An
effective health surveillance programme led by the occupational health service
is the key to the detection and management of bakers’ asthma. By Olivia Walpole
Designing
a health surveillance programme to meet the needs of a multi-sited
organisation, with a peripatetic occupational health service, some 5,000
individuals with "bakery" as part of their job title and in a
fast-moving retail environment with a high staff turnover, was never going to
be easy!
A
considerable amount of research and benchmarking was used in the design of the
model described on these pages, and I am indebted to the Occupational and
Environmental Medicine Department at the Royal Brompton Hospital for all their
help and advice.
This
project was undertaken against a background of increasing pressure from the
Health and Safety Executive and the National Federation of Bakers to monitor
and control the risks to health of handling flour and other ingredients in
bakeries, where individuals remain close to the process.
There
is an accepted link between exposure to ingredient dust and development of
respiratory symptoms, which normally fall into one of two distinct patterns1:
–
Non-specific irritant symptoms in the presence of high inhalable dust levels or
related to the chemical nature of ingredients
–
Acquired allergy to substances within the dust.
Incidence
of asthma in bakers
The
incidence of occupational asthma among bakers is second only to that among
those who work with isocyanates. It is most common in bakers in the 45-65 age
range who have worked in bakeries for more than seven years and onset is often
late. Bakers with occupational asthma are usually antigen positive to wheat,
flour and/or flour improver.
There
is a direct correlation between exposure and risk, and the interval between
first symptoms and removal from exposure determines the degree of recovery. The
prognosis for occupational asthma is generally poor. However, the outcome is
more favourable the earlier the individual is removed from the exposure.
The
view taken by many health professionals in the field is that asthmatics should
be excluded by pre-employment health assessment.
The
effect of sensitisers may be made more potent by the presence of irritants, as
these are thought to act as carriers across lung epithelium.
General
practitioners are apt to diagnose "bakers’ asthma" on the basis of
their patient reporting respiratory symptoms and working in a bakery.
There
needs to be an effective health surveillance programme led by the occupational health
service to coordinate the management of this issue, as this has been shown to
improve management and detection.
Clinical
aspects
Work-related
asthma occurs where there is a sensitivity to dust. The individual is usually
sensitive to other substances such as pollen, house dust, furs and feathers.
In
the case of bakers, flour dust and/or moulds and fungi can trigger chest
symptoms such as tightness and wheeze. These symptoms occur in the upper and
lower respiratory tract, and are generally transient and intermittent in
nature. There is no evidence that non-specific irritant symptoms result in
long-term health problems and individuals may carry on working. Continuous
monitoring should take place as part of a yearly surveillance programme.
Occupational
rhinitis, that is. runny/ blocked nose, itchy eyes and so on, can also occur
independently of chest symptoms in susceptible individuals. There is no
evidence that occupational rhinitis leads to occupational asthma, and these
individuals are also able to carry on working. The process of surveillance on a
large and changeable population will need some parameters in order to make the
workload manageable and pinpoint the individuals most at risk. Consequently,
the initial survey may aim to identify as a benchmark those who use inhalers.
Occupational
asthma is almost always accompanied by occupational rhinitis. Individuals
complaining of both wheeze and chest tightness, together with runny/blocked
nose will generally need to be referred for further investigation. Sensitivity
generally takes some time to develop, and while the latency period may be some
years, the peak risk time is six to 18 months after starting in the bakery.
Clinical
investigation
When
taking the history from a presenting individual, there are three main areas to
investigate:
–
When did symptoms start? If symptoms were noticed within the first six months
of starting work, they are more likely
to be due to work-related asthma or occupational rhinitis. It is important to
note whether symptoms started prior to working for the current employer
–
What is the timing and pattern of symptoms? Generally, individuals with
work-related asthma do not have symptoms when away from the work environment.
If the symptoms are taking longer and longer to go away, and if the chest
symptoms are relieved more quickly than the rhinitis when away from work, the
individual may need further investigation
–
What happens during sleep? Another feature of occupational asthma is that the
individual wakes up at night with chest symptoms. If the individual has become
sensitised, there is generally an immediate response in the nose/eyes, and
further respiratory reaction some hours later
Occupational
asthma must be suspected if the individual complains of always having a blocked
or runny nose (even when not at work); having symptoms that developed some
months or years after starting work in bakeries and has a wheeze (although this
may not yet have developed noticeably if in the early stages).
A
past history of childhood asthma and atopic disease may pose a higher risk to
certain individuals. Smoking appears to be irrelevant.
Legislation
The
Control of Substances Hazardous to Health Regulations 1994 sets out the legal
requirements for protecting the health of employees exposed to substances that
may be harmful to their health, including respiratory sensitisers. Employers
must inform staff of the risk and the control measures that exist to safeguard
their health. Failure to comply with COSHH is an offence subject to penalties
under the Health and Safety at Work Act 1974.
Respiratory
sensitisers, that is substances known to cause occupational asthma, include
those routinely used in the baking process (flour, barley, wheat, oats, rye and
flour improvers).
The
Health and Safety Executive has identified risks to health from exposure to
flour dust through skin/eye contact, ingestion and inhalation2. Under COSHH,
health surveillance (or regular monitoring/screening of health) is required for
all employees who may be exposed to known causative agents of work-related
disease.
HSE
guidance suggests companies should instigate initial pre-employment/placement
screening using a pre-exposure questionnaire, followed by periodic assessment
throughout the duration of employment (via self-report questionnaire, lung
function testing or both).
Health
surveillance is required in addition to the application of good standards of
control because for many sensitisers "safe" levels of exposure are
not known. Maximum Exposure Limits for
respiratory sensitisers are set out in schedule 1 of the COSHH Regulations.
These are revised and published annually and are designed to help employers
decide what standards of controls are required. Currently, the HSC is
considering introducing a MEL for flour dust3. In the meantime, a Chemical
Hazard Alert Notice was issued in November 19984. Studies in organisations with
a recognised risk of sensitisation revealed that up to 30 per cent of workers
may have occupational asthma. SWORD (Surveillance of Work-related and
Occupational Respiratory Disease) statistics indicate that for 1:1,000
employees with asthma the condition is made worse by work.
The
HSE perspective
The
HSE has emphasised that training in safe handling procedures is fundamental to
the reduction of ill-health attributed to flour dust and bread improvers. It
advises taking a broad approach to the control of exposure to flour dust, which
may include air monitoring, risk assessment; engineering controls; and training
and health surveillance programmes. Under COSHH regulations, recommendations
for controlling dust in bakeries fall into four stages (see box).
Enforcement
will be based on compliance in the following areas:
–
Industry agreed standard of <10mg/m3 airborne dust.
–
Provision of PPE and clothing
–
Health surveillance procedures are in place.
Surveillance
The
two main tenets for protecting the health of individuals working with flour and
enzymes are control of exposure and surveillance of the working population.
Thus the approach has to be multi-disciplinary.
Under
Regulation 11 of COSHH regulations, where there is evidence of specified
respiratory sensitisers, employers are obliged to introduce a positive system
of enquiry seeking evidence of symptoms amongst employees. These specified
substances include flour and grains, and proteolytic enzymes such as amylase.
The
study
A
simple questionnaire was administered by a trained responsible person in
accordance with the instructions of the occupational health service. The
designated person was part of a multi-disciplinary team and was trained to
oversee the administration of the health surveillance programme, including pre-employment assessment, induction,
training, use of PPE and environmental hygiene.
This
person could be from management, the bakery or human resources, but must be
sufficiently empowered to manage his or her responsibilities within the
programme.
The
questionnaire sought information by means of a "yes/no" response on
the following symptomatology: wheezing, chest tightness, bouts of coughing,
recurrent blocked or runny nose, and recurrent soreness or watering of eyes.
The questionnaire was also used to ascertain whether the individual was using
any prescribed medication such as an inhaler, and contained a declaration that
details supplied were accurate.
Where
indicated, that is following one or more "yes" responses, a more
detailed history was taken by an OHA, who completed a respiratory assessment
questionnaire. In order to ensure commonality of standards, the OHAs carried
out a structured interview using agreed clinical criteria, including details of
past medical and employment history, nature of symptoms, and relationship of
symptoms to work.
Clients
were referred for specific IgE diagnosis through skin prick/blood testing to
the Department of Occupational and Environmental Medicine at the Royal Brompton
and Harefield NHS Trust. This ensured continuity and accurate diagnosis of
sensitivity to particular allergens.
If
there is a potential for permanent redeployment or retirement on the grounds of
ill-health, an accurate diagnosis is essential.
Respiratory
measurement by means of peak flow testing is of arguable value in the
occupational health situation, as there are a number of variables that may
affect the accuracy of the information gained.
Recruitment
health questionnaires should include a section on respiratory conditions that
may predispose an individual to developing problems when working within
bakeries. This should include asking individuals to declare if they have asthma
or use prescribed inhalers.
Conclusions
Many
physicians do not routinely refer their patients for testing for IgE to fungal
amylase or wheat flour, but diagnose occupational asthma on the basis of
history alone.
It
came as a surprise to the occupational health department just how many bakers
were using inhalers prescribed by their GPs, where there had been no
investigation of the working environment or substances handled. If there is to
be a truly integrated public health policy, occupational health must ensure
that opportunities are taken for the education of the primary health team as
well as the client.
Acknowledgments
In
compiling this report, advice has been sought from Dr Trevor Smith, the CMA at
Rank Hovis McDougal; Dr Paul Cullinan, Senior Lecturer in Occupational and
Environmental Medicine; Dr David Ross,
at the Epidemiological Surveillance Unit, at the Brompton Hospital; Dr Dennis
Brennan, Company Medical Adviser at Sainsbury’s Supermarkets; and Colin Davey, Occupational Hygiene Unit
at the HSE.
References
1.
Smith TA, Lumley KPS, Hui EHK. (1997) Allergy to flour and fungal amylase in
bakery workers. Occupational Medicine, 47: 21-4.
2.
Health and Safety Executive (2000) EH72/11 Flour dust risk assessment document.
11/99 HSE 3. Health and Safety Executive. EH40/2000 Occupational Exposure Limits 2000. 2/2000 HSE.
4.
Health and Safety Executive (1998) Chemical hazard alert notice. Flour Dust.
11/98 HSE.
Further
Reading
1.
Cannon J, Cullinan P, Newman Taylor A. (1995) Consequences of occupational
asthma. BMJ, 311: 602-3.
2.Cullinan
P, Lowson D, Nieuwenhuijsen MJ, et al. (1994) Work-related symptoms,
sensitisation and estimated exposure in workers not previously exposed to
flour. Occupational Environmental Medicine, 51:579-83.
3.
Health and Safety Executive (1991)
Guidance Note MS25: Medical Aspects of Occupational Asthma.(pp 5-6) HMSO.
4.
Smith TA, Patton J. (1999) Health surveillance in milling, baking and other
food manufacturing operations – five years’ experience. Occupational Medicine,
49: 147-53.
Olivia
Walpole, RGN DOHN is occupational health manager at Addenbrookes NHS Trust
Recommendations
for controlling dust in bakeries
Stage
1
Reduce dust exposure to < 10mg/m3 where practicable using
engineering controls and safe working practices.
Stage
2
Control high exposure activities such as hand throwing, cleaning up of
spillages, tipping and mixing through training individuals to handle dusty
ingredients correctly and safely.
Sign up to our weekly round-up of HR news and guidance
Receive the Personnel Today Direct e-newsletter every Wednesday
Stage
3
Provision and use of respiratory protective equipment and protective
clothing, especially during high exposure activities such as general cleaning
and clearing up of spillages.
Stage
4
Health surveillance to ensure control measures are effective.
