Patients with Alzheimer's disease have reduced activities in midlife compared with healthy control-group members

The development of Alzheimer's disease (AD) later in life may be reflective of environmental factors operating over the course of a lifetime. Educatio nal and occupational attainments have been found to be protective against t he development of the disease but participation in activities has received little attention. In a case-control study, we collected questionnaire data about 26 nonoccupational activities from ages 20 to 60. Participants includ ed 193 people with probable or possible AD and 358 healthy control-group me mbers. Activity patterns for intellectual, passive, and physical activities were classified by using an adaptation of a published scale in terms of "d iversity" (total number of activities), "intensity" (hours per month), and "percentage intensity" (percentage of total activity hours devoted to each activity category). The control group was more active during midlife than t he case group was for all three activity categories, even after controlling for age, gender, income adequacy, and education. The odds ratio for AD in those performing less than the mean value of activities was 3.85 (95% confi dence interval: 2.65-5.58, P < 0.001). The increase in time devoted to inte llectual activities from early adulthood (20-39) to middle adulthood (40-60 ) was associated with a significant decrease in the probability of membersh ip in the case group. We conclude that diversity of activities and intensit y of intellectual activities were reduced in patients with AD as compared w ith the control group. These findings may be because inactivity is a risk f actor for the disease or because inactivity is a reflection of very early s ubclinical effects of the disease, or both.