Head Trauma and Age of Onset of Dementia of the Alzheimer Type

To the Editor.— Two recent epidemiologic case-control studies¹,²have found a statistically significant association of premorbid head trauma with an increased risk of dementia of the Alzheimer type (DAT), although the largest study published to date³did not find such an association. To investigate this matter further, we conducted a case-control study of 17 DAT cases and 17 controls. Study.— Cases were from two DAT special care facilities, and controls were matched by age, sex, and race from Severe Head Injuries Reported by Surrogates of Cases and Controlsamong residents of the same nursing homes. The diagnosis of DAT was established by review of medical records following recently published clinical criteria.⁴History of head trauma was ascertained by telephone interviews with next-of-kin surrogates for both cases and controls. The average age of cases was 78.8 ±6.5 years (mean±SD) and 79.4 ± 6.1 years for controls, a difference