Public health implications of 1990 air toxics concentrations across the United States.

Occupational and toxicological studies have demonstrated adverse health effects from exposure to toxic air contaminants. Data on outdoor levels of toxic air contaminants have not been available for most communities in the United States, making it difficult to assess the potential for adverse human health effects from general population exposures. Emissions data from stationary and mobile sources are used in an atmospheric dispersion model to estimate outdoor concentrations of 148 toxic air contaminants for each of the 60,803 census tracts in the contiguous United States for 1990. Outdoor concentrations of air toxics were compared to previously defined benchmark concentrations for cancer and noncancer health effects. Benchmark concentrations are based on standard toxicological references and represent air toxic levels above which health risks may occur. The number of benchmark concentrations exceeded by modeled concentrations ranged from 8 to 32 per census tract, with a mean of 14. Estimated concentrations of benzene, formaldehyde, and 1,3-butadiene were greater than cancer benchmark concentrations in over 90% of the census tracts. Approximately 10% of all census tracts had estimated concentrations of one or more carcinogenic HAPs greater than a 1-in-10,000 risk level. Twenty-two pollutants with chronic toxicity benchmark concentrations had modeled concentrations in excess of these benchmarks, and approximately 200 census tracts had a modeled concentration 100 times the benchmark for at least one of these pollutants. This comprehensive assessment of air toxics concentrations across the United States indicates hazardous air pollutants may pose a potential public health problem.     

Estimating Rn-induced lung cancer in the United States

The proportion of lung cancer deaths attributable to Rn among residents of single-family homes in the U.S. (approximately 70% of the housing stock) is estimated using the log-normal distribution of Rn concentrations proposed by Nero et al. (1986) and the risk model developed by the National Academy of Sciences' BEIR IV Committee. The risk model, together with the exposure distribution, predicts that approximately 14% of lung cancer deaths among such residents (about 13,300 deaths per year, or 10% of all U.S. lung cancer deaths) may be due to indoor Rn exposure. The 95% confidence interval is 7%-25%, or approximately 6600 to 24,000 lung cancer deaths. These estimated attributable risks due to Rn are similar for males and females and for smokers and nonsmokers, but higher baseline risks of lung cancer result in much larger absolute numbers of Rn-attributable cancers among males (approximately 9000) and among smokers (approximately 11,000). Because of the apparent skewness of the exposure distribution, most of the contribution to the attributable risks arises from exposure rates below 148 Bq m-3 (4 pCi L-1), i.e., below the EPA "action level." As a result, if all exposure rates that exceed 148 Bq m-3 (approximately 8% of homes) were eliminated, the models predict that the total annual lung cancer burden in the U.S. would drop by 4-5%, or by about 3800 lung cancer deaths, in contrast to a maximum reduction of 14% if all indoor Rn exposure above the 1st percentile were eliminated.     

Estimating deaths attributable to obesity in the United States

Estimates of deaths attributable to obesity in the United States rely on estimates from epidemiological cohorts of the relative risk of mortality associated with obesity. However, these relative risk estimates are not necessarily appropriate for the total US population, in part because of exclusions to control for baseline health status and exclusion or underrepresentation of older adults. Most deaths occur among older adults; estimates of deaths attributable to obesity can vary widely depending on the assumptions about the relative risks of mortality associated with obesity among the elderly. Thus, it may be difficult to estimate deaths attributable to obesity with adequate accuracy and precision. We urge efforts to improve the data and methods for estimating this statistic.     

PCB concentrations in shrimp from major import markets and the United States

Currently, environmental studies describing levels of polychlorinated biphenyls (PCBs) in imported shrimp are limited, particularly studies of aquaculture shrimp. In the present study, we measured concentrations of the 209 PCB congeners in 84 uncooked, warm-water shrimp samples from the United States and 14 other countries in three continents. Total PCB and dioxin-like PCB (DL-PCB) levels were not significantly different between wild-caught and farm-raised shrimp, and the distribution of total PCB levels did not vary considerably by country of origin although significant differences were observed in some cases. Regional trends in both total PCB and DL-PCB concentrations were observed, with the highest concentrations measured in shrimp from North America followed by Asia and then South America. The lower chlorinated homologues (i.e., mono-, di-, and tri-PCBs) generally comprised a greater fraction of the total levels measured in farm-raised shrimp and shrimp from Asia and South America whereas higher chlorinated homologues (i.e., hepta-, octa-, nona-, and deca-PCBs) contributed more to levels in wild-caught shrimp and shrimp from North America. Estimated daily intake of PCBs associated with shrimp consumption ranged from 2?pg/kg/d (shrimp from South America) to 15?pg/kg/d (shrimp from North America). Results from the present study were comparable to other studies conducted recently and demonstrate that exposure to PCBs from consumption of farm-raised and wild-caught shrimp imported from different regions are not likely to pose any health risks.     

Benchmarking variation in coding accuracy across the United States

The objective of this study was to measure the consistency of coded medical data through information managers' reports of the overall coding error level in patients' medical records. Using a cross-sectional design, we examined the reported percent of records containing coding errors significant enough to change a diagnostic related group (DRG). Results indicate about 87 percent, 9 percent, and 5 percent of respondents reported that significant coding errors existed in less than 5 percent, 6-10 percent, and greater than 10 percent of the medical records in their institutions, respectively. Significant variation was found in the accuracy and consistency of coding practice and associated data quality across key demographic and organizational variables. Significantly large error rates in coded data exist in some organizations. Given variations across key demographic characteristics, providers may tend to distrust all coded data, when aggregated. As the United States moves toward an evidence-based medicine environment, the use of current patient data classification methods may be of limited value without increased attention to coding practices.     

Estimating the cost of unmet HIV-prevention needs in the United States

BACKGROUND: Although new HIV infection cases have dropped from over 160,000 per year in the mid-1980s to 40,000 per year in the 1990s, HIV incidence has been relatively unchanged for a decade. This number of annual incident infections suggests that substantial, unmet HIV-prevention needs continue to fuel the HIV epidemic in the United States. OBJECTIVES: This study estimates the cost of addressing the unmet HIV-prevention needs in the United States and establishes a performance standard by estimating the number of HIV infections that would have to be prevented in order for these programs to be considered cost saving to society. METHODS: Standard methods of cost and threshold analysis were employed in this study. Interventions needed to address unmet behavioral risks include services to reduce sexual risk of HIV infection, services to provide access to sterile syringes for people who cannot stop injecting drugs, HIV counseling and testing, and intensive preventive services to help HIV-seropositive people avoid transmitting the virus to others. RESULTS: If brief interventions are utilized to address sexual behavior risk, the total program cost (over and above current resource levels) is just over $817 million; and if more expensive multisession, small-group interventions are used, the costs increase to over $1.85 billion. However, even the higher-cost program has a threshold of only 12,000 infections that must be prevented in order for the program to be considered a cost saving to society. CONCLUSIONS: Addressing the remaining unmet HIV-preventive needs in the United States will require a substantial commitment of resources. However, even a greatly expanded HIV-preventive program in the United States could pay for itself through savings in averted medical care costs.     

Dietary exposures to food contaminants across the United States

Food consumption is an important route of human exposure to pesticides and industrial pollutants. Average dietary exposures to 37 pollutants were calculated for the whole United States population and for children under age 12 years by combining contaminant data with food consumption data and summing across food types. Pollutant exposures were compared to benchmark concentrations, which are based on standard toxicological references, for cancer and noncancer health effects. Average food ingestion exposures for the whole population exceeded benchmark concentrations for arsenic, chlordane, DDT, dieldrin, dioxins, and polychlorinated biphenyls, when nondetects were assumed to be equal to zero. For each of these pollutants, exposure through fish consumption accounts for a large percentage of food exposures. Exposure data for childhood age groups indicated that benchmark concentrations for the six identified pollutants are exceeded by the time age 12 years is reached. The methods used in this analysis could underestimate risks from childhood exposure, as children have a longer time to develop tumors and they may be more susceptible to carcinogens; therefore, there may be several additional contaminants of concern. In addition, several additional pollutants exceeded benchmark levels when nondetects were assumed to be equal to one half the detection limit. Uncertainties in exposure levels may be large, primarily because of numerous samples with contaminant levels below detection limits.     

Estimating cancer risk from outdoor concentrations of hazardous air pollutants in 1990

A public health concern regarding hazardous air pollutants (HAPs) is their potential to cause cancer. It has been difficult to assess potential cancer risks from HAPs, due primarily to lack of ambient concentration data for the general population. The Environmental Protection Agency's Cumulative Exposure Project modeled 1990 outdoor concentrations of HAPs across the United States, which were combined with inhalation unit risk estimates to estimate the potential increase in excess cancer risk for individual carcinogenic HAPs. These were summed to provide an estimate of cancer risk from multiple HAPs. The analysis estimates a median excess cancer risk of 18 lifetime cancer cases per 100,000 people for all HAP concentrations. About 75% of estimated cancer risk was attributable to exposure to polycyclic organic matter, 1,3-butadiene, formaldehyde, benzene, and chromium. Consideration of some specific uncertainties, including underestimation of ambient concentrations, combining upper 95% confidence bound potency estimates, and changes to potency estimates, found that cancer risk may be underestimated by 15% or overestimated by 40-50%. Other unanalyzed uncertainties could make these under- or overestimates larger. This analysis used 1990 estimates of concentrations and can be used to track progress toward reducing cancer risk to the general population.     

Estimating the total number of newly-recognized silicosis cases in the United States

BACKGROUND: The US employer-based surveillance system for documenting occupational injuries and illnesses undercounts chronic diseases. We suggest a method to estimate the number of individuals who are newly-recognized with silicosis each year in the United States. METHODS: Data from US death certificates, the Michigan state-based surveillance system, and capture-recapture analysis were used to calculate national estimates of silicosis. RESULTS: From 1987 to 1996, 2,787 deaths occurred in the United States where silicosis was mentioned on the death certificates. During the same period, in Michigan 77% of death certificates with a mention of silicosis were confirmed as silicosis-related deaths and the ratio of the number of living to deceased confirmed silicosis cases was 6.44. The proportion of confirmed silicosis deaths, the ratio of the living to deceased silicosis cases and capture-recapture analysis from the Michigan surveillance system, were used to estimate that there were 3,600-7,300 cases per year of silicosis in the United States from 1987 to 1996. CONCLUSIONS: Our estimate of the annual number of newly-recognized silicosis cases is significantly larger than the estimate from the employer-based reporting system used for counting occupational disease in the United States. This employer-based surveillance system is inadequate for determining the frequency of occupational disease. Our analysis which combines a readily-available and relatively inexpensive national administrative database (i.e., death certificates) with a more costly state-based active surveillance system is a cost-effective model that could be used to provide better estimates of a number of different occupational diseases. Accurate estimates of occupational illnesses are essential to both determine temporal trends and evaluate efforts to prevent silicosis.     

Weight gain trends across sociodemographic groups in the United States

OBJECTIVES: To better understand health disparities, we compared US weight gain trends across sociodemographic groups between 1986 and 2002. METHODS: We analyzed mean and 80th-percentile body mass index (BMI), calculated from self-reported weight and height, for subpopulations defined by education, relative income, race/ethnicity, and gender. Data were from the Behavioral Risk Factor Surveillance System, a random-digit-dialed telephone survey (total sample=1.88 million adult respondents). RESULTS: Each sociodemographic group experienced generally similar weight gains. We found no statistically significant difference in increase in mean BMI by educational attainment, except that individuals with a college degree gained less weight than did others. The lowest-income group gained as much weight on average as the highest-income group, but lowest-income heavier individuals (80th percentile of BMI) gained weight faster than highest-income heavier individuals. We found no differences across racial/ethnic groups except that non-Hispanic Blacks gained more weight than other groups. Women gained more weight than men. CONCLUSIONS: We found fewer differences, especially by relative income and education, in weight gain across subpopulations than we had expected. Women and non-Hispanic Blacks gained weight faster than other groups.     

Health across the life span in the United States and England

This study systematically compared health indicators in the United States and England from childhood through old age (ages 0-80 years). Data were from the 1999-2006 National Health and Nutrition Examination Survey for the United States (n = 39,849) and the 2003-2006 Health Survey for England (n = 69,084). Individuals in the United States have higher rates of most chronic diseases and markers of disease than their same-age counterparts in England. Differences at young ages are as large as those at older ages for most conditions, including obesity, low high-density lipoprotein cholesterol, high cholesterol ratio, high C-reactive protein, hypertension (for females), diabetes, asthma, heart attack or angina (for females), and stroke (for females). For males, heart attack or angina is higher in the United States only at younger ages, and hypertension is higher in England than in the United States at young ages. The patterns were similar when the sample was restricted to whites, the insured, nonobese, nonsmoking nondrinkers, and specific income categories and when stratified by normal weight, overweight, and obese weight categories. The findings from this study indicate that US health disadvantages compared with England arise at early ages and that differences in the body weight distributions of the 2 countries do not play a clear role.     

Estimating the Prevalence of United States Women with Alcohol-exposed Pregnancies and Births

Aims

Researchers at the U.S. Centers for Disease Control and Prevention (CDC) recently estimated the number of women at risk for alcohol-exposed pregnancies (AEPs) as 3.3 million per month. The number of women at risk was widely interpreted as the actual number of AEPs. The actual number of AEPs may be easier to interpret and may be more a more relevant public health metric for evaluating efforts to reduce AEPs. We estimated the expected actual number of AEPs among U.S. women 15–44 years of age and the expected actual number of alcohol-exposed births (AEBs).

Comparing social determinants of self-rated health across the United States and Canada

A large body of research shows that social determinants of health have significant impact on the health of Canadians and Americans. Yet, very few studies have directly compared the extent to which social factors are associated with health in the two countries, in large part due to the historical lack of comparable cross-national data. This study examines differences in the effect of a wide-range of social determinants on self-rated health across the two populations using data explicitly designed to facilitate comparative health research-Joint Canada/United States Survey of Health. The results show that: 1) sociodemographic and socioeconomic factors have substantial effects on health in each country, though the size of the effects tends to differ-gender, nativity, and race are stronger predictors of health among Americans while the effects of age and marital status on health are much larger in Canada; the income gradient in health is steeper in Canada whereas the education gradient is steeper in the U.S.; 2) Socioeconomic status (SES) mediates or links sociodemographic variables with health in both countries-the observed associations between gender, race, age, and marital status and health are considerably weakened after adjusting for SES; 3) psychosocial, behavioural risk and health care access factors are very strong determinants of health in each country, however being severely/morbidly obese, a smoker, or having low life satisfaction has a stronger negative effect on the health of Americans, while being physically inactive or having unmet health care needs has a stronger effect among Canadians; and 4) risk and health care access factors together play a relatively minor role in linking social structural factors to health. Overall, the findings demonstrate the importance of social determinants of health in both countries, and that some determinants matter more in one country relative to the other.