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Polychlorinated biphenyls (PCB) have been a major environmental health concern because of their wide distribution and persistence in the environment. Estimating joint effects of all congeners in a single analysis is complicated by correlation among exposure levels, and the resulting collinearity makes the results difficult to interpret.

OBJECTIVE: To determine whether non-Hodgkin's lymphoma mortality is associated with sunlight exposure. DESIGN: Three case-control studies based on death certificates of non-Hodgkin's lymphoma, melanoma, and skin cancer mortality examining associations with potential sunlight exposure from residence and occupation. SETTING: 24 states in the United States. SUBJECTS: All cases were deaths from non-Hodgkin's lymphoma, melanoma, and non-melanotic skin cancer between 1984 and 1991. Two age, sex, and race frequency matched controls per case were selected from non-cancer deaths. MAIN OUTCOME MEASURES: Odds ratios for non-Hodgkin's lymphoma, melanoma, and skin cancer from residential and occupational sunlight exposure adjusted for age, sex, race, socioeconomic status, and farming occupation. RESULTS: Non-Hodgkin's lymphoma mortality was not positively associated with sunlight exposure based on residence. Both melanoma and skin cancer were positively associated with residential sunlight exposure. Adjusted odds ratios for residing in states with the highest sunlight exposure were 0.83 (95% confidence interval 0.81 to 0.86) for non-Hodgkin's lymphoma, 1.12 (1.06 to 1.19) for melanoma, and 1.30 (1.18 to 1.43) for skin cancer. In addition, non-Hodgkin's lymphoma mortality was not positively associated with occupational sunlight exposure (odds ratio 0.88; 0.81 to 0.96). Skin cancer was slightly positively associated with occupational sunlight exposure (1.14; 0.96 to 1.36). CONCLUSIONS: Unlike skin cancer and to some extent melanoma, non-Hodgkin's lymphoma mortality was not positively associated with exposure to sunlight. The findings do not therefore support the hypothesis that sunlight exposure contributes to the rising rates of non-Hodgkin's lymphoma.

The roles of nonagricultural occupations, tobacco use, beverage consumption, medical history, and other factors in the development of soft-tissue sarcoma were examined in a population-based case-control study in Kansas. Based on 133 cases diagnosed between 1976-1982 and 948 controls, there were significant excesses associated with use of the drug chloramphenicol (odds ratio (OR) = 5.4, 95% confidence interval (Cl) 1.2-23.9) and chewing tobacco or snuff (OR = 1.8, 95% Cl 1.1-2.9). The risk associated with smokeless tobacco varied with the location of the tumors; greater risks were observed for tumors of the upper gastrointestinal tract (OR = 3.3), the lung, pleura, and thorax (OR = 3.1), and the head, neck, and face region (OR = 2.4) than other regions of the body (OR = 1.4). A nonsignificant excess was seen with the use of cholesterol-lowering drugs, such as clofibrate (OR = 1.7). Four cases reported histories of prior radiation treatment to the same area of their bodies as their tumors. Soft-tissue sarcoma was also associated with employment in woodworking occupations (OR = 1.7, 95% Cl 0.9-3.2) and risk increased with increasing duration of employment. Persons with first-degree blood relatives with a history of Hodgkin's disease, lymphoma, or cancers of the pancreas, prostate, brain, or skin were at increased risk. Many of the associations observed in this study, notably the risk of soft-tissue sarcoma with smokeless tobacco and medications such as chloramphenicol, deserve further evaluation.

A case-control study was conducted to investigate occupational risks for colon cancer. The Missouri Cancer Registry was used to identify a total of 1,993 white male cases and 9,965 age-matched cancer controls diagnosed between 1984 and 1987. Effect estimates were calculated for specific occupations and industries and for three levels of occupational physical activity. Odds ratios (ORs) and 95% confidence intervals (Cls) were also calculated according to anatomic subsite of colon cancer. Elevated risks were identified for workers in several occupations and industries including printing machine operators (OR = 1.9, 95% Cl 1.0-3.3), workers in food manufacturing (OR = 1.6, 95% Cl 1.2-2.2), communications workers (OR = 1.8, 95% Cl 1.0-3.3), and workers employed in the petroleum product trade (OR = 2.7, 95% Cl 1.0-7.2). Previous findings of excess risk among selected occupations of higher socioeconomic status were confirmed. Analyses by anatomic subsite showed that excess risk for an occupational group was usually confined to a single subsite, which suggests some specificity of effect. For example, elevated risk among males employed in manufacturing-related industries was shown primarily for cancer of the cecum. The findings by level of occupational physical activity corroborated recent reports of increased colon cancer risk associated with employment in sedentary occupations. Excess risk (OR = 1.4, 95% Cl 1.0-1.9) was shown among males employed in sedentary jobs and an inverse linear trend in risk was shown according to level of occupational physical activity. Risk associated with sedentary occupations was highest for cancer of the cecum (OR = 2.1, 95% Cl 1.1-4.0). Despite the limitations of the cancer registry-collected data, some associations were observed that deserve further study.