Sex-specific characteristics for the coexistence of asthma and COPD in the Canadian population: a cross-sectional analysis of CLSA data.

Objective: The coexistence of asthma and COPD (asthma + COPD) is a condition found among patients who present with clinical features of both asthma and COPD. Epidemiological evidence points to an increasingly disproportionate burden of asthma + COPD and COPD in females. The objective of this cross-sectional study is to identify female and male-specific epidemiological and clinical characteristics associated with asthma + COPD.Methods: Baseline data from the comprehensive cohort of Canadian Longitudinal Study on Aging (CLSA) were used in this cross-sectional study which included 30,097 subjects between the ages of 45- and 85-years Participants were categorized into four mutually exclusive groups: asthma + COPD, COPD-only, asthma-only and neither asthma nor COPD.Results: The prevalence was significantly greater in females than males for asthma + COPD (2.71% vs. 1.41%; p < 0.001), COPD-only (3.22% vs. 2.87%; p < 0.001) and asthma-only (13.31% vs. 10.11%; p < 0.001). The association between smoking and asthma + COPD was modified by age in females. Osteoporosis and underactive thyroid disease were significantly more prevalent in females than in males in asthma + COPD, COPD-only and asthma-only groups. In asthma + COPD group, a greater proportion of respiratory symptoms associated with asthma was observed in females whereas a greater proportion of respiratory symptoms associated with COPD was observed in males. Severity of airway obstruction determined by spirometry measurements was greater in males than females.Conclusions: In the Canadian adult population, several epidemiological and clinical characteristics in asthma + COPD varied between females and males. The findings in this study will help healthcare professional in the recognition and management of coexisting asthma and COPD in females and males.

Sex-Specific Genetic Determinants of Asthma-COPD Phenotype and COPD in Middle-Aged and Older Canadian Adults: An Analysis of CLSA Data.

The etiology of sex differences in the risk of asthma-COPD phenotype and COPD is still not completely understood. Genetic and environmental risk factors are commonly believed to play an important role. This study aims to identify sex-specific genetic markers associated with asthma-COPD phenotype and COPD using the Canadian Longitudinal Study on Aging (CLSA) Baseline Comprehensive and Genomic data. There were a total of 1,415 COPD cases. Out of them, 504 asthma-COPD phenotype cases were identified. 20,524 participants without a diagnosis of asthma and COPD served as controls. We performed genome-wide SNP-by-sex interaction analysis. SNPs with an interaction p-value < 10-5 were included in a sex-stratified multivariable logistic regression for asthma-COPD phenotype and COPD outcomes. 18 and 28 SNPs had a significant interaction term p-value < 10-5 with sex in the regression analyses of asthma-COPD phenotype and COPD outcomes, respectively. Sex-stratified multivariable analysis of asthma-COPD phenotype showed that 7 SNPs in/near SMYD3, FHIT, ZNF608, RIMBP2, ZNF133, BPIFB1, and S100B loci were significant in males. Sex-stratified multivariable analysis of COPD showed that 8 SNPs in/near MAGI1, COX18, OSTC, ELOVL5, C7orf72 FGF14, and NKAIN4 were significant in males, and 4 SNPs in/near genes CAMTA1, SATB2, PDE10A, and LINC00908 were significant in females. An SNP in the ZPBP gene was associated with COPD in both males and females. Identification of sex-specific loci associated with asthma-COPD phenotype and COPD may offer valuable evidence toward a better understanding of the sex-specific differences in the pathophysiology of the diseases.

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.

Characteristics and Prognostic Factors for Return to Work in Public Safety Personnel with Work-Related Posttraumatic Stress Injury Undergoing Rehabilitation.

PURPOSE: Public safety personnel (PSP) are at risk of developing posttraumatic stress injury (PTSI) due to exposure to traumatic experiences and accidents. Rehabilitation programs are available, but their success varies. We studied: (1) characteristics of PSP undergoing PTSI rehabilitation in comparison to non-PSP workers; and (2) predictive value of various factors for return to work. Methods A population-based cohort study was conducted using data on injured workers undergoing PTSI rehabilitation. Of the 488 workers included, 131 were PSP. Outcome measures were: (1) return to pre-accident work at rehabilitation discharge; (2) days receiving wage replacement benefits in the year following rehabilitation. Results PSP were mainly employed (90.8%), male (59.5%), paramedics/ambulance workers (58.0%); a minority (43.5%) returned to pre-accident work after rehabilitation. Compared to non-PSP workers, PSP were more likely to initially be diagnosed with psychological injuries (94.7% versus 59.4%, p < 0.001) rather than musculoskeletal injuries. Return to pre-accident work was predicted by shorter injury duration, having a primary mental health diagnosis, working at time of admission, and not having symptoms requiring treatment in a complex rehabilitation program. PSPs were slower to experience full recovery in the year after rehabilitation. Factors predicting fewer benefit days included not having a secondary psychological injury, being employed, and working at time of admission. Conclusions Most PSP did not return to work in full after PTSI rehabilitation. Outcomes are likely to improve by starting treatment earlier and maintaining connections with the workplace.

Current Knowledge of Asthma-COPD Overlap (ACO) Genetic Risk Factors, Characteristics, and Prognosis.

Asthma-COPD overlap (ACO) is a newly identified phenotype of chronic obstructive airway diseases with shared asthma and COPD features. Patients with ACO are poorly defined, and some evidence suggests that they have worse health outcomes and greater disease burden than patients with COPD or asthma. Generally, there is no evidence-based and universal definition for ACO; several consensus documents have provided various descriptions of the phenotype. In addition, the mechanisms underlying the development of ACO are not fully understood. Whether ACO is a distinct clinical entity with its particular discrete genetic determinant different from asthma and COPD alone or an intermediate phenotype with overlapping genetic markers within asthma and COPD spectrum of obstructive airway disease remains unproven. This review summarizes the current knowledge of the genetic risk factors, characteristics, and prognosis of ACO.

Patient Reported Outcomes Predicting Spontaneous Stone Passage May Not Have Acceptable Accuracy.

PURPOSE: We assessed the accuracy of patient reported outcomes for predicting spontaneous ureteral stone passage. MATERIALS AND METHODS: Patients with new unilateral ureteral calculi were prospectively assessed regarding current symptoms and whether they believed their stone had passed. The primary outcome was successful spontaneous stone passage as confirmed by ultrasound, and kidney, ureter and bladder x-ray. Spontaneous stone passage was compared to patient reported outcome responses to assess accuracy. RESULTS: Of the 212 patients 105 (49.5%) had successful spontaneous stone passage at a mean followup of 17.6 days. Compared to the unsuccessful spontaneous stone passage group, those with successful spontaneous stone passage had significantly smaller (mean 5.4 vs 7.6 mm), more distal (71.4% vs 34.6%) stones with slightly longer average time to followup at first visit (19.2 vs 16.0 days). Additionally, there was more patient reported cessation of pain (77.1% vs 44.9%) and perceived stone passage (55.2% vs 13.1%) in this group. Cessation of pain was 79.7% (95% CI 67.1-89.0) sensitive and 55.8% (95% CI 44.0-67.1) specific for successful spontaneous stone passage. Likewise, patient reported stone passage was 59.3% (95% CI 45.7-71.9) sensitive and 87.0% (95% CI 77.4-93.5%) specific. In the multivariable logistic regression analysis cessation of pain (OR 4.02, 95% CI 1.91-8.47, p <0.01) and reported stone passage (OR 3.79, 95% CI 1.73-8.28, p <0.01) were independent predictors of successful spontaneous stone passage. CONCLUSIONS: Cessation of pain and patient reported stone passage are independent predictors of successful spontaneous stone passage. However, both assessments may incorrectly gauge spontaneous stone passage, which raises concern for their validity as a sole clinical end point.

Characteristics of asthma and COPD overlap syndrome (ACOS) in the Canadian population.

Objective: Asthma is a chronic disease affecting both children and adults, whereas chronic obstructive pulmonary disease (COPD) is a respiratory disease most commonly related to smoking and is usually seen in adults. When the airway disease shares features of both asthma and COPD, the phenotype is referred to as asthma and COPD overlap syndrome (ACOS). The objective of this cross-sectional study is to characterize ACOS in the Canadian population. Methods: Data from the first three cycles of the Canadian Health Measures Survey (CHMS) were used in this study. The study included 9059 subjects aged 30 years and above. The CHMS included a detailed interviewer-administered questionnaire and spirometry measurements. Based on the self-report, subjects were categorized into control, ACOS, COPD only and asthma only groups. Results: The prevalence of ACOS, COPD and asthma groups was 1.59%, 2.21% and 6.65%, respectively. The proportion of females was significantly greater than males in the ACOS group. The proportion of wheeze was highest in the ACOS group (64.93%) whereas the prevalence of shortness of breath was the highest in the COPD group (46.25%). Heart disease, cancer, arthritis and liver disease were more prevalent in the ACOS group than in COPD, asthma and control groups. Severity of airway obstruction was the highest in the ACOS group and was followed by COPD, asthma and control groups, respectively. Conclusions: Characteristics of ACOS in the Canadian population were similar to those observed in the developed countries and longitudinal studies are required to determine the incidence and risk factors of ACOS.

Reasons and outcomes for patients receiving ICS/LABA agents prior to, and one month after, emergency department presentations for acute asthma.

Objective: Asthma is a common emergency department (ED) presentation. This study examined factors associated with inhaled corticosteroids/long-acting beta-agonist (ICS/LABA) use; and management and outcomes before and after ED presentation. Methods: Secondary analysis of a prospective cohort study; adults treated for acute asthma in Canadian EDs underwent a structured interview before discharge and were followed-up four weeks later. Patients received oral corticosteroids (OCS) at discharge and, at physician discretion, most received ICS or ICS/LABA inhaled agents. Analyses focused on ICS/LABA vs "other" treatment groups at ED presentation. Results: Of 807 enrolled patients, 33% reported receiving ICS/LABA at ED presentation; 62% were female, median age was 31 years. Factors independently associated with ICS/LABA treatment prior to ED presentation were: having an asthma action plan; using an asthma diary/peak flow meter; influenza immunization; not using the ED as usual site for prescriptions; ever using OCS and currently using ICS. Patients were treated similarly in the ED and at discharge; however, relapse was higher in the ICS/LABA group, even after adjustment. Conclusion: One-third of patients presenting to the ED with acute asthma were already receiving ICS/LABA agents; this treatment was independently associated with preventive measures. While ICS/LABA management improves control of chronic asthma, patients using these agents who develop acute asthma reflect higher severity and increased risk of future relapse.

The relationship between physical fitness and occupational injury in emergency responders: A systematic review.

BACKGROUND: Emergency responders have jobs with physical demands that put them at risk of musculoskeletal injuries. OBJECTIVES: This paper systematically reviews existing literature examining the relationship between fitness and occupational injury in this group. METHODS: Comprehensive electronic searches were conducted using key words relating to musculoskeletal injury, fitness, and emergency responders. RESULTS: Eleven articles included in the review provided limited evidence for the relationship between physical fitness test scores and injury risk. There appears to be a correlation between better aerobic fitness and decreased risk of injury. CONCLUSIONS: Evidence of the relationship between aspects of physical fitness and occupational injury in emergency responders is extremely limited. More research is required to expand the knowledge in this area and to draw more definitive conclusions.

Short- and long-term mortality after pulmonary embolism in patients with and without cancer.

Pulmonary embolism (PE) is a major cause of mortality and morbidity. It is known that the risk of death varies by provoking factors; however, it is unknown if the risk of death persists beyond the initial diagnosis among patients with cancer-associated and non-cancer provoked patients. In this study, we aimed to investigate the effect of cancer on overall, short- and long-term mortality in a cohort of consecutive incident PE patients. Using administrative databases, we identified all incident cases of PE between 2004 and 2012 in Alberta, Canada. Cases were stratified by provoking factors (i.e. unprovoked, provoked, and cancer-associated). A multivariate Cox survival model was used to estimate the hazard ratios of short- and long-term death. We identified 8641 patients with PE, among which 42.2% were unprovoked, 37.9% were provoked and 19.9% were cancer-associated. The 1-year and 5-year survival probabilities were 60% (95% CI: 57-64%) and 39% (95% CI: 36-43%) in patients with cancer-associated PE, 93% (95% CI: 92-94%) and 80% (95% CI: 78-81%) in provoked PE, and 94% (95% CI: 93-95%) and 85% (95% CI: 83-87%) in unprovoked PE, respectively. Compared to patients with unprovoked events, both short-term and long-term survival in patients with cancer-associated PE have a higher observed risk of all-cause mortality in all age groups ( p<0.001). In contrast, patients with provoked events had a similar short- and long-term all-cause mortality. While PE has a significant mortality in all risk groups, patients with cancer have a higher risk of short-term mortality compared to patients with unprovoked PE.

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.

Agricultural injuries among farm and non-farm children and adolescents in Alberta, Canada.

BACKGROUND: Understanding of the specific risk of agricultural injury sustained by different populations of children and adolescents is needed for effective safety intervention. OBJECTIVE: To compare the rates and patterns of agricultural injury incidence (fatal and non-fatal injury) between farm and non-farm children less than 18 years of age in Alberta, Canada. METHODS: A total of 115 378 children (five subgroups: two groups of farm children and three groups of non-farm children) in Alberta were followed from 1999 to 2010 to examine injury incidence using the linkage of three administrative health databases. A recurrent event survival analysis using Cox proportional hazards regression was carried out. RESULTS: A total of 1 849 agricultural injury episodes (1 616 emergency department visits, 225 hospitalizations, and 8 deaths) were identified from 1999 to 2010. The age- and gender-adjusted rate (per 100 000 person years) of agricultural injury was 672.3 for rural-living farm children, 369.4 for urban-living farm children, 180.2 for rural non-First Nations (FN) children, 64.4 for rural FN children, and 23.7 for urban children in descending order. CONCLUSION: Specific strategies for different children's populations to prevent agricultural injuries and to extend agricultural injury controls to non-farming populations are needed.

Association of living in a farming environment with asthma incidence in Canadian children.

OBJECTIVE: The objective of this population-based 14-year follow-up study was to examine the effect of living in a farm environment on asthma incidence in children. METHODS: A total of 10,941 children of ages 0 to 11 years who were free of asthma and wheeze at the baseline (1994-1995) in the National Longitudinal Survey of Children and Youth were considered in the study. Children's living environment was classified, based on interviewer's observation, into three categories: non-rural, rural non-farming, and farming. An incidence of asthma was obtained from health-professional diagnosed asthma reported either by the person most knowledgeable for children under 15 years or by the children themselves if they were of ages 16 years and over. RESULTS: The 14-year cumulative incidence of asthma among children living in farming environments was 10.18%, which was significantly lower than that observed for children living in rural non-farming (13.12%) and non-rural environments (16.50%). After adjusting for age group, number of older siblings, allergy, parental history of asthma, dwelling in need of repairs and SES index, a dose-response relationship was observed with children living in rural non-farming and farming environments having significantly reduced risk of asthma [hazard ratio (HR): 0.77; 95% confidence interval (CI): (0.60, 1.00); p = 0.047 and HR: 0.56; 95% CI: (0.41,0.77); p < 0.001] in comparison to those living in non-rural environments. CONCLUSION: This cohort study provides further evidence that living in a farming environment during childhood is protective of asthma incidence in adolescence and adulthood and this finding provides further support for the hygiene hypothesis.

Gender Differences in the Association of Individual and Contextual Exposures with Lung Function in a Rural Canadian Population.

INTRODUCTION: To investigate the association of individual and contextual exposures with lung function by gender in rural-dwelling Canadians. METHODS: A cross-sectional mail survey obtained completed questionnaires on exposures from 8263 individuals; a sub-sample of 1609 individuals (762 men, 847 women) additionally participated in clinical lung function testing. The three dependent variables were forced expired volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio. Independent variables included smoking, waist circumference, body mass index, indoor household exposures (secondhand smoke, dampness, mold, musty odor), occupational exposures (grain dust, pesticides, livestock, farm residence), and socioeconomic status. The primary analysis was multiple linear regression, conducted separately for each outcome. The potential modifying influence of gender was tested in multivariable models using product terms between gender and each independent variable. RESULTS: High-risk waist circumference was related to reduced FVC and FEV1 for both genders, but the effect was more pronounced in men. Greater pack-years smoking was associated with lower lung function values. Exposure to household smoke was related to reduced FEV1, and exposure to livestock, with increased FEV1. Lower income adequacy was associated with reduced FVC and FEV1. CONCLUSION: High-risk waist circumference was more strongly associated with reduced lung function in men than women. Longitudinal research combined with rigorous exposure assessment is needed to clarify how sex and gender interact to impact lung function in rural populations.

Pesticide exposures and respiratory health in general populations.

Human exposures to pesticides can occur in the workplace, in the household and through the ambient environment. While several articles have reviewed the impact of pesticide exposures on human respiratory health in occupational settings, to the best of our knowledge, this article is the first one to review published studies on the association between pesticide exposures and human respiratory health in the general populations. In this article, we critically reviewed evidences up to date studying the associations between non-occupational pesticide exposures and respiratory health in general populations. This article also highlighted questions arising from these studies, including our recent analyses using the data from the Canadian Health Measures Survey (CHMS), for future research. We found few studies have addressed the impact of environmental pesticide exposures on respiratory health, especially on lung function, in general populations. In the studies using the data from CHMS Cycle 1, exposures to OP insecticides, pyrethroid insecticides, and the organochlorine pesticide DDT were associated with impaired lung function in the Canadian general population, but no significant associations were observed for the herbicide 2,4-D. Future research should focus on the potential age-specific and pesticide-specific effect on respiratory health in the general population, and repeated longitudinal study design is critical for assessing the temporal variations in pesticide exposures. Research findings from current studies of non-occupational pesticide exposures and their health impact in general population will help to improve the role of regulatory policies in mitigating pesticide-related public health problems, and thereafter providing greater benefit to the general population.

A retrospective, multicenter analysis of the predictive value of mitotic rate for sentinel lymph node (SLN) positivity in thin melanomas.

BACKGROUND: There is a paucity of studies to substantiate whether the presence of a single mitosis justifies sentinel lymph node (SLN) biopsy (SLNB) in thin melanomas. OBJECTIVE: We sought to determine if mitotic rate is associated with SLNB outcome when taking into account other prognostic factors. METHODS: All cases of melanoma that underwent SLNB in the province of Alberta, Canada, between 2007 and 2013 were reviewed through a provincial tumor database. RESULTS: A total of 1072 patients fulfilled inclusion criteria. When analyzing all melanomas regardless of thickness, mitotic rate was a good predictor of SLN status. When stratified by Breslow thickness, only intermediate melanomas (1.01-2.0 mm) demonstrated a significant relationship between mitotic rate and positive SLN status (P = .010). For melanomas 1 mm or smaller, mitotic rate was not associated with SLN status. A statistically significant interaction was identified between Breslow thickness and mitotic rate such that for decreasing Breslow depth, the effect of mitotic rate on SLNB status diminished (P = .028). LIMITATIONS: The study was retrospective in nature. There is underlying variability in mitotic rate reporting methods over time, and between different dermatopathologists. CONCLUSIONS: Mitotic rate does not have unequivocal utility in predicting SLNB status in thin melanomas. There is a significant interaction between mitotic rate and Breslow depth, such that the predictive value of mitotic rate on SLN positivity may be dependent on Breslow thickness.

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.

Urinary concentrations of pyrethroid metabolites and its association with lung function in a Canadian general population.

OBJECTIVES: While there is increasing concern about the health impact of pyrethroid insecticides, little is known about their effect on lung function. In this cross-sectional study, urinary concentrations of pyrethroid (PYR) metabolites and their associations with lung function were examined among a Canadian general population using data from the Canadian Health Measures Survey (CHMS). METHODS: Urinary concentrations of 5 pyrethroid metabolites (3-PBA, 4-F-3-PBA, cis-DCCA, trans-DCCA and cis-DBCA) were available for 5436 CHMS participants aged 6-79 years. Lung function parameters considered were forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC ratio and forced expiratory flow between 25% and 75% of FVC. Multiple linear regression analyses were used to examine associations between PYR concentrations and lung function in children (6-11 years), adolescents (12-19 years) and adults (20-79 years), respectively. RESULTS: Almost all CHMS participants (99.8%) had PYR metabolites detectable in urine. In multiple linear regression analyses, 1 unit increase in log transformed urinary concentration (nmol/g creatinine) of total pyrethorid metabolites (ΣPYR) was associated with a 17.4 mL reduction in FEV1 (p=0.045) in children, a 37.1 mL reduction in FVC (p=0.05) in adolescents and a 0.3% (p=0.01) increase in FEV1/FVC ratio in adults. CONCLUSIONS: These results show evidence of widespread exposures to pyrethroid insecticides among the Canadian general population. Pyrethroid exposures were associated with lower FEV1 in children, lower FVC in adolescents and relatively higher FEV1/FVC ratio in adults. Further research is necessary to confirm the potential effect of pyrethroid insecticides on lung function reported in this study.