Walsh & Hoyt: Alzheimer's Disease

Alzheimer's disease (AD) is the most common dementia in many countries throughout the world. It was initially described in 1907 in a 51-year-old woman who had a progressive dementing illness and senile plaques and neurofibrillary tangles at postmortem. Epidemiologic data suggest that the incidence of AD is similar everywhere in the world. It is an age-related disorder, its incidence doubling every 5 years after the age of 65. More women are affected than men, probably reflecting their longer life expectancy. A surprising factor is that the prevalence of AD is much greater among illiterate persons, but paradoxically there is an increased mortality in patients with more advanced educational and occupational attainment. Other factors, including head injury, depression, thyroid disease, and parental age at birth, are thought to be associated with an increased incidence of AD, but these factors require confirmation.