Introduction Due to its widespread use, toxicity and volatility, exposure to the chemical formaldehyde has important implications for human health. Asthma is a common chronic inflammatory disease with both genetic and environmental factors. The common symptoms of asthma include wheezing, coughing, and shortness of breath. The objective of the present study is to evaluate the association between exposure to formaldehyde and adult asthma through systematic review. Methods A literature search was conducted using PubMed with keywords of formaldehyde, adult asthma, and other relevant terms. The basic exclusion and inclusion criteria in this study are as follows: Original randomized controlled trials (RCTs) and observational studies were eligible, but not editorials, reviews, case-reports and case‐series. Studies that focused on behavioral change or other outcomes unrelated to asthma were excluded. Lastly, articles in which full text was unavailable were excluded. Finally, after 3 selection rounds, 7 studies were included in the present systematic review. Results: These 7 studies included 3 RCTs, 2 case‐control studies and 2 cross‐sectional studies, published from 1986 to 2013. The 3 RCTs examined participants with and without asthma and investigated the acute effects of formaldehyde on respiratory phenotypes; in contrast, the 4 observational studies examined the long‐term effects of low dose formaldehyde exposure on asthma. Only 1 RCT reported a strong association between formaldehyde and adult asthma, with the intervention group developed an immediate bronchial response at a significantly lower dose of mite allergen than that of the control group with air exposure. The other 2 RCTs found no significant deleterious effect on airway allergen responses after exposure to 500 μg/m3 formaldehyde; and the concentration of formaldehyde found in the indoor environment was of minor importance for developing pulmonary symptoms. Two case-control studies reported a positive association between formaldehyde exposure and asthma symptoms, while the results in the cross‐sectional studies suggested no significant association between formaldehyde exposure and adult asthma. Conclusions Among the 3 reviewed RCTs, only 1 reported a significant association between formaldehyde and asthma. In the 4 reviewed case‐control and cross‐sectional studies, 2 suggested that exposure to formaldehyde had significant effects on bronchial responses. However, these studies represented different characteristics, hence, after integration of them, this review suggests that exposure to formaldehyde in relative low concentration may not have strong association with adult asthma. However, further studies are required to A: Try to identify more potential confounders and choose most suitable model in various conditions; B: investigate multiple patterns of formaldehyde exposure and provide different outcome measurements in RCTs. In addition, this report indicates that it is important to increase the population awareness of choosing environmental friendly decoration materials for reducing formaldehyde exposure. / published_or_final_version / Public Health / Master / Master of Public Health

published_or_final_version / abstract / toc / Clinical Psychology / Master / Master of Social Sciences

published_or_final_version / abstract / toc / Clinical Psychology / Master / Master of Social Sciences

No description available.

Rationale: Methacholine and mannitol challenges are used clinically to assess airway hyperresponsiveness (AHR). Cough during (a) high-dose methacholine challenge in individuals with methacholine-induced cough and normal airway sensitivity and (b) mannitol challenge in some individuals with asthma both occur in the absence of significant declines in forced expiratory volume in one second (FEV1). We hypothesized mechanical responses to these challenges would reflect a continuum amongst subjects with: (i) asthma; (ii) cough variant asthma (CVA) and (iii) methacholine-induced cough and normal airway sensitivity due to varying degrees of impairment/preservation of the beneficial effects of deep inspirations. Purpose: To compare cough and airway responses to mannitol and high-dose methacholine challenges between these groups. Methods: Individuals with asthma or suspected CVA were invited to participate. Subjects were challenged with mannitol and high-dose methacholine in random order 2-14 days apart. Cough frequency, spirometry and esophageal-pressure were recorded at baseline and after each dose of mannitol and methacholine to a maximal decline in FEV1 of 15% and 50% respectively. Plethysmography was used to measure lung volumes at baseline, the dose nearest to a 15% decline in FEV1 during mannitol challenge (PD15) and 20% decline in FEV1 during methacholine challenge (PC20), and at the highest dose of methacholine. Measurements were compared: (a) between groups at PD15, PC20 and the highest dose of methacholine; and (b) within groups at PD15 and PC20, and the highest equivalent level of bronchoconstriction. Results: 22 subjects (17 female; 48.0±12.7 (mean±SD years)) who completed both challenges were included. All subjects coughed during both challenges. Mechanical responses to mannitol and high-dose methacholine challenges reflected a continuum amongst groups. Six of 8 subjects with asthma were mannitol postitive (PD15=115.2±100.0 mg) and were significantly more sensitive to mannitol compared to 3 of 5 mannitol positive subjects with CVA (PD15=533.6±88.3 mg; p=0.020) and 3 of 9 mannitol positive subjects with methacholine-induced cough and normal airway sensitivity (PD15=472.8±203.0 mg; p=0.037). At the highest equivalent level of bronchoconstriction, methacholine induced significant declines in FEF50% and FEF25-75% in all subjects groups while mannitol did not. Conclusion: Mechanical responses to mannitol and high-dose methacholine challenges reflected a continuum amongst groups. / Thesis (Master, Physiology) -- Queen's University, 2012-07-27 08:58:05.298

TLRs play a key role in initiating innate immunity and in regulating the nature of the adaptive immune response. We hypothesized that functional responsiveness to TLR stimulation differs in clinically; environmentally; ethnically distinct pediatric populations. PBMC obtained from 272 children were stimulated with a panel of TLR ligands. Levels of pro- and anti-inflammatory, Th1-, Th2-associated cytokines were quantified by ELISA. We demonstrate that use of threshold concentrations of TLR4 and TLR2 ligands reveal striking differences in cytokine responses between asthmatic and non-atopic children. Specifically, non-atopic controls produce higher levels of pro-inflammatory cytokines, whereas asthmatics exhibit increased anti-inflammatory IL-10 responses. Asthmatic children exposed to environmental tobacco smoke (ETS) demonstrated elevated levels of chemokines relative to non-ETS exposed asthmatics and controls. First Nation children favor anti-inflammatory IL-10 responses, whereas Caucasian population respond to TLR activation by production of more robust pro-inflammatory and Th1 biased cytokine and chemokine responses.

The study was conducted with a total of 13980 children of the 1995 birth cohort, who were living in Manitoba by the end of December, 2006. Higher frequency of RSV-associated LRTI before 2 years was associated with higher risks of asthma diagnosis at 7 and 11 years and also with risks of transient wheeze and early persistent asthma. Higher risk of asthma diagnosis was associated with more severe episode(s) of RSV-associated LRTI within the first 2 years of life. First clinically significant RSV-LRTI between 6 and 12 months was associated with the highest risks of asthma diagnosis at 7 and at 11 years. But first RSV-associated LRTI within the first 6 months of life was associated with the highest risk of asthma/transient wheezing before the age of 3 years and early persistent asthma and transient wheeze. These associations were diminishing with increasing age of the children of the study cohort.

No description available.

New Zealand has one of the highest asthma prevalence rates among developed countries and previous research attributes this partly to poor socioeconomic conditions and to insufficient home heating in particular. Retrospective empirical studies from overseas suggest that home heating is associated with asthma rates. However, the evidence to date is not conclusive. In this thesis, I present a theoretical framework and empirically investigate the link between home heating and asthma hospital admissions in New Zealand using panel data techniques and controlling for endogeneity. The hypothesis that higher electricity prices (via less adequate heating) increase asthma admissions is tested and receives strong empirical support across a number of model specifications and datasets used.

There is evidence that children with asthma exhibit more externalizing behaviour problems than other children. Impulsive behaviours can mark the onset and severity of externalizing behaviour problems. The present paper reports an exploratory examination of relationships between functional asthma severity and impulsivity in 6 and 7 year old children with asthma (N = 16). Participants with varying functional asthma severity were recruited at age 5 from a larger community study (the Children’s Learning Study). Parents completed items from three subscales of the Connors’ Parent Rating Scale-Revised (CPRS-R), the Hyperactive-Impulsive, Conners’ Global Index: Restless-Impulsive and the DSM-IV Hyperactive-Impulsive subscales. Children completed the Two Choice Paradigm (TCP), a computer program measuring delay aversion type impulsive behaviours. Mean (SD) CPRS-R Hyperactive-Impulsive, Conners’ Global Index: Restless-Impulsive and DSM-IV Hyperactive-Impulsive subscale scores were 59 (11), 56 (10) and 59 (10) respectively. There was no correlation between functional asthma severity and delay aversion or CPRS-R subscale scores and there was no evidence of a trend for such a relationship. Preliminary investigations conducted with a small sample of 6-7 year-old children with asthma thus suggest that functional asthma severity is not related to impulsivity.