Document M4GJG0g6MbD13LMq5w4VgRByk
British Journal of Industrial Mediant 1988:45.645-646
Asbestos associated tumours in car mechanics
B JARVHOLM. J BR1SMAN From the Department of Occupational Medicine. Sahlgren Hospital. S-4I2 66 Gothenburg. Sweden
Asbestos in brake linings and clutches is considered to be a major source of asbestos exposure to the general public. Nevertheless, the asbestos exposure to the car mechanics from this source during repair of brakes and dutches is several limes higher. It has been suspected that the exposure may cause lung cancer or mesothelioma in car mechanics and the union asked for an investigation. To study this subject we used linkages between the census of 1960 in Sweden and the Swedish Cancer Register and the Swedish Death Register respectively. This is a report on the preliminary findings.
Methods
The census of I960 contains information about occupational title and industrial category in I960. We used "mechanic" as the occupational title (code 752) and "car repair" as the industry (code 354). According to this selection procedure the census contained in total 21 905 men (table 1).
The Swedish Death Register contains all Swedes who have died since 1952 and the underlying cause of death according to the death certificates. A linkage between the death register and the census is commercially available. It gives the observed number of cases 1961--73 for a certain diagnosis and the expected numbers calculated from death rates of the general population. The linkage between the Swedish Cancer Register and the census includes the years 1961 to 1979 and is called the Cancer Environment Register. It gives only the cases of cancer for different sites. From Statistics Sweden we received the mortality
Accepted 7 September 1987
Table I Year ofbirth of the car mechanics
Year at birth
-1890 1891-1900 1901-1910 1911-1920 1921-1930 1931-1940 1941-1945
So
SIS 493 1587 2948 4755 7420 4664
for each age class and calendar year between 1961 and 1970 and could subsequently calculate the personyears for this period. By assuming the same mortality as the general population we estimated the personyears for 1971 to 1979. The expected number of cases was then calculated by multiplying national incidence rates with the corresponding person-years stratifying for age, class, and calendar year. When using the data from the Cancer Environment Register we restricted the analysis to between ages 20 and 69. The linkage between the death register and the census contains all ages.
Results and discussion
There was only one case ofmesothelioma in the cancer register and none in the death register. This was a 42 year old car mechanic who was diagnosed in 1978. He had also worked in the construction industry at least since 1965 but his medical record contained no information on total work history or possible exposure to asbestos. Between 1961 and 1973. 741 mechanics had died versus 776 expected. Of these. 187 had died of cancer versus 154 expected (p < 0 01) whereas 39 had died of lung cancer compared with 23 expected (p < 0-01).
Table 2 Cancer morbidity in car mechanics 1961-79 in men aged 20-69 compared with the male generalpopulation
mi-to
Form of cancer
Observed Expected
All Lung cancer Mesothelioma
Stomach cancer
265 249 7 30 258 0 ---* 15 22-6
* Raters not available for calculation of expected incidence.
19?1-9
Observed
396 63
1 29
Expected
388 7 47-2
25-6
645
1961-79
Observed
66) 93 1 44
Expected
638-4 730
... 48 2
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646
The cancer morbidity shown in table 2 also includes stomach cancer for comparison. Thus the data indicate no increased risk of mesothelioma in car mechanics but a possibly higher risk of lung cancer compared with the general population. There arc. however, several confounders that may explain this increase of lung cancer. The smoking habits of car mechanics may be heavier than those of the genera! population. The car mechanics may also be exposed to air pollutants other than asbestos such as exhaust gases, chromate containing paints, or lubricants. None of these factors can be ruled out as a possible
Jurvhnfr'i Brumar
explanation and this tvpe of linkage stud) cannoi answer the question car mechanics, however, form _ large occupational group and even a slight increase o: a common cancer such as lung cancer means soera. cases. It therefore seems reasonable to stud> whethe the occupational exposure of car mechanics causes ar increased nsk oflung cancer in more detail.
We acknowledge the support from the Swedish Metalworkers Union and the Swedish Work Environment Fund and the cooperation with Mr Roll Ahlbcrg.
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