A case-control study of occupation and breast-cancer risk in Connecticut.

BACKGROUND: Several occupations have recently been related to breast-cancer. The results, however, are inconsistent. We analyse data from a case-control study of breast cancer in Connecticut conducted in 1994-97 to further examine the potential relationship between occupation and breast-cancer risk. METHODS: A total of 608 breast-cancer cases and 609 controls, 31-85 years old, were included in the study. Information regarding occupation and other breast-cancer risk-factors was obtained through in-person interviews by trained interviewers, using a standardised, structured questionnaire. RESULTS: after adjustment for major breast-cancer risk-factors, a significantly increased risk of breast cancer was observed for teachers and librarians [odds ratio (OR), = 1.9, 95% confidence interval (CI) 1.3-2.7]. A significantly reduced risk, on the other hand, was observed for technicians and related supports (OR = 0.5, 95% CI 0.3-0.9). No other occupational groups showed a significant association with breast-cancer risk. CONCLUSIONS: The observed increase in breast-cancer risk among teachers and librarians is consistent with most earlier studies. It is currently unknown, however, what factors may explain the observed increase. Considering that teachers and librarians represent one of the largest single occupational groups among employed US women, further investigation of this association is warranted.

Cancer risk in the rubber industry: a review of the recent epidemiological evidence.

OBJECTIVES: To examine the recent epidemiological evidence on cancer risk among workers in the rubber industry. METHODS: Epidemiological studies published after the last detailed review by the International Agency for Research on Cancer (IARC) in 1982 were reviewed. 12 cohort studies in nine countries that examined distinct populations of workers in the rubber industry, seven industry based nested case-control studies, 48 community based case-control studies in 16 countries, and 23 studies based on administrative data that reported risks for employment in the rubber industry were identified. RESULTS: Excess risks of bladder cancer, lung cancer, and leukaemia were found in most studies, with risks above 1.5 in about half of the studies. A moderate excess risk for laryngeal cancer was consistent across studies. Excess risks were found in a few studies for cancers of the oesophagus, stomach, colon, liver, pancreas, skin, prostate, kidney, brain, and thyroid, and for malignant lymphoma and multiple myeloma, but overall results were not consistent for these neoplasms. CONCLUSIONS: Magnitude of the observed risks varied considerably between studies, but overall the findings indicate the presence of a widespread moderate increased cancer risk among rubber workers. The most consistent results were for bladder, laryngeal, and lung cancer and for leukaemia. Excess risks were also found for other neoplasms but an evaluation of the consistency of the findings is difficult because of the possible selective reporting of results. Recent studies do not provide information associating specific exposures with cancer risk. The preventive measures taken in the rubber industry in recent years may decrease risks, but this has not been documented yet in epidemiological studies.

Role of the herbicide atrazine in the development of non-Hodgkin's lymphoma.

Atrazine is the most commonly used herbicide in the United States and is a wide-spread groundwater contaminant in the Midwest. The role of atrazine in the development of human non-Hodgkin's lymphoma (NHL) was investigated in three case-referent studies conducted in four midwestern states in the United States. A total of 993 white men with NHL and 2918 population-based referents were interviewed concerning their agricultural practices. When the results of the three studies were combined, atrazine use was associated with an odds ratio of 1.4 [95% confidence interval (95% CI) 1.1-1.8, 130 cases, 249 referents) for NHL. However, adjustments for the use of 2,4-dichlorophenoxyacetic acid and organophosphate insecticides reduced the apparent association between NHL and atrazine in all but one state and reduced the associations for the long-term and frequent users in Nebraska. Detailed analyses suggested that there was little or no increase in the risk of NHL attributable to the agricultural use of atrazine.

A case-referent study of soft-tissue sarcoma and Hodgkin's disease. Farming and insecticide use.

A population-based case-referent study in Kansas examined the relationship between exposure to insecticides and the development of soft-tissue sarcoma (STS) and Hodgkin's disease (HD). Data from telephone interviews for 133 STS cases, 121 HD cases, and 948 referents indicated that STS was associated with use of insecticides on animals, but not on crops. HD was not significantly associated with either use. STS risk was higher among the farmers who themselves mixed or applied insecticides to animals than among farmers who did not. Farmers who failed to use any protective equipment to reduce insecticide exposure were at a significantly elevated risk of STS. Risk rose with early calendar year of first use. The excess risk appeared to be primarily among fibrous and myomatous sarcomas with little association seen for lipomatous or other STS neoplasms. Myomatous sarcomas increased significantly with duration and time since first use of insecticides on animals. If the reported association between STS and insecticides is causal, the data suggest that exposure to the agent(s) responsible may have been reduced in the mid-1950s or the agent(s) have an average latency period for STS of at least 20 years.