Occupational risk factors for Alzheimer disease: a case-control study.

There is evidence to support the role of a number of environmental factors in Alzheimer disease (AD). This study examines the role of chemical and physical exposures in the occupational environment. The sample included 170 patients with AD and 170 medical-practice-based controls, matched for age and sex, who were assessed for histories of occupational exposures to a range of chemical and physical agents, including hydrocarbon solvents, lead, mercury, organophosphates, aluminum, asbestos and other silicates, vibration, and physical underactivity. Occupational histories were obtained from informants for both patients and controls. Exposure was assessed by a panel of occupational hygienists, blinded to the case or control status of each subject, using the occupational histories and the Job-Exposure Matrix of the U.S. National Institute for Occupational Safety and Health. No statistically significant associations were found between any of the exposures and the occurrence of AD, either in the overall study group or in patients with a family history of AD. The findings suggest the absence of any occupational cause for AD.