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To observe the relationship between physical and mental activities and dementia risk over longer time spans, a team of Swedish researchers evaluated 800 women from the Prospective Population Study of Women in Gothenburg, which looks at factors that can influence the development of cardiovascular disease, diabetes, cancer, and dementia in old age.
Researchers followed participants, whose average age was 47 at the start of the study, for 44 years, from 1968 to 2012. In 1968, participants answered a series of questions that assessed five cognitive activities: intellectual (reading and writing), artistic (concert or singing in a choir), manual (needlework or gardening), club (membership), and religious (church attendance), with activity frequency rated as no or low (score 0), moderate (score 1), or high (score 2).
For example, moderate intellectual activity was defined as reading a book in the last six months; high intellectual activity was defined as reading more frequently or writing. The total possible score was 10. Researchers divided participants into two groups: 44 percent were in the low group with scores of 0 to 2, 56 percent were in the high group with scores of 3 to 10.
To measure physical activity, the researchers asked participants to choose one option—physically inactive, light physical activity, regular activity and training, or training for competition—that reflected how much they exerted themselves physically in the past year. Based on their options, the participants were divided into either an active (82 percent) or an inactive group (17 percent).
The active group participated in activities that ranged from walking, gardening, bowling, or biking at least four hours a week, to regular intense exercise like running or swimming several times a week or competitive sports. The inactive group participated in more sedentary activities, including watching television or movies.
Neuropsychiatric examinations to detect and diagnose dementia were administered by psychiatrists every five years between 1968 and 1993, and by psychiatric research nurses between 2000 and 2010.
Over the span of 44 years, 194 women developed dementia: 102 had Alzheimer's disease; 27 had vascular dementia; 41 had mixed dementia; and 81 had dementia with cerebrovascular disease. The average age at onset was 80.
Women who were more mentally active were 46 percent less likely to develop Alzheimer's disease and 34 percent less likely to develop dementia than women who were less mentally active.
Women who were physically active were 52 percent less likely to develop dementia with cerebrovascular disease and 56 percent less likely to develop mixed dementia compared to their inactive counterparts.
