Moderate and severe head injuries in young men may be associated with increased risk of AD and other dementias in late life. However, the authors cannot exclude the possibility that other unmeasured factors may be influencing this association.

A case-control study was performed to determine the possible roles of various environmental factors, prior illnesses, drug use, and personal habits in the development of Alzheimer's disease. Such information was collected from 40 patients with onset of dementia prior to age 70 and from 80 community control subjects matched for age, sex, and race. No significant differences were found between patients and control subjects in toxic environmental exposures, animal contacts, smoking, drinking, or unusual dietary habits. A significantly higher frequency of prior thyroid disease was found in women patients than in women control subjects (25.0% and 7.1%, respectively). A history of severe head injury was also obtained significantly more often among the patients than among the controls (15.0% and 3.8%, respectively). Aside from these differences, which may prove to be important associative factors in this illness, there appeared to be no major premorbid demographic or clinical factors associated with this form of dementia. There was evidence, however, of a genetic factor that was manifested in an excess of dementia and mental retardation (including Down's syndrome) in families of patients with Alzheimer's disease.

No abstract

We conducted a co-twin control study among 50 elderly twin pairs with onsets of Alzheimer's disease (AD) separated by 3 or more years. Twenty-three male pairs (46%) were screened from the (U.S.) National Academy of Sciences-National Research Council Registry (NAS-NRC Registry) of World War II veteran twins; others (mostly women) had responded to advertisements or were referred from AD clinics. Twenty-six pairs (52%) were monozygous. The onset of AD was inversely associated with prior use of corticosteroids or ACTH (odds ratio [OR], 0.25; 95% confidence interval [CI], 0.06 to 0.95; p = 0.04). Similar but weaker trends were present among pairs discordant for history of arthritis or for prior daily use of nonsteroidal anti-inflammatory drugs (NSAIDs) or aspirin. The association was strongest when we combined use of steroids/ACTH or NSAIDs post hoc into a single variable of anti-inflammatory drugs (AIs) (OR, 0.24; CI, 0.07 to 0.74; p = 0.01). The inverse relation was strong in female (volunteer) twin pairs but was not present in the younger men from the NAS-NRC Registry. AIs had typically been taken for arthritis or related conditions, but a similar result was apparent after controlling statistically for the arthritis variable (OR, 0.08; CI, 0.01 to 0.69; p = 0.02). AIs have been proposed as a means of retarding the progression of AD symptoms, and these data suggest that AIs may also prevent or delay the initial onset of AD symptoms. Because of limitations in the case-control method, our results require corroboration with hypothesis-driven research designed to control bias and confounding.