Occupation and cancer - European Trade Union Institute (ETUI)

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778 E. Pukkala et al.
studies indicate that persons with a high socioeconomic
status practice more healthy behaviours
than in low socio-economic status groups [180].
The intake of potatoes was higher among men in
the lowest social class in Denmark in 1985 than in
the highest social class, but the intake of vegetables
and fruit varied in the opposite direction [119].
Consumption of milk and milk products among
men was higher in the highest social class. The
food consumption among women varied less by
social class than among men but showed the
same tendencies. Food consumption by educational
groups among Swedish men in 1989 resembled
that reported for Danish men: there was a higher
consumption of potatoes among the low educated
men compensated by a higher consumption of fruit
and vegetables among high educated men [120].
The same pattern was observed among Norwegian
men in 1986 1988 [181].
In Finland, the intake of milk and butter in 1992
was significantly higher in men with low education,
whereas the intake of vitamin C and carotenoids
was significantly lower than in the highest educational
category [182]. FINJEM includes estimates
of average consumption of food items in each
occupation based on surveys on health habits of
the Finnish adult population 1978 1991 [173].
Regular use of butter is considered to be a proxy
of a less healthy diet. In men, the proportion was
low among university teachers (16%) and architects
(17%) and highest among farmers (70%), miners
(63%) and forestry workers (60%). In women, the
variation was from 11 12% among university teachers
and commercial managers to 52% among
butchers and dairy workers and 67% among farmers
and agricultural workers.
In Iceland, male unskilled workers, lower service
workers, employers, fishermen and farmers consumed
more fat and less carbohydrates and fibres
than men with higher education. Dietary habits
among women varied less by occupation than among
men but showed the same tendencies [183].
We cannot rule out that some of the associations
we found in our study may be at least partially
explained by socio-economic and occupational
differences in dietary habits. The strongest indication
of the potential effect of dietary factors was
in stomach cancer, where all low risk occupations
represented high socio-economic status with a diet
presumably rich in fruit and vegetable.
Occupation, body fatness and physical activity. There is
convincing evidence that body fatness is associated
with an increased risk of oesophageal adenocarcinoma,
colorectal cancer, pancreatic cancer,
endometrial cancer, kidney cancer, and postmenopausal
breast cancer [184]. Body fatness is probably
associated with cancer of the gallbladder directly
and indirectly, through the formation of gallstones.
Abdominal fatness has linked with cancers of the
pancreas, breast, and endometrium but is specifically
associated with an increased risk of colorectal cancer.
There is limited evidence that body fatness may be
associated with an increased risk for liver cancer and
that low body fatness is associated with lung cancer
risk [184]. The latter finding may be explained
by residual confounding due to smoking. Highly
educated persons in the Nordic countries tend to be
leaner than persons with limited education.
Physical activity at work, household, commuting
and leisure probably reduces the risk of at least
colon cancer, postmenopausal breast cancer and
endometrial cancer [185]. In the Nordic countries,
as elsewhere, occupations with high physical actvity
tend to be those with short education, such
as miners, forestry workers, fishermen, farmers,
construction workers, cleaning workers or assistant
nurses. On the other hand, highly educated persons
who work mainly in sedentary occupations, tend to
do more leisure time exercise.
FINJEM includes estimates of average body mass
index (BMI) in each occupation based on surveys on
the health habits of the Finnish adult population
1978 1991 [173]. Men working as university teachers,
physicians, computer operators or programmers
were leanest (BMI 23.5 24.0), and the BMI
was highest (27.7 27.8) in several occupations on
ships. In women, the BMI was lowest among
physiotherapists (22.1), university teachers (22.3)
and highest among typographers (27.8) and farmers
(26.5). Part of the variation may be attributable
to age distribution (the youngest men tend to be
leanest) and physical demands of the work (strong
muscles increase the weight).
In this first phase of the NOCCA study we did not
yet have means to adjust risk estimates according to
information on body size or physical activity. Thus,
we cannot give numerical estimates on how much of
the occupational variation in cancer risk is attributable
to body fatness and physical activity. Such
cofactor data will be available in the later phases of
the NOCCA study. On the other hand, lack of
physical activity at work can be considered as one
of the most serious occupational health hazards
in the modern work life, and thus it is also important
to show risk estimates without adjustment for
work-related physical activity.
Occupation and reproductive pattern. Reproductive
factors are associated with the risk of cancer of the