***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: 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 prospect i ve 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 question naire 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 ( h and grip ) 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 BACKGROUND Participation in leisure activities has been associated with a lower risk of dementia .  It is unclear whether increased participation in leisure activities lowers the risk of dementia or participation in leisure activities declines during the pre clinical phase of dementia . METHODS We examined the relation between leisure activities and the risk of dementia in a prospect i ve cohort of 469 subjects older than 75 years of age who resided in the community and did not have dementia at base line . We examined the frequency of participation in leisure activities at enrollment and derived  cognitive-activity and physical-activity scales in which the units of measure were activity-days per week . Cox proportional-hazards analysis was used to evaluate the risk of dementia according to the base-line level of participation in leisure activities , with adjustment for age , sex , educational level , presence or absence of chronic medical illnesses , and base-line cognitive status . RESULTS Over a median follow-up period of 5.1 years ,  dementia  developed in 124 subjects ( Alzheimer 's disease in 61 subjects , vascular dementia in 30 , mixed dementia in 25 , and other types of dementia in 8) . Among leisure activities , reading , playing board games , playing musical instruments , and dancing were associated with a reduced risk of dementia . A one-point increment in the cognitive-activity score was significantly associated with a reduced risk of dementia ( hazard ratio , 0.93 [ 95 percent confidence interval , 0.90 to 0.97 ] ) , but a one-point increment in the physical-activity score was not ( hazard ratio , 1.00 ) . The association with the cognitive-activity score persisted after the exclusion of the subjects with possible pre clinical dementia at base line . Results were similar for Alzheimer 's disease and vascular dementia . In linear mixed models , increased participation in cognitive activities at base line was associated with reduced rates of decline in memory . CONCLUSIONS Participation in leisure activities is associated with a reduced risk of dementia , even after adjustment for base-line cognitive status and after the exclusion of subjects with possible pre clinical dementia . Controlled trials are needed to assess the protective effect of cognitive leisure activities on the risk of dementia Background Older adults free of dementia but with subjective memory complaints ( SMC ) or mild cognitive impairment ( MCI ) are considered at increased risk of cognitive decline . Vascular risk factors ( VRF ) , including hypertension , heart disease , smoking , hypercholesterolemia and lack of physical activity ( PA ) have been identified as modifiable risk factors contributing to cognitive decline , and white matter hyperintensities ( WMH ) are associated with VRF , SMC and cognitive impairment . Findings from a growing number of clinical trials with older adults are providing strong evidence for the benefits of physical activity for maintaining cognitive function , but few studies are investigating these benefits in high-risk population s. The aim of AIBL Active is to determine whether a 24-month physical activity program can delay the progression of white matter changes on magnetic resonance imaging ( MRI ) . Methods / design This single-blind r and omized controlled trial ( RCT ) is offered to 156 participants , aged 60 and older , in the Melbourne arm of the Australian Imaging Biomarkers and Lifestyle Flagship Study of Aging ( AIBL ) . Participants must have SMC with or without MCI and at least one VRF . The PA intervention is a modification of the intervention previously trialed in older adults with SMC and MCI ( Fitness for the Ageing Brain Study ) . It comprises 24 months of moderate , home-based PA ( 150 minutes per week ) and a behavioral intervention package . The primary outcome measure will be change in WMH after 24 months on MRI . Cognition , quality of life , functional fitness , level of physical activity , plasma biomarkers for cerebrovascular disease and amyloid positron emission tomography ( PET ) imaging comprise secondary measures . Discussion Currently , there is no effective pharmacological treatment available to delay cognitive decline and dementia in older adults at risk . Should our findings show that physical activity can slow down the progression of WMH , this RCT would provide an important proof of concept . Since imbedded in AIBL this RCT will also be able to investigate the interaction between vascular and Alzheimer 's disease pathologies . Trial Registration Australia New Zeal and Clinical Trials Registry BACKGROUND Data regarding the relationship between physical activity and  cognitive impairment  are limited and controversial . We examined whether physical activity is associated with incident cognitive impairment during follow-up . METHODS As part of a community-based prospect i ve cohort study in southern Bavaria , Germany , 3903 participants older than 55 years were enrolled between 2001 and 2003 and followed up for 2 years .  Physical activity ( classified as no activity , moderate activity [ <3 times/wk ] , and high activity [ > or =3 times/wk ] ) , cognitive function ( assessed by the 6-Item Cognitive Impairment Test )  , and potential confounders were evaluated . The main outcome measure was incident cognitive impairment after 2 years of follow-up . RESULTS At baseline , 418 participants ( 10.7 % ) had cognitive impairment . After a 2-year follow-up , 207 of 3485 initially unimpaired subjects ( 5.9 % ) developed incident cognitive impairment . Compared with participants without physical activity , fully adjusted multiple logistic regression analysis showed a significantly reduced risk of incident cognitive impairment after 2 years for participants with moderate or high physical activity at baseline ( odds ratio [ OR ] , 0.57 ; 95 % confidence interval [ CI ] , 0.37 - 0.87 [ P = .01 ] ; and OR , 0.54 ; 95 % CI , 0.35 - 0.83 [ P = .005 ] ; respectively ) . Further sub analysis including participants ( n = 2029 ) without functional impairment and without prodromal phase of dementia result ed in an even higher reduction of risk of incident cognitive impairment for participants with moderate or high physical activity ( OR , 0.44 ; 95 % CI , 0.24 - 0.83 [ P = .01 ] ; and OR , 0.46 ; 95 % CI , 0.25 - 0.85 [ P = .01 ] ; respectively ) compared with no activity . CONCLUSION Moderate or high physical activity is associated with a reduced incidence of cognitive impairment after 2 years in a large population -based cohort of elderly subjects CONTEXT Evidence suggests that physical activity may be related to the clinical expression of dementia . Whether the association includes low-intensity activity such as walking is not known . OBJECTIVE To examine the association between walking and future risk of dementia in older men . DESIGN Prospect i ve cohort study . SETTING AND PARTICIPANTS Distance walked per day was assessed from 1991 to 1993 in 2257 physically capable men aged 71 to 93 years in the Honolulu-Asia Aging Study . Follow-up for incident dementia was based on neurological assessment at 2 repeat examinations ( 1994 - 1996 and 1997 - 1999 ) . MAIN OUTCOME MEASURES Overall dementia , Alzheimer disease , and vascular dementia . RESULTS During the course of follow-up , 158 cases of dementia were identified ( 15.6/1000 person-years ) . After adjusting for age , men who walked the least ( < 0.25 mile/d ) experienced a 1.8-fold excess risk of dementia compared with those who walked more than 2 mile/d ( 17.8 vs 10.3/1000 person-years ; relative hazard [ RH ] , 1.77 ; 95 % confidence interval [ CI ] , 1.04 - 3.01 ) . Compared with men who walked the most ( > 2 mile/d ) , an excess risk of dementia was also observed in those who walked 0.25 to 1 mile/d ( 17.6 vs 10.3/1000 person-years ; RH , 1.71 ; 95 % CI , 1.02 - 2.86 ) . These associations persisted after accounting for other factors , including the possibility that limited amounts of walking could be the result of a decline in physical function due to pre clinical dementia . CONCLUSIONS Findings suggest that walking is associated with a reduced risk of dementia . Promoting active lifestyles in physically capable men could help late-life cognitive function CONTEXT Both higher adherence to a Mediterranean-type diet and more physical activity have been independently associated with lower Alzheimer disease ( AD ) risk but their combined association has not been investigated . OBJECTIVE To investigate the combined association of diet and physical activity with AD risk . DESIGN , SETTING , AND PATIENTS Prospect i ve cohort study of 2 cohorts comprising 1880 community-dwelling elders without dementia living in New York , New York , with both diet and physical activity information available . St and ardized neurological and neuropsychological measures were administered approximately every 1.5 years from 1992 through 2006 . Adherence to a Mediterranean-type diet ( scale of 0 - 9 ; trichotomized into low , middle , or high ; and dichotomized into low or high ) and physical activity ( sum of weekly participation in various physical activities , weighted by the type of physical activity [ light , moderate , vigorous ] ; trichotomized into no physical activity , some , or much ; and dichotomized into low or high ) , separately and combined , were the main predictors in Cox models . Models were adjusted for cohort , age , sex , ethnicity , education , apolipoprotein E genotype , caloric intake , body mass index , smoking status , depression , leisure activities , a comorbidity index , and baseline Clinical Dementia Rating score . MAIN OUTCOME MEASURE Time to incident AD . RESULTS A total of 282 incident AD cases occurred during a mean ( SD ) of 5.4 ( 3.3 ) years of follow-up . When considered simultaneously , both  Mediterranean-type diet adherence  ( compared with low diet score , hazard ratio [ HR ] for middle diet score was 0.98 [ 95 % confidence interval { CI } , 0.72 - 1.33 ] ; the HR for high diet score was 0.60 [ 95 % CI , 0.42 - 0.87 ] ; P = .008 for trend ) and physical activity ( compared with no physical activity , the HR for some physical activity was 0.75 [ 95 % CI , 0.54 - 1.04 ] ; the HR for much physical activity was 0.67 [ 95 % CI , 0.47 - 0.95 ] ; P = .03 for trend ) were associated with lower AD risk . Compared with individuals neither adhering to the diet nor participating in physical activity ( low diet score and no physical activity ; absolute AD risk of 19 % ) , those both adhering to the diet and participating in physical activity ( high diet score and high physical activity ) had a lower risk of AD ( absolute risk , 12 % ; HR , 0.65 [ 95 % CI , 0.44 - 0.96 ] ; P = .03 for trend ) . CONCLUSION In this study , both higher Mediterranean-type diet adherence and higher physical activity were independently associated with reduced risk for AD Objective : This study evaluated the protective role of physical activity ( PA ) against  cognitive impairment ( CI ) in the oldest old ( age ≥ 85 ) . Method : Prospect i ve data on 66 optimally healthy , oldest old adults ( mean age  
    Output:
    
Conclusions Longitudinal observational studies show an association between higher levels of physical activity and a reduced risk of cognitive decline and dementia .