Preventing baker's asthma: an alternative strategy

BACKGROUND: Although baker's asthma has attracted considerable research interest over the last 30 years, success in its prevention has been slow to achieve. This paper describes the results of an alternative preventive strategy, based on an observation that the excess of sensitization in bread bakers is largely due to IgE-mediated allergy to fungal amylase, contained in bread improvers. The practical application of the strategy has been to limit bread improver exposures to <1 mg/m3 [8 h time-weighted average (TWA)], whilst exposures to all other ingredients, including flour, have been limited to <10 mg/m3 (8 h TWA). METHOD: The paper describes the findings of in-house respiratory health surveillance and dust sampling programmes, from a UK food company whose primary interests are milling and baking, over the period following the introduction of the strategy to target the reduction in bread improver exposure. RESULTS: Over the 10 year period of surveillance, the incidence of symptomatic sensitization in the bread baking sector (2240 per million employees per annum) was greater than for the other flour-using groups (330 per million employees per annum), despite broadly similar total inhalable dust exposures. There was an overall reduction in the incidence of new cases of symptomatic sensitization, from 2085 per million employees per year in the first 5 years of the surveillance programme, to 405 per million employees per year in the subsequent 5 years. CONCLUSION: The strategy of targeting bread improver exposure is an effective approach for the prevention of new cases of symptomatic sensitization in bread bakeries.     

Health surveillance in milling, baking and other food manufacturing operations--five years' experience.

The objective of this study was to describe the incidence of allergic respiratory disease and its outcome in terms of symptoms and jobs, across different flour-using industries. It uses the findings of a health surveillance programme in a large food organization over a five-year period. The population under surveillance consisted of 3,450 employees with exposure to ingredient dusts, of whom 400 were in flour milling, 1,650 in bread baking, 550 in cake baking and 850 in other flour-using operations. A total of 66 employees with either asthma or rhinitis symptoms attributable to sensitization to allergens in the workplace were identified. The majority of these (48/66) had become symptomatic prior to the commencement of the health surveillance programme in 1993. The incidence rates (per million employees per year) for those who developed symptoms between 1993 and 1997 were 550 for flour milling, 1,940 for bread baking, 0 for cake baking and 235 for other flour-using operations. The agent believed to be responsible for symptoms was most commonly grain dust in flour millers and fungal amylase in bread bakers. Wheat flour appeared to have a weaker sensitizing potential than these other two substances. In terms of outcome, at follow-up 18% of symptomatically sensitized employees had left the company. Two of the ex-employees retired through ill health due to occupational asthma. Of those still in employment, 63% described an improvement in symptoms, 32% were unchanged and 4% were worse than when first diagnosed. Over half the cases still in employment were continuing to work in the same job as at the time of diagnosis.     

Respiratory symptoms and sensitization in bread and cake bakers

This purpose of this study was to examine the relationship betweenexposure to wheat flour, soya flour and fungal amylase and thedevelopment of work-related symptoms and sensitization in breadand cake bakery employees who have regular exposure to thesesubstances. The study populations consisted of 394 bread bakeryworkers and 77 cake bakery workers whose normal jobs involvedthe sieving, weighing and mixing of ingredients. The groupswere interviewed with the aim of identifying the prevalence,nature and pattern of any work-related respiratory symptoms.They were also skin-prick tested against the common bakery sensitizingagents, i.e., wheat flour, soya flour, rice flour and fungalamylase. The results of personal sampling for sieving, weighingand mixing operations at the bakeries from which the study groupswere taken were collated in order to determine typical exposuresto total inhalable dust from the ingredients, expressed as 8hour time-weighted average exposures. Data from the health surveillanceand collated dust measurements were compared with the aim ofestablishing an exposure-response relationship for sensitization.The prevalence of work-related symptoms in bread bakery andcake bakery ingredient handlers was 20.4% and 10.4% respectively.However, in a large proportion of those reporting symptoms inconnection with work, the symptoms were intermittent and ofshort duration. It is considered that the aetiology of suchsymptoms is likely to be due to a non-specific irritant effectof high total dust levels, rather than allergy. None of thecake bakers and only 3.1% of the bread bakers had symptoms whichwere thought to be due to allergy to baking ingredients. Usingskin-prick testing as a marker of sensitization, the prevalenceof positive tests to wheat flour was 6% for the bread bakersand 3% for the cake bakers. Comparable prevalences for soyaflour were 7% and 1 % respectively. However, the prevalenceof positive skin-prick tests to fungal amylase was 16% amongstthe bread baking group with only a single employee (1 %) inthe cake baking group having a positive test. Furthermore, thisemployee had previously worked in a bread bakery. The differencein rates of sensitization to wheat flour between the bread andcake bakers is not statistically significant, whereas the differencefor soya flour is at the borderline of statistical significance(p=0.045). In contrast, the difference in fungal amylase sensitizationis significant at the 0.1% level. For both bread and cake bakers,the 8 hour time-weighted average exposures for each of the activitiesshowed a wide variation with mixing having the lowest averageexposure and sieving the highest. Out of the allergens studiedin this investigation, fungal amylase is the principal sensitizerin large scale bread bakeries, with the main source of exposurebeing the handling of bread improvers. In contrast, the riskof sensitization to wheat flour is low in both bread and cakebakeries. The absence of positive skin-prick tests in the subgroupof cake bakery employees who regularly handle fungal-amylase-containingflour suggests that their levels of exposure are below the thresholdfor sensitization to amylase.     

Concerns for asthma at pre-placement assessment and health surveillance in platinum refining--a personal approach

Platinum, a noble metal, is inert in the body and has an important use in medical applications. It is used in autocatalysts to control harmful vehicular emissions and the catalytic effects improve efficiencies of pharmaceutical and petrochemical processes. The refining process involves exposure to halogeno complex salts of platinum which are potent allergens. They induce symptoms typical of a type I allergy, the most significant of which is asthma. Platinum refining not only exposes employees to the risk of sensitization to these salts but also to respiratory irritants. Inhalation of these aggravates pre-existing asthma. The increasing incidence of asthma in the community requires that prospective employees for platinum refining be assessed carefully to establish their respiratory health status in relation to the risk of sensitization or aggravation of pre-existing asthma. Routine medical surveillance has been shown to reduce persistence of asthma in sensitized workers who cease exposure to the platinum salts upon diagnosis. Skin prick test using dilute platinum salt solutions can detect sensitization at an early stage and this has become the mainstay of surveillance programmes as it is objective and reproducible as well as predictive for the development of symptoms when exposure is allowed to continue. Symptoms are not sensitive or specific. Smoking is a significant risk factor.     

Incidence of occupational skin conditions in a food manufacturing company: results of a health surveillance programme

BACKGROUND: The food industry has been associated with a high risk of work-related skin problems. Aim To examine the incidence of work-related skin conditions and the likely causative agents in a single large food company. METHOD: Analysis of a health surveillance programme, conducted over a 7 year period, in a food company with 21 000 employees working in diverse manufacturing processes. RESULTS: The mean incidence of skin conditions, taking all of the different food manufacturing operations together, was 1310 per million employees per annum. The mean incidence was greatest in the manufacturing sector whose operations involved chilled or frozen product (3180 per million employees per annum). Most of the cases reported (184/192 = 96%) were due to primary irritant dermatitis. The two commonest suspected causes of the dermatitis were contact with ingredients and hand washing. Taken together, these factors accounted for 58% of all cases. Although the wearing of gloves is often considered necessary to prevent dermatitis from exposure to ingredients and to lessen the need for hand washing, this factor itself was responsible for 9% of all cases. CONCLUSION: Analysis of a company health surveillance scheme showed the average incidence of work-related skin problems to be lower than previously reported in the food industry.     

Allergy to flour and fungal amylase in bakery workers

The purpose of this study was to describe the prevalence ofrespiratory symptoms and skin prick test findings in a groupof 383 employees in a plant bakery population who had the greatestregular exposure to ingredient dusts. The prevalence of positiveskin prick tests to fungal amylase was 16%, in contrast to 6%to wheat flour, suggesting that the principal sensitiser isfungal amylase and not flour. Furthermore, the findings suggestthat symptomatic allergy to bread-baking ingredients is uncommon(3.1%). In comparison, occasional short-lived symptoms whichdo not appear to have an allergic aetiology are relatively prevalent(17.2%). Where sensitisation to ingredients arises, fungal amylasepresent in bread improvers is the principal allergen.     

Sensitization to king scallop (Pectin maximus) and queen scallop (Chlamys opercularis) proteins

OBJECTIVE: To report a case of occupational asthma and urticaria due to the queen scallop (Chlamys opercularis) and king scallop (Pectin maximus). BACKGROUND: A 40-year-old female worked in a shellfish-processing plant, handling king and queen scallops for 5 years. At the time of investigation, she described a 2-year history of work-related respiratory symptoms. METHODS: Serial peak expiratory flow rate readings were recorded and an OASYS study completed. A workplace visit was undertaken and specific immunoglobulin (IgE) radioallergosorbent (RAST) testing of scallop extracts was performed. RESULTS: The OASYS study was consistent with occupational asthma. RAST testing demonstrated evidence of specific sensitization (IgE) to queen and king scallop. There was also some cross-reactivity observed with other shellfish (prawns and crabs). CONCLUSION: Workers exposed to aerosols from scallop species are at risk of occupational asthma and require effective respiratory health surveillance.     

A cross-sectional study of employer and employee occupational health needs and priorities within the Irish Civil Service

BACKGROUND: This study aimed to establish how important an occupational health unit (OHU) is to its clients, and to identify the perceived needs and priorities for such a service. METHODS: A cross-sectional postal survey of a stratified, randomly selected group of employees (n = 760) and all human resources (HR) managers (n = 34) was conducted in the Irish Civil Service. Each participant was requested to rate the overall importance of the OHU and to prioritize eight proposed functions for the unit: medical surveillance, general health education, pre-employment/promotion medical assessments, ill-health retirement assessments, return-to-work (after sick leave) assessments, occupational health education, research, and general medical screening. The results were analysed according to age group, gender, grade and occupation. RESULTS: There was a response rate of 69% from employees and 74% from personnel managers. Significantly more HR managers than employees (92 versus 81%) thought an occupational health service was either important or very important. There were also differences in prioritization of functions by employees and HR managers. HR managers prioritized those functions concerned with assessing individuals' fitness for work, notably pre-employment/promotional health assessments, whereas employees consider group-directed 'preventative' functions to be more important, i.e. general medical screening, health education and medical surveillance. Both sets of opinions are not mutually exclusive, and considerable overlap exists, notably in the areas of occupational and general health education.     

Factors associated with premature departure from working life among ageing food industry employees

AIM: To find out how health status, work ability and job-related factors were associated with premature departure from working life in an 11 year follow-up period. METHODS: The study population was composed of 126 ageing food industry employees. Baseline data were derived from medical examinations and self-completed questionnaires in 1989. The follow-up data were collected in 2000. Data analyses were performed by independent samples t-tests and Mann-Whitney and chi(2) tests. RESULTS: Several chronic diseases, higher degree of work impairment due to diseases, long-term sickness absence, stress symptoms, low scores in work ability index, poor subjective work ability and physical work ability, and heavy physical workload seemed to be factors associated with early departure from working life among ageing food industry employees. CONCLUSION: Identification of these factors, prevention of sickness and promotion of work ability seem to be the most important tools to reduce premature exit from working life.     

Occupational asthma after exposure to plaster casts containing methylene diphenyl diisocyanate

BACKGROUND: The case of a 34-year-old female nurse is presented. She worked in an accident and emergency department in a district general hospital, with methylene diphenyl diisocyanate (MDI)-containing synthetic plaster casts. She worked with MDI on a daily basis for 4 years. She was out of the department for 1 year and on her return developed cough, wheeze and dyspnoea within 5 min of exposure to MDI- containing synthetic casts. METHOD: A bronchial provocation test was performed and confirmed an early asthmatic response. RESULTS: There was a 39% decrease in the forced expiratory volume in 1 s 15 min after exposure, which required the administration of a bronchodilator on two occasions. The patient has subsequently avoided MDI-containing synthetic plaster casts and has experienced no further respiratory symptoms. CONCLUSION: This case illustrates that respiratory sensitization can occur as a result of exposure to MDI-containing synthetic casts and highlights the need for vigilance when health care workers are using isocyanate-containing synthetic casts.     

Respiratory symptoms among glass bottle workers--cough and airways irritancy syndrome?

Glass bottle workers have been shown to experience an excess of respiratory symptoms. This work describes in detail the symptoms reported by a cohort of 69 symptomatic glass bottle workers. Symptoms, employment history and clinical investigations including radiology, spirometry and serial peak expiratory flow rate records were retrospectively analyzed from clinical records. The results showed a consistent syndrome of work-related eye, nose and throat irritation followed after a variable period by shortness of breath. The latent interval between starting work and first developing symptoms was typically 4 years (median = 4 yrs; range = 0-28). The interval preceding the development of dysponea was longer and much more variable (median = 16 yrs; range = 3-40). Spirometry was not markedly abnormal in the group but 57% of workers had abnormal serial peak expiratory flow rate charts. Workers in this industry experience upper and lower respiratory tract symptoms consistent with irritant exposure. The long-term functional significance of these symptoms should be formally investigated.     

Implementation of statutory occupational respiratory health surveillance

Health surveillance is required by UK regulations in certain circumstances, and is usually provided through an occupational health organization. Although there are studies assessing the provision of health surveillance across the country, there are no published studies addressing the practical application of legislation, guidelines and medical research to respiratory health surveillance programmes. An audit of a multidisciplinary health surveillance programme was carried out, using review of occupational health records, occupational hygiene reports and managers' risk assessments, to compare the implementation of health surveillance in different organizations and under different contractual relationships. Sixty-six per cent of National Health Service (NHS) and 56% of industrial workplaces were able to provide risk assessments but were unable to link these with appropriate health surveillance. Twenty-seven per cent of NHS employees potentially exposed to respiratory sensitizers had baseline surveillance, compared with 87% in industry. Fifty-five per cent of Medical Research Council questionnaires were inappropriately administered by the employee themselves, rather than an interviewer as recommended. Other follow-up questionnaires in use had not been formally validated. Non-regular lung function assessment using spirometry was the predominant tool used for follow-up surveillance. There was no overall strategic approach to respiratory health surveillance in the organization studied. Health surveillance programmes should focus on disease prevention without becoming a repetitious application of unvalidated tools. Clinical governance demands quality assurance standards that will effectively implement a coordinated approach to health surveillance.     

Latex glove allergy among hospital employees: a study in the north-west of England

The frequency of use and duration of wearing latex gloves among hospital employees has increased due to concerns about AIDS and hepatitis. In many countries there is increased consciousness about latex sensitization. In the UK, the Medical Device Agency has been monitoring latex allergy for a number of years but has not found any conclusive evidence of any significant problem. We report following a detailed questionnaire study in two hospitals in the north-west of England. A total of 1,827 members of staff were questioned about latex allergy at work. One hundred and twenty-four (7%) of these hospital employees had experienced symptoms strongly suggestive of latex allergy. Of this group, 56 had a-RAST test (IgE specific to latex), which was positive in seven (12.5%). There was a history of atopy in 31%, and a family history of atopy in 17% of the individuals. As a result of the study it was found that 17% (21 of the affected individuals) had already changed their working practice by using latex-free gloves. We were able to increase awareness of latex allergy within the hospitals. Both individuals and health care organizations need to be aware of the problem and hospital organizations should encourage staff to seek guidance to address the problem and, if necessary, to take appropriate measures to improve working practices. Practical guidelines are given with regard to identifying the problem and glove use for hospital staff.     

Use of keyboards and symptoms in the neck and arm: evidence from a national survey

The objective of this study was to examine the relationship between upper limb symptoms and keyboard use in a population survey. A questionnaire was mailed to 21,201 subjects aged 16-64 years, selected at random from the registers of 34 British general practices. Information was collected on occupation and on regular use of keyboards (for >4 h in an average working day), pain in the upper limbs and neck, numbness or tingling in the upper limbs, headaches, and feelings of tiredness or stress. Associations were explored by logistic regression, with the resultant odds ratios converted into prevalence ratios (PRs). Among 12,262 respondents, 4899 held non-manual occupations. These included 1871 regular users of keyboards (e.g. computer operators, data processors, clerks, administrators, secretaries and typists). Pain in the neck or upper limbs and sensory symptoms were common in the non-manual workers overall (with 1 week period prevalences of 30 and 15%, respectively), and were associated with older age, smoking, headaches and tiredness or stress. After adjustment for these factors, regular keyboard use was significantly associated with pain in the past week in the shoulders (PRs 1.2-1.4) and the wrists or hands (PR 1.4), but not with elbow pain or sensory symptoms over the same period, or with neck or upper limb pain that prevented normal activities in the past year. Disabling symptoms were somewhat less prevalent among symptomatic keyboard users than among other symptomatic workers. We conclude that use of keyboards was associated with discomfort at the shoulder and wrist or hand, but risk estimates were lower than generally reported in workplace surveys. Previous estimates of risk in the occupational setting may have been biased by shared expectations, concerns, or other aspects of illness behaviour.     

Morbidity in expatriates--a prospective cohort study

BACKGROUND: Expatriates comprise an important, but rarely studied subset of international travellers. This study was performed to assess the incidence of health events in an expatriate group and to evaluate factors affecting this incidence. METHODS: A cohort of 2020 Foreign and Commonwealth Office (FCO) staff and partners living abroad were followed-up over 1 year. The main outcome measure was incidence of illness or injury serious enough to require consultation with a doctor. Data collection was by means of a self-administered questionnaire. Poisson regression was used to estimate the rates of health events and to test for association between health events and a number of independent variables. RESULTS: The incidence of health events was 21%. Trauma (incidence 5%), musculoskeletal disorders (incidence 4%) and infectious disease (incidence 3%) were the principal causes of morbidity. The incidence of psychological disorders was low (1%). Of significance, employees were at increased risk of morbidity when compared to partners, with a higher incidence of health events [incidence rate ratio (IRR) 1.4, 95% CI 1.1-1.9] and psychological disorders (IRR 5.9, 95% CI 1.0-34.1). Moreover, unaccompanied employees were at increased risk of health events (IRR 1.3, 95% CI 1.0-1.7), and of traumatic injury (IRR 2.3, 95% CI 1.3-4.3) when compared to accompanied employees. CONCLUSION: While the morbidity in FCO personnel is low in comparison to other expatriate groups, the higher risk of morbidity in employees and unaccompanied individuals merits further research, particularly to ascertain whether work demands, isolation or risk-taking behaviour are contributory factors.     

Identifying workers at risk of sickness absence by questionnaire

BACKGROUND: Sickness absence is an important economic problem, because of high costs and lost productivity. Determining factors associated with increased risk of sickness absence may lead to the development of preventive measures. AIMS: To determine whether self-report questionnaires can identify those employees at risk of sickness absence METHODS: Prospective study of 238 healthy administrative workers. Participants completed a questionnaire proven to be valid and consistent. The questionnaire consisted of 116 items about health, work and working conditions. Sickness absence was followed-up for a period of 1 year. RESULTS: The questionnaires of 191 workers (80%) were suitable for analysis. The number of reported health complaints was significantly (P < 0.01) associated with sickness absence (OR 2.18; 95% CI 1.32-3.61). Concentration problems were correlated with more frequent absences, and both nervous complaints and coping problems with longer duration. Age (OR 0.96; 95% CI 0.93-0.99; P = 0.02) and job insecurity (OR 0.68; 95% CI 0.47-0.98; P = 0.04) were negatively associated with sickness absence. Psychosocial and physical work factors were not associated with sickness absence. CONCLUSIONS: Questionnaires on health and work can identify employees at future risk of sickness absence. Workers who report multiple health complaints, especially concentration problems, nervous complaints or coping problems, may be at increased risk of sickness absence.     

Surveillance on self-report: a trial of health and safety monitoring in occupational settings

A method for monitoring health and safety in the workplace, referred to as 'surveillance on self-report', is presented. This occupational health and safety monitoring method consists of a collection of data on certain aspects of health and safety obtained by dispensing self-administered questionnaires to employees or managers and supervisors in workplaces, and administering regular feedback on the responses. Based on the responses, a continual monitoring and improvement on certain aspects of health and safety were possible in two workplaces in New Zealand. This study has shown a methodology for the surveillance of hazard control and monitoring, injuries and illnesses, and organizational policies in occupational settings.     

Inequality in the health status of workers in small-scale enterprises

BACKGROUND: Small-scale enterprises (SSEs) usually share poorer resources for promoting occupational health. AIM: To investigate inequality of health status among SSEs in Japan. METHOD: A cross-sectional, multiple-centred study was carried out using the periodical health check-up data for the fiscal year 2000 to compare the age-adjusted proportions of workers with hypertension (HT), hyperlipidaemia, impaired glucose tolerance (IGT) and obesity and of current smokers by size of enterprise, i.e. or=1000 employees in Japan. RESULTS: From five leading occupational health organizations, data were collected for 9833 enterprises with a total of 436 729 subjects, 302 383 males and 134 346 females. The proportions of workers in SSEs with or=50 male employees. The prevalence of smokers in SSEs with or=50 male employees. These proportions showed a significantly increasing tendency with decreasing size of male workforce. CONCLUSION: Despite the cross-sectional design and only adjusting age as a potential confounder, higher proportions of HT, IGT, obesity and smoking in male workers were found in SSEs compared to larger organizations.