This report presents 20 years' of cancer incidence data by occupational group for the Nordic populations. The study covers the 10 million people aged 24-64 years at the time of the 1970 censuses in Denmark, Finland, Norway, and Sweden, and the 1 million incident cancer cases diagnosed among these people during the subsequent 20 years. The project was undertaken as a cohort study with linkage of individual records based on the personal identification numbers used in all the Nordic countries. In the 1970 censuses, information on occupation for each economically active member of the household was provided in free text in self-administered questionnaires. The data were centrally coded and computerized in the statistical offices. Norway, Sweden, and Finland used the Nordic Classification of Occupations, while Denmark used a national coding scheme. However, all the data could be reclassified into 53 occupational groups and 1 group of economically inactive persons. Person-years at risk were accumulated from 1 January 1971 until the date of emigration, date of death or 31 December 1987 in Denmark, 1989 in Sweden, 1990 in Finland, and 1991 in Norway. The 4 countries all had nationwide registration of incident cancer cases during the entire study period. All incident cancer cases during the individual risk periods were included in the analysis. Despite minor differences between the countries, the International Classification of Diseases, 7th revision, formed the core basis for the diagnostic coding in all 4 countries. For the present study the incident cancer cases have been classified into 35 broad diagnostic groups. The observed number of cancer cases in each group of persons defined by country, gender, and occupation was compared with the expected number calculated from the age-, gender-, and period-specific person-years and the incidence rates for the national population. The result has been presented as a standardized incidence ratio (SIR), defined as the observed number of cases divided by the expected number and multiplied by 100. In the tables of this report, all the SIR values for which the upper limit of the 95% confidence interval is below 100 are printed in green and all those for which the lower limit of the confidence interval is above 100 are printed in red. For all cancers combined, the study showed a wide variation among the men, from an SIR of 79 for fanners to 159 for waiters. The occupations with the highest SIR values also included seamen and workers producing beverages and tobacco. Among the women the SIR valuesvaried from 83 for gardeners to 129 for tobacco workers. Low SIR values were found for farmers and teachers. Outdoor workers such as fishermen and gardeners had the highest risk of lip cancer, while the lowest risk was found among indoor workers such as physicians and artistic workers. Almost all pleural cancers are associated with asbestos exposure. Accordingly, plumbers, welders, mechanics, and seamen were the occupations with the highest risk. There was also an excess risk of pleural cancer in the occupational group of technical, chemical, physical, and biological workers, including, among others, engineers and chemists potentially exposed to asbestos. The wood workers included in the present study had the highest risk of nasal cancer. Most studies of nasal cancer have shown increased risks associated with exposure to wood dust, both for those in furniture making and for those exposed exclusively to soft wood. Nickel refinery workers are also known for their high risk of nasal cancer. In the present study they were included in the occupational group of smelting workers. Lung cancer was the most frequent cancer among men in the present study. Tobacco smoking is the major risk factor for this disease, but occupational exposures also play an important role. Waiters and tobacco workers had the highest risk of lung cancer. Miners and quarry workers also had a high risk of lung cancer, which may be related to their exposure to silica dust and radon daughters. Among women, tobacco workers had the highest risk of lung cancer and farmers and gardeners had the lowest risk. Waiters had the highest risk of bladder cancer for men, and they were one of the groups at highest risk among the women. Chimney sweeps and male hairdressers also had high SIR values for bladder cancer. Chimney sweeps are exposed to polycyclic aromatic hydrocarbons from chimney soot, and the carcinogenicity of these compounds is well documented. Almost all occupational groups with low SIR values for bladder cancer also had low SIR values for lung cancer, groups such as farmers, gardeners, and those working in pedagogical work. Exposure to the known hepatocarcinogens, Hepatitis B virus and aflatoxins is rare in the Nordic countries, and a large proportion of primary liver cancers can therefore be attributed to alcohol consumption. When primary liver cancer was classified by occupation, high risks werefound for occupational groups with easy access to alcohol at the workplace or with cultural traditions for high alcohol consumption. Among men, waiters, journalists, cooks, beverage workers, and seamen had the highest risk. The lowest SIR values were found for farmers, forestry workers, teachers, wood workers, and gardeners.The risk of colon cancer has been related to sedentary work. The findings in the present study were in agreement, especially for men with this pattern, as journalists and physicians had the highest risk and outdoor workers such as farmers and forestry workers had the lowest risk.The occupational categories with the highest risks of breast cancer in the present study are accompanied by a university or equivalent education. This pattern is in agreement with a relatively late age at first birth among the well-educated Nordic women from the relevant birth cohorts. Malignant melanoma showed the same strong social gradient as cancers of the colon and breast.
|Tidsskrift||Scandinavian Journal of Work, Environment and Health|
|Udgave nummer||SUPPL. 2|
|Status||Udgivet - 1 jan. 1999|