Environmental risk factors for Alzheimer's disease: their relationship to age of onset and to familial or sporadic types.

Data from a case-control study of Alzheimer's disease (AD) were analysed in relation to age of onset and familial/sporadic status. The analyses were restricted to environmental exposures which might injure the brain. Later-onset AD was found to be positively associated with starvation/malnutrition and with nose-picking and negatively with analgesics, while earlier-onset was associated with physical underactivity and nervous breakdown more than 10 years before. Sporadic AD was associated with starvation/malnutrition and with head injury. These analyses merit replication in other large case-control studies of AD.