***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: BACKGROUND The order and magnitude of pathologic processes in Alzheimer 's disease are not well understood , partly because the disease develops over many years . Autosomal dominant Alzheimer 's disease has a predictable age at onset and provides an opportunity to determine the sequence and magnitude of pathologic changes that culminate in symptomatic disease . METHODS In this prospect i ve , longitudinal study , we analyzed data from 128 participants who underwent baseline clinical and cognitive assessment s , brain imaging , and cerebrospinal fluid ( CSF ) and blood tests .  We used the participant 's age at baseline assessment and the parent 's age at the onset of symptoms of Alzheimer 's disease to calculate the estimated years from expected symptom onset ( age of the participant minus parent 's age at symptom onset ) . We conducted cross-sectional analyses of baseline data in relation to estimated years from expected symptom onset in order to determine the relative order and magnitude of pathophysiological changes . RESULTS Concentrations of amyloid-beta (Aβ)(42 ) in the CSF appeared to decline 25 years before expected symptom onset . Aβ deposition , as measured by positron-emission tomography with the use of Pittsburgh compound B , was detected 15 years before expected symptom onset . Increased concentrations of tau protein in the CSF and an increase in brain atrophy were detected 15 years before expected symptom onset . Cerebral hypometabolism and impaired episodic memory were observed 10 years before expected symptom onset . Global cognitive impairment , as measured by the Mini-Mental State Examination and the Clinical Dementia Rating scale , was detected 5 years before expected symptom onset , and patients met diagnostic criteria for dementia at an average of 3 years after expected symptom onset . CONCLUSIONS We found that autosomal dominant Alzheimer 's disease was associated with a series of pathophysiological changes over decades in CSF biochemical markers of Alzheimer 's disease , brain amyloid deposition , and brain metabolism as well as progressive cognitive impairment . Our results require confirmation with the use of longitudinal data and may not apply to patients with sporadic Alzheimer 's disease . ( Funded by the National Institute on Aging and others ; DIAN Clinical Trials.gov number , NCT00869817 . ) BACKGROUND Adherence to a Mediterranean diet may improve longevity , but relevant data are limited . METHODS We conducted a population -based , prospect i ve investigation involving 22,043 adults in Greece who completed an extensive , vali date d , food-frequency question naire at base line .  Adherence to the traditional Mediterranean diet was assessed by a 10-point Mediterranean-diet scale that incorporated the salient characteristics of this diet ( range of scores , 0 to 9 , with higher scores indicating greater adherence ) . We used proportional-hazards regression to assess the relation between adherence to the Mediterranean diet and total mortality , as well as mortality due to coronary heart disease and mortality due to cancer , with adjustment for age , sex , body-mass index , physical-activity level , and other potential confounders . RESULTS During a median of 44 months of follow-up , there were 275 deaths . A higher degree of adherence to the Mediterranean diet was associated with a reduction in total mortality ( adjusted hazard ratio for death associated with a two-point increment in the Mediterranean-diet score , 0.75 [ 95 percent confidence interval , 0.64 to 0.87 ] ) . An inverse association with greater adherence to this diet was evident for both death due to coronary heart disease ( adjusted hazard ratio , 0.67 [ 95 percent confidence interval , 0.47 to 0.94 ] ) and death due to cancer ( adjusted hazard ratio , 0.76 [ 95 percent confidence interval , 0.59 to 0.98 ] ) . Associations between individual food groups contributing to the Mediterranean-diet score and total mortality were generally not significant . CONCLUSIONS Greater adherence to the traditional Mediterranean diet is associated with a significant reduction in total mortality BACKGROUND Subjects with a mild cognitive impairment ( MCI ) have a memory impairment beyond that expected for age and education yet are not demented . These subjects are becoming the focus of many prediction studies and early intervention trials . OBJECTIVE To characterize clinical ly subjects with MCI  cross-sectionally and longitudinally . DESIGN A prospect i ve , longitudinal inception cohort . SETTING General community clinic . PARTICIPANTS A sample of 76 consecutively evaluated subjects with MCI were compared with 234 healthy control subjects and 106 patients with mild Alzheimer disease ( AD ) , all from a community setting as part of the Mayo Clinic Alzheimer 's Disease Center/Alzheimer 's Disease Patient Registry , Rochester , Minn. MAIN OUTCOME MEASURES The 3 groups of individuals were compared on demographic factors and measures of cognitive function including the  Mini-Mental State Examination , Wechsler Adult Intelligence Scale-Revised , Wechsler Memory Scale-Revised , Dementia Rating Scale , Free and Cued Selective Reminding Test , and Auditory Verbal Learning Test .  Clinical classifications of dementia and AD were determined according to the Diagnostic and Statistical Manual of Mental Disorders , Revised Third Edition and the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer 's Disease and Related Disorders Association criteria , respectively . RESULTS The primary distinction between control subjects and subjects with MCI was in the area of memory , while other cognitive functions were comparable . However , when the subjects with MCI were compared with the patients with very mild AD , memory performance was similar , but patients with AD were more impaired in other cognitive domains as well . Longitudinal performance demonstrated that the subjects with MCI declined at a rate greater than that of the controls but less rapidly than the patients with mild AD . CONCLUSIONS Patients who meet the criteria for MCI can be differentiated from healthy control subjects and those with very mild AD . They appear to constitute a clinical entity that can be characterized for treatment interventions CONTEXT Higher adherence to a Mediterranean-type diet is linked to lower risk for mortality and chronic diseases , but its association with cognitive decline is unclear . OBJECTIVE To investigate the association of a Mediterranean diet with change in cognitive performance and risk for dementia in elderly French persons . DESIGN , SETTING , AND PARTICIPANTS Prospect i ve cohort study of 1410 adults ( > or = 65 years ) from Bordeaux , France , included in the Three-City cohort in 2001 - 2002 and reexamined at least once over 5 years .  Adherence to a Mediterranean diet ( scored as 0 to 9 ) was computed from a food frequency question naire and 24-hour recall . MAIN OUTCOME MEASURES Cognitive performance was assessed on 4 neuropsychological tests : the Mini-Mental State Examination ( MMSE ) , Isaacs Set Test ( IST ) , Benton Visual Retention Test ( BVRT ) , and Free and Cued Selective Reminding Test ( FCSRT ) . Incident cases of dementia ( n = 99 ) were vali date d by an independent expert committee of neurologists . RESULTS Adjusting for age , sex , education , marital status , energy intake , physical activity , depressive symptomatology , taking 5 medications/d or more , apolipoprotein E genotype , cardiovascular risk factors , and stroke , higher Mediterranean diet score was associated with fewer MMSE errors ( beta = -0.006 ; 95 % confidence interval [ CI ] , -0.01 to -0.0003 ; P = .04 for 1 point of the Mediterranean diet score ) . Performance on the IST , BVRT , or FCSRT over time was not significantly associated with Mediterranean diet adherence . Greater adherence as a categorical variable ( score 6 - 9 ) was not significantly associated with fewer MMSE errors and better FCSRT scores in the entire cohort , but among individuals who remained free from dementia over 5 years , the association for the highest compared with the lowest group was significant ( adjusted for all factors , for MMSE : beta = -0.03 ; 95 % CI , -0.05 to -0.001 ; P = .04 ; for FCSRT : beta = 0.21 ; 95 % CI , 0.008 to 0.41 ; P = .04 ) . Mediterranean diet adherence was not associated with the risk for incident dementia ( fully adjusted model : hazard ratio , 1.12 ; 95 % CI , 0.60 to 2.10 ; P = .72 ) , although power to detect a difference was limited . CONCLUSIONS Higher adherence to a Mediterranean diet was associated with slower MMSE cognitive decline but not consistently with other cognitive tests . Higher adherence was not associated with risk for incident dementia 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 XXXto assess the effect on cognition of a controlled intervention testing Mediterranean diets ( MedDiet ) . Design XXXr and omized trial after 6.5 years of nutritional intervention . Setting Eight primary care centers affiliated to the University of Navarra . Participants A r and om sub sample of 285 participants ( 95 r and omly allocated to each of 3 groups ) of the PREDIMED-NAVARRA trial . All of them were at high vascular risk ( 44.8 % men , 74.1± 5.7 years at cognitive evaluation ) . Interventions Nutritional intervention comparing two MedDiets ( supplemented with extra-virgin olive oil [ EVOO ] or mixed nuts ) versus a low-fat control diet . Participants received intensive education to increase adherence to the intended intervention . Participants allocated to the MedDiet groups received EVOO ( 1 l/week ) or 30 g/day of mixed nuts . Dietary habits were evaluated using a vali date d 137-item food frequency question naire ( FFQ ) . Additionally , adherence to MedDiet was appraised using a 14-item question naire both at baseline and yearly thereafter . Measurements XXXcognitive performance as a main outcome and cognitive status ( normal , mild cognitive impairment [ MCI ] or dementia ) as a secondary outcome were evaluated by two neurologists blinded to group assignment after 6.5 years of nutritional intervention . Results Better post-trial cognitive performance versus control in all cognitive domains and significantly better performance across fluency and memory tasks were observed for participants allocated to the MedDiet+EVOO group . After adjustment for sex , age , education , apolipoprotein E genotype , family history of cognitive impairment/dementia , smoking , physical activity , body mass index , hypertension , dyslip 
    Output:
    
While the overall number of studies is small , pooled results suggest that a higher adherence to the MeDi is associated with a reduced risk of developing MCI and AD , and a reduced risk of progressing from MCI to AD .