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.

Survival and epidemiology of amyotrophic lateral sclerosis (ALS) cases in the Chicago and Detroit metropolitan cohort: incident cases 2009-2011 and survival through 2018.

Amyotrophic lateral sclerosis (ALS) is a fatal, progressive neurodegenerative disorder. The National ALS Registry launched surveillance projects to understand the distribution of ALS in targeted geographic cohorts. OBJECTIVE: To describe the demographics, incidence, and survival of persons with ALS (PALS) identified in the Chicago and Detroit area population-based cohort. METHODS: Neurologists in the catchment area provided case reports for eligible ALS cases diagnosed and/or cared for from 1 January 2009 through 31 December 2011. Crude incidence rates were calculated for 2009-2011 and stratified by race and ethnicity. Using data from the National Death Index through 2018, we modeled the effect of patient covariates on mortality using the Cox proportional hazard regression. RESULTS: Of the 574 cases, 372 (64.8%) were diagnosed from 2009 to 2011. The combined crude incidence rates for 2009, 2010, and 2011 were 1.44, 1.53, and 1.73 cases per 100,000 person-years, respectively. Of the 486 subjects with complete survival data, 81% were deceased at the end of follow-up. Median survival time was 2.2 years, with 30% and 9% of subjects surviving past 5 and 10 years after diagnosis, respectively. Additionally, female PALS and PALS with longer time between symptom onset and diagnosis experienced longer survival. Nonwhites also experienced longer survival than Whites, except for those cases diagnosed in the younger age categories. CONCLUSION: Understanding the survival of ALS patients can aid in understanding variable prognostic factors, which can potentially extend survival and improve disease management.

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.

Atlanta metropolitan area amyotrophic lateral sclerosis (ALS) surveillance: incidence and prevalence 2009-2011 and survival characteristics through 2015.

Amyotrophic lateral sclerosis (ALS) is a fatal, rare, and hard to diagnose neurological disease with unknown etiology. Objective: To understand the incidence, prevalence, and survival characteristics of ALS cases in the Atlanta metropolitan area. Methods: Neurologists in Clayton, Cobb, DeKalb, Fulton, and Gwinnett counties provided case reports for ALS patients under their care from 1 January 2009 to 31 December 2011. Incidence and prevalence rates were calculated for 2009, 2010, and 2011 by sex, race, and ethnicity. Using data from the National Death Index, survival time was calculated for age, sex, race, ethnicity, and El Escorial criteria. Results: There were 281 unique ALS cases reported, which is approximately 104% of the expected cases. The majority of the 281 cases were white, non-Hispanic, male, and in the 50-59 age category. The overall average incidence rate for 2009 to 2011 was 1.54 per 100,000 person-years, with higher annual incidence rates for whites, males, and non-Hispanics. The prevalence rates for 2009, 2010, and 2011 were 5.05, 5.44, and 5.56 per 100,000, respectively. Median survival time was highest for the 18-39 age group, Asians, non-Hispanics, and males. Additionally, the log-rank tests for homogeneity across strata indicate a statistical significance between strata for the age category for survival time. Conclusion: The findings for Atlanta are similar to other population-based studies in the United States. Although the Atlanta metropolitan area was selected to over-represent the minority population, the strongest predictor of survival time was age at diagnosis.

A new way to estimate neurologic disease prevalence in the United States: Illustrated with MS.

OBJECTIVE: Considerable gaps exist in knowledge regarding the prevalence of neurologic diseases, such as multiple sclerosis (MS), in the United States. Therefore, the MS Prevalence Working Group sought to review and evaluate alternative methods for obtaining a scientifically valid estimate of national MS prevalence in the current health care era. METHODS: We carried out a strengths, weaknesses, opportunities, and threats (SWOT) analysis for 3 approaches to estimate MS prevalence: population-based MS registries, national probability health surveys, and analysis of administrative health claims databases. We reviewed MS prevalence studies conducted in the United States and critically examined possible methods for estimating national MS prevalence. RESULTS: We developed a new 4-step approach for estimating MS prevalence in the United States. First, identify administrative health claim databases covering publicly and privately insured populations in the United States. Second, develop and validate a highly accurate MS case-finding algorithm that can be standardly applied in all databases. Third, apply a case definition algorithm to estimate MS prevalence in each population. Fourth, combine MS prevalence estimates into a single estimate of US prevalence, weighted according to the number of insured persons in each health insurance segment. CONCLUSIONS: By addressing methodologic challenges and proposing a new approach for measuring the prevalence of MS in the United States, we hope that our work will benefit scientists who study neurologic and other chronic conditions for which national prevalence estimates do not exist.

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.

A Qualitative Analysis of Health Education Practice in Applied Work Settings.

Job analysis projects play a critical role in the health education profession by validating what is constant in the profession and identifying emerging patterns of effective practice. In this regard, the Role Delineation Project, Competencies Update Project (CUP), and Health Educator Job Analysis Project (HEJA) have provided frameworks for the accreditation of professional preparation programs, credentialing, and continuing education of health education specialists. To date, projects (CUP, HEJA, and Health Education Specialist Practice Analysis) have revalidated the framework to help describe the contemporary practice of health education specialists. Evidence is lacking regarding exactly how the frameworks have been integrated into applied practice and what guides the practice of health educators. In context of the Areas of Responsibility for health education specialists, the purpose of this qualitative study was to examine the gap between the "state of the art" and the "state of the practice" among health education practitioners in a range of workplace settings. Data were collected through structured interviews and analyzed for emergent themes. Major themes included the use of formal and informal assessment methods, program-specific planning materials and implementation strategies, supplemental materials for planning and conveying information, and the influence and work with organizations. Based on the emergent themes, the gaps between the "state of the art" and the "state of the practice" were described, with suggestions for advancing the profession.

Integrating a Biorepository Into the National Amyotrophic Lateral Sclerosis Registry.

As part of our continuing effort to highlight innovative approaches to improving the health and environment of communities, the Journal is pleased to publish a bimonthly column from the Agency for Toxic Substances and Disease Registry (ATSDR). ATSDR is a federal public health agency of the U.S. Department of Health and Human Services (HHS) and shares a common office of the Director with the National Center for Environmental Health (NCEH) at the Centers for Disease Control and Prevention (CDC). ATSDR serves the public by using the best science, taking responsive public health actions, and providing trusted health information to prevent harmful exposures and diseases related to toxic substances. The purpose of this column is to inform readers of ATSDR's activities and initiatives to better understand the relationship between exposure to hazardous substances in the environment and their impact on human health and how to protect public health. We believe that the column will provide a valuable resource to our readership by helping to make known the considerable resources and expertise that ATSDR has available to assist communities, states, and others to assure good environmental health practice for all is served. The conclusions of this column are those of the author(s) and do not necessarily represent the views of ATSDR, CDC, or HHS. Kevin Horton is chief of the Environmental Health Surveillance Branch within the Division of Toxicology and Human Health Sciences at ATSDR. Wendy Kaye is a senior epidemiologist at McKing Consulting Corporation. Laurie Wagner is a research associate at McKing Consulting Corporation.

State and metropolitan area-based amyotrophic lateral sclerosis (ALS) surveillance.

UNLABELLED: Our objective was to develop state and metropolitan area-based surveillance projects to describe the characteristics of those with ALS and to assist with evaluating the completeness of the National ALS Registry. Because the literature suggested that ethnic/racial minorities have lower incidence of ALS, three state and eight metropolitan areas were selected to over-represent ethnic/racial minorities to have a sufficient number of minority patients. Project activities relied on reports from medical providers and medical records abstraction. The project areas represented approximately 27% of the U.S. POPULATION: The combined racial and ethnic distribution of these areas is 64.4% white, 16.0% African-American, 6.7% Asian, and 28.3% Hispanic. Most neurologists did not diagnose or provide care for ALS patients. The number of unique patients reported was close to expected (5883 vs. 6673). Age and gender distribution of patients was similar to the literature. The crude average annual incidence rate was 1.52 per 100,000 person-years, CI 1.44-1.61, and the 2009 prevalence rate was 3.84 per 100,000 population, CI 3.70-3.97. In conclusion, this study represents the largest number of clinically diagnosed ALS patients reported by neurologists in the U.S. Comparison of these data with those in the National ALS Registry will help evaluate the completeness of administrative databases.

Updated Prevalence and Demographic Characteristics for ALS Cases in Texas, 2009-2011.

OBJECTIVES: Amyotrophic lateral sclerosis (ALS) is a rare motor neuron disease with incidence rates ranging from 1 to 2/100,000 person-years. The Texas Department of State Health Services previously conducted surveillance for ALS in three metropolitan areas of Texas. This project provides an update to this research, while expanding its scope to the entire state. METHODS: The Texas Department of State Health Services contacted neurologists throughout Texas to determine whether they diagnose or treat patients with ALS. Those neurologists who cared for Texas residents with ALS between 2009 and 2011 were asked to complete a one-page case reporting form for each patient. RESULTS: A total of 1422 unique cases were received. The average crude annual incidence rate was 1.30/100,000 person-years and the 2009 period prevalence rate was 2.92/100,000 individuals. Reported cases were most likely to be 60 to 69 years old, non-Hispanic, white, and men. CONCLUSIONS: This project provides an update to previously published Texas-specific epidemiological data regarding ALS; also, we note that our findings are consistent with previously published studies.

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.

Racial and ethnic differences among amyotrophic lateral sclerosis cases in the United States.

Our objective was to describe racial and ethnic differences of amyotrophic lateral sclerosis (ALS) in distinct geographic locations around the United States (U.S.). ALS cases for the period 2009-2011 were identified using active case surveillance in three states and eight metropolitan areas. Of the 5883 unique ALS cases identified, 74.8% were white, 9.3% were African-American/black, 3.6% were Asian, 12.0% were an unknown race, and 0.3% were marked as some other race. For ethnicity, 77.5% were defined as non-Hispanic, 10.8% Hispanic, and 11.7% were of unknown ethnicity. The overall crude average annual incidence rate was 1.52 per 100,000 person-years and the rate differed by race and ethnicity. The overall age-adjusted average annual incidence rate was 1.44 per 100,000 person-years and the age-adjusted average incidence rates also differed by race and ethnicity. Racial differences were also found in payer type, time from symptom onset to diagnosis, reported El Escorial criteria, and age at diagnosis. In conclusion, calculated incidence rates demonstrate that ALS occurs less frequently in African-American/blacks and Asians compared to whites, and less frequently in Hispanics compared to non-Hispanics in the U.S. A more precise understanding of racial and ethnic variations in ALS may help to reveal candidates for further studies of disease etiology and disease progression.

Improving a Case-Control Study of Multiple Sclerosis Using Formative Research.

Formative research (i.e. focus groups and key informant interviews) was conducted to understand risk perceptions and identify barriers to participation in a case-control study of environmental exposures and genetic susceptibility as risk factors for multiple sclerosis (MS). Individuals with MS were recruited to participate in a focus group discussion and individual interviews. Participants were asked to review and comment on study materials and process including participation, interview, genetic testing, confidentiality, and questionnaire. A structured discussion guide was used with all participants to ensure uniformity and coverage of all predetermined topics. Participants reported an increased likelihood of participation if they were informed about the study by their neurologist and not a government agency. All participants expressed willingness to provide a blood sample for genotyping but disagreed about the setting for the blood draw (at home or in a lab). Participants were concerned that they would not receive their individual genotyping results. The study protocol and materials were revised based on comments from the focus group participants. Formative research is an under-utilized resource for researchers conducting epidemiologic studies. Even with limited resources, piloting study materials with individuals similar to the proposed study population can provide opportunities to make modifications to effectively meet the needs of participants and promote participation and retention.

Prevalence of amyotrophic lateral sclerosis in Texas, 1998-2003.

A prevalence study of amyotrophic lateral sclerosis (ALS) was conducted in 3 areas in Texas to enable the state health department to better respond to community concerns regarding the occurrence of ALS and to contribute to national prevalence estimates. The overall ALS point prevalence was lower than previously published US estimates. This study provides ALS prevalence estimates for Texas, including Hispanic populations.

The prevalence of multiple sclerosis in 3 US communities.

INTRODUCTION: We estimated the prevalence of multiple sclerosis (MS) in 3 large geographic areas in the southern, middle, and northern United States. METHODS: The primary data source was medical records from office visits to private neurologists' practices or to neurology departments in tertiary care facilities during a 3-year period. Additional data sources included patient advocacy groups, nursing homes, and general practitioners. RESULTS: Three-year US age-adjusted prevalence estimates for the study areas varied substantially. The prevalence was lowest (47.2 per 100,000 population) in the Texas study area (33 degrees 30' north latitude), intermediate (86.3 per 100,000 population) in the Missouri study area (39 degrees 07' north latitude), and highest (109.5 per 100,000 population) in the Ohio study area (41 degrees 24' north latitude). The geographic differences remained strong after age-adjustment to the world standard population. The inverse association between UV light exposure and MS prevalence estimates was consistent with this observed latitude gradient. In all 3 areas, MS prevalence was highest among women, people aged 40 to 59 years, and non-Hispanics. CONCLUSION: These results provide necessary prevalence estimates for community cluster investigations and establish baseline estimates for future studies to evaluate temporal trends in disease prevalence.

Updated prevalence estimates of multiple sclerosis in Texas, 1998 to 2003.

The Texas Department of State Health Services extended a prevalence study of multiple sclerosis (MS) in a 19-county area in North Texas to include 3 additional years of data and included a new geographic area with a predominantly Hispanic population (El Paso County). Patients in whom MS was diagnosed by a neurologist, who resided in the study areas, and who had an office visit between 1998 and 2003 were included in the study. The 6-year MS prevalence estimate for the North Texas counties was 71.5 per 100,000, and for El Paso County it was 49.4 per 100,000. In both areas, prevalence estimates were higher for females, age groups 40 to 49 and 50 to 59, and for non-Hispanic whites. These estimates provide valuable information about the epidemiology of MS in Texas and allow for a comparison with national estimates. The results also provide much needed prevalence data for the Hispanic population.