Alternate ranging methods for cancer mortality maps.

BACKGROUND: Mapping techniques can highlight the spatial or temporal variations in rates of cancer mortality. In mapping geographic patterns of cancer mortality, spatial units are grouped into categories defined by specified rate ranges, and then the units in each category are assigned a particular color in the map. We examined the consequences of using different ranging methods when comparing maps over several time intervals. METHODS: Maps of mortality rates for cancers of the breast, lung (including the lung, trachea, bronchus, and pleura), and cervix uteri in the United States by county or state economic area are created for different time intervals between 1950 and 1994. Two ranging methods are employed: 1) Ranges are defined for individual time interval by the deciles of rates in that interval (ranging within intervals), and 2) constant ranges for all time intervals are defined by the deciles of rates for the entire 45-year period from 1950 through 1994 (ranging across intervals). The time intervals from 1950 through 1969 and from 1970 through 1994 were chosen to accommodate the availability of detailed county-level population estimates specifically for blacks starting in 1970. RESULTS: The ranging method has little impact on maps for breast cancer mortality, which changed little over time. For lung cancer, which increased over time, and cervix uteri cancer, which decreased over time, ranging within time intervals shows the geographic variability but does not convey the temporal trends. Trends are evident when ranging across time intervals is employed; however, geographic variability is partially obscured by the predominance of spatial units in the highest rate categories in the recent time intervals for lung cancer and in the early time intervals for cervix uteri cancer. CONCLUSIONS: Ranging within time intervals displays geographic patterns and changes in geographic patterns, regardless of time trends in rates. Ranging across time intervals shows temporal changes in rates but with some loss of information about geographic variability.

Cancer surveillance series: changing geographic patterns of lung cancer mortality in the United States, 1950 through 1994.

BACKGROUND: Geographic surveys revealing variations in lung cancer mortality rates across the United States have prompted epidemiologic studies in high-risk communities. We have updated these maps to track the changing patterns and to provide further clues to the determinants of lung cancer. METHODS: Age-adjusted race- and sex-specific lung cancer mortality rates from 1950 through 1994 were calculated for nine Census Divisions and 508 State Economic Areas of the United States. RESULTS: Pronounced geographic variation in lung cancer rates was evident, with the patterns changing substantially over time. Among white males in the 1950s and 1960s, high rates were observed in urban areas of the northeast and north central states and in areas along the southeast and Gulf coasts. By the 1970s, the northern excess began to fade, with high rates starting to cover wider areas of the south. By the 1980s to the mid-1990s, clustering of elevated rates was prominent across the southeast and south central areas, with relatively low rates throughout much of the northeast. Among white females, little geographic variation was evident in the 1950s, but thereafter relatively high rates began to appear in clusters along the Atlantic and Pacific coasts. For both sexes, consistently low rates were seen in the mountain and the plains states. Rates among blacks were consistently elevated in northern areas and low across the south. CONCLUSIONS: The changing mortality patterns for lung cancer generally coincide with regional trends in cigarette smoking, indicating that public health measures aimed at smoking prevention and cessation should have a dramatic effect in reducing lung cancer rates.

Recent cancer patterns among men and women in the United States: clues for occupational research.

Investigation of cancer rates--including trends over time, geographic variations, and differences by race, gender, and age--may identify patterns suggesting environmental exposures of potential occupational origin. National mortality data spanning the 40-year period from 1950 to 1989 were used to assess the patterns of several cancers for which occupational components have been identified among men, including cancers of the lung and bladder, non-Hodgkin's lymphoma, and leukemia, and for cancers of particular concern to women, such as breast and ovarian cancer, but for which occupational factors have not been well characterized. Newly available preliminary data show substantial geographic variation in cancer mortality rates at the county level during the 1970s and 1980s. Future analyses of the patterns, correlations with industrial indicators, and analytic studies should be fruitful in identifying occupational and other risk factors for cancers among women.

Retrospective cohort mortality study of workers at an aircraft maintenance facility. I. Epidemiological results.

A retrospective cohort study of 14,457 workers at an aircraft maintenance facility was undertaken to evaluate mortality associated with exposures in their workplace. The purpose was to determine whether working with solvents, particularly trichloroethylene, posed any excess risk of mortality. The study group consisted of all civilian employees who worked for at least one year at Hill Air Force Base, Utah, between 1 January 1952 and 31 December 1956. Work histories were obtained from records at the National Personnel Records Centre, St. Louis, Missouri, and the cohort was followed up for ascertainment of vital state until 31 December 1982. Observed deaths among white people were compared with the expected number of deaths, based on the Utah white population, and adjusted for age, sex, and calendar period. Significant deficits occurred for mortality from all causes (SMR 92, 95% confidence interval (95% CI) 90-95), all malignant neoplasms (SMR 90, 95% CI 83-97), ischaemic heart disease (SMR 93, 95% CI 88-98), non-malignant respiratory disease (SMR 87, 95% CI 76-98), and accidents (SMR 61, 95% CI 52-70). Mortality was raised for multiple myeloma (MM) in white women (SMR 236, 95% CI 87-514), non-Hodgkin's lymphoma (NHL) in white women (SMR 212, 95% CI 102-390), and cancer of the biliary passages and liver in white men dying after 1980 (SMR 358, 95% CI 116-836). Detailed analysis of the 6929 employees occupationally exposed to trichloroethylene, the most widely used solvent at the base during the 1950s and 1960s, did not show any significant or persuasive association between several measures of exposure to trichloroethylene and any excess of cancer. Women employed in departments in which fabric cleaning and parachute repair operations were performed had more deaths than expected from MM and NHL. The inconsistent mortality patterns by sex, multiple and overlapping exposures, and small numbers made it difficult to ascribe these excesses to any particular substance. Hypothesis generating results are presented by a variety of exposures for causes of death not showing excesses in the overall cohort.

Lung cancer and other causes of death among licensed pesticide applicators.

The mortality experience of a cohort of 3,827 white men licensed to apply pesticides in Florida was evaluated to investigate health effects associated with chronic exposure to pesticides. Although the overall standardized mortality ratio (SMR) for these structural pest control workers was not significantly elevated (SMR = 103), excess deaths were observed for leukemia, particularly acute myeloid leukemia (3 observed vs. 0.9 expected), and cancers of the brain (SMR = 200) and lung (SMR = 135). The risk of lung cancer rose with the number of years licensed with SMR of 101, 155, and 289 among those licensed for less than 10 years, for 10-19 years, and for 20 years or more, respectively. Ratios of directly adjusted rates showed similar patterns with observed-to-expected ratios of 100, 175, and 186 for the length of licensure categories. Mortality from lung cancer was greater among persons first licensed before age 40 (SMR = 234) than among those first licensed after age 40 (SMR = 115). Although information on tobacco use was not available, the increasing risk of lung cancer with number of years licensed and the capacity of certain pesticides to produce neoplasms in laboratory animals suggested that some pesticides may be carcinogenic in humans.