Prevalence of amyotrophic lateral sclerosis - United States, 2010-2011.

Problem/condition: Amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig's disease, is a progressive and fatal neuromuscular disease for which no cure has been identified. Although ALS has no known definitive cause, familial ALS (a hereditary form) occurs in 5%-10% of cases. Many hypotheses have been formulated about what causes ALS, including chemical exposures, occupational exposure, military service, infectious agents, nutritional intake, physical activity, and trauma. Worldwide, ALS affects white males aged >60 years more often than any other group. In the United States, ALS surveillance is necessary to estimate the incidence and prevalence of ALS and collect data on risk factors. ALS is not a nationally notifiable condition in the United States (i.e., it is not a reportable condition in all jurisdictions), and individual state reporting requirements differ, with Massachusetts being the only state that mandates reporting.

Period covered: October 19, 2010-December 31, 2011.

Description of system: In 2009, the federal Agency for Toxic Substances and Disease Registry (ATSDR) implemented the National ALS Registry to collect and analyze data regarding persons with ALS in the United States. The main goals of the Registry, as defined by the 2008 ALS Registry Act, are to describe the incidence and prevalence of ALS better, examine risk factors such as environmental and occupational exposures, and characterize the demographics of those living with ALS. The Registry uses a two-pronged approach to identify all cases of ALS. The first approach uses four existing national administrative databases (maintained by Medicare, Medicaid, the Veterans Health Administration, and the Veterans Benefits Administration) to identify prevalence of ALS. The second approach uses a secure web portal (http://www.cdc.gov/als) that was launched to the public on October 19, 2010, to identify cases not included in the four national administrative databases and to collect risk-factor data on known ALS cases. ALS patients who have registered via the web portal can complete brief risk-factor surveys online that are intended to attain a better understanding of ALS (e.g., genetics and environmental and occupational exposures) and help determine disease progression.

Results: During October 19, 2010-December 31, 2011, a total of 12,187 persons meeting the surveillance case definition of definite ALS were identified by the Registry, for a prevalence of 3.9 cases of ALS per 100,000 persons in the U.S. general population. Incidence cannot be measured because the date of diagnosis was not noted in all patient records. Overall, ALS was more common among white males, non-Hispanics, and persons aged 60-69 years. The age groups with the lowest number of persons with ALS were age 18-39 years and age >80 years. Males had a higher prevalence rate of ALS than females overall and across all data sources.

Interpretation: This is the first (and to date the only) effort to estimate the national prevalence of ALS in the United States. Using the combined approach of the national databases and the web-based portal enables researchers to estimate ALS prevalence more accurately. Registry findings for the prevalence of ALS are consistent with findings from long-established ALS registries in Europe and from smaller-scale epidemiologic studies conducted previously in the United States. Although incidence cannot be measured with Registry data at this time, incidence is being measured in smaller geographic areas that have participated in ATSDR's State and Metropolitan Area ALS surveillance projects.

Public health actions: Data collected by the National ALS Registry are being used to better describe the prevalence of ALS in the United States and to help facilitate research. The combined approach of using national administrative databases and a self-enrollment web portal to collect data is novel and potentially could be used for other non-notifiable diseases such as Parkinson's disease or multiple sclerosis. ATSDR is working closely with ALS advocacy and support groups, researchers, health-care professionals, and others to promote the National ALS Registry in order to capture all cases of ALS. To further enhance and strengthen the Registry, ATSDR is 1) adding new modules to the portal to examine other potential risk factors, 2) launching a feasibility study for a novel ALS biorepository (available at http://wwwn.cdc.gov/als/ALSBioRegistry.aspx) linked to the Registry that would potentially provide biologic specimens from patient enrollees to help researchers learn more about disease etiology, 3) engaging in surveillance activities in selected states and large metropolitan areas to help test the completeness of the Registry as well as calculating incidence in these areas, and 4) using the Registry to recruit patient enrollees for new clinical trials and epidemiologic studies. Additional information about the National ALS Registry is available at http://www.cdc.gov/als or by calling toll-free at 1-877-442-9719.