OAT CELL CARCINOMA
OCCUPATIONAL DISEASE AND INJURY
oat cell carcinoma A form of
also known as
small cell carcinoma.
obesity A condition in which excess fat
has accumulated in the body. A person
per cent above the recommended
weight for his or her height (see
is obese rather than overweight. About
people in the UK are overweight
and a further
Obesity is usually caused by consuming
more food than is needed for energy.
Energy requirements are determined by
metabolic rate (see
of physical activity. Family history is
sometimes a factor. Obesity is associated
with some hormonal disorders, but these
are not generally the cause.
Obesity increases the risk of
Coronary artery disease
is more com-
mon, particularly in obese men under
. Obesity in men is also associated
with increased risk of cancer of the colon,
rectum, and prostate, and, in women, of
the breast, uterus, and cervix. Extra
weight may aggravate
The first line of treatment is a slimming
) plus regular
exercise. Drugs such as appetite sup-
pressants are rarely used due to their
Wiring of the jaws,
of the stomach, and intestinal bypass
operations are attempted only if obesity
is endangering a person's health.
obsessive-compulsive disorder A psy-
chiatric condition in which a person is
dogged by persistent ideas (obsessions)
that lead to repetitive, ritualized acts
(compulsions). Obsessions are com-
monly based on fears about security or
becoming infected. In obsessional rum-
ination, there is constant brooding over
a word, phrase, or unanswerable prob-
lem. Compulsions may occur frequently
enough to disrupt work and social life.
The disorder is often accompanied by
If severe, a per-
son may become housebound.
The disorder usually starts in adoles-
cence. Genetic factors, an obsessive
personality, or a tendency to neurotic
symptoms may contribute. Some types
of brain damage, especially in
can cause obsessional symptoms.
Many sufferers respond well to
which may be combined
, but symp-
toms may recur under stress.
obstetrics The branch of medicine con-
. It is
also the study of the structure and func-
tion of the female
obstructive airways disease See
monary disease, chronic obstructive.
occiput The lower back part of the head,
where it merges with the neck.
occlusion Blockage of a passage, canal,
opening, or vessel in the body. This may
be due to disease (for example, a
) or medically induced.
Occlusion also describes eye-patching
and the relationship
between the upper and lower teeth when
the jaw is shut. (See also
occult Hidden or obscure, such as occult
blood in a sample of faeces.
occult blood, faecal The presence in
the faeces of blood that cannot be seen
by the naked eye, but can be detected
by chemical tests. Such tests are widely
used in screening for cancer of the colon
of). Faecal occult
blood may also be a sign of a gastroin-
testinal disorder such as
the intestine (see
rectal cancer (see
rectum, cancer of
in the colon;
; or irritation of the
stomach or intestine by drugs such as
aspirin. (See also
occupational disease and injury Ill-
nesses, disorders, or injuries that result
from exposure to chemicals or dust, or
are due to physical, psychological, or bio-
logical factors in the workplace.
of the lung
due to inhalation of industrial dusts,
such as coal.