting investigation in other populations.

Occupational exposures and Hodgkin Lymphoma: Canadian case-control study.

Objective: The objective was to study the association between Hodgkin Lymphoma (HL) and occupational exposures related to long-held occupation among males in Canada. Methods: A population-based case–control study of HL was conducted among males stratified by province of residence and age group. Conditional logistic regression was used to fit statistical models. Results: Several factors independently increased the risk of HL. Ever exposure to ionizing radiation from uranium showed a significant association with HL. Men who had smoked cigarettes for 25 years or more were the most likely to develop HL. Exposure to ultraviolet light and diagnosis with measles were negatively associated with HL, whereas diagnosis with shingles increased the risk of HL. Conclusions: The higher risk of developing HL may be associated with exposure to uranium ionizing radiation and years of cigarette smoking.

Occupational exposures and non-Hodgkin's lymphoma: Canadian case-control study

BackgroundThe objective was to study the association between Non-Hodgkins Lymphoma (NHL) and occupational exposures related to long held occupations among males in six provinces of Canada.MethodsA population based case-control study was conducted from 1991 to 1994. Males with newly diagnosed NHL (ICD-10) were stratified by province of residence and age group. A total of 513 incident cases and 1506 population based controls were included in the analysis. Conditional logistic regression was conducted to fit statistical models.ResultsBased on conditional logistic regression modeling, the following factors independently increased the risk of NHL: farmer and machinist as long held occupations; constant exposure to diesel exhaust fumes; constant exposure to ionizing radiation (radium); and personal history of another cancer. Men who had worked for 20 years or more as farmer and machinist were the most likely to develop NHL.ConclusionAn increased risk of developing NHL is associated with the following: long held occupations of faer and machinist; exposure to diesel fumes; and exposure to ionizing radiation (radium). The risk of NHL increased with the duration of employment as a farmer or machinist.

Stressful Life Events Antedating Chronic Childhood Arthritis

Objective. To investigate associations between antecedent stressful life events and occurrence of juvenile arthritis (JA). Methods. The study population comprised patients with JA referred to a pediatric rheumatology clinic between 1981 and 2010. A questionnaire, which was developed as a screening tool by the clinic, was completed at the first clinic visit by patients’ parents and, for comparison, by parents of unrelated age, sex, geographically, and temporally matched healthy controls. The entire questionnaire captured a broad array of clinical, demographic, psychosocial, and environmental data, including questions about stressful life events from 686 patients with JA and from 1042 controls. Results. Patients were more likely to have experienced a serious upset (OR 4.81; p < 0.0001), a currently ill family member (OR 2.29; p < 0.0001), separated parents (OR 1.96; p < 0.0001), or difficulties with interpersonal relationships (OR 2.54; p < 0.0001) prior to first clinic presentation compared to controls. Children with oligoarticular JA were more likely than controls to have experienced a serious upset (OR 3.46; p = 0.008), an ill family member (OR 3.79; CI 2.02, 7.11; p < 0.0001), or problems with interpersonal interactions (OR 3.32; p < 0.0001). Children with polyarticular JA were more likely to have experienced a serious upset (OR 5.68; p < 0.0001), separated parents (OR 2.66; p = 0.001), a deceased parent (OR 6.75, p = 0.017), or problems with interpersonal relationships (OR 2.39; p = 0.009). No significant differences were observed when comparing systemic JA patients to controls. Conclusion. Strong associations between stressful life events antedating the first clinic visit of patients with JA indicate that life event stresses should be identified and addressed when first encountering and managing children with JA.

Ethnicity and incidence of Hodgkin lymphoma in Canadian population

BackgroundResearch has shown that ethnicity is a significant predictor of Hodgkin lymphoma (HL). Variations in cancer incidence among ethnic groups in the same country can lead to important information in the search for etiological factors. Other risk factors important in the etiology of HL are medical history and exposure to pesticides. In this report we investigated the association between ethnicity and HL in the presence of medical history, and exposure to pesticides.MethodsThe data resulting from a matched population-based case-control study conducted in six provinces of Canada (Ontario, Quebec, Manitoba, Saskatchewan, Alberta, and British Columbia) was analyzed to determine whether or not there was any association between ethnicity and incidence of HL when adjusted for personal medical history and pesticide exposure. Information on ethnicity, personal medical history, and pesticide exposure was collected by questionnaires via mail on 316 men diagnosed with HL; and on 1506 controls. A conditional logistic regression was utilized and results were presented as odds ratios and 95% confidence intervals.ResultsIn our study population, the distribution of ethnic groups was: 38.5% North American, 15% British, 8.4% Western European, 8.2% Eastern European, 1.7% Asian, 1.4% Scandinavian and 27% of other ethnic origin. Compared to North Americans (i) the risk of HL was greater among the Eastern European descendents (Odds Ratio (ORadj): 1.82; 95% confidence interval (CI): 1.02, 3.25) and Western European (ORadj: 1.62; 95% CI: 0.95–2.76) descent population (borderline significance at 5% level); and (ii) the risk of HL was lower in Asian descents. Diagnosis with measles (ORadj: 0.72, 95% C.I.: 0.53–0.98) and/or positive history of allergy desensitization shots (ORadj: 0.55, 95% C.I.: 0.30–0.99) were negatively associated with the incidence of HL, while diagnosis with acne (ORadj: 2.12, 95% C.I.: 1.19–3.78), shingles (ORadj: 2.41, 95% C.I.: 1.38–4.22) and positive family history of cancer (ORadj: 1.93, 95% C.I.: 1.40–2.65) increased the risk of HL. Exposure to individual herbicide dichlorprop showed an increased risk of HL (ORadj: 6.35, 95% C.I.: 1.56–25.92).ConclusionIn Canada, compared to North Americans descendents, the risk of HL was significantly greater among the Eastern European and Western European descent population. Our results related to association between ethnicity and HL support the findings reported by other researchers. Our data showed that subjects who were diagnosed with measles or had allergy desensitization shots negatively associated with the incidence of HL; and other medical conditions, ever diagnosed with acne, and positive family history of cancer were positively associated with the incidence of HL.

A community-based participatory research methodology to address, redress, and reassess disparities in respiratory health among First Nations

BackgroundTo date, determinants of respiratory health in First Nations people living on reserves and means of addressing and redressing those determinants have not been well established. Hence the Saskatchewan First Nations Lung Health Project (FNLHP) is a new prospective cohort study of aboriginal people being conducted in two First Nations reserves to evaluate potential health determinants associated with respiratory outcomes. Using the population health framework (PHF) of Health Canada, instruments designed with the communities, joint ownership of data, and based on the 4-phase concept of the First Nations Regional Longitudinal Health Survey, the project aims to evaluate individual factors, contextual factors, and principal covariates on respiratory outcomes. The objective of this report is to clearly describe the methodology of (i) the baseline survey that consists of two components, an interviewer-administered questionnaire and clinical assessment; and (ii) potential intervention programs; and present descriptive results of the baseline data of longitudinal FNLHP.MethodsThe study is being conducted over 5 years (2012–2017) in two phases, baseline and longitudinal. Baseline survey has been completed and consisted of (i) an interviewer-administered questionnaire-based evaluation of individual and contextual factors of importance to respiratory health (with special focus on chronic bronchitis, chronic obstructive pulmonary disease, asthma and obstructive sleep apnea), and (ii) clinical lung function and allergy tests with the consent of study participants. The address-redress phase consists of potential intervention programs and is currently being rolled out to address-at community level (via green light program and environmental study), and redress-at policy level (via obesity reduction and improved diagnosis and treatment of obstructive sleep apnea) the issues that have been identified by the baseline data.ResultsInterviewer-administered surveys were conducted in 2012–2013 and collected data on 874 individuals living in 406 households from two reserve communities located in Saskatchewan, Canada. Four hundred and forty six (51%) females and 428 (49%) males participated in the FNLHP.ConclusionsThe information from this project will assist in addressing and redressing many of the issues involved including the provision of adequate housing, health lifestyle practices, and in planning for health service delivery.