Biomedical subjects

H Ghezzo

Publications and source records attributed to H Ghezzo.

At least 19 recordsLinked to original sources

PubMed2006

Assessment of impairment/disability due to occupational asthma through a multidimensional approach.

Subjects with occupational asthma (OA) are often left with permanent sequelae after removal from exposure, and assessing their impairment/disability should utilise various tools. The aim of the present study was to examine whether: 1) assessment of inflammation in induced sputum is relevant to impairment; and 2) use of questionnaires on quality of life and psychological factors can be useful for the evaluation of disability. In total, 40 subjects were prospectively assessed for permanent impairment/disability due to OA 2 yrs after cessation of exposure. Impairment was assessed as follows: 1) need for asthma medication; 2) asthma severity; 3) airway calibre and responsiveness; and 4) degree of inflammation in induced sputum. Disability was assessed according to quality of life and psychological distress. There was a significant improvement in airway responsiveness and inflammation from diagnosis to the present assessment. Sputum eosinophils > or =2% and neutrophils >60% were present in eight (20%) and 12 (30%) out of all subjects, respectively, one or the other feature being the only abnormalities in 15% of subjects. Quality of life was moderately affected and there was a prevalence of depression and anxiety close to 50%. In the assessment of subjects with occupational asthma, information on airway inflammation and psychological impacts are relevant to the assessment of impairment/disability, although these findings need further investigation.

Analysis of Variance↗

PubMed2006

Airway hyperresponsiveness and risk of chest symptoms in an occupational model.

BACKGROUND: The clinical outcome of asymptomatic airway hyperresponsiveness (AHR) remains unclear. A study was undertaken to evaluate the incidence of respiratory symptoms in a cohort of asymptomatic subjects with AHR at baseline. METHODS: A 3 year prospective study involving methacholine challenge tests and serially administered questionnaires was undertaken in 769 apprentices exposed to high molecular weight allergens. Analyses were performed on 428 initially asymptomatic subjects. RESULTS: Thirty eight subjects (8.9%) were airway hyperresponsive (PC(20) < or =8 mg/ml) and asymptomatic at the start of the study. Forty four apprentices (10.3%) developed two or more respiratory symptoms unrelated to work, 13 (34.2%) in the AHR group and 31 (7.9%) in the non-AHR group (risk ratio (RR) 7.88 (95% CI 2.53 to 24.55) among subjects with AHR). The RR of developing two or more respiratory symptoms increased as the degree of PC(20) decreased with a significant trend (p<0.001). In a multivariate analysis, AHR (RR 8.33, 95% CI 2.65 to 26.16) and self-reported rhinitis on exposure to pollen through an interaction with a family history of asthma (RR 6.3, 95% CI 1.29 to 31.89) were associated with the incidence of two or more respiratory symptoms; atopy was not a significant covariate. CONCLUSION: AHR in asymptomatic subjects is an important determinant for the development of respiratory symptoms outside the workplace among apprentices exposed to high molecular weight allergens in their training environment.

Adolescent↗

PubMed2005

What are the questionnaire items most useful in identifying subjects with occupational asthma?

The present study assessed the usefulness of key items obtained from a clinical "open" questionnaire prospectively administered to 212 subjects, referred to four tertiary-care hospitals for predicting the diagnosis of occupational asthma (OA). Of these subjects, 72 (34%) were diagnosed as OA (53% with OA due to high-molecular-weight agents) according to results of specific inhalation challenges, and 90 (42%) as non-OA. Wheezing at work occurred in 88% of subjects with OA and was the most specific symptom (85%). Nasal and eye symptoms were commonly associated symptoms. Wheezing, nasal and ocular itching at work were positively, and loss of voice negatively associated with the presence of OA in the case of high-, but not low molecular-weight agents. A prediction model based on responses to nasal itching, daily symptoms over the week at work, nasal secretions, absence of loss of voice, wheezing, and sputum, correctly predicted 156 out of 212 (74%) subjects according to the presence or absence of OA by final diagnosis. In conclusion, key items, i.e. wheezing, nasal and ocular itching and loss of voice, are satisfactorily associated with the presence of occupational asthma in subjects exposed to high-molecular-weight agents. Therefore, these should be addressed with high priority by physicians. However, no questionnaire-derived item is helpful in subjects exposed to low-molecular-weight agents.

Adult↗

PubMed2003

Rhinoconjunctivitis, bronchial responsiveness, and atopy as determinants for incident non-work-related asthma symptoms in apprentices exposed to high-molecular-weight allergens.

OBJECTIVE: The aim of this study was to explore the role of rhinoconjunctivitis (RC), taking into account atopy and the level of bronchial responsiveness to methacholine, on the incidence of respiratory symptoms and in the development and/or worsening of asthma. METHODS: We examined data from a prospective study in 769 students starting exposure to high-molecular-weight occupational allergens and who were serially followed for up to 44 months. RESULTS: The presence of RC symptoms at baseline was significantly associated with an increased risk of developing shortness of breath and wheezing in atopic subjects regardless of PC20 level and in subjects with a PC20 <or= 32 mg/ml regardless of atopic status. RC symptoms were significantly associated with the development of exercise-induced respiratory symptoms. Multivariate analyses indicated that having a measurable PC20 was significantly associated with the incidence of all respiratory symptoms studied, whereas baseline seasonal RC was associated only with incident exercise-induced respiratory symptoms; atopy played a minimal role, and only through an interaction with seasonal RC. CONCLUSION: Of the three potential factors for the development of respiratory symptoms that we considered, i.e. RC symptoms, having a measurable PC20 and atopy, having a measurable PC20 is the most significant one.

Adolescent↗

PubMed2002

Incidence and host determinants of work-related rhinoconjunctivitis in apprentice pastry-makers.

BACKGROUND: The authors recently assessed the incidence and determinants of immunologic sensitization to flour in apprentice pastry-makers. The aim of this work was to determine the incidence of work-related rhinoconjunctivitis (RC) symptoms and their determinants. METHODS: For this 188/230 entrants (81.7%) were evaluated before starting exposure to flour, and again 10.8 and 16.8 months after. Questionnaires and skin prick testing to common and work-related allergens were administered at each visit. Bronchial responsiveness to methacholine was assessed at baseline in all subjects and in a subgroup at follow-up. RESULTS: Thirty subjects (16.1%) reported new work-related RC symptoms (13.1 per 100 person-years); in three subjects (1.6%), these were accompanied by incident skin prick test reactivity to flour-derived allergens. Skin prick test reactivity to grass pollens (OR = 3.0, 95% CI, 1.3-6.7) and to pets (OR = 2.5, 95% CI, 1.1-5.9), persistent rhinitis (OR = 3.1, 95% CI, 1.1-8.4), seasonal RC (OR = 2.5, 95% CI, 1.1-5.5), RC on contact with pets (OR = 2.3, 95% CI, 1.03-5.0) and skin prick test reactivity to wheat flour (OR = 10.5, 95% CI, 2.3-46.8), assessed at baseline, were significantly associated with the incidence of work-related RC symptoms. Multivariate logistic regression analysis yielded significant OR of skin prick test reactivity to wheat flour at baseline (OR = 7.1, 95% CI, 1.7-35.1) and persistent rhinitis (OR = 3.9, 95% CI, 1.01-9.6) for the incidence of work-related RC symptoms. Increased bronchial hyperresponsiveness at follow-up was more frequent, although not significantly, in subjects positive to skin prick test to flour on entry and reporting new work-related symptoms (3/5), than in other subjects (4/17). CONCLUSIONS: The incidence of work-related RC symptoms among apprentice pastry-makers was high (16.1% 30/186), while a minority (3/30) also developed skin prick test reactivity to flour. Skin prick test reactivity to wheat flour and persistent allergic rhinitis on starting exposure to flour are significant determinants for the development of work-related RC symptoms.

Adolescent↗

PubMed2002

Tidal expiratory flow limitation and chronic dyspnoea in patients with cystic fibrosis.

Cystic fibrosis (CF) eventually leads to hyperinflation linked to tidal expiratory flow limitation (FL) and ventilatory failure. Presence of FL was assessed at rest in 22 seated children and adults with CF (forced expiratory volume in one second (FEV1) range: 16-92% predicted), using both the negative expiratory pressure (NEP) technique and the "conventional" method based on comparison of tidal and maximal expiratory flow/volume curves. In addition, chronic dyspnoea was scored with the modified Medical Research Council (MRC) scale. Measurements were made before and 15 min after inhalation of salbutamol. With NEP, FL was present in only three malnourished patients, who had the lowest FEV1 values (16-27% pred) and claimed very severe dyspnoea (MRC score 5). By contrast, an additional seven patients were classified as FL with the conventional method. Six of these patients had little or no dyspnoea (MRC scores 0-1). Salbutamol administration had no effect on the extent of FL, and the concomitant decrease in functional residual capacity (FRC) was too small to play any clinically significant role. This study concluded that in seated patients with cystic fibrosis, expiratory flow limitation is absent at rest, unless the forced expiratory volume in one second is <30% predicted. If present, expiratory flow limitation is associated with severe chronic dyspnoea. The conventional method for assessing expiratory flow limitation is not reliable and bronchodilator administration has little effect on expiratory flow limitation.

Adolescent↗

PubMed2002

Host determinants for the development of allergy in apprentices exposed to laboratory animals.

The aim of this study was to evaluate whether determinants of work-related symptoms, skin sensitization and diseases differ between atopic and nonatopic subjects starting a career with exposure to laboratory animals (LA). A cohort of 417 apprentices in animal-health technology was prospectively followed during 32 or 44 months. The effect on the study outcomes of variables derived from questionnaire, skin reactivity, and lung function assessments at baseline were compared in atopic (n=212) and nonatopic (n=183) subjects. Eighty-five incident cases of sensitization to a LA-derived allergen were identified, 67 among atopic and 18 among nonatopic subjects. Baseline rhinitis symptoms in contact with pets and skin sensitization to pets were associated with the development of work-related rhinoconjunctivitis (RC) symptoms in atopic subjects, whereas perannual rhinitis symptoms and having a PC20 (provocative concentration causing a 20% fall in forced expiratory volume in one second) < or = 32 mg x mL(-1) were associated in nonatopic subjects. Baseline rhinitis symptoms on contact with pets and a PC20 value < or = 32 mg x mL(-1) were significant determinants for developing sensitization to a specific allergen in atopic subjects only. Finally, baseline rhinitis symptoms in contact with pets and perannual rhinitis symptoms were associated with the development of occupational RC in atopic subjects, whereas in nonatopic subjects this was associated with having a PC20 value < or = 32 mg x mL(-1). In conclusion, the determinants for the development of specific skin sensitization, symptoms and disease are different between atopic and nonatopic apprentices starting occupational exposure to laboratory-animal-derived allergens.

Animals↗

PubMed2002

Risk factors for bronchial hyperresponsiveness in late childhood and early adolescence.

The prevalence of asthma and bronchial hyperresponsiveness (BHR) tends to decrease in male children but increase in female children in the transition from childhood to adolescence. Hormonal factors may be involved in the natural history of asthma during this period. In a prospective study of Montreal school children, the authors examined the determinants of BHR according to the child's pubertal status; 156 male children and 168 female children without a prior diagnosis of asthma were followed for an average of 4.6 yrs. Average age at follow-up was 13.4 yrs and 59% had reached puberty. The prevalence of BHR at follow-up was similar among pre- and postpubertal male children (25.0% versus 29.2%),while BHR was more common among post- compared with prepubertal female children (33.1% versus 14.2%). There were no differences in the determinants (measured in childhood) of BHR at follow-up according to pubertal status. The major determinant of BHR was a positive skin test to dust-mite antigen. BHR was also linked to exposure to gas cooking and the presence of exercise-induced bronchospasm. In conclusion, the results of this study do not support a change in asthma phenotype with the onset of puberty. Pre- and postpuberty, the major determinant of bronchial hyperresponsiveness was skin sensitivity to mite allergen.

Adolescent↗

PubMed2001

Greater velocity and magnitude of airway narrowing in immature than in mature rabbit lung explants.

Methacholine (MCh)-induced bronchoconstriction in vivo produces greater maximal increases in pulmonary and airway resistances in immature than in mature rabbits. Our recent findings of lower shear modulus and greater airway distensibility suggest a lower elastic load limiting airway smooth muscle (ASM) shortening in immature rabbit lungs. We hypothesized that a lower elastic load should result in greater velocity of airway narrowing. Lung explants were prepared from three immature and five mature rabbits. Dynamic narrowing of intraparenchymal airways after maximal MCh stimulation was assessed by video microscopy. Immature airways (n = 80) compared with mature airways (n = 110) demonstrated greater peak velocity of shortening (6.98 +/- 0.32 versus 4.22 +/- 0.18% of baseline perimeter/s) and greater maximal airway narrowing, expressed as percentage of baseline area (31.9 +/- 1.6 versus 42.2 +/- 1.8%). For both groups, a greater velocity of shortening resulted in greater airway narrowing. As available data do not support maturational differences in rabbit ASM, our results are consistent with a lower elastic load limiting ASM shortening in the immature rabbit.

Age Factors↗

PubMed2001

Incidence of sensitization, symptoms, and probable occupational rhinoconjunctivitis and asthma in apprentices starting exposure to latex.

Latex is a well-known sensitizer. Prospective studies in apprentices beginning to be exposed to latex have not been carried out. We wanted to determine the incidence of skin reactivity, cutaneous symptoms, rhinoconjunctivitis (RC) symptoms, respiratory symptoms, probable occupational RC, and asthma in apprentices in dental hygiene. A total of 122 students starting a program in dental hygiene technology were recruited between 1993 and 1995. A questionnaire, skin-prick tests with common aeroallergens and latex, and assessment of spirometry and responsiveness to methacholine were carried out on entry and at follow-up visits at 20 and 32 months after the start of exposure. Of the 110 subjects who participated for at least 1 follow-up visit, skin reactivity to latex developed in 7. Cutaneous symptoms developed in 6 of the 7, RC symptoms developed in 2, and respiratory symptoms developed in 1. Five of the 7 subjects had significant changes in methacholine responsiveness and fulfilled the definition of probable occupational asthma. Sensitized subjects were more likely to be atopic and to have a previous history of asthma and respiratory symptoms on exercise than were nonsensitized subjects. Three subjects at the 20-month assessment and 4 subjects at the 32-month visit showed skin reactivity. The cumulative incidences for skin sensitization, probable occupational RC, and occupational asthma to latex were 6.4%, 1.8%, and 4.5%, respectively.

Adolescent↗

PubMed2001

Incidence and host determinants of probable occupational asthma in apprentices exposed to laboratory animals.

Laboratory animal (LA) workers are frequently affected with allergic sensitization and occupational asthma (OA). The role of preexposure host factors, in particular airway responsiveness, on the incidence of OA has not been satisfactorily studied. A prospective cohort study of 417 apprentices in animal-health technology was conducted to investigate the incidence and determinants of probable OA. Questionnaire and skin-prick tests with common and work-specific allergens were administered on entry and at follow-up visits (up to three) from 8 to 44 mo after starting apprenticeship. Responsiveness to inhaled methacholine was assessed at baseline and at follow-up in apprentices who developed a new specific skin sensitization and in control subjects. Preexposure host characteristics and the school attended were compared between cases and all cohort subjects not meeting the criteria for probable OA. Twenty-eight apprentices satisfied the definition for probable OA, i.e., onset of immediate skin reactivity to > 1 occupational inhalant and > 3.2-fold decrease in the provocative concentration causing a 20% reduction in FEV(1) (PC(20)). The incidence of probable OA was 2.7% (28/1,043 person-years). Baseline immediate skin reactivity to pets (rate ratio [RR] 4.1, 95% confidence interval [CI] = 1.6 to 10.8), and bronchial responsiveness (PC(20) < or = 32 versus PC(20) > 32 mg/ ml) (RR = 2.5, 95% CI = 1.0 to 5.8) were associated with an increased risk of probable OA; a lower FEV(1) had an apparent, protective effect (RR = 0.58, 95% CI = 0.43 to 0.78). It is concluded that apprentices in animal health show a high incidence of probable OA, and that preexposure airway caliber and responsiveness as well as sensitization to pets are associated with an increased risk.

Adult↗

PubMed2001

Breathing pattern and gas exchange at peak exercise in COPD patients with and without tidal flow limitation at rest.

Expiratory flow limitation (FL) at rest is frequently present in chronic obstructive pulmonary disease (COPD) patients. It promotes dynamic hyperinflation with a consequent decrease in inspiratory capacity (IC). Since in COPD resting IC is strongly correlated with exercise tolerance, this study hypothesized that this is due to limitation of the maximal tidal volume (VT,max) during exercise by the reduced IC. The present study investigated the role of tidal FL at rest on: 1) the relationship of resting IC to VT,max; and 2) on gas exchange during peak exercise in COPD patients. Fifty-two stable COPD patients were studied at rest, using the negative expiratory pressure technique to assess the presence of FL, and during incremental symptom-limited cycling exercise to evaluate exercise performance. At rest, FL was present in 29 patients. In the 52 patients, a close relationship of VT,max to IC was found using non-normalized values (r=0.77; p < 0.0001), and stepwise regression analysis selected IC as the only significant predictor of VT,max. Subgroup analysis showed that this was also the case for patients both with and without FL (r=0.70 and 0.76, respectively). In addition, in FL patients there was an increase (p < 0.002) in arterial carbon dioxide partial pressure at peak exercise, mainly due to a relatively low VT,max and consequent increase in the physiological dead space (VD)/VT ratio. The arterial oxygen partial pressure also decreased at peak exercise in the FL patients (p < 0.05). In conclusion, in chronic obstructive pulmonary disease patients the maximal tidal volume, and hence maximal oxygen consumption, are closely related to the reduced inspiratory capacity. The flow limited patients also exhibit a significant increase in arterial carbon dioxide partial pressure and a decrease in arterial oxygen partial pressure during peak exercise.

Aged↗

PubMed2001

Natural history of sensitization, symptoms and occupational diseases in apprentices exposed to laboratory animals.

The natural history of the development of sensitization and disease due to high-molecular-weight allergens is not well characterized. This study describes the time-course of the incidence of work-related symptoms, skin reactivity and occupational rhinoconjunctivitis (RC) and asthma (OA); and assesses the predictive value of skin testing and RC symptoms in apprentices exposed to laboratory animals, in a 3-4-yr programme. Four-hundred and seventeen apprentices at five institutions were assessed prospectively with questionnaire, skin-testing with animal-derived allergens, spirometry and airway responsiveness (n=373). Depending on the school, students were seen 8 (n=136), 20 (n=345), 32 (n=355) and 44 (n=98) months after starting the programme. At all visits, the incidence was greater for work-related RC symptoms followed in order by skin reactivity, occupational RC, and, almost equally, OA and work-related respiratory symptoms. The incidence-density figures were comparable for each follow-up period and for most indices up to 32 months after entry into the study and then tended to decrease. The positive predictive values (PPVs) of skin reactivity to work-related allergens for the development of work-related RC and respiratory symptoms were 30% and 9.0%, respectively, while the PPVs of work-related RC for the development of OA was 11.4%. Sensitization, symptoms and diseases occur maximally in the first 2-3 yrs after starting exposure to laboratory animals. Skin reactivity to work-related allergens and rhinoconjuctivitis symptoms have low positive predictive values.

Adolescent↗

PubMed2001

Lymphocyte population and apoptosis in the lungs of smokers and their relation to emphysema.

Previously, it had been shown that T-lymphocytes are the predominant inflammatory cells found in the alveolar wall of smokers and their numbers correlated with the extent of emphysema. However, the phenotype of these cells was not defined. The aim of this study was to describe the different T-cell phenotypes and investigate the possible presence of apoptosis in the lung parenchyma of smokers. Samples from lungs were obtained at surgery from 15 patients who smoked and six who had never smoked. Samples were frozen and prepared for histological and immunocytochemical examination. Slides were stained for CD3+, CD4+, CD8+, gammadelta T-cells, CD56 natural killers ((NK) cells), and elastase (neutrophils). Anti-CD95 monoclonal antibodies and in situ end-labelling techniques were used to detect Fas expression and apoptosis. Positive staining cells were expressed as cells-mm alveolar wall-, percentage of total cells, and Fas/APO and apoptosis index. Emphysema was identified macroscopically, microscopically and reported as present or absent. All subjects had pulmonary function tests before surgery. Neutrophils were the predominant cell in the lung parenchyma of nonsmokers and smokers without emphysema. In smokers with emphysema, the CD3+ and CD8+ were the predominant cells (p<0.05) in the alveolar wall. gammadelta cells were increased in all smokers and no increased numbers of NK cells was found. The T-cell numbers x mm alveolar wall(-1) showed a bilinear relationship with the amount smoked increasing at an inflection point of 30 packs yr(-1) (R2= 0.345; p < 0.01). Apoptosis in smokers showed a bilinear relationship with the amount smoked increasing sharply in smokers with emphysema (R2=0.3613; p < 0.009). It is concluded that the pathogenesis of emphysema might be mediated by T-lymphocytes, mainly CD8+ cytolytic T-cells, and that apoptosis might be one of the mechanisms of lung destruction leading to the development of emphysema. If this is the case, it could be speculated that T-cell inflammation is a response to antigenic stimuli originating in the lung and induced by cigarette smoking.

Aged↗

PubMed2001

Orthopnea and tidal expiratory flow limitation in patients with stable COPD.

BACKGROUND: Orthopnea is a common feature in COPD patients, although its nature is poorly understood. OBJECTIVE: To study the role of tidal expiratory flow limitation (FL) in the genesis of orthopnea in patients with stable COPD. MEASUREMENTS: Tidal FL was assessed in 117 ambulatory COPD patients in sitting and supine positions using the negative expiratory pressure method. The presence or absence of orthopnea was also noted. RESULTS AND CONCLUSIONS: In patients with stable COPD with tidal expiratory FL in seated and/or supine position, there is a high prevalence of orthopnea, which probably results in part from increased inspiratory efforts due to dynamic pulmonary hyperinflation and the concomitant increase in inspiratory threshold load due to intrinsic positive end-expiratory pressure. Increased airway resistance in supine position due to lower end-expiratory lung volume probably also plays a role in the genesis of orthopnea.

Aged↗

PubMed2000

Occurrence and risk factors of oral candidiasis treated with oral antifungals in seniors using inhaled steroids.

Oral candidiasis (OC) is a frequent side effect of inhaled corticosteroids (iCSTs). This study estimated occurrence and significance of risk factors of OC treated with antifungals in users of iCSTs under conditions of normal use. This retrospective analysis used data drawn from drug insurance plan records in Quebec, Canada. The sample contained 27,000 seniors using anti-asthma medications during 1990. Three years of data (1989-1991) were searched for use of oral antifungals concurrent with exposure to iCSTs. A case-control study examined factors leading to increased probability of first incidence of OC in new users of iCSTs. Three-year occurrence for OC was 7%. Increased risk for a first occurrence of OC was significantly associated with higher doses of iCST, increased length of iCST exposure, use of antibiotics, use of oral steroids, having three or more prescribers, a history of use of both high and low strengths of iCST, and concurrent use of oral steroids and diabetes medications. The occurrence of OC is relatively high. Knowledge of factors leading to increased risk could facilitate the targetting of patients who need timely intervention, under conditions of normal use.

Aged↗

PubMed2000

Role of inspiratory capacity on exercise tolerance in COPD patients with and without tidal expiratory flow limitation at rest.

Expiratory flow limitation promotes dynamic hyperinflation during exercise in chronic obstructive pulmonary disease (COPD) patients with a consequent reduction in inspiratory capacity (IC), limiting their exercise tolerance. Therefore, the exercise capacity of patients with tidal expiratory flow limitation (FL) at rest should depend on the magnitude of IC. The presented study was designed to evaluate the role of FL on the relationship between resting IC, other respiratory function variables and exercise performance in COPD patients. Fifty-two patients were included in the study. Negative expiratory pressure (NEP) uptake (VO2,max) were measured during an incremental symptom-limited cycle exercise. Twenty-nine patients were FL at rest. The IC was normal in all non-FL patients, while in most FL subjects it was decreased. Both WRmax and VO2,max were lower in FL patients (p<0.001, each). A close relationship of WRmax and O2,max to IC was found (r=0.73 and 0.75, respectively; p<0.0001, each). In the whole group, stepwise regression analysis selected IC and forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) (% predicted) as the only significant contributors to exercise tolerance. Subgroup analysis showed that IC was the sole predictor in FL patients, and FEV1/FVC in non-FL patients. Detection of flow limitation provides useful information on the factors that influence exercise capacity in chronic obstructive pulmonary disease patients. Accordingly, in patients with flow limitation, inspiratory capacity appears as the best predictor of exercise tolerance, reflecting the presence of dynamic hyperinflation.

Aged↗

PubMed2000

Individual characteristics and quitting in apprentices exposed to high-molecular-weight agents.

To determine whether specific immunological sensitization (SIS) and symptoms of allergy are associated with quitting apprenticeships with exposure to high-molecular-weight (HMW) agents. In a cohort study of 769 apprentices starting career programs in animal health technology (AHT), pastry-making (PM), and dental hygiene technology (DHT), health status was assessed at baseline and yearly for up to 44 mo. Subjects who quit the apprenticeship were contacted and offered a last series of measurements as if they pursued. The effect of various factors-at baseline and during the career program-on quitting was examined. Eighty-nine of 769 subjects (11.6%) quit, of whom 74 participated in this study. In multivariate analysis, a history of hay fever (OR = 1.66, 95% CI = 1.0 to 2.75) and attending the pastry-making program (OR = 2.33, 95% CI = 1.11 to 4.91) were significant determinants for quitting. In the subgroup of AHT, SIS to laboratory animals, hay fever, and shortness of breath were significant determinants by univariate analysis; in PM, the only determinant was age; and in DHT, hay fever. Work-related symptoms during training were not associated with quitting. In a multivariate logistic regression analysis in AHT, including characteristics at baseline and at follow-up, baseline SIS (OR = 2.8, 95% CI = 0.94 to 8.38) and symptoms of asthma in general during follow-up (OR = 2.2, 95% CI = 0.94 to 5.38) were the main determinants for quitting, though they were of borderline significance. We conclude that health-related self-selection out of an apprenticeship with exposure to HMW agents is likely to occur and to cause an attrition bias.

Adult↗