A case-control study of amyotrophic lateral sclerosis.

A retrospective case-control study was conducted using 46 patients affected by amyotrophic lateral sclerosis and 92 closely matched healthy controls. Cases were ascertained through typical clinical and instrumental findings. Putative risk factors (bone fractures or major trauma, exposure to domestic animals, surgical operations, disease among first degree relatives and others) were investigated anamnestically using a standard questionnaire. Using Mantel-Haenzsel estimates of the odds ratio, no association was found between amyotrophic lateral sclerosis and the investigated variables.