Background: The etiology of amyotrophic lateral sclerosis (ALS) likely involves an environmental component. We qualitatively assessed literature on ALS and lead exposure. Problems of study design make case reports and studies of lead in blood or tissues difficult to interpret. Most previous case-control studies found an association of ALS with self-reported occupational exposure to lead, with increased risks of 2- to >4-fold. However, these results may have been affected by recall bias. Objective: To address inconsistencies among published reports, we used both lead biomarkers and interview data to assess lead exposure, and we evaluated the role of genetic susceptibility to lead. Methods: We conducted a case-control study in New England in 1993-1996 with 109 ALS cases and 256 population-based controls. We measured blood and bone lead levels, the latter using X-ray fluorescence, and interviewed participants regarding sources of lead exposure. Results: In our study, ALS was associated with self-reported occupational lead exposure, with a dose response for cumulative days of exposure. ALS was also associated with blood and bone lead levels, with a 1.9-fold increase in risk for each µg/dl increment in blood lead and a 2.3- to 3.6-fold increase for each doubling of bone lead. A polymorphism in the d-aminolevulinic acid dehydratase gene was associated with a 1.9-fold increase in ALS risk. Conclusion: These results, together with previous studies, suggest that lead exposure plays a role in the etiology of ALS. An increase in mobilization of lead from bone into blood may play a role in the acute onset of disease.
Etiology; Environmental exposure; Lead; Exposure levels; Risk factors; Blood; Case control studies; Biomarkers; Genetics; Bone structure; X-rays; X-ray fluorescence analysis; Diseases;
Author Keywords: Amyotrophic lateral sclerosis; Epidemiology; Lead exposure; Environment
Freya Kamel, PhD, MPH, Epidemiology Branch, National Institute of Environmental Health Sciences PO Box 12233, MD A3-05, Research Triangle Park, NC 27709
We take your privacy seriously. You can review and change the way we collect information below.
These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site. All information these cookies collect is aggregated and therefore anonymous. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance.
Cookies used to make website functionality more relevant to you. These cookies perform functions like remembering presentation options or choices and, in some cases, delivery of web content that based on self-identified area of interests.
Cookies used to track the effectiveness of CDC public health campaigns through clickthrough data.
Cookies used to enable you to share pages and content that you find interesting on CDC.gov through third party social networking and other websites. These cookies may also be used for advertising purposes by these third parties.