Epidemiology

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Occupational asthma is the most frequently reported occupational respiratory disorder in westernised industrialised populations (Kor 2001, McDonald 2000, Provencher 1997). In countries such as South Africa and the Czech Republic, where mining is common, occupational asthma is the second most prevalent occupational respiratory disorder after pneumoconiosis (Brehl 2003, Hnizdo 2001).

What is the frequency of occupational asthma?

There are no complete registries for reporting occupational diseases such as occupational asthma and the true frequency of the disease is not known. Underreporting is likely and reports may not differentiate between the various types of work-related asthma. Published frequencies come from surveillance schemes, compensation registries or from epidemiological studies of the relationship between asthma and occupation. The incidence of occupationally associated asthma varies between countries depending on the methodology of data collection, definition of cases and the predominant work sectors and occupations. A systematic review of 43 risk estimates from 19 countries demonstrated an attributable risk of 9% whilst the 12 highest scoring studies demonstrated an attributable risk of 15% (Blanc 1999). Another review of 21 studies similarly demonstrated an attributable risk of 15% (Balmes 2003).

*** 2++ Occupational factors are estimated to account for 9-15% of cases of asthma in adults of working age, including new onset or recurrent disease.

(Full Text Available for: American Thoracic Society Statement: Occupational Contribution to the Burden of Airway Disease Balmes 2003, Abstract Available for: How much adult asthma can be attributed to occupational factors? Blanc 1999)

*** 2++ The annual population incidence of occupationally related asthma ranges from an estimated 12 to 170 cases per million workers with an estimated mean of 47 cases per million workers.

(Full Text Available for: Reported incidence of occupational asthma in France Ameille 2003, Abstract Available for: How much adult asthma can be attributed to occupational factors? Blanc 1999, Abstract Available for: Incidence Of Occupational Asthma By Occupation and Industry In Finland Karjalainen 2000, Abstract Available for: Occupational respiratory disease in the United Kingdom 1989: a report to the British Thoracic Society and the Society of Occupational Medicine by the SWORD project group Meredith 1991)

* 3 The population incidence of occupational asthma may be underestimated by as much as 50%.

(Full Text Available for: Occupational asthma: a community based study deBono 1999)

* 3 The reported incidence of occupational asthma has not decreased in recent years.

(Abstract Available for: Allergopatie professionali respiratorie: l'esperienza delle Unita Operative Ospedaliere di Medicina del Lavoro in Lombardia dal 1990 al 1998. [Respiratory occupational allergies: the experience of the Hospital Operative Unit of Occupational Medicine in Lombardy from 1990 to 1998] Cortona 2001, Full Text Available for: SWORD 99: Surveillance Of Work-Related And Occupational Respiratory Disease In The UK Meyer 2001, Full Text Available for: Incidence of occupational asthma and persistent asthma in young adults has increased in Finland Reijula 1996)

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Which agents cause occupational asthma and which workers are at risk?

Several hundred agents have been reported to cause occupational asthma and new causes are reported regularly in the medical literature. The predominant causative agents and the jobs most commonly reported to incur high risk reflect variations of economic activity both between and within different countries, methods of data collection - surveillance schemes and population studies - occupational classifications of workers and different perceptions of whether asthma is occupational or not.

*** 2++ The most frequently reported agents include isocyanates, flour and grain dust, colophony and fluxes, latex, animals, aldehydes and wood dust.

(Full Text Available for: Reported incidence of occupational asthma in France Ameille 2003, Abstract Available for: Occupational respiratory diseases in the Czech Republic Brhel 2003, Abstract Available for: Allergopatie professionali respiratorie: l'esperienza delle Unita Operative Ospedaliere di Medicina del Lavoro in Lombardia dal 1990 al 1998. [Respiratory occupational allergies: the experience of the Hospital Operative Unit of Occupational Medicine in Lombardy from 1990 to 1998] Cortona 2001, Full Text Available for: The SHIELD scheme in the West Midlands Region, United Kingdom Gannon 1993, Full Text Available for: Reported Incidence Of Occupational Asthma In The United Kingdom 1989-97. McDonald 2000, Abstract Available for: Occupational respiratory disease in the United Kingdom 1989: a report to the British Thoracic Society and the Society of Occupational Medicine by the SWORD project group Meredith 1991, Full Text Available for: SWORD '98: surveillance of work-related and occupational respiratory disease in the UK Meyer 1999, Abstract Available for: SWORD '93. Surveillance of work-related and occupational respiratory disease in the UK Sallie 1994, Abstract Available for: Adult-onset asthma and occupational exposures Toren 1999)

*** 2++ The workers most commonly reported to surveillance schemes of occupational asthma include paint sprayers, bakers and pastry makers, nurses, chemical workers, animal handlers, welders, food processing workers and timber workers.

(Full Text Available for: Reported incidence of occupational asthma in France Ameille 2003, Abstract Available for: Occupational respiratory diseases in the Czech Republic Brhel 2003, Full Text Available for: The SHIELD scheme in the West Midlands Region, United Kingdom Gannon 1993, Abstract Available for: Exploration of asthma risk by occupation - extended analysis of an incidence study of the finnish population Karjalainen 2002, Full Text Available for: Reported Incidence Of Occupational Asthma In The United Kingdom 1989-97. McDonald 2000, Abstract Available for: Occupational respiratory disease in the United Kingdom 1989: a report to the British Thoracic Society and the Society of Occupational Medicine by the SWORD project group Meredith 1991, Full Text Available for: SWORD '98: surveillance of work-related and occupational respiratory disease in the UK Meyer 1999, Full Text Available for: Incidence of occupational asthma and persistent asthma in young adults has increased in Finland Reijula 1996, Abstract Available for: SWORD '93. Surveillance of work-related and occupational respiratory disease in the UK Sallie 1994, Abstract Available for: Adult-onset asthma and occupational exposures Toren 1999)

** 2+ The workers reported from population studies to be at increased risk of developing asthma include bakers, food processors, forestry workers, chemical workers, plastics and rubber workers, metal workers, welders, textile workers, electrical and electronic production workers, storage workers, farm workers, waiters, cleaners, painters, plastic workers, dental workers and laboratory technicians.

(Full Text Available for: Occupation and Asthma: A Population-based Incident Case-Control Study Jaakkola 2003, Full Text Available for: Occupational asthma in adults in six canadian communities Johnson 2000, Abstract Available for: The risk of asthma attributable to occupational exposures. A population-based study in Spain. Spanish Group of the European Asthma Study Kogevinas 1996, Abstract Available for: Occupational asthma in europe and other industrialised areas: a population-based study Kogevinas 1999)

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What are the risk factors for developing occupational asthma?

Most studies of risk factors for occupational asthma are of cross-sectional design. Where a disease is clearly attributable to exposures at work it is likely to result in differential assortment of employees with or without disease both within and out of an occupation or workplace. Cross-sectional analyses of a current workforce may reflect the resulting survivor effects; moreover they are generally incapable of distinguishing cause from effect. As a result, the absence of any perceptible effect of a putative risk factor may be a consequence more of study design, than of reality. There are few published studies of more robust cohort or case-referent study design. Furthermore there is likely to be considerable publication bias in this area. However, four risk factors have been identified for a number of agents including the predisposing factors of atopy and genetic predisposition, the causative factor of exposure to an agent at work and the contributing factor of cigarette smoking.

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Is exposure to agents in the workplace a risk factor for developing occupational asthma?

A direct relationship between occupational asthma and allergen exposure at work has been demonstrated with acid anhydrides (Grammer 1994, Liss 1993), cimetidine (Coutts 1984), colophony (Burge 1981), enzymes (Cathcart 1997, Cullinan 2000, Juniper 1997, Vanhanen 1997, Weill 1971), green coffee and castor bean (Osterman 1982), flour allergens (Brisman 2000, Cullinan 1994, Cullinan 2001 Heederik 2001, Houba 1998, Musk 1989), crab (Ortega 2001), isocyanates (Meredith 2000, Petsonk 2000, Tarlo 1997a), laboratory animal allergens (Cullinan 1999, Kruize 1997, Platts-Mills 1987), piperazine (Hagmar 1984), platinum salts (Calverley 1995), prawns (McSharry 1994) and western red cedar (Brooks 1981). Most of these studies have also demonstrated a positive exposure-response relationship for sensitisation. Studies limited to sensitisation, rather than asthma, have demonstrated a relationship with exposure to acid anhydrides (Nielsen 2001), bakery enzymes (Houba 1996, Nieuwenhuijsen 1999, Vanhanen 1997), laboratory animals (Heederik 1999) and platinum salts (Merget 2000).

*** 2++ The risk of sensitisation and occupational asthma is increased by higher exposures to many workplace agents.

(Full Text Available for: Exposure-response relations for self report asthma and rhinitis in bakers Brisman 2000, No Abstract Available for: An epidemiologic study of workers exposed to western red cedar and other wood dusts Brooks 1981, Abstract Available for: Platinum salt sensitivity in refinery workers: incidence and effects of smoking and exposure Calverley 1995, Full Text Available for: Enzyme exposure, smoking and lung function in employees in the detergent industry over 20 years. Medical Subcommittee of the UK Soap and Detergent Industry Association Cathcart 1997, No Abstract Available for: Respiratory symptoms related to work in a factory manufacturing cimetidine tablets Coutts 1984, Abstract Available for: Work-related symptoms, sensitisation, and estimated exposure in workers not previously exposed to flour Cullinan 1994, Full Text Available for: Allergen exposure, atopy and smoking as determinants of allergy to rats in a cohort of laboratory employees Cullinan 1999, Abstract Available for: An Outbreak Of Asthma In A Modern Detergent Factory Cullinan 2000, Full Text Available for: Allergen and dust exposure as determinants of work-related symptoms and sensitisation in a cohort of flour-exposed workers; A case-control analysis Cullinan 2001, Abstract Available for: Risk factors for immunologically mediated respiratory disease from hexahydrophthalic anhydride Grammer 1994, Abstract Available for: Piperazine-induced airway symptoms: exposure-response relationships and selection in an occupational setting Hagmar 1984, Full Text Available for: An exploratory quantitative risk assessment for high molecular weight sensitizers: wheat flour Heederik 2001, Abstract Available for: Occupational Asthma As Identified By The Surveillance Of Work-Related And Occupational Respiratory Diseases Programme In South Africa Hnizdo 2001, No Abstract Available for: Bacillus Subtilis Enzymes: a 7 year clinical, epidemiological and immunological study of an industrial allergen Juniper 1977, Abstract Available for: Respiratory allergy in laboratory animal workers: a retrospective cohort study using pre-employment screening data Kruize 1997, Abstract Available for: Assessment of risk factors for IgE-mediated sensitisation to tetrachlorophthalic anhydride Liss 1993, Abstract Available for: The IgE and IgG antibody responses to aerosols of Nephrops norvegicus (prawn) antigens: the association with clinical hypersensitivity and with cigarette smoking. McSharry 1994, Abstract Available for: Occupational respiratory disease in the United Kingdom 1989: a report to the British Thoracic Society and the Society of Occupational Medicine by the SWORD project group Meredith 1991, Abstract Available for: Respiratory symptoms, lung function, and sensitisation to flour in a British bakery Musk 1989, Abstract Available for: Respiratory Symptoms Among Crab Processing Workers In Alaska: Epidemiological And Environmental Assessment Ortega 2001, No Abstract Available for: Coffee workers asthma Osterman 1982, Abstract Available for: Occupational asthma and rhinitis related to laboratory rats: serum IgG and IgE antibodies to the rat urinary allergen PlattsMills 1987, Abstract Available for: Assessment of the relationship between isocyanate exposure levels and occupational asthma Tarlo 1997, Abstract Available for: Sensitisation to industrial enzymes in enzyme research and production Vanhanen 1997, No Abstract Available for: A study of workers exposed to detergent enzymes Weill 1971)

Users of this website have put forward more evidence for this question. This is not validated and is not a part of the BOHRF occupational asthma guidelines.

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Is atopy a risk factor for developing occupational asthma?

Atopy is a state characterised by the propensity to produce specific immunoglobulin IgE on ordinary exposure to common allergens in the subject's environment. Differences between studies relating to the ascertainment of atopy range from those that use an immunological test such as skin prick testing to those that rely on a personal or family history of allergic disease i.e., asthma, eczema or hayfever. This can cause inconsistencies between reported observations. Atopy has been reported to increase the risk of occupational asthma in workers exposed to detergent enzymes (Juniper 1984, Weill 1971, Zentner 1997), isocyanates (Meredith 2000, Ucgun 1998) laboratory and other animals (Agrup 1986, Botham 1987, Cockcroft 1981, Cullinan 1999, Gautrin 2001a, Gautrin 2001b, Jeal 2003, Sjostedt 1989, Sjostedt 1993, Krakowiak 2002, Kruize 1997, Platts-Mills 1987, Venables 1988a), bakery allergens (Baur 1998a, De Zotti 1997, De Zotti 2000, Droste 2003, Houba 1998, Talini 2002) and some reactive dyes (Docker 1987). Other studies have demonstrated no such association between atopy and occupational asthma due to exposure to cork (Winck 2004), isocyanates (Butcher 1977, Cullen 1996, Petsonk 2000), detergent enzymes (Cullinan 2000), glutaraldehyde (Di Stefano 1999), salmon (Douglas 1995), crab (Cartier 1984), hexahydrophthalic anhydride (Grammer 1996), platinum salts (Merget 2000, Venables 1989a) and plicatic acid in western red cedar (Chang-Yeung 1982). As with exposure, some studies that examined asthma also examined, where possible, specific sensitisation. Atopy has been associated with an increased risk of sensitisation in workers exposed to various enzymes (Cullinan 2001, Flood 1985, Greenberg 1970, Houba 1996, Juniper 1977, Newhouse 1970, Vanhanen 1997, Witmeur 1973, Zentner 1997), green coffee and castor bean (Osterman 1982, Romano 1995), bakery allergens (Baur 1998a, Cullinan 2001, De Zotti 1994, De Zotti 1997, Houba 1998, Heederik 2001, Prichard 1984), laboratory animals (Cullinan 1999), crab (Cartier 1984), prawn (McSharry 1994) and acid anhyrides (Venables 1985a, Nielsen 2001).

*** 2++ Atopy increases the risk of developing occupational asthma caused by exposure to many high molecular weight agents that induce the production of specific IgE antibodies.

(Abstract Available for: Allergy to laboratory animals in laboratory technicians and animal keepers Agrup 1986, Abstract Available for: Baker's asthma: still among the most frequent occupational respiratory disorders Baur 1998, Abstract Available for: Allergy to laboratory animals: a prospective study of its incidence and of the influence of atopy on its development Botham 1987, Full Text Available for: Allergen exposure, atopy and smoking as determinants of allergy to rats in a cohort of laboratory employees Cullinan 1999, Abstract Available for: Respiratory symptoms and occupational sensitisation in a group of trainee bakers: results of a 6-month follow up DeZotti 1997, Full Text Available for: Prospective study of work-related respiratory symptoms in trainee bakers DeZotti 2000, Abstract Available for: Allergic sensitisation, symptoms, and lung function among bakery workers as compared with a nonexposed work population Droste 2003, Full Text Available for: Incidence and host determinants of probable occupational asthma in apprentices exposed to laboratory animals Gautrin 2001, Full Text Available for: Natural history of sensitisation, symptoms and occupational diseases in apprentices exposed to laboratory animals Gautrin 2001, Abstract Available for: HLA associations with occupational sensitisation to rat lipocalin allergens: a model for other animal allergies? Jeal 2003, No Abstract Available for: Enzyme asthma: fourteen years clinical experience of a recently prescribed disease Juniper 1984, Abstract Available for: Allergy to animal fur and feathers among zoo workers Krakowiak 2002, Abstract Available for: Respiratory allergy in laboratory animal workers: a retrospective cohort study using pre-employment screening data Kruize 1997, Abstract Available for: Occupational asthma and rhinitis related to laboratory rats: serum IgG and IgE antibodies to the rat urinary allergen PlattsMills 1987, Abstract Available for: Predisposing factors in laboratory animal allergy: a study of atopy and environmental factors Sjostedt 1989, Abstract Available for: A follow-up study of laboratory animal exposed workers: the influence of atopy for the development of occupational asthma Sjostedt 1993, Abstract Available for: Diagnosis Of Flour-Induced Occupational Asthma In A Cross-Sectional Study Talini 2002, Abstract Available for: Laboratory animal allergy in a pharmaceutical company Venables 1988, No Abstract Available for: A study of workers exposed to detergent enzymes Weill 1971, No Abstract Available for: Multiple IgE-mediated sensitisations to enzymes after occupational exposure: evaluation by skin prick test, RAST, and immunoblot Zentner 1997)

Users of this website have put forward more evidence for this question. This is not validated and is not a part of the BOHRF occupational asthma guidelines.

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Is there a genetic predisposition for developing occupational asthma?

That only a proportion of workers develop occupational asthma despite similar exposures, suggests an underlying genetic susceptibility to occupational asthma. A number of studies have examined the role of genes coding for Class I or II human leukocyte antigen (HLA) and respiratory anti-oxidant expression in occupational asthma attributed to isocyanates (Balboni 1996, Beghe 2004, Bernstein 1997, Bignon 1994, Mapp 2000, Mapp 2002, Piirila 2001, Rihs 1997), complex platinum salts (Newman Taylor 1999), western red cedar (Horne 2000), acid anhydrides (Young 1995) and laboratory animal proteins (Sjostedt 1996, Jeal 2003). Most studies were based on small sample sizes and the findings are either inconsistent or unreplicated.

** 2- Genetic polymorphisms that code for human leukocyte antigen class II genes or respiratory anti-oxidant mechanisms may predispose to occupational asthma for a number of agents.

(Abstract Available for: Association between toluene di-isocyanate-induced asthma and DQB1 markers: a possible role for aspartic acid at position 57 Balboni 1996, Abstract Available for: HLA class II alleles in isocyanate-induced asthma Bignon 1994, Full Text Available for: Distribution of DRB1 and DQB1 HLA class II alleles in occupational asthma due to western red cedar Horne 2000, Abstract Available for: HLA associations with occupational sensitisation to rat lipocalin allergens: a model for other animal allergies? Jeal 2003, Abstract Available for: Glutathione S-transferase GSTP1 is a susceptibility gene for occupational asthma induced by isocyanates Mapp 2002, No Abstract Available for: Association between hla genes and susceptibility to toluene di-isocyanate-induced asthma Mapp 2000)

Users of this website have put forward more evidence for this question. This is not validated and is not a part of the BOHRF occupational asthma guidelines.

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Is smoking a risk factor for developing occupational asthma?

Smoking has been identified to increase the risk of occupational asthma in workers exposed to: isocyanates (Cullen 1996, Meredith 2000, Ucgun 1998), platinum salts (Calverley 1995, Venables 1989a), salmon (Douglas 1995) and snow crab (Cartier 1984). One study demonstrated a dose-dependent effect (Venables 1989a). Smoking has been identified to increase the risk of sensitisation in only a few studies with exposure to green coffee and castor bean (Osterman 1982, Romano 1995), platinum salts (Baker 1990, Merget 2000, Niezborala 1996), prawn (McSharry1994), flour (De Zotti 1994). The role of cigarette smoking is unclear for asthma due to exposure to acid anhydrides, enzymes and laboratory animals. Some studies have shown an increased risk of laboratory animal asthma in smokers (Cullinan 1999, Krakowiak 1997, Venables 1988a), whereas others have shown no effect (Agrup 1986, Gautrin 2001a, Gautrin 2001b, Kruize 1997, Meijer 2002). For exposure to acid anhydrides, studies have demonstrated both negative (Grammer 1996, Liss 1993) and positive (Venables 1985a) correlation with specific IgE. Similar conflicting evidence is available for detergent enzymes (Johnsen 1997, Weill 1971). Whilst one study demonstrated an increased risk of sensitisation in bakery workers (DeZotti 1994), smoking does not appear to increase the risk of asthma in bakery workers (Baur 1998a, Cullinan 2001, De Zotti 1994, Houba 1998).

** 2+ Cigarette smoking can increase the risk of developing occupational asthma with some sensitising agents.

(Abstract Available for: Platinum salt sensitivity in refinery workers: incidence and effects of smoking and exposure Calverley 1995, Abstract Available for: Occupational asthma in snow crab processing workers Cartier 1984, Abstract Available for: Feasibility study of respiratory questionnaire and peak flow recordings in autobody shop workers exposed to isocyanate-containing spray paint: observations and limitations Cullen 1996, Full Text Available for: Occupational asthma caused by automated salmon processing Douglas 1995, Abstract Available for: Occupational respiratory disease in the United Kingdom 1989: a report to the British Thoracic Society and the Society of Occupational Medicine by the SWORD project group Meredith 1991, Abstract Available for: Allergy to complex platinum salts: A historical prospective cohort study Niezborala 1996, Abstract Available for: Smoking and occupational allergy in workers in a platinum refinery Venables 1989)

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Is occupational rhinitis a risk factor for developing occupational asthma?

Rhinitis and asthma frequently occur together. There is epidemiological evidence from the general population of a strong association between the development of asthma and a previous history of either allergic or perennial rhinitis. Occupational rhinitis is purported to be a risk factor for the development of occupational asthma, especially for high-molecular-weight sensitisers. One population study reported that occupational rhinitis (defined as work-related symptoms, specific sensitisation to a work substance, positive nasal challenge and exclusion of other causes) carried a crude relative risk of asthma of 4.8 (Karjalainen 2003). The relative risk was highest among farmers and wood workers and the greatest risk of asthma was in the year after rhinitis was reported. Rates of co-morbid rhinitis or rhino-conjunctivitis of between 45% and 90% have been reported in subjects suffering from IgE associated occupational asthma attributed to acid anhydrides (Grammer 2002a, Wernfors 1986), laboratory animals (Cullinan 1999, Gautrin 2001a, Gautrin 2001b), snow crab (Cartier 1984) and wheat flour (Houba 1998). The intensity of nasal symptoms appears to be significantly more pronounced in the case of HMW agents (Malo 1997).

** 2+ Occupational rhinitis and occupational asthma frequently occur as co-morbid conditions in IgE associated occupational asthma.

(Abstract Available for: Occupational asthma in snow crab processing workers Cartier 1984, Abstract Available for: Allergopatie professionali respiratorie: l'esperienza delle Unita Operative Ospedaliere di Medicina del Lavoro in Lombardia dal 1990 al 1998. [Respiratory occupational allergies: the experience of the Hospital Operative Unit of Occupational Medicine in Lombardy from 1990 to 1998] Cortona 2001, Full Text Available for: Allergen exposure, atopy and smoking as determinants of allergy to rats in a cohort of laboratory employees Cullinan 1999, Full Text Available for: Incidence and host determinants of probable occupational asthma in apprentices exposed to laboratory animals Gautrin 2001, Full Text Available for: Natural history of sensitisation, symptoms and occupational diseases in apprentices exposed to laboratory animals Gautrin 2001, Abstract Available for: Prevalence and onset of rhinitis and conjunctivitis in subjects with occupational asthma caused by trimellitic anhydride (TMA) Grammer 2002, Abstract Available for: Wheat Sensitisation and Work-related Symptoms in the Baking Industry Are Preventable. An Epidemiologic Study Houba 1998, Full Text Available for: Prevalence and intensity of rhinoconjunctivitis in subjects with occupational asthma Malo 1997, Abstract Available for: Phthalic anhydride-induced occupational asthma Wernfors 1986)

** 2+ Rhino-conjunctivitis is more likely to appear before the onset of IgE associated occupational asthma.

(Abstract Available for: Allergopatie professionali respiratorie: l'esperienza delle Unita Operative Ospedaliere di Medicina del Lavoro in Lombardia dal 1990 al 1998. [Respiratory occupational allergies: the experience of the Hospital Operative Unit of Occupational Medicine in Lombardy from 1990 to 1998] Cortona 2001, Full Text Available for: Allergen exposure, atopy and smoking as determinants of allergy to rats in a cohort of laboratory employees Cullinan 1999, Full Text Available for: Incidence and host determinants of probable occupational asthma in apprentices exposed to laboratory animals Gautrin 2001, Full Text Available for: Natural history of sensitisation, symptoms and occupational diseases in apprentices exposed to laboratory animals Gautrin 2001, Abstract Available for: Prevalence and onset of rhinitis and conjunctivitis in subjects with occupational asthma caused by trimellitic anhydride (TMA) Grammer 2002, Full Text Available for: Risk of asthma among Finnish patients with occupational rhinitis Karjalainen 2003, Full Text Available for: Prevalence and intensity of rhinoconjunctivitis in subjects with occupational asthma Malo 1997)

* 2- The risk of developing occupational asthma is highest in the year after the onset of occupational rhinitis.

(Abstract Available for: Allergopatie professionali respiratorie: l'esperienza delle Unita Operative Ospedaliere di Medicina del Lavoro in Lombardia dal 1990 al 1998. [Respiratory occupational allergies: the experience of the Hospital Operative Unit of Occupational Medicine in Lombardy from 1990 to 1998] Cortona 2001, Full Text Available for: Risk of asthma among Finnish patients with occupational rhinitis Karjalainen 2003)

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When are symptoms of occupational asthma most likely to develop?

The latent interval between first exposure and the onset of recognisable symptoms can vary depending on the agent, the management of exposure and biological variability. Whilst the latent interval can extend to many years (Bar-Sela 1984, Cortona 2001, Kim 1999, Munoz 2003), the risk of occupational asthma appears to be highest soon after first exposure to laboratory animal allergens (Agrup 1986, Cullinan 1999, Gautrin 2001a, Gautrin 2001b, Krakowiak 1997, Platts-Mills 1987), isocyanates (Venables 1985b), platinum salts (Calverley 1995, Niezborala 1996, Venables 1989a and azodicarbonamide (Slovak 1981).

** 2+ Sensitisation and occupational asthma are most likely to develop in the first years of exposure for workers exposed to enzymes, complex platinum salts, isocyanates and laboratory animal allergens.

(Abstract Available for: Allergy to laboratory animals in laboratory technicians and animal keepers Agrup 1986, Abstract Available for: Platinum salt sensitivity in refinery workers: incidence and effects of smoking and exposure Calverley 1995, Full Text Available for: Allergen exposure, atopy and smoking as determinants of allergy to rats in a cohort of laboratory employees Cullinan 1999, Full Text Available for: Incidence and host determinants of probable occupational asthma in apprentices exposed to laboratory animals Gautrin 2001, Full Text Available for: Natural history of sensitisation, symptoms and occupational diseases in apprentices exposed to laboratory animals Gautrin 2001, Abstract Available for: Allergy risk in an enzyme producing plant: a retrospective follow up study Johnsen 1997, Abstract Available for: Occupational respiratory diseases in laboratory animal workers; initial results Krakowiak 1997, Abstract Available for: Allergy to complex platinum salts: A historical prospective cohort study Niezborala 1996, Abstract Available for: Occupational asthma and rhinitis related to laboratory rats: serum IgG and IgE antibodies to the rat urinary allergen PlattsMills 1987, Abstract Available for: Occupational asthma caused by a plastics blowing agent, azodicarbonamide Slovak 1981, Abstract Available for: Smoking and occupational allergy in workers in a platinum refinery Venables 1989)

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