Population-Based Estimates for the Prevalence of Multiple Sclerosis in the United States by Race, Ethnicity, Age, Sex, and Geographic Region.

Importance: Racial, ethnic, and geographic differences in multiple sclerosis (MS) are important factors to assess when determining the disease burden and allocating health care resources. Objective: To calculate the US prevalence of MS in Hispanic, non-Hispanic Black (hereafter referred to as Black), and non-Hispanic White individuals (hereafter referred to as White) stratified by age, sex, and region. Design, Setting, and Participants: A validated algorithm was applied to private, military, and public (Medicaid and Medicare) administrative health claims data sets to identify adult cases of MS between 2008 and 2010. Data analysis took place between 2019 and 2022. The 3-year cumulative prevalence overall was determined in each data set and stratified by age, sex, race, ethnicity, and geography. The insurance pools included 96 million persons from 2008 to 2010. Insurance and stratum-specific estimates were applied to the 2010 US Census data and the findings combined to calculate the 2010 prevalence of MS cumulated over 10 years. No exclusions were made if a person met the algorithm criteria. Main Outcomes and Measurements: Prevalence of MS per 100 000 US adults stratified by demographic group and geography. The 95% CIs were approximated using a binomial distribution. Results: A total of 744 781 persons 18 years and older were identified with MS with 564 426 cases (76%) in females and 180 355 (24%) in males. The median age group was 45 to 54 years, which included 229 216 individuals (31%), with 101 271 aged 18 to 24 years (14%), 158 997 aged 35 to 44 years (21%), 186 758 aged 55 to 64 years (25%), and 68 539 individuals (9%) who were 65 years or older. White individuals were the largest group, comprising 577 725 cases (77%), with 80 276 Black individuals (10%), 53 456 Hispanic individuals (7%), and 33 324 individuals (4%) in the non-Hispanic other category. The estimated 2010 prevalence of MS per 100 000 US adults cumulated over 10 years was 161.2 (95% CI, 159.8-162.5) for Hispanic individuals (regardless of race), 298.4 (95% CI, 296.4-300.5) for Black individuals, 374.8 (95% CI, 373.8-375.8) for White individuals, and 197.7 (95% CI, 195.6-199.9) for individuals from non-Hispanic other racial and ethnic groups. During the same time period, the female to male ratio was 2.9 overall. Age stratification in each of the racial and ethnic groups revealed the highest prevalence of MS in the 45- to 64-year-old age group, regardless of racial and ethnic classification. With each degree of latitude, MS prevalence increased by 16.3 cases per 100 000 (95% CI, 12.7-19.8; P < .001) in the unadjusted prevalence estimates, and 11.7 cases per 100 000 (95% CI, 7.4-16.1; P < .001) in the direct adjusted estimates. The association of latitude with prevalence was strongest in women, Black individuals, and older individuals. Conclusions and Relevance: This study found that White individuals had the highest MS prevalence followed by Black individuals, individuals from other non-Hispanic racial and ethnic groups, and Hispanic individuals. Inconsistent racial and ethnic classifications created heterogeneity within groups. In the United States, MS affects diverse racial and ethnic groups. Prevalence of MS increases significantly and nonuniformly with latitude in the United States, even when adjusted for race, ethnicity, age, and sex. These findings are important for clinicians, researchers, and policy makers.

Analysis of Biospecimen Demand and Utilization of Samples from the National Amyotrophic Lateral Sclerosis Biorepository.

Amyotrophic lateral sclerosis (ALS) is a rare neurological condition affecting upper and lower motor neurons. The National ALS Biorepository (referred to as the Biorepository) was initiated in 2015, with biospecimen collection beginning in 2017, as a repository for biospecimens for future ALS research. To help ensure the usefulness of the Biorepository, a biospecimen demand analysis is conducted on an annual basis, as well as an analysis of the utilization of the Biorepository. To determine the types of biospecimens to be collected for the Biorepository, an in-depth initial examination occurred followed by ongoing biospecimen demand and utilization analyses. The initial examination included input from an expert panel, discussions with ALS research experts, review of other ALS biorepositories, assessment of biospecimen demand, and analysis of the biospecimen types historically used in ALS research. Of all biospecimen types reported in the literature, the most frequently used were DNA, postmortem spinal cord, blood, and cerebrospinal fluid; while the frequently reported types of biospecimens used in ALS-related grants were induced pluripotent stem cells, brain, blood, and spinal cord. Continuous analysis of potential sample demand and tissues collected, based on an analysis of the literature and funded grants, and actual sample requests can assist the Biorepository in ensuring that the appropriate samples are available for researchers when they are needed.

Keratinous biomarker of mercury exposure associated with amyotrophic lateral sclerosis risk in a nationwide U.S. study.

Objective: The majority of cases of the fatal neurodegenerative disease amyotrophic lateral sclerosis (ALS) are of unknown etiology. A proportion of these cases are likely to be attributable to contaminant exposures, although the specific environmental etiology of ALS remains largely a mystery. Certain forms of the neurotoxic metal mercury readily cross into the central nervous system. Fish is a dietary source of methylmercury, but also of beneficial components, such as omega-3 polyunsaturated fatty acids. Prior work using clinic-based studies of toenails and hair as keratinous biomarkers of exposure suggest elevated mercury levels in ALS patients compared with controls. We sought to validate this relationship in a U.S. case-control comparison of mercury levels in nail clippings. Methods: We performed trace element analysis using inductively coupled plasma mass spectrometry (ICP-MS) on the nail clippings of n = 70 female, geographically representative ALS patients from the National ALS Biorepository and compared them to n = 210 age-matched controls from a set of n = 1216 nationally distributed controls from the Sister and Two Sister Studies. Results: Compared to the lowest quartile of nail mercury, moderate levels were associated with decreased risk of ALS (P = 4.18e-6). However, the odds of having nail mercury levels above the 90th percentile were 2.3-fold higher among ALS patients compared with controls (odds ratio (OR) = 2.3, 95% confidence interval 1.10-4.58, adjusted for age and smoking status). Conclusion: This finding suggests that excessive mercury exposure may be associated with the neurodegenerative health of aging populations.

Feasibility of Using a Nationally Representative Telephone Survey to Monitor Multiple Sclerosis Prevalence in the United States.

BACKGROUND: Multiple sclerosis (MS) is the most common chronic neurologic disease of young adults, placing a heavy burden on patients, families, and the healthcare system. Ongoing surveillance of the incidence and prevalence of MS is critical for health policy and research, but feasible options are limited in the United States and many other countries. We investigated the feasibility of monitoring the prevalence of MS using a large national telephone survey of the adult US population. METHODS: We developed questions to estimate the lifetime prevalence and age of onset of MS using the US-based Behavioral Risk Factor Surveillance System (BRFSS) and piloted these questions in 4 states (MN, RI, MD, and TX). There was a total of 45,198 respondents aged 18 years and above. Analyses investigated individual state and combined prevalence estimates along with health-related comorbidities and limitations. MS prevalence estimates from the BRFSS were compared to estimates from multi-source administrative claims and traditional population-based methods. RESULTS: The estimated lifetime prevalence of self-reported MS (per 100,000 adults) was 682 (95% CI 528-836); 384 (95% CI 239-529) among males and 957 (95% CI 694-1,220) among females. Estimates were consistent across the 4 states but much higher than recently published estimates using population-based administrative claims data. This was observed for both national results and for MS prevalence estimates from other studies within specific states (MN, RI, and TX). Prevalence estimates for Caucasian, African American, and Hispanic respondents were 824, 741, and 349 per 100,000 respectively. Age and sex distributions were consistent with prior epidemiologic reports. Comorbidity and functional limitations were more pronounced among female than male respondents. CONCLUSIONS: While yielding higher overall MS prevalence estimates compared to recent studies, this large-scale self-report telephone method yielded relative prevalence estimates (e.g., prevalence patterns of MS by sex, age, and race-ethnicity) that were generally comparable to other surveillance approaches. With certain caveats, population-based telephone surveys may eventually offer the ability to investigate novel disease correlates and are relatively feasible, and affordable. Further work is needed to create a valid question set and methodology for case ascertainment before this approach could be adopted to accurately estimate MS prevalence.

The prevalence of MS in the United States: A population-based estimate using health claims data.

OBJECTIVE: To generate a national multiple sclerosis (MS) prevalence estimate for the United States by applying a validated algorithm to multiple administrative health claims (AHC) datasets. METHODS: A validated algorithm was applied to private, military, and public AHC datasets to identify adult cases of MS between 2008 and 2010. In each dataset, we determined the 3-year cumulative prevalence overall and stratified by age, sex, and census region. We applied insurance-specific and stratum-specific estimates to the 2010 US Census data and pooled the findings to calculate the 2010 prevalence of MS in the United States cumulated over 3 years. We also estimated the 2010 prevalence cumulated over 10 years using 2 models and extrapolated our estimate to 2017. RESULTS: The estimated 2010 prevalence of MS in the US adult population cumulated over 10 years was 309.2 per 100,000 (95% confidence interval [CI] 308.1-310.1), representing 727,344 cases. During the same time period, the MS prevalence was 450.1 per 100,000 (95% CI 448.1-451.6) for women and 159.7 (95% CI 158.7-160.6) for men (female:male ratio 2.8). The estimated 2010 prevalence of MS was highest in the 55- to 64-year age group. A US north-south decreasing prevalence gradient was identified. The estimated MS prevalence is also presented for 2017. CONCLUSION: The estimated US national MS prevalence for 2010 is the highest reported to date and provides evidence that the north-south gradient persists. Our rigorous algorithm-based approach to estimating prevalence is efficient and has the potential to be used for other chronic neurologic conditions.

Validation of an algorithm for identifying MS cases in administrative health claims datasets.

OBJECTIVE: To develop a valid algorithm for identifying multiple sclerosis (MS) cases in administrative health claims (AHC) datasets. METHODS: We used 4 AHC datasets from the Veterans Administration (VA), Kaiser Permanente Southern California (KPSC), Manitoba (Canada), and Saskatchewan (Canada). In the VA, KPSC, and Manitoba, we tested the performance of candidate algorithms based on inpatient, outpatient, and disease-modifying therapy (DMT) claims compared to medical records review using sensitivity, specificity, positive and negative predictive values, and interrater reliability (Youden J statistic) both overall and stratified by sex and age. In Saskatchewan, we tested the algorithms in a cohort randomly selected from the general population. RESULTS: The preferred algorithm required ≥3 MS-related claims from any combination of inpatient, outpatient, or DMT claims within a 1-year time period; a 2-year time period provided little gain in performance. Algorithms including DMT claims performed better than those that did not. Sensitivity (86.6%-96.0%), specificity (66.7%-99.0%), positive predictive value (95.4%-99.0%), and interrater reliability (Youden J = 0.60-0.92) were generally stable across datasets and across strata. Some variation in performance in the stratified analyses was observed but largely reflected changes in the composition of the strata. In Saskatchewan, the preferred algorithm had a sensitivity of 96%, specificity of 99%, positive predictive value of 99%, and negative predictive value of 96%. CONCLUSIONS: The performance of each algorithm was remarkably consistent across datasets. The preferred algorithm required ≥3 MS-related claims from any combination of inpatient, outpatient, or DMT use within 1 year. We recommend this algorithm as the standard AHC case definition for MS.

Evaluating the completeness of the national ALS registry, United States.

Our objective was to evaluate the completeness of the United States National ALS Registry (Registry). We compared persons with ALS who were passively identified by the Registry with those actively identified in the State and Metropolitan Area ALS Surveillance project. Cases in the two projects were matched using a combination of identifiers, including, partial social security number, name, date of birth, and sex. The distributions of cases from the two projects that matched/did not match were compared and Chi-square tests conducted to determine statistical significance. There were 5883 ALS cases identified by the surveillance project. Of these, 1116 died before the Registry started, leaving 4767 cases. We matched 2720 cases from the surveillance project to those in the Registry. The cases identified by the surveillance project that did not match cases in the Registry were more likely to be non-white, Hispanic, less than 65 years of age, and from western states. The methods used by the Registry to identify ALS cases, i.e. national administrative data and self-registration, worked well but missed cases. These findings suggest that developing strategies to identify and promote the Registry to those who were more likely to be missing, e.g. non-white and Hispanic, could be beneficial to improving the completeness of the Registry.

Survival and Cause of Death among a Cohort of Confirmed Amyotrophic Lateral Sclerosis Cases.

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder. Estimates of survival from disease onset range from 20 to 48 months and have been generated using clinical populations or death records alone. METHODS: Data on a cohort of ALS cases diagnosed between 2009-2011 were collected as part of the Los Angeles and San Francisco Bay Area Metropolitan ALS Surveillance projects; death records 2009-2013 were linked to these confirmed cases to determine survival post diagnosis and factors associated with survival time. RESULTS: There were 618 cases identified and 283 of these died during the follow up time period. Median age at death was 64.3 years, and median survival time post-diagnosis was 2.6 years. Age at diagnosis and year of diagnosis were predictors of survival time in adjusted models; those diagnosed at age 80 or older had shorter survival than those diagnosed at age 50 or younger. Most (92%) had ALS noted as a cause of death. DISCUSSION: Survival post-diagnosis may be improved compared with previous reports. Age at diagnosis continues to be the strongest predictor of prognosis; recall case reporting bias may play a role in estimates of survival time.

Geographic Variation of Amyotrophic Lateral Sclerosis Incidence in New Jersey, 2009-2011.

Few analyses in the United States have examined geographic variation and socioeconomic disparities in amyotrophic lateral sclerosis (ALS) incidence, because of lack of population-based incidence data. In this analysis, we used population-based ALS data to identify whether ALS incidence clusters geographically and to determine whether ALS risk varies by area-based socioeconomic status (SES). This study included 493 incident ALS cases diagnosed (via El Escorial criteria) in New Jersey between 2009 and 2011. Geographic variation and clustering of ALS incidence was assessed using a spatial scan statistic and Bayesian geoadditive models. Poisson regression was used to estimate the associations between ALS risk and SES based on census-tract median income while controlling for age, sex, and race. ALS incidence varied across and within counties, but there were no statistically significant geographic clusters. SES was associated with ALS incidence. After adjustment for age, sex, and race, the relative risk of ALS was significantly higher (relative risk (RR) = 1.37, 95% confidence interval (CI): 1.02, 1.82) in the highest income quartile than in the lowest. The relative risk of ALS was significantly lower among blacks (RR = 0.57, 95% CI: 0.39, 0.83) and Asians (RR = 0.63, 95% CI: 0.41, 0.97) than among whites. Our findings suggest that ALS incidence in New Jersey appears to be associated with SES and race.

Results of Florida's Amyotrophic Lateral Sclerosis Surveillance Project, 2009-2011.

OBJECTIVE: Studies to determine the incidence and prevalence of amyotrophic lateral sclerosis (ALS) in defined geographic areas in the USA are needed. The Florida Department of Health received funding from the federal Agency for Toxic Substances and Disease Registry to implement a state-wide ALS Surveillance Project. The objectives of the project were to describe the demographic characteristics of ALS cases and to calculate the incidence and prevalence of ALS in Florida. SETTING/PARTICIPANTS: All neurologists were asked to submit case reports for persons with ALS diagnosed and/or under their care during 1 January 2009 through 31 December 2011. A medical record verification form and an electromyogram (EMG) report were requested for a sample of cases and reviewed by an independent consulting neurologist to confirm ALS diagnosis. Death data were used to aid with case report collection. PRIMARY AND SECONDARY OUTCOME MEASURES: Demographics, relevant history and clinical characteristics, El Escorial classifications, time from symptom onset to diagnosis, crude annual incidence rates and 2009 period prevalence are presented. RESULTS: The 1450 reported ALS cases were more likely to be older, male, white and non-Hispanic. Slightly more than 4% of cases were reported as also having dementia, and 4.8% were reported to have an immediate family member diagnosed with ALS. Incidence rates ranged from 1.7 to 1.9 per 100,000 person-years during the project period and the 2009 period prevalence was 4.0 per 100,000 persons. CONCLUSIONS: Project findings are generally consistent with findings of population-based studies in Europe, as well as geographically limited studies in the USA. Our findings add to the growing body of epidemiological literature about ALS in the USA. Future epidemiological studies in the USA should focus on identifying cases from minority groups and those that may have limited access to healthcare, and should consider conducting capture-recapture analysis to assess case ascertainment.

Amyotrophic lateral sclerosis surveillance in Baltimore and Philadelphia.

INTRODUCTION: Limited epidemiological data on amyotrophic lateral sclerosis (ALS) exist in defined geographic areas in the United States. METHODS: Neurologists submitted case reports for patients under their care between January 1, 2009, and December 31, 2011, who met the El Escorial criteria. Diagnosis was confirmed for a sample of cases by the consulting neurologist. Death certificate data were used for supplemental case identification. RESULTS: The 248 reported cases were most likely to be 50-69 years old, men, white, and non-Hispanic. The total crude average annual incidence rate was 1.46 per 100,000 person-years. CONCLUSIONS: The reported demographic characteristics were consistent with previously published findings. The crude annual incidence was slightly lower than the expected rate of 1.6 but was within the range reported previously (0.7-2.5). These findings help quantify the burden of ALS in the United States.

Feasibility of creating a National ALS Registry using administrative data in the United States.

Uncertainty about the incidence and prevalence of amyotrophic lateral sclerosis (ALS), as well as the role of the environment in the etiology of ALS, supports the need for a surveillance system/registry for this disease. Our aim was to evaluate the feasibility of using existing administrative data to identify cases of ALS. The Agency for Toxic Substances and Disease Registry (ATSDR) funded four pilot projects at tertiary care facilities for ALS, HMOs, and state based organizations. Data from Medicare, Medicaid, the Veterans Health Administration, and Veterans Benefits Administration were matched to data available from site-specific administrative and clinical databases for a five-year time-period (1 January 2001-31 December 2005). Review of information in the medical records by a neurologist was considered the gold standard for determining an ALS case. We developed an algorithm using variables from the administrative data that identified true cases of ALS (verified by a neurologist). Individuals could be categorized into ALS, possible ALS, and not ALS. The best algorithm had sensitivity of 87% and specificity of 85%. We concluded that administrative data can be used to develop a surveillance system/registry for ALS. These methods can be explored for creating surveillance systems for other neurodegenerative diseases.

Acute hazardous substance releases resulting in adverse health consequences in children: Hazardous Substances Emergency Events Surveillance system, 1996-2003.

Because of their small size and ongoing organ development, children may be more susceptible than adults to the harmful effects of toxic chemicals. The objective of the study reported here was to identify frequent locations, released substances, and factors contributing to short-term chemical exposures associated with adverse health consequences experienced by children. The study examined the Hazardous Substances Emergency Events Surveillance (HSEES) system data from 1996-2003. Eligible events involved the acute release of a hazardous substance associated with at least one child being injured. The study found that injured children were predominantly at school, home, or a recreational center when events took place. School-related events were associated with the accidental release of acids and the release of pepper spray by pranksters. Carbon monoxide poisonings occurring in the home, retail stores, entertainment facilities, and hotels were responsible for about 10 percent of events involving child victims. Chlorine was one of the top chemicals harmful to children, particularly at public swimming pools. Although human error contributed to the majority of releases involving child victims, equipment failure was responsible for most chlorine and ammonia releases. The authors conclude that chemical releases resulting in injury to children occur mostly in schools, homes, and recreational areas. Surveillance of acute hazardous chemical releases helped identify contributing causes and can guide the development of prevention outreach activities. Chemical accidents cannot be entirely prevented, but efforts can be taken to provide safer environments in which children can live, learn, and play. Wide dissemination of safety recommendations and education programs is required to protect children from needless environmental dangers.

Potential residential exposure to toxics release inventory chemicals during pregnancy and childhood brain cancer.

BACKGROUND: Although the susceptibility of the developing fetus to various chemical exposures is well documented, the role of environmental chemicals in childhood brain cancer etiology is not well understood. OBJECTIVES: We aimed to evaluate whether mothers of childhood brain cancer cases had greater potential residential exposure to Toxics Release Inventory (TRI) chemicals than control mothers during pregnancy. METHODS: We included 382 brain cancer cases diagnosed at < 10 years of age from 1993 through 1997 who were identified from four statewide cancer registries. One-to-one matched controls were selected by random-digit dialing. Computer-assisted telephone interviews were conducted. Using residential history of mothers during pregnancy, we measured proximity to TRI facilities and exposure index, including mass and chemicals released. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using conditional logistic regression to estimate brain cancer risk associated with TRI chemicals. RESULTS: Increased risk was observed for mothers living within 1 mi of a TRI facility (OR = 1.66 ; 95% CI, 1.11-2.48) and living within 1 mi of a facility releasing carcinogens (OR = 1.72 ; 95% CI, 1.05-2.82) for having children diagnosed with brain cancer before 5 years of age, compared to living > 1 mi from a facility. Taking into account the mass and toxicity of chemical releases, we found a nonsignificant increase in risk (OR = 1.25 ; 95% CI, 0.67-2.34) comparing those with the lowest versus highest exposure index. CONCLUSIONS: Risk of childhood brain cancers may be associated with living near a TRI facility ; however, this is an exploratory study and further studies are needed.

Lead exposure and birth outcomes in five communities in Shoshone County, Idaho.

INTRODUCTION: This study examined birth outcomes in five towns in Shoshone County, Idaho, where residents were exposed to high levels of lead in air emissions during a 6-month period after a fire had damaged the main baghouse (pollution-control device) of a local lead smelter plant in September 1973. METHODS: We studied birth certificate data of 169,878 live singleton infants born to mothers who resided in Idaho at the time of delivery. The outcomes evaluated were preterm infants, small-for-gestational-age (SGA) infants, low birthweight among term infants (TLBW), and mean birthweight among term infants (TMBW). The study compared births in the five towns in Shoshone County (exposed group) to births in the rest of Idaho during three exposure periods: "pre-fire," January 1, 1970-August 31, 1973; "high exposure," September 1, 1973-December 31, 1974; and "post-fire," January 1, 1975-December 31, 1981. RESULTS: During the high-exposure period, the exposed group had an increased prevalence of TLBW (OR=2.4; 90% CI: 1.6-3.6) and SGA (OR=1.9; 90% CI: 1.3-2.8) compared with the rest of Idaho. During the pre- and post-fire periods, the ORs for TLBW were 0.8 and 1.3, respectively, and for SGA, 1.0, and 1.3, respectively. During the high-exposure period, TMBW for the exposed group was 71 g lower than in the comparison group. The TMBW in the exposed group was 8 g lower in the pre-fire period and 26 g lower in the post-fire period than in the comparison group. The study found no increased risk for preterm birth in the exposed group. CONCLUSIONS: Maternal exposures to airborne lead emissions appeared to be associated with increased risks for SGA, TLBW, and reduced TMBW.

Wilms' tumor and exposures to residential and occupational hazardous chemicals.

This case-control study examines the association between residential and occupational exposures to hazardous chemicals and the risk of Wilms' tumor. The study included 303 cases recruited from six state cancer registries, who were diagnosed between January 1, 1992 and December 31, 1995. A total of 575 controls selected through random digit dialing were frequency matched to the cases. A standard questionnaire was administered to participants during a telephone interview. Parental residential addresses and locations of US Environmental Protection Agency National Priority List (NPL) sites were geocoded and analyzed, along with occupational exposure information. There were no cases of Wilms' tumor found in individuals living within one-half mile distance of a hazardous waste site. However, elevated odds ratios were found for using hairdressing chemicals, motor oil, paint, paint stripper, and pesticides during the pregnancy term and during the 2-year period prior to birth. The findings do not support the hypothesis that Wilms' tumor is associated with residing near an NPL site.

Secondary contamination of emergency department personnel from o-chlorobenzylidene malononitrile exposure, 2002.

In a hazardous materials event in 2002, the unannounced presentation of 3 symptomatic, contaminated patients to an emergency department (ED) resulted in secondary contamination of 2 ED personnel who experienced skin, eye, and respiratory irritation. The material that caused these injuries was o-chlorobenzylidene malononitrile, a white powder with a peppery odor used largely as a tear gas and riot-control agent. Secondary contamination can cause adverse symptoms and injuries in ED personnel, further contaminate the ED, and potentially lead to costly ED closures and evacuations. To prevent secondary exposure, EDs can educate their staff about the potential for secondary contamination, implement a team approach for handling contaminated patients, establish decontamination protocols, ensure proper selection of and training in the use of personal protective equipment, and simulate drills for receiving contaminated patients.

Surveillance of hazardous substance emergency events: identifying areas for public health prevention.

The Hazardous Substances Emergency Events Surveillance (HSEES) system is a comprehensive, state-based surveillance system of hazardous substance releases and public health consequences. Maintained by the Agency for Toxic Substances and Disease Registry (ATSDR) since 1990, the system captures information on acute releases of hazardous substances that need to be cleaned up or neutralized according to federal, state, or local law. Information about threatened releases that result in public health action such as evacuation is also included. Of the 39,766 events reported to HSEES for 1996--2001, 8% resulted in deaths or injuries. Funded through a competitive program announcement, 15 states currently participate in HSEES. State coordinators actively collect data from multiple sources after an eligible event occurs and enter data about the event into a standardized ATSDR-provided web-based system. The information in HSEES describes the distribution and characteristics of hazardous substances emergencies and the morbidity and mortality experienced by employees, responders, and the general public as the result of hazardous substances releases. Analysis of HSEES data helps identify risk factors associated with hazardous substances releases. For example, although events in which chlorine was released account for only 1.6% of all events, they were 3.52 times more likely to result in injuries. Knowledge of these factors is useful in planning public safety interventions and can impact the formulation of guidelines and policies to help reduce the number of events (primary prevention) and the morbidity and mortality associated with these events (secondary prevention). Utilizing state-specific analyses of HSEES data, participating states have been able to develop prevention outreach activities such as awareness training of first responders, primary prevention of spills, and secondary prevention of related injuries and deaths caused by ammonia, chlorine, and mercury. Specific examples involving ammonia, chlorine, and mercury releases will be presented in detail.

The usefulness of computed tomography in detecting asbestos-related pleural abnormalities in people who had indeterminate chest radiographs: the Libby, MT, experience.

This epidemiological study was conducted to determine whether high-resolution computed tomography (HRCT) is useful to screen for pulmonary abnormalities in people exposed to vermiculite containing asbestos. During June-September 2001, we evaluated HRCT of 353 people in Libby, MT, who had been exposed to asbestiform minerals associated with vermiculite. Of these, 334 participants of the summer 2000 medical testing program underwent HRCT of the chest at St. John's Lutheran Hospital and 19 eligible people who recently had undergone an HRCT scan at the same facility and under the same testing protocol allowed the study reviewers to use that scan. All 353 study participants were former vermiculite mine/mill workers (n = 55), their household contacts (n = 99), and people exposed to vermiculite through recreational or other activities (n = 199). Participants' 2000 medical testing results indicated only one of the three B-reader chest radiograph reviewers had reported a pleural abnormality (indeterminate chest radiograph). Three expert computer tomography (CT) scan evaluators reviewed the HRCT scans and identified pleural abnormalities in 98 (27.8%) of the 353 participants whose previous chest radiographs were classified indeterminate. Of these 98 people, 69 (70.4%) were either former vermiculite mine/mill workers or household contacts, and 40 (40.8%) showed pleural calcification on HRCT. Thirty out of the 40 people with pleural calcification reported having no occupational exposure to either Libby vermiculite or asbestos. Our findings indicate that low-dose HRCT can be considered for screening certain former vermiculite mine/mill workers and their household contacts who have indeterminate chest radiographs and may be useful for diagnosing a suspicious finding on a chest radiograph, particularly in a high-risk person.