Walking Linked to a Reduced Risk of Dementia in Older Men
Robert D. Abbott, PhD, and colleagues found that walking is associated with a reduced risk of dementia in older men. Results from their prospective cohort study published in a recent issue of the Journal of the American Medical Association, as well as past evidence, suggest that walking and active lifestyles in general both show this association with lower dementia risk.
Distance walked per day was ascertained at the beginning of follow-up (1991-1993) in 2257 physically capable men ranging in age from 71 to 93 years in the Honolulu-Asia Aging Study. Participants were considered to be physically capable if they presented for a baseline clinical examination and reported engaging in slight or moderate activities in an ordinary 24-hour period.
Initial screening for dementia in this cohort involved the participants’ age and cognitive performance as measured by the Cognitive Abilities Screening Instrument (CASI); scores range from 0-100, with high scores indicating better cognitive function. This screening instrument was administered twice at baseline (1991-1993) as part of three phases of screening. Men who scored < 74 were asked to participate in a second phase. If their CASI scores were < 74 at phase 2, or if their scores on the Informant Questionnaire on COgnitive Decline in the Elderly (IQCODE) were > 3.6, participants were requested to have a complete dementia assessment.
For the two follow-up examinations (1994-1996 and 1997-1999), which identified incident cases of dementia, the CASI was administered once. For the first exam, complete dementia assessment was recruited for those in whom one of the following occurred: repeat CASI score decreased at least 9 points from baseline; repeat CASI score was < 77 and the participant had < 12 years of education; or repeat CASI score was < 79 and the participant had > 12 education. Complete dementia assessment was required at the second follow-up for those with CASI scores < 70. For a diagnosis of dementia, researchers took into account a history given by participants’ family, standardized neuropsychological evaluation, and a thorough neurological examination; laboratory findings and computed tomography were also used. During this follow-up, 158 cases of dementia were identified (15.6/1000 person-years). After adjustments were made for age, men who walked < 0.25 miles per day experienced a 1.8-fold excess risk of dementia compared with those who walked > 2 miles per day (17.8 vs 10.3/1000 person-years; RH, 1.77; 95% CI, 1.04-3.01). An excess risk of dementia was also observed in participants who walked 0.25-1 miles per day compared with those who walked > 2 miles per day (17.6 vs 10.3/1000 person-years; RH, 1.71; 95% CI, 1.02-2.86). These trends persisted after researchers accounted for other factors including the possibility that less walking could be the result of a decline in physical function caused by preclinical dementia. The authors concluded that promoting active lifestyles in physically capable men may help late-life cognitive function.