A population-based case-control study was carried out in three geographic areas of the U.S. to examine reasons for differences in incidence between Blacks and Whites for a variety of cancers. Several analyses were reported in the past year, including results on multiple myeloma, and cancers of the esophagus and pancreas with population-based controls. Elevated risks were associated with obese vs. normal weight (OR = 1.9, 95% CI = 1.2-3.1 for whites and OR = 1.5, 95% CI = 0.9-2.4 for blacks), while the frequency of obesity was greater for black than white controls. Reduced risks were related to frequent intake of cruciferous vegetables (OR = 0.7, 95% CI = 0.6-0.99) and fish (OR = 0.7, 95% CI = 0.5-0.9) in both races combined, and to vitamin C supplements in whites (OR = 0.6, 95% CI = 0.5-0.9) and blacks (OR = 0.8, 95% CI = 0.5-1.4), with the frequency of vitamin supplement use being greater for white than black controls. However, frequent intake of vitamin C from food and supplements combined was associated with a protective effect in whites (OR = 0.6, 95% CI = 0.4-0.9), but not blacks (OR = 1.2, 95% CI = 0.8-2.1). The greater use of vitamin C supplements by whites and the higher frequency of obesity among blacks may explain part of the higher incidence of multiple myeloma among blacks compared to whites in the United States. In another analysis of these data, no association was found between case-control status and the total number of reported diagnostic X-rays of any type. A total of 484 cases of cancer of the pancreas and 2,095 controls were used to evaluate the role of exposure to pesticides. Elevated ORs were reported for low (OR=1.3 with 95% CI=1.0-1.7), and moderate/high (OR=1.4 with 95% CI=0.7-3.4) exposure relative to no pesticide exposure. Increased ORs were reported for exposure to herbicides and fungicides, but not to insecticides. Analyses were reported on the roles of family history of cancer and of use of mouthwash in the cause of oral and pharyngeal cancer in Puerto Rico. The study consisted of 342 cases and 521 population-based controls. After controlling for alcohol and tobacco use, there was an increased risk of oral and pharyngeal cancer for subjects reporting a first-degree relative with the same disease. This suggests a heritable component to oral and pharyngeal cancer or shared environmental factors other than alcohol and tobacco. Another analysis indicated no overall risk of oral cancer with use of mouthwash, with an alcohol content of 25% or greater. A study was reported that examined cancer mortality in a cohort 40,581 Navy veterans with increased potential exposure to radar. Compared to mortality rates for U.S. white men, SMRs for the entire cohort and for men in occupations with a high potential exposure were 0.9 (95% CI = 0.7-1.1) and 0.7 (95% CI = 0.5-1.0), respectively. No adverse health effects appeared attributable to radar exposure during the Korean war. An analysis examined the effects of timing of occupational asbestos exposure to lung cancer using pooled data from two large case-control studies conducted in Germany. Odds ratios increased with duration of asbestos exposure (OR=1.8 with 95% CI=1.2-2.7 and OR=2.4 with 95% CI=1.7-3.4 for subjects working 3 to 7 years and 8 or more, respectively, in jobs with potential asbestos exposure compared to never-exposed). The odds ratio decreased significantly with time since last exposure to about one-half after more than 20 years since exposure ceased. A spline weight function model revealed that the risk effect reached a maximum 10 to 15 years prior to interview, then declined. Investigators also examined the disease mortality in a large cohort of U.S. radiologic technologists. The relationship between circulatory disease mortality and protracted low-dose radiation exposure was evaluated in a large cohort of U.S. radiation technologists. In the absence of individual dose information, work history variables were analyzed using external and internal comparisons to account for secular trends. The relationship between mortality and protracted low-dose radiation exposure was evaluated in a large cohort of U.S. radiation technologists with emphasis on radiation sensitive cancers and circulatory disease. Work history variables were analyzed using external and internal comparisons to account for secular trends. Results suggest increased risk for breast cancer, leukemia, and circulatory disease, especially stroke, for subjects working in early years when radiation exposure was likely to be high. No consistent increase of risk was found for multiple myeloma and lymphoma. Extended mortality follow-up of a formaldehyde worker cohort was evaluated to provide information about the potential effect of formaldehyde on lung cancer risk. Multivariate analyses including exposure to formaldehyde and several other agents revealed no relation with lung cancer risk but with malignancies of the hematopoietic system. Investigators in DCEG conducted a hospital-based case-control study of invasive cutaneous melanoma. There were 718 case patients and 945 control patients matched by gender, race, age, and geographic area. Results showed that a 10% increase in annual UVB flux was associated with a 19% increase in individual odds of melanoma for men and 16% for women. The effect of UVB intensity during the ages 0-19 is as important as UVB intensity during the adult ages. Total time outdoors has an important effect on the risk of melanoma. Investigators also analyzed results from two animal studies of UVB and skin cancer. Mice with genetically determined high susceptibility to UV-induced immunosuppression show accelerated UV carcinogenesis. Levels of dietary L-histidine are associated with greater risk of UV-induced skin cancer. Several analyses were conducted using data from the Breast Cancer Detection Demonstration Project. Follow-up through 1995 of post-menopausal women who developed breast cancer from 1973 to 1981 revealed that those who were using replacement estrogens at the time of diagnosis experienced reductions in breast cancer mortality, which waned with the time since diagnosis. In a cohort of post-menopausal women, effects of hormone replacement therapy was examined in 2,082 incidence breast cancer cases occurring prior to 1995. The excess relative risk increased linearly by 0.01 (95% CI=0.002-0.03) with each year of estrogen-only use and 0.08 (95% CI=0.02-0.16) for each year of estrogen-progestin-only use. This difference was statistically significant, suggesting a more deleterious effect with the combined hormone therapy. Investigators reported results from a case-control study of incident lung cancer in a rural area of China, including 886 cases and 1,659 frequency matched controls, for residential radon exposure, exposure to environmental tobacco smoke, previous diagnosis of lung disease, air pollution, and exposure to cooking oil fumes. Time-weighted average radon concentrations were 230.4 Bq/m3 for cases and 222.2 Bq/m3 for controls. Risk increased with increasing radon level. The excess odds ratio at 100 Bq/m3 was 0.19 (95% CI= 0.05-0.47) for all subjects, and 0.31 (95% CI=0.10-0.81) for subjects with 100% coverage of the exposure interval. Adjusting for exposure uncertainties increased estimates 50 percent. Lung cancer risk was also associated with previous diagnosis of pulmonary tuberculosis (OR=2.1, 95% CI=1.4-3.1) and chronic bronchitis/emphysema (OR=1.4, 95% CI=1.1-1.8). Non-significant associations were observed for a previous diagnosis of asthma (OR=1.4, 95% CI=0.9-2.1) and pneumonia (OR=1.5, 95% CI=1.0-2.3). The OR for lung cancer associated with burning coal compared to biomass was 1.29 (95% CI=1.0-1.6) and increased with percent of time coal was used over the past 30 years (p=0.02). Among 200 female and 33 male lung cancer cases and 407 female and 114 male controls who never smoked. The OR for ever-exposed to environmental tobacco smoke was 1.19 (95% CI=0.7-2.0), with a significant trend (p<0.05) with increasing exposure. Among 233 incident, female lung cancer cases and 459 controls the OR associated with ever-use of rapeseed oil, alone or in combination with linseed oil, was 1.67 (95% CI=1.0-2.5), compared to use of linseed oil alone. ORs for stir-frying with either linseed or rapeseed oil 15-29, 30, and >31 times per month were 1.96, 1.73, and 2.24, respectively (trend, p=0.03), relative to a lower frequency of stir-frying. Lung cancer risks also increased with total number of years cooking (trend, p<0.09).
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