RISK-FACTORS FOR ALZHEIMERS-DISEASE AND DEMENTIA - A CASE-CONTROL STUDY BASED ON THE MRC ELDERLY HYPERTENSION TRIAL

We surveyed 1,545 subjects-recruited into the UK Medical Research Coun cil elderly hypertension treatment trial between 1982 and 1987-to dete ct incident cases of dementia, identifying 50 cases of dementia, inclu ding 31 cases of probable or possible Alzheimer's disease (AD). These we compared with 223 unimpaired, unmatched controls from the same popu lation for exposure to familial, cardiovascular, educational, and geog raphic risk factors for dementia. Our study confirms the association o f family history of dementia with dementia (odds ratio [OR] = 4.36) an d AD (OR = 4.69), and of advanced age with dementia (OR = 2.81). Rural residence exerted a protective effect for dementia (OR = 0.21) and AD (OR = 0.28). We report near-significant associations between AD and d ementia and several cardiovascular risk factors (ECG ischemia, systoli c hypertension, and smoking) among subjects lacking a family history o f dementia. We postulate the existence of a nonfamilial form of dement ia transcending traditional categories of multiinfarct dementia and AD , more common among urban residents, and mediated through Vascular pat hology. Risk factors reported elsewhere but not confirmed in this stud y were advanced maternal age and winter season of birth.