Abstract
To evaluate the predictive effects of subjective measures of physical activity (PA) and objective measures of physical fitness (PF) on dementia risk, Participants of the prospective population-based ILSE-study (*1930-1932; 12-year follow-up) were examined at three examination waves (t1 : 1993/94; t2 : 1997/98; t3 : 2005/07). 381 subjects of the original cohort (n = 500) were re-examined at t3. 29% of the subjects who were cognitively healthy at baseline received the diagnosis of mild cognitive impairment (MCI) and 7% of Alzheimer's disease (AD). Subjects were screened for physical and mental health using medical interviews, physical, and neuropsychological examinations. Participants completed a questionnaire on their current and past PA at t1. Subjects were classified as physically active if they reported a regular sport activity for at least 2 hours per week in the past year. Muscular strength (handgrip) and motor coordination (balance) served as objective indicators of PF. Subjects who passed the balance-test at t1 had a reduced risk of developing MCI/AD at t3 (OR = 0.35, 95%CI 0.19–0.66, p < 0.01) and performed significantly better on various neuropsychological measures. Muscular strength or subjective reports of PA did not predict MCI/AD development. Our results confirm the hypothesis that PF acts as a protective factor for the development of cognitive disorders. In our study, context, motor coordination served as a better predictor than muscular strength or self-rated PA. Since subjects with cognitive disorders due to cerebral and/or systemic disorders were excluded from the analyses, our findings suggest that the effect of skill-related PF extends beyond the reduction of cardiovascular risk factors.