No description available.

A thirty year follow-up survey was carried out to determine the prevalence of adult onset wheeze in a randomly selected community cohort of 2,056 adults who had had no childhood respiratory symptoms when they were originally studied in 1964. New onset wheezing symptoms developed at a steady rate of 0.5 per 100 person years between age 15 and 14; 11.5% of subjects reported having had an attack of wheezing for the first time during this period of their lives. Adult onset disease accounted for a greater proportion (62.9%) of current wheezing in middle age than child onset disease (37.1%). The risk of adult onset wheeze among all cases who had ever wheezed since age 15 increased with low socioeconomic status, current smoking, positive atopic status and positive family history of atopic disease. Gender was not related to risk of wheeze. Vitamin C and E consumption were inversely related to the risk of current wheeze (i.e. wheeze in the previous 12 months); analyses stratified by social class and smoking habit suggested that these inverse associations were stronger in the manual compared to the nonmanual class, and among smokers compared to nonsmokers. Childhood factors, including father's social class, sibship structure and common childhood infections were not related to adult onset wheeze. The pattern of significant independent risk factors differed between three distinct subgroups of cases who reported doctor-diagnosed asthma (n=24), chronic cough and phlegm (n=31) or other wheeze (n=47). Manual social class was associated with cough and phlegm and other wheeze. Smoking was only related to cough and phlegm. Atopy was associated with doctor-diagnosed asthma and with cough and phlegm. Family history of atopic disease was related to all subgroups, suggesting that despite apparent heterogeneity in diagnostic labelling, concurrent symptoms and other risk factors, the different forms of adult onset wheeze may share a common allergic basis.

Doctor of Philosophy(PhD) / Over the last 20 years both asthma and obesity have increased in prevalence. What is the link? There are data to suggest that increasing obesity is a risk for the increase in prevalence of asthma. A number of mechanisms have been postulated including the effects of reduced lung volume on bronchial reactivity and mechanical changes with lower lung volumes. Other possibilities include other obesity-induced co-morbidities including gastro-oesophageal reflux. The aim of this thesis was to evaluate the link between asthma and obesity in both adult and childhood populations and to undertake experimental studies to examine the effects of changes in lung volume on bronchial reactivity. In chapter 1, the literature is reviewed. The current literature suggests that there is a link between diagnosis of asthma, new onset of asthma, symptoms of shortness of breath and wheeze. In chapter 2, data on 1997 adults in 3 population studies were analysed and the association between body mass index (BMI) and symptoms of shortness of breath and wheeze, diagnosis of asthma, medication usage for asthma, lung function and bronchial responsiveness were studied. This study showed that obesity was a risk for recent asthma (OR 2.04; 95%CI 1.02-3.76, p=0.048), symptoms of shortness of breath and wheeze (OR 2.6; 95%CI 1.46- 4.70, p=0.001), and medication usage for asthma (OR 2.53; 95%CI 1.36-4.70, p=0.003). There was a reduction in lung volume as measured by forced vital capacity (FVC), but there was no increase in bronchial hyperresponsiveness (BHR) (OR 0.87; 95% CI 0.35-2.21, p=0.78). Thus although the symptoms of asthma are increased there were no increases in BHR, despite significantly reduced lung volumes. The increase the medication usage is unlikely to have normalised the BHR, as there were ongoing symptoms suggestive of asthma. In chapter 3, data on 5993 children in 7 population studies were analysed and the association between BMI percentile and symptoms of cough, wheeze, ix diagnosis of asthma, medication usage for asthma, atopy, lung function and bronchial responsiveness was studied. After adjusting for atopy, sex, age, smoking and family history, BMI was a significant risk factor for wheeze ever (OR=1.06; 95%CI 1.01-1.10, p=0.008) and cough (OR=1.09; 95%CI 1.05-1.14, p=0.001) but not for recent asthma (OR=1.02; 95%CI 0.98-1.07 p=0.43), or bronchial hyperresponsiveness (OR=0.97; 95%CI 0.95-1.04 p=0.77). In girls, a higher BMI was significantly associated with higher prevalence of atopy (x2 trend 7.9, p=0.005), wheeze ever (x2 trend 10.4, p=0.001), and cough (x2 trend 12.3, p<0.001). These were not significant in boys. With increasing BMI in children, there was no reduction in lung volume, no increase in airway obstruction and no increase in bronchial responsiveness. In chapter 4, the hypothesis that obesity per se is associated with bronchial responsiveness was tested. Six obese women without asthma were compared to 6 non-obese women without asthma with high dose methacholine challenges to assess the bronchial responsiveness. There was no increase in bronchial responsiveness, and no difference in the position or shape of the high dose methacholine curve despite the fact that these women had reduced lung volumes associated with their obesity. In chapter 5, the hypothesis whether reduced lung volume per se would cause a change in greater mechanical effect, ie more marked airway narrowing in both non-asthmatic and asthmatic subjects was tested. Lung volumes and methacholine challenges were undertaken in the supine and erect position on different days. As expected in normal subjects there was a small reduction in lung volume on lying down, this was associated with an increase in the measure of bronchial reactivity DRR. In contrast, in asthmatics, there was no acute fall in lung volume and there were variable changes in the index of reactivity suggesting non-homogeneity in the lung function abnormality. This suggests changes in bronchial reactivity can occur without any relationship to lung volume change. These negative results suggest that lung volume changes that may occur in obesity are unlikely contributors to the apparent increase in asthma symptoms. In chapter 6, the hypothesis that the supposed increase in asthma symptoms in the obese were due to the effects of gastro-oesophageal reflux were assessed in 147 obese subjects graded for gastro-oesophageal reflux severity using manometry and gastroscopy. This study showed that subjects with increased gastro-oesophageal reflux did not have subjective increases in asthma prevalence, obstructive sleep apnoea, or snoring however they had a clear worsening of gas transfer as measured by carbon monoxide transfer suggesting a greater level of parenchymal disease. The overall results are that there is an increase of diagnosis of asthma, increase in symptoms of asthma and medication usage for the treatment of asthma in the obese. Objectively despite reductions in lung volume, there is no increase in bronchial responsiveness in this group suggesting that these symptoms are not related to true asthma, but to alternative co-morbidities associated with obesity such as gastro-oesophageal reflux. Notably gastrooesophageal reflux was not associated with increased asthma prevalence or airway obstruction. However it was associated with reduced gas transfer suggesting parenchymal disease. This suggests that the increase in symptoms of wheeze and shortness of breath in the obese should not be attributed to asthma in the absence of variable airflow limitation that is reversible spontaneously or with treatment, or with an increase in the existing bronchial hyperresponsiveness (BHR) to a variety of stimuli.

Doctor of Philosophy(PhD) / Over the last 20 years both asthma and obesity have increased in prevalence. What is the link? There are data to suggest that increasing obesity is a risk for the increase in prevalence of asthma. A number of mechanisms have been postulated including the effects of reduced lung volume on bronchial reactivity and mechanical changes with lower lung volumes. Other possibilities include other obesity-induced co-morbidities including gastro-oesophageal reflux. The aim of this thesis was to evaluate the link between asthma and obesity in both adult and childhood populations and to undertake experimental studies to examine the effects of changes in lung volume on bronchial reactivity. In chapter 1, the literature is reviewed. The current literature suggests that there is a link between diagnosis of asthma, new onset of asthma, symptoms of shortness of breath and wheeze. In chapter 2, data on 1997 adults in 3 population studies were analysed and the association between body mass index (BMI) and symptoms of shortness of breath and wheeze, diagnosis of asthma, medication usage for asthma, lung function and bronchial responsiveness were studied. This study showed that obesity was a risk for recent asthma (OR 2.04; 95%CI 1.02-3.76, p=0.048), symptoms of shortness of breath and wheeze (OR 2.6; 95%CI 1.46- 4.70, p=0.001), and medication usage for asthma (OR 2.53; 95%CI 1.36-4.70, p=0.003). There was a reduction in lung volume as measured by forced vital capacity (FVC), but there was no increase in bronchial hyperresponsiveness (BHR) (OR 0.87; 95% CI 0.35-2.21, p=0.78). Thus although the symptoms of asthma are increased there were no increases in BHR, despite significantly reduced lung volumes. The increase the medication usage is unlikely to have normalised the BHR, as there were ongoing symptoms suggestive of asthma. In chapter 3, data on 5993 children in 7 population studies were analysed and the association between BMI percentile and symptoms of cough, wheeze, ix diagnosis of asthma, medication usage for asthma, atopy, lung function and bronchial responsiveness was studied. After adjusting for atopy, sex, age, smoking and family history, BMI was a significant risk factor for wheeze ever (OR=1.06; 95%CI 1.01-1.10, p=0.008) and cough (OR=1.09; 95%CI 1.05-1.14, p=0.001) but not for recent asthma (OR=1.02; 95%CI 0.98-1.07 p=0.43), or bronchial hyperresponsiveness (OR=0.97; 95%CI 0.95-1.04 p=0.77). In girls, a higher BMI was significantly associated with higher prevalence of atopy (x2 trend 7.9, p=0.005), wheeze ever (x2 trend 10.4, p=0.001), and cough (x2 trend 12.3, p<0.001). These were not significant in boys. With increasing BMI in children, there was no reduction in lung volume, no increase in airway obstruction and no increase in bronchial responsiveness. In chapter 4, the hypothesis that obesity per se is associated with bronchial responsiveness was tested. Six obese women without asthma were compared to 6 non-obese women without asthma with high dose methacholine challenges to assess the bronchial responsiveness. There was no increase in bronchial responsiveness, and no difference in the position or shape of the high dose methacholine curve despite the fact that these women had reduced lung volumes associated with their obesity. In chapter 5, the hypothesis whether reduced lung volume per se would cause a change in greater mechanical effect, ie more marked airway narrowing in both non-asthmatic and asthmatic subjects was tested. Lung volumes and methacholine challenges were undertaken in the supine and erect position on different days. As expected in normal subjects there was a small reduction in lung volume on lying down, this was associated with an increase in the measure of bronchial reactivity DRR. In contrast, in asthmatics, there was no acute fall in lung volume and there were variable changes in the index of reactivity suggesting non-homogeneity in the lung function abnormality. This suggests changes in bronchial reactivity can occur without any relationship to lung volume change. These negative results suggest that lung volume changes that may occur in obesity are unlikely contributors to the apparent increase in asthma symptoms. In chapter 6, the hypothesis that the supposed increase in asthma symptoms in the obese were due to the effects of gastro-oesophageal reflux were assessed in 147 obese subjects graded for gastro-oesophageal reflux severity using manometry and gastroscopy. This study showed that subjects with increased gastro-oesophageal reflux did not have subjective increases in asthma prevalence, obstructive sleep apnoea, or snoring however they had a clear worsening of gas transfer as measured by carbon monoxide transfer suggesting a greater level of parenchymal disease. The overall results are that there is an increase of diagnosis of asthma, increase in symptoms of asthma and medication usage for the treatment of asthma in the obese. Objectively despite reductions in lung volume, there is no increase in bronchial responsiveness in this group suggesting that these symptoms are not related to true asthma, but to alternative co-morbidities associated with obesity such as gastro-oesophageal reflux. Notably gastrooesophageal reflux was not associated with increased asthma prevalence or airway obstruction. However it was associated with reduced gas transfer suggesting parenchymal disease. This suggests that the increase in symptoms of wheeze and shortness of breath in the obese should not be attributed to asthma in the absence of variable airflow limitation that is reversible spontaneously or with treatment, or with an increase in the existing bronchial hyperresponsiveness (BHR) to a variety of stimuli.

No description available.

Trabalhadores expostos a animais de laboratório possuem elevado risco de desenvolvimento de reações alérgicas a proteínas animais, conhecidas como alergia a animais de laboratório. A constante eliminação de proteínas dos animais através da saliva, suor e principalmente pela urina faz com que os laboratórios e biotérios tornem-se lugares propícios para o desenvolvimento de reações alérgicas. É de conhecimento que a atopia, definida como teste cutâneo de hipersensibilidade imediata (TCHI) a qualquer alérgeno, é um dos principais fatores de risco para alergia a animais de laboratório. Ao se estudar atopia como fator de risco, acreditamos que seria mais efetivo analisar os efeitos da sensibilização a alérgenos ocupacionais em comparação aos comuns, pois nossa hipótese é de que, assim, chegamos ao principal marcador de risco. O presente estudo teve como objetivo investigar a associação entre sensibilização alérgica ocupacional e a presença de desfechos clínicos. Especulamos que a contínua exposição ocupacional ao alérgeno ocupacional sensibilizante faça com que a sensibilização ocupacional seja melhor marcador de risco para tais reações alérgicas do que a sensibilização comum. O presente estudo transversal foi realizado em duas universidades brasileiras, onde trabalhadores e estudantes eram expostos a pelo menos um dos seguintes animais: rato, camundongo, cobaia, coelho e hamster. Os voluntários foram submetidos à TCHI, com 5 alérgenos denominados ocupacionais (alérgenos de rato, camundongo, cobaia, coelho e hamster) e 11 alérgenos chamados comuns (alérgenos de ácaros, gato, cachorro, baratas, fungos e mistura de gramíneas). Os indivíduos foram alocados em grupos de acordo com o resultado do TCHI: grupo não sensibilizado (TCHI negativo para todos os alérgenos testados), grupo sensibilização comum (TCHI positivo para qualquer alérgeno comum) e grupo sensibilização ocupacional (TCHI positivo para qualquer alérgeno ocupacional). Os indivíduos responderam questões sobre características da exposição a animais, sintomas, doenças alérgicas e respiratórias, e também foram submetidos à espirometria e teste de broncoprovocação com manitol para detectar hiperreatividade brônquica (HRB). Razão de prevalência (RP) foi estimada usando regressão de Poisson. Dados de 453 indivíduos foramanalisados. O grupo não sensibilizado foi composto por 237 indivíduos, o grupo sensibilização comum, composto por 142 indivíduos e o grupo sensibilização ocupacional, composto por 74 indivíduos. A sensibilização ocupacional associou-se ao aumento de risco para os seguintes desfechos: sintomas cutâneos (RP: 1,36; intervalo de confiança de 95% (IC95%): 1,01-1,85), sibilo (RP: 1,75; IC95%: 1,21-2,53), rinite (RP: 1,25; IC95%: 1,11- 1,40), dispneia noturna (RP: 2,40; IC95%: 1,31-4,40), HRB (RP: 2,47; IC95%: 1,50-4,09) e asma confirmada (RP: 2,65; IC95%: 1,45-4,85), quando comparado ao grupo sensibilização comum. Além disso, a sobreposição de asma, rinite e sintomas cutâneos no mesmo indivíduo foi mais frequente no grupo sensibilização ocupacional com valor de 16,2% versus 4,9% do grupo sensibilização comum e 1,6% do grupo não sensibilizado (p<0,01). Concluímos que a sensibilização alérgica ocupacional esteve associada com aumento de prevalência dos desfechos estudados, quando comparada à sensibilização comum, exceto para eczema ou alergia cutânea. Acreditamos que a realização periódica de TCHI com alérgenos ocupacionais poderia contribuir para detecção de risco elevado para doenças alérgicas e respiratórias entre trabalhadores expostos a animais de laboratório. / Workers exposed to laboratory animals have a high risk of developing allergic reactions to laboratory animals, known as laboratory animal allergy (LAA). Animals constantly eliminate proteins through saliva, sweat and especially urine, which makes laboratories and animal rooms favorable to the development of allergic reactions. We know that atopy, defined as a positive skin prick test (SPT) to any allergen, is a major risk factor for LAA. When considering atopy as a risk factor, we believe that it would be more effective to analyze the effects of occupational sensitization than the effects of common sensitization, thus our hypothesis is that occupational sensitization would lead to the main risk biomarker. The present study aimed to investigate the association between occupational allergic sensitization and the presence of clinical outcomes. We speculate that the continuous occupational exposure to the sensitizing occupational allergen will make occupational sensitization a better marker of risk than common sensitization. The present cross-sectional study was carried out in two Brazilian universities, where workers and students were exposed to at least one of the following animals: rat, mouse, guinea pig, rabbit and hamster. The volunteers were submitted to SPT with 5 occupational allergens (rat, mouse, guinea pig, rabbit and hamster allergens) and 11 common allergens (mite, cat, dog, cockroaches, fungi and grass mix allergens). Individuals were allocated into groups according to the outcome of SPT: non-sensitized group (negative SPT for all allergens tested), common sensitization group (positive SPT for any common allergen) and occupational sensitization group (positive SPT for any occupational allergen). Individuals answered questions about characteristics of animal exposure, symptoms, allergic and respiratory diseases, and also underwent spirometry and bronchial challenge test with mannitol to detect bronchial hyperresponsiveness (BHR). Prevalence ratio (PR) was estimated using Poisson regression. Data from 453 individuals were analyzed. Occupational sensitization was associated with an increased risk for skin symptoms (PR: 1.36, 95% confidence interval (95% CI: 1.01-1.85), wheezing (RP: 1.75, 95% CI: 1.21-2.53), rhinitis (RP: 1.25, 95% CI: 1.11-1.40), nocturnal dyspnoea (RP: 2.40, 95% CI: 1.31-4.40),BHR (PR: 2.47, 95% CI: 1.50-4.09) and confirmed asthma (PR: 2.65; 95% CI: 1.45-4.85) when compared to the common sensitization group. In addition, overlap of asthma, rhinitis, and skin symptoms in the same individual was more frequent in the occupational sensitization group, 16.2% versus 4.9% in the common sensitization group and 1.6% in the non-sensitized group (p <0.01). We concluded that occupational allergic sensitization was associated with an increased prevalence of all studied outcomes when compared to common sensitization, except for eczema or skin allergy. We believe that periodic SPT with occupational allergens could contribute to the detection of high risk for allergic and respiratory diseases among workers exposed to laboratory animals.