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GAZETTE
JANUARY/FEBRUARY 1990
Occupational Diseases —
The Problem of Time
Occupational disease may be acute, chronic, allergic, localised, or
systemic. It may be due to a multiplicity of causes or one obvious
and specific cause. There is also the problem of sorting out those
occupational diseases which are specific to the occupation from
those which can occur spontaneously in the general population.
Examples of what I mean by
acute occupational disease would
include gassing accidents, which
may either kill the unfortunate
worker or result in long-term disa-
bility, and acute irritant dermatitis
(which can also be referred to as a
"chemical burn"). By chronic I
mean those diseases which are
neither curable nor self limiting
such as asbestosis. By allergic
occupational disease I am referring
to dermatitis of the allergic variety
and one of our biggest problems at
the moment, occupational asthma.
Allergic alveolitis is best known in
this country as farmers lung, but
the condition can also occur in malt
workers, mushroom growers and a
host of other, agriculturally related,
occupations where exposure to
various spores occurs.
By isolated conditions I refer of
course to dermatitis and the
various diseases of the lung. Skin
diseases, using data from the
Department of Social Welfare
Occupational Injuries Benefit
Scheme, make up roughly two
thirds of occupational diseases
claimed for under this scheme.
Lung diseases would be a consider-
ably smaller proportion but skin
"At the moment . . . there is no
meesurable way in which a
particular state of ill-health
can be attributed to a
particular stressful work
situation"
disease and lung disease are a
sizeable proportion of occupational
disease overall. The reason is
obvious: this is where the hazard
strikes first, either directly on the
skin or by being inhaled. Systemic
disease such as heavy metal
poisoning (lead), or organic
chemical poisoning (benzene) will
have effects on many different
areas of the body (the brain, blood,
and various organs).
Dr. Dan Murphy M.B.,
F.F.O.M., D.I.H.*, Director
Occupational Medical
Services, National
Authority for Occupational
Safety & Health
Something we may well have to
deal with in the future are the
effects of stress on general health.
At the moment, despite many well
founded suspicions about the
effects of stress there is no meas-
urable way in which a particular
state of ill-health can be attributed
to a particular stressful work
situation.
There are two final problems
when dealing with occupational
diseases which I will try to cover
briefly. The first of these is that in
fact many occupational diseases
have more than one cause whether
in the occupation itself or in the
occupation and the individual's
private life (asbestos and cigarette
smoking). Next there is the problem
of specific occupational disease
versus non-specific. Asbestosis is
a specific occupational disease.
Lung cancer, also known as
carcinoma of the bronchus, is sadly
a common cancer. One study
showed that in a group of asbestos
workers, with asbestosis, followed
up to the year 1963, just over 50%
of them had died from lung cancer.
Thus, lung cancer is a risk faced by
asbestos workers, but how do you
tell what proportion of the lung
cancer in asbestos workers is due
to their asbestos exposure or to
their smoking, or just plain chance?
Asbestos - A useful example
In a brief introduction to some of
the problems of the relationship in
time between occupational disease
and its cause, I am going to take the
example of asbestos and asbestos
related diseases. I believe it will
serve as a useful example to indi-
cate problems of multiple causes,
non-specific as well as specific
occupational disease, the problem
of attributability, and, in the case of
cancer, the problem of the long
latent period.
Asbestos related Diseases
The problem of what diseases are
related to asbestos is in fact com-
pounded by the fact that there are
certain health effects (such as
"pleural plaque") which are not
considered as diseases at all by
most clinicians. In other words they
Dr. Dan Murphy.
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