Air pollution and daily mortality in three U.S. counties

I used generalized additive models to analyze the time-series of daily total nonaccidental and cause-specific (cardiovascular, cerebrovascular, and chronic obstructive pulmonary disease) deaths over the period 1987-1995 in three major U.S. metropolitan areas: Cook County, Los Angeles County, and Maricopa County. In all three counties I had monitoring information on particulate matter [less than/equal to] 10 microm (PM(10)), carbon monoxide, sulfur dioxide, nitrogen dioxide, and ozone. In Los Angeles, monitoring information on particulate matter [less than/equal to] 2.5 microm (PM(2.5)) was available as well. I present the results of both single and multi-pollutant analyses. Air pollution was associated with each of the mortality end points. With respect to the individual components of the pollution mix, the results indicate considerable heterogeneity of air pollution effects in the different geographic locations. In general, the gases, particularly CO, but not ozone, were much more strongly associated with mortality than was particulate matter. This association was particularly striking in Los Angeles County.     

Cancer mortality in U.S. counties with chemical industries.

Geographic analysis of U. S. cancer mortality, 1950–1969, revealed excess rates for bladder, lung, liver, and certain other cancers among males in 139 counties where the chemical industry is most highly concentrated. The correlation could not be explained by confounding variables such as urbanization, socioeconomic class, or employment in nonchemical industries. If the excess cancer mortality in these areas is due to industrial exposures, the actual risk of cancer among certain chemical workers must be very high. The correlation was limited to counties associated with specific categories of the chemical industry; many involve known occupational hazards, while others suggest new leads to chemically induced cancer in man.     

Cancer mortality in U.S. counties with hazardous waste sites and ground water pollution

Since the late 1950s, more than 750 million tons of toxic chemical wastes have been discarded in an estimated 30,000 to 50,000 hazardous waste sites (HWSs). Uncontrolled discarding of chemical wastes creates the potential for risks to human health. Utilizing the National Priorities Listing (NPL) of hazardous waste sites developed by the United States Environmental Protection Agency (EPA), this study identified 593 waste sites in 339 U.S. counties in 49 states with analytical evidence of contaminated ground drinking water providing a sole source water supply. For each identified county, age-adjusted, site-specific cancer mortality rates for 13 major sites for the decade 1970-1979, for white males and females, were extracted from U.S. Cancer Mortality and Trends 1950-1979. Also, HWS and non-HWS counties that showed excess numbers of deaths were enumerated for each cancer selected. Significant associations (p less than .002) between excess deaths and all HWS counties were shown for cancers of the lung, bladder, esophagus, stomach, large intestine, and rectum for white males; and for cancers of the lung, breast, bladder, stomach, large intestine, and rectum for white females when compared to all non-HWS counties. There were no consistent geographical patterns that suggested a broad distribution of gastrointestinal cancers associated with HWSs throughout the United States, although we did identify a cluster of excess gastrointestinal cancers in counties within states located in EPA Region 3 (Delaware, Maryland, Pennsylvania, Virginia, West Virginia).(ABSTRACT TRUNCATED AT 250 WORDS)     

Cancer mortality in U.S. counties with shipyard industries during World War II

Respiratory cancer mortality, 1950–1969, was consistently high in U.S. counties where shipyards were engaged in the construction and repair of large naval and cargo vessels during World War II. Over three-fourths of the shipyard counties had elevated rates (in comparison to rates in counties of similar population size in the same region of the country) for lung and laryngeal cancer among white males, with the excess particularly evident in the South. Mortality from lung cancer was high also among white females, and the rate of increase in both sexes was greater than recorded nationally. In addition, rates for oropharyngeal, esophageal, and gastric cancers tended to be elevated in the shipyard counties, but mortality from other tumors was roughly comparable to national levels. A causal relation to asbestos exposures in shipyards cannot be inferred from this correlational analysis, but the unusual mortality patterns underscore the need for broadly based analytic studies to evaluate the risk of cancer in persons with wartime shipyard employment.     

The residential radon-lung cancer association in U.S. counties: a commentary

There is little doubt that underground miners exposed to radon and its progeny have increased rates of lung cancer. Residential radon exposures should carry a possibly smaller risk of increased cancer. When it became possible to collect radon data in a large number of U.S. homes and the data were aggregated by counties, the apparent association with lung cancer was a negative one, even when many other variables were taken into account. Residential radon levels are higher in suburban residences leading to a negative association with population density. Population density is strongly positively associated with lung cancer. It follows that aggregate residential radon and lung cancer rates should be negatively associated for reasons having nothing to do with the possibility of radon being carcinogenic to the lung. A second problem presented by the data is the one of sampling bias since the county lung cancer data are from the whole county population, but only a few residences are tested. Examples of other inherent associations in environmental epidemiology are cited. One strategy is to study areas of the same population density but with radon exposure gradients. This is approximated by choice of rural high radon states. Counties in such states have weak and inconsistent associations between radon and lung cancer, some of which are positive. I conclude that counties are generally inappropriate units for study of radon and lung cancer associations.     

Simultaneous smoothing and adjusting mortality rates in U.S. counties: melanoma in white females and white males

Detecting patterns in health-related data for geographic areas is facilitated with the use of exploratory methods, especially smoothing. In addition, these data often must be adjusted for known prognostic factors such as age and gender. The analysis in this paper focuses on mortality rates due to malignant melanoma in White males and White females; these data are adjusted for both age and latitude, separately for males and females, and then smoothed using (a) a non-linear smoother known as weighted head-banging, and (b) a new method that incorporates the adjustment and the smoothing simultaneously. Maps of the continental United States show regions of high rates, even after having adjusted for age and latitude, and suggest the possibility of other variables that may influence the rates.     

U.S. lung cancer mortality and declining cigarette tobacco consumption

The usual method for estimating population exposure to cigarette tobacco has been annual per capita consumption of cigarettes, expressed as pack-years or numbers of cigarettes consumed. This technique is shown to result in an inaccurate estimate of exposure. It underestimates by 11 years the latency period from peak exposure to peak mortality. Over the years, cigarettes changed markedly. Filters came into prominence and tobacco was "fluffed". On average, tobacco content of cigarettes decreased 39.1% from 1953 to 1981. National per capita consumption of cigarette tobacco declined by 43%. Total exposure to cigarette tobacco has been declining for males for approximately 35 years; for females for 20 years. As of 1982, the secular trend for lung cancer mortality was declining for women below age 45 and for most age groups of men below 65. We appear to be at the threshold of a reversal in overall lung cancer mortality.     

Family planning clinic services in U.S. counties, 1983

Organized family planning clinics are a major source of contraceptive services for low-income women, who are less likely than higher income women to be using a contraceptive method. A 1983 study estimated that 9.5 million U.S. women with family incomes below 150 percent of poverty were at risk of unintended pregnancy, and identified a network of 5,106 clinics providing them with services. Seventy-six percent of all counties in the United States have organized clinics that offer family planning services; almost all of those without services are nonmetropolitan counties. An estimated 52 percent of low-income women at risk of unintended pregnancy were served by organized family planning clinics in 1983, while the rest either went unserved or sought care elsewhere. Ten percent of low-income women not served by clinics live in counties that have no family planning clinics, but 67 percent live in counties where existing clinics reach fewer than half of potential low-income patients. More sites may be needed, particularly in counties without clinics, to effectively serve low-income women at risk of unintended pregnancy. However, since the majority of unserved women live in counties where at least one clinic exists, coverage might be improved through increased accessibility and outreach.     

Using quantile regression to examine the effects of inequality across the mortality distribution in the U.S. counties

The U.S. has experienced a resurgence of income inequality in the past decades. The evidence regarding the mortality implications of this phenomenon has been mixed. This study employs a rarely used method in mortality research, quantile regression (QR), to provide insight into the ongoing debate of whether income inequality is a determinant of mortality and to investigate the varying relationship between inequality and mortality throughout the mortality distribution. Analyzing a U.S. dataset where the five-year (1998-2002) average mortality rates were combined with other county-level covariates, we found that the association between inequality and mortality was not constant throughout the mortality distribution and the impact of inequality on mortality steadily increased until the 80th percentile. When accounting for all potential confounders, inequality was significantly and positively related to mortality; however, this inequality-mortality relationship did not hold across the mortality distribution. A series of Wald tests confirmed this varying inequality-mortality relationship, especially between the lower and upper tails. The large variation in the estimated coefficients of the Gini index suggested that inequality had the greatest influence on those counties with a mortality rate of roughly 9.95 deaths per 1000 population (80th percentile) compared to any other counties. Furthermore, our results suggest that the traditional analytic methods that focus on mean or median value of the dependent variable can be, at most, applied to a narrow 20 percent of observations. This study demonstrates the value of QR. Our findings provide some insight as to why the existing evidence for the inequality-mortality relationship is mixed and suggest that analytical issues may play a role in clarifying whether inequality is a robust determinant of population health.     

Arsenic in drinking water and bladder cancer mortality in the United States: an analysis based on 133 U.S. counties and 30 years of observation

This study analyzes the relationship between arsenic exposure through drinking water and bladder cancer mortality. The county-specific white male bladder cancer mortality data (1950-1979) and county-specific groundwater arsenic concentration data were obtained for 133 U.S. counties known to be exclusively dependent on groundwater for their public drinking water supply. No arsenic-related increase in bladder cancer mortality was found over the exposure range of 3 to 60 microg/L using stratified analysis and regression analyses (both unweighted and weighted by county population and using both mean and median arsenic concentrations). These results, which provide a direct estimate of arsenic-related cancer risk for U.S. residents, exclude the National Research Council's 2001 risk estimate that was based on Southwest Taiwan data and required adjusting for differences between the body mass and water consumption rates of U.S. and Taiwanese residents.     

Detecting spatiotemporal clusters of accidental poisoning mortality among Texas counties, U.S., 1980 – 2001

Background  

Accidental poisoning is one of the leading causes of injury in the United States, second only to motor vehicle accidents. According to the Centers for Disease Control and Prevention, the rates of accidental poisoning mortality have been increasing in the past fourteen years nationally. In Texas, mortality rates from accidental poisoning have mirrored national trends, increasing linearly from 1981 to 2001. The purpose of this study was to determine if there are spatiotemporal clusters of accidental poisoning mortality among Texas counties, and if so, whether there are variations in clustering and risk according to gender and race/ethnicity. The Spatial Scan Statistic in combination with GIS software was used to identify potential clusters between 1980 and 2001 among Texas counties, and Poisson regression was used to evaluate risk differences.     

Detecting spatiotemporal clusters of accidental poisoning mortality among Texas counties, U.S., 1980 - 2001

BACKGROUND: Accidental poisoning is one of the leading causes of injury in the United States, second only to motor vehicle accidents. According to the Centers for Disease Control and Prevention, the rates of accidental poisoning mortality have been increasing in the past fourteen years nationally. In Texas, mortality rates from accidental poisoning have mirrored national trends, increasing linearly from 1981 to 2001. The purpose of this study was to determine if there are spatiotemporal clusters of accidental poisoning mortality among Texas counties, and if so, whether there are variations in clustering and risk according to gender and race/ethnicity. The Spatial Scan Statistic in combination with GIS software was used to identify potential clusters between 1980 and 2001 among Texas counties, and Poisson regression was used to evaluate risk differences. RESULTS: Several significant (p < 0.05) accidental poisoning mortality clusters were identified in different regions of Texas. The geographic and temporal persistence of clusters was found to vary by racial group, gender, and race/gender combinations, and most of the clusters persisted into the present decade. Poisson regression revealed significant differences in risk according to race and gender. The Black population was found to be at greatest risk of accidental poisoning mortality relative to other race/ethnic groups (Relative Risk (RR) = 1.25, 95% Confidence Interval (CI) = 1.24 - 1.27), and the male population was found to be at elevated risk (RR = 2.47, 95% CI = 2.45 - 2.50) when the female population was used as a reference. CONCLUSION: The findings of the present study provide evidence for the existence of accidental poisoning mortality clusters in Texas, demonstrate the persistence of these clusters into the present decade, and show the spatiotemporal variations in risk and clustering of accidental poisoning deaths by gender and race/ethnicity. By quantifying disparities in accidental poisoning mortality by place, time and person, this study demonstrates the utility of the spatial scan statistic combined with GIS and regression methods in identifying priority areas for public health planning and resource allocation.     

Diet and cancer mortality in the counties of Sweden

The association between standardized cancer mortality rate ratios from 1969-1978 and dietary practices was examined in an ecologic study of the 24 counties of Sweden by means of several independent data sources. The study supports the hypothesis that a high intake of cereal fiber protects against colorectal cancer (r = -0.75 for males and r = -0.67 for females). This study found no association between fat intake and colorectal cancer. However, a negative correlation between milk consumption and this type of cancer was found. A suggested hypothesis is that calcium protects against colorectal cancer, since milk is the major source for calcium intake in Sweden. This could indicate that, for societies with a high fat intake, preventive measures which increase the intake of fiber and milk or calcium might have a greater impact on mortality from cancer of the colon and rectum than would a moderate decrease in the intake of fat. There are no indications in this study that fat intake promotes breast cancer.     

Testing a BEIR-VI suggestion for explaining the lung cancer vs. radon relationship for U.S. counties

The BEIR-VI Report suggests that the large discrepancy between the observed lung cancer rate vs. radon exposure relationship for U.S. counties, and the predictions of linear no-threshold theory, may be explained by a strong negative correlation between smoking intensity and radon exposure. It proposes a model for testing that suggestion. We apply that model to the detailed data for U.S. counties; analysis shows that even a perfect negative correlation explains little more than half of the discrepancy, and the largest not-implausible correlation can explain less than a quarter of the discrepancy. We then extend the BEIR-VI suggestion to include a strong negative correlation between both the prevalence of smoking and the intensity of smoking. The largest not-implausible correlations can explain no more than 30% of the discrepancy. It is concluded that the previous interpretation of these data, that linear no-threshold theory fails this test, is sustained.     

Place-of-residence errors on death certificates for two contiguous U. S. counties

Background  

Based on death certificate data, the Texas Department of Health Bureau of Vital Statistics calculates age adjusted all-cause mortality rates for each Texas county yearly. In 1998 the calculated rates for two adjacent Texas counties was disparate. These counties contain one city (Amarillo) and are identical in size. This study examined the accuracy of recorded county of residence for deaths in the two counties in 1998. In our jurisdiction, the county of residence is assigned by funeral homes.     

Factor analysis of digestive cancer mortality and food consumption in 65 Chinese counties.

Dietary factors were analyzed for the regional difference of GI tract cancer mortality rates in China. Sixty-five rural counties were selected among a total of 2,392 counties to represent a range of rates for seven most prevalent cancers. The dietary data in the selected 65 counties were obtained by three-day dietary record of households in 1983. The four digestive cancer mortality rates (annual cases per 100,000 standardized truncated rates for ages 35-64) and per capita food consumption were analyzed by the principal components factor analysis. Esophageal cancer associated with poor area, dietary pattern rich in starchy tubers, and salt, lack of consumption of meat, eggs, vegetables and rice. Stomach cancer seemed to be less associated with diet in this study because of its small model Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy, suggesting some other carcinogenic factors would play more important role in the development of this cancer in China. The colon and rectal cancer showed close relation to diet; rich in sea vegetables, eggs, soy sauce, meat and fish, while lack in consumption of milk and dairy products. Rapeseed oil was more important risk factor for colon cancer than that of rectum. Rice, processed starch and sugar were closely associated with colon cancer, supporting the insulin/colon cancer hypothesis.     

Cause-specific mortality in the unionized U.S. trucking industry

BACKGROUND: Occupational and population-based studies have related exposure to fine particulate air pollution, and specifically particulate matter from vehicle exhausts, to cardiovascular diseases and lung cancer. OBJECTIVES: We have established a large retrospective cohort to assess mortality in the unionized U.S. trucking industry. To provide insight into mortality patterns associated with job-specific exposures, we examined rates of cause-specific mortality compared with the general U.S. population. METHODS: We used records from four national trucking companies to identify 54,319 male employees employed in 1985. Cause-specific mortality was assessed through 2000 using the National Death Index. Expected numbers of all and cause-specific deaths were calculated stratifying by race, 10-year age group, and calendar period using U.S. national reference rates. Standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) were calculated for the entire cohort and by job title. RESULTS: As expected in a working population, we found a deficit in overall and all-cancer mortality, likely due to the healthy worker effect. In contrast, compared with the general U.S. population, we observed elevated rates for lung cancer, ischemic heart disease, and transport-related accidents. Lung cancer rates were elevated among all drivers (SMR = 1.10; 95% CI, 1.02-1.19) and dockworkers (SMR = 1.10; 95% CI, 0.94-1.30); ischemic heart disease was also elevated among these groups of workers [drivers, SMR = 1.49 (95% CI, 1.40-1.59); dockworkers, SMR = 1.32 (95% CI, 1.15-1.52)], as well as among shop workers (SMR = 1.34; 95% CI, 1.05-1.72). CONCLUSIONS: In this detailed assessment of specific job categories in the U.S. trucking industry, we found an excess of mortality due to lung cancer and ischemic heart disease, particularly among drivers.     

A history and critique of U.S. mortality atlases

This article presents a brief history of U.S. small area mortality atlases published since 1975, focusing on their content, cartographic style and findings resulting from the maps. The atlas designs are evaluated on the basis of map design recommendations from cartographers and from a series of cognitive experiments on information extraction from rate maps. Despite some design limitations, the atlases adequately described patterns of U.S. mortality data, resulting in important etiologic findings and action to reduce cancer rates and health disparities.