ORIGINAL CONTRIBUTION Walking and Dementia in Physically Capable Elderly Men

PHYSICAL AND ENVIRONMENTALfactors associated with the riskof dementia remain largelyundefined. Although equivo-cal, evidencesuggests thatphysical activ-itymayhavearelationshipwith theclini-cal expression of dementia.1-7 Whether the association includes low-intensity activity such as regular walking is not known. One study showed that a com-positemeasure of physical activity, par-tially basedonwalkinghistories, is asso-ciated with a reduced risk of dementia.1 In a large cohort of women, those who walked more had significantly smaller declines in amodifiedMini-Mental State Examination score over a 6- to 8-year periodof follow-up.2Othersdescriberela-tions that areweakwhile also providing contrastingevidenceforanimportantand protectiveeffectof cognitiveactivitieson riskofdementia.8-10Whilecognitiveactiv-ity appears to be a predictor of future dementia, overlapwithphysical activity maymake it difficult to detect a relation between walking and dementia. The purpose of this report is to ex-amine the association between walk-ing and future risk of dementia. Find-ings are based on a sample of physically capable elderlymen enrolled in theHo-nolulu-Asia Aging Study. To account for the possibility that limited amounts of walking in late life could be the re-sult of a decline in physical functiondue to preclinical dementia, adjustments were made for genetic susceptibility to dementia, cognitive performance, and declines in physical activity since mid adulthood