Occupational Asthma (eBook)

Title Page 4
Copyright Page 5
Table of Contents 6
List of contributors 8
Preface 12
References 14
The history of research on asthma in the workplace – Development, victories and perspectives 15
Introduction 15
From occupational asthma to asthma in the workplace 16
Suspicion that chemicals and not only proteins can cause “sensitisation” 17
Assessment of frequency 18
Occupational asthma as a model for environmental asthma 19
Exposure is a more important determinant than personal and genetic factors 19
Diagnostic means 21
Persistence of disease after removal from exposure 21
Impairment and disability 22
Can we prevent the disease and modify its outcome? 22
Irritant-induced asthma and reactive airways disease syndrome 23
Occupational rhinitis 23
Perspectives 23
References 24
Epidemiology and risk factors of occupational respiratory asthma and occupational sensitization 30
General introduction 30
Occupational asthma in an epidemiological context 31
Incidence data from monitoring systems 32
Occurrence in general population studies 33
Occurrence of occupational asthma in workforce-based studies 34
Exposure 35
Atopy 36
Smoking 37
Genetic markers 38
Prognosis 38
Prevention 39
Future developments 39
References 39
Epidemiology of laboratory animal allergy 46
Introduction 46
Causes, species and allergens 47
Clinical characteristics of laboratory animal allergy 49
Disease frequency 49
Cross-sectional surveys 50
Cohort studies 51
Surveillance schemes 55
Risk factors 58
Allergen exposure 58
Atopy 62
Human leucocyte antigen 63
Conclusion 64
References 64
Population-attributable fraction for occupation and asthma 69
Introduction 69
Estimating PAR 70
Previous systematic reviews of occupationally associated PAR for asthma 71
Recent longitudinal studies of PAR 72
Cross-sectional studies 76
Other data sources 77
Conclusion 78
References 79
Definition and diagnosis of occupational asthma 83
Definitions 83
Investigation 84
History 84
Pulmonary function tests and diagnosis of asthma 85
Work visit 86
Immunological testing 86
Monitoring of PEF and NABR and sputum cell counts 87
Specific inhalation challenges 89
Challenges preformed in the laboratory 91
Tests in the workplace 92
Interpretation of the tests 92
Conclusion 94
Unanswered questions 94
References 95
Work-exacerbated asthma 100
Introduction and definitions 100
Prevalence of WEA 101
Exposures and WEA 104
Clinical characteristics and natural history of WEA 106
Socioeconomic impact 107
Diagnosis, management and prevention of WEA 107
Summary 108
References 109
Natural history and prognosis 112
Introduction 112
Onset of disease 112
Outcome of patients after cessation of exposure 113
Outcome of patients with continuous exposure 116
Inflammation and airway remodeling in the course of occupational asthma 117
Fatal outcomes 117
Outcome of reactive airways dysfunction syndrome 118
Conclusion 118
References 119
Mechanisms of allergic occupational asthma 122
Introduction 122
Pathophysiology and immunology of allergic OA 124
Determinants of allergic OA 126
Occupational allergens 127
List of known occupational allergens 127
Clinical aspects 128
Diagnosis of allergic occupational asthma 129
New diagnostic tools 131
Appendix: Occupational asthma-inducing occupations and work environ- ments comprising some specific, heterogeneous or unidentified allergens 132
Animal confinements and farm working 132
Industrial enzyme production 133
Floricultures, florists greenhouses134
Exposure to other important plant allergens 135
Hairdressing salons 135
Drug-manufacturing plants 136
Isocyanate application 136
References 137
Mechanisms of occupational asthma caused by low-molecular-weight chemicals 152
Introduction 152
Pathophysiology 154
Immunologically mediated OA 154
Irritant-induced OA 156
Animal models 157
Stimulation of the cholinergic and sensory nerves 158
Lung function measurements 159
Airway inflammation 159
Immunoglobulins 160
Controversial issues 161
Neutrophils and OA 161
The skin and OA 161
Specific antibodies and OA 162
Mechanisms of IIA 162
Transient receptor potential channels and IIA 163
Putative mechanism of action 163
References 165
Asthma-like diseases in agriculture 174
Introduction 174
Respiratory symptoms in agriculture 175
Studies of asthma-like symptoms in agriculture 175
Exposures in agriculture 179
Human experiments 183
Swine 184
Laboratory animal-exposure studies 184
The modification of disease by farming exposure 185
Susceptibility factors 187
References 187
Allergen and irritant exposure and exposure-response relationships 195
Introduction 195
Allergens and irritants 196
Exposure and exposure routes 197
Variability of exposure and exposure patterns 199
Physical and chemical aspects of airborne allergen exposure 200
Exposure-response relationships 204
Effect modification of exposure-response relationships 206
Special issues in exposure-response modeling 208
Exposure-exposure interactions 209
References 209
Gene-environment interactions in occupational asthma 215
Introduction 215
Occupational asthma: A complex disease 216
Literature review 220
Candidate interactions 226
Studying all genes in the genome-wide association era? 227
Challenges on the genetic, phenotypic, and environmental aspects 231
Multiple comparisons 231
Extracting the relevant information from large tables, such as those of GWAS is difficult 231
Looking at the appropriate phenotype is a challenge 232
Improving environmental characterization is a challenge 233
Conclusion 233
References 234
Asthma in apprentice workers The birth cohort parallel: Using apprentices as a powerful cohort design for studying occupational asthma 239
Introduction 239
Concept of the model of occupational asthma 240
The application of the model of occupational asthma 241
Studied apprentice populations 243
Investigated outcomes (events) 243
Major findings 248
Incidence 248
Time course of ‘events’ (stages) 249
The ‘allergic march’ 249
Factors associated with asthma 250
Factors at inception 250
Atopy 250
Skin sensitization to the training-specific allergen(s) 250
History of symptoms of allergy 251
History of allergic disease 251
Bronchial responsiveness 251
Smoking and other host factors 251
Intermediate outcomes assessed throughout an apprenticeship 251
Exposure 252
Assessment of selection bias 253
Long-term follow-up 253
Conclusions 254
Directions of future research 255
References 256
Management of an individual worker with occupational asthma 259
Introduction 259
Evidence-based guidelines 261
Confidence in the diagnosis 264
Is the current work exposure causing temporary or permanent damage to the lungs? 266
A security guard with acute exposure to diesel fumes 267
Removal from exposure or reduction of exposure? 268
Substitution 268
Two workers coating steel sheet with PVC 268
Reducing exposure 270
Respiratory protective equipment 270
Two workers manufacturing car engines 270
The role of compensation 272
Heightened surveillance for relocated workers 273
A laboratory scientist 273
A university professor with OA from rats 274
SPIROLA 274
A manufacturer of breakfast cereals 277
Treatment 278
Conclusion 279
References 279
Social consequences and quality of life in work-related asthma 281
Introduction 281
Healthcare utilization 282
Work productivity 282
Earning capacity 284
Psycho-social and quality-of-life impacts 284
Determinants of adverse socio-economic consequences 285
Conclusion 286
References 286
Prevention of work-related asthma seen from the workplace and the public health perspective 290
Introduction 290
Primary prevention 291
Control of occupational exposure 291
Use of respiratory protective equipment 294
Vocational guidance and pre-employment screening 294
Secondary prevention 295
Medical surveillance of work-related asthma 296
Prediction research and risk stratification 298
An example of a prediction model in occupational health practice 299
Use of public health surveillance data to stimulate, guide, and document prevention of work-related asthma 301
Future developments 302
References 302
Prevention and regulatory aspects of exposure to asthmagens in the workplace 308
Introduction 308
Primary prevention 310
Role of regulatory authorities 312
Pre-employment screening 314
Secondary prevention 316
Examples of preventive approaches in specific work environments 317
Enzymes 318
Natural rubber latex 318
Laboratory animal allergy 319
Flour dust 320
Diisocyanates 322
Work-exacerbated asthma 323
Asthma attributable to work 325
Is prevention feasible and worthwhile? 326
Feasibility issues 326
Is prevention worthwhile? 327
Future developments 328
References 328
Design, conduct and analysis of surveys on work-related asthma 335
Introduction 335
Before a study design is chosen 337
Design options 338
Cross-sectional studies 338
Case-control studies 339
Cohort and intervention studies 339
Health outcome tools 341
Questionnaires 341
Spirometry 342
Bronchial hyperreactivity 343
Exhaled indices 343
Induced sputum indices 344
Immunological tests 344
Nasal inflammatory indices 345
Exposure assessment in occupational asthma surveys 345
Occurrence of and variability in allergen exposure 346
Sampling for allergen exposure 349
Measuring sensitizers 350
Exposure assessment strategies 350
Analysis of exposure-response relationships 351
Power and biological relevance 352
Research needs 354
References 354
Index 362