title: Aerobic exercise increases hippocampal volume in older women with probable mild cognitive impairment: a 6-month randomised controlled trial Apolipoprotein E ε4 magnifies lifestyle risks for dementia: a population-based study Too much sitting: the population health science of sedentary behavior. Physical activity and risk of cognitive impairment and dementia in elderly persons. Exercise is medicine, for the body and the brain Rates and risk factors for dementia and Alzheimer’s disease Power and sample size calculations. A review and computer program. Memory evaluation with a new cued recall test in patients with mild cognitive impairment and Alzheimer’s disease Self-administered questionnaire compared with interview to assess past-year physical activity. Calibration of the Computer Science and Applications, Inc. accelerometer.
abstract: Background Mild cognitive impairment ( MCI ) is a well-recognised risk factor for dementia and represents a vital opportunity for intervening . Exercise is a promising strategy for combating cognitive decline by improving brain structure and function . Specifically , aerobic training ( AT ) improved spatial memory and hippocampal volume in healthy community-dwelling older adults . In older women with probable MCI , we previously demonstrated that resistance training ( RT ) and AT improved memory . In this secondary analysis , we investigated : ( 1 ) the effect of RT and AT on hippocampal volume and ( 2 ) the association between change in hippocampal volume and change in memory . Methods 86 women aged 70–80 years with probable MCI were r and omly assigned to a 6-month , twice-weekly programme of : ( 1 ) AT , ( 2 ) RT or ( 3 ) balance and tone training ( BAT ; ie , control ) . At baseline and trial completion , participants performed a 3 T MRI scan to determine hippocampal volume . Verbal memory and learning were assessed by Rey 's Auditory Verbal Learning Test . Results Compared with the BAT group , AT significantly improved left , right and total hippocampal volumes ( p≤0.03 ) . After accounting for baseline cognitive function and experimental group , increased left hippocampal volume was independently associated with reduced verbal memory and learning performance as indexed by loss after interference ( r=0.42 , p=0.03 ) . Conclusions Aerobic training significantly increased hippocampal volume in older women with probable MCI . More research is needed to ascertain the relevance of exercise-induced changes in hippocampal volume on memory performance in older adults with MCI . Trail registration number NCT00958867 The risk of dementia and Alzheimer 's disease ( AD ) probably results from an interaction between genetic and environmental factors . The aim of this study was to investigate the effects and putative interactions between the apoE ε4 allele and lifestyle related risk factors for dementia and AD . Participants of the Cardiovascular Risk Factors , Aging , and Dementia ( CAIDE ) study were derived from r and om , population -based sample s previously studied in 1972 , 1977 , 1982 or 1987 . After an average follow-up of 21 years , 1449 individuals ( 72.5 % ) aged 65–79 years were re-examined in 1998 . The apoE ε4 allele was an independent risk factor for dementia/AD even after adjustments for sociodemographic , lifestyle and vascular factors ( odds ratio [OR]= 2.83 , 95 % confidence interval [CI]ε1.61–4.97 ) . Physical inactivity , alcohol drinking and smoking increased the risk of dementia/AD particularly among the apoE ε4 carriers . Furthermore , low – moderate intake of polyunsaturated , and moderate – high intake of saturated fats were associated with an increased risk of dementia/AD more pronouncedly among apoE ε4 carriers . Composite effect of the lifestyle factors was particularly seen among the ε4 carriers ( OR = 11.42 , 95 % CI = 1.94–67.07 in the 4th quartile ) . Physical inactivity , dietary fat intake , alcohol drinking and smoking at midlife are associated with the risk of dementia and AD , especially among the apoE ε4 carriers . The apoE ε4 carriers may be more vulnerable to environmental factors , and thus , lifestyle interventions may greatly modify dementia risk particularly among the genetically susceptible individuals Even when adults meet physical activity guidelines , sitting for prolonged periods can compromise metabolic health .  Television ( TV ) time and objective measurement studies show deleterious associations , and breaking up sedentary time is beneficial .  Sitting time , TV time , and time sitting in automobiles increase premature mortality risk . Further evidence from prospect i ve studies , intervention trials , and population -based behavioral studies is required CONTEXT Dementia is common , costly , and highly age related . Little attention has been paid to the identification of modifiable lifestyle habits for its prevention . OBJECTIVE To explore the association between physical activity and the risk of cognitive impairment and dementia .  DESIGN , SETTING , AND SUBJECTS Data come from a community sample of 9008 r and omly selected men and women 65 years or older , who were evaluated in the 1991 - 1992 Canadian Study of Health and Aging , a prospect i ve cohort study of dementia . Of the 6434 eligible subjects who were cognitively normal at baseline , 4615 completed a 5-year follow-up .  Screening and clinical evaluations were done at both waves of the study . In 1996 - 1997 , 3894 remained without cognitive impairment , 436 were diagnosed as having cognitive impairment-no dementia , and 285 were diagnosed as having dementia . MAIN OUTCOME MEASURE Incident cognitive impairment and dementia by levels of physical activity at baseline . RESULTS Compared with no exercise , physical activity was associated with lower risks of cognitive impairment , Alzheimer disease , and dementia of any type . Significant trends for increased protection with greater physical activity were observed . High levels of physical activity were associated with reduced risks of cognitive impairment ( age- , sex- , and education-adjusted odds ratio , 0.58 ; 95 % confidence interval , 0.41 - 0.83 ) , Alzheimer disease ( odds ratio , 0.50 ; 95 % confidence interval , 0.28 - 0.90 ) , and dementia of any type ( odds ratio , 0.63 ; 95 % confidence interval , 0.40 - 0.98 ) . CONCLUSION Regular physical activity could represent an important and potent protective factor for cognitive decline and dementia in elderly persons Cognitive decline is one of the most pressing healthcare issues of the 21st century . Worldwide , one new case of major cognitive decline ( ie , dementia ) is detected every 4 s.1 Given that no effective pharmacological treatment to alter the progress of cognitive decline exists , there is much interest in lifestyle approaches for preventing or treating dementia . Ideally , such strategies should be cost-efficient and widely accessible at a societal level to have the largest benefit for older adults with varying income and functional status levels . One attractive solution that aligns with the above criteria is exercise . However , despite a large and consistent pool of evidence generated over the past five decades linking exercise to improved cognitive functions in older adults,2 there is a reluctance among academics , healthcare practitioners and the public alike to embrace exercise as a prevention and treatment strategy for cognitive decline . For example , the National Institutes of Health ( NIH ) consensus statement from 20103 concedes that there appears to be preliminary data to support the efficacy of exercise in improving cognitive function . However , they caution that there is currently no strong evidence to suggest that modifiable lifestyle factors can alter the trajectory of cognitive decline . Adding fuel to the fire are publications such as a 2013 systematic review of r and omised controlled trials ( RCTs ) ( prior to 31 October 2011 ) reporting ‘ weak ’ evidence for the effects of exercise on cognition.4 We must highlight that the search strategy used in that systematic review failed to capture many pertinent papers providing evidence from RCTs that exercise  promotes cognitive and brain plasticity not only in healthy older adults but also in those with cognitive impairment . Furthermore , there are a number of animal studies that provide insight into the molecular and cellular mechanisms by which exercise  promotes neuroplasticity.5 In a previous commentary , Objective : To investigate the risk of AD associated with a family history of dementia , female gender , low levels of education , smoking , and head trauma . Background : These putative factors have been identified in cross-sectional studies . However , those studies are prone to bias due to systematic differences between patients and control subjects regarding survival and how risk factors are recalled . Methods : The authors performed a pooled analysis of four European population -based prospect i ve studies of individuals 65 years and older , with 528 incident dementia patients and 28,768 person-years of follow-up . Patients were detected by screening the total cohort with brief cognitive tests , followed by a diagnostic assessment of those who failed the screening tests . Dementia was diagnosed with the Diagnostic and Statistical Manual of Mental Disrders , 3rd ed . ( revised ) , and AD was diagnosed according to National Institute of Neurological and Communicative Disorders and Stroke – Alzheimer ’s Disease and Related Disorders Association criteria . Incident rates and relative risk ( 95 % CI ) express the association of a risk factor for dementia . Results : Incident rates for dementia and AD were similar across studies . The incidence of AD increased with age . At 90 years of age and older the incidence was 63.5 ( 95 % CI , 49.7 to 81.0 ) per 1,000 person-years . Female gender , current smoking ( more strongly in men ) , and low levels of education ( more strongly in women ) increased the risk of AD significantly . A history of head trauma with unconsciousness and family history of dementia did not increase risk significantly . Conclusion : Contrary to previous reports , head trauma was not a risk factor for AD , and smoking did not protect against AD . The association of family history with the risk of AD is weaker than previously estimated on the basis of cross-sectional studies . Female gender may modify the risk of AD , whether it be via biological or behavioral factors Methods of sample size and power calculations are review ed for the most common study design s. The sample size and power equations for these design s are shown to be special cases of two generic formulae for sample size and power calculations . A computer program is available that can be used for studies with dichotomous , continuous , or survival response measures . The alternative hypotheses of interest may be specified either in terms of differing response rates , means , or survival times , or in terms of relative risks or odds ratios . Studies with dichotomous or continuous outcomes may involve either a matched or independent study design . The program can determine the sample size needed to detect a specified alternative hypothesis with the required power , the power with which a specific alternative hypothesis can be detected with a given sample size , or the specific alternative hypotheses that can be detected with a given power and sample size . The program can generate help messages on request that facilitate the use of this software . It writes a log file of all calculated estimates and can produce an output file for plotting power curves . It is written in FORTRAN-77 and is in the public domain Free delayed recall is considered the memory measure with the greatest sensitivity for the early diagnosis of dementia . However , its specificity for dementia could be lower , as deficits other than those of pure memory might account for poor performance in this difficult and effortful task . Cued recall is supposed to allow a better distinction between poor memory due to concurrent factors and impairments related to the neurodegenerative process . The available cued recall tests suffer from a ceiling effect . This is a prospect i ve , longitudinal study aim ing to assess the utility of a new memory test based on cued recall that avoids the ceiling effect in the early diagnosis of Alzheimer ’s disease ( AD ) . Twenty-five patients with mild cognitive impairment ( MCI ) , 22 probable AD patients ( NINCDS-ADRDA ) at a mild stage , 22 elderly patients with subjective memory complaints ( SMC ) and 38 normal age-matched controls took part in the study . The patients underwent a thorough cognitive evaluation and the recommended screening procedure for the diagnosis of dementia . All patients were re-examined 12–18 months later . A newly devised delayed cued recall test using semantic cues ( The RI48 Test ) was compared with three established memory tests : the Ten Word-List Recall  from CERAD , the “ Doors ” and the “ Shapes ” Tests from “ The Doors and People Test Battery ” . Forty-four % of the MCI patients fulfilled criteria for probable AD at follow-up . The RI48 Test classified correctly 88 % of the MCI and SMC participants and was the best predictor of the status of MCI and mild AD as well as the outcome of the MCI patients . Poor visual memory was the second best predictor of those MCI patients who evolved to AD . A cued recall test which avoids the ceiling effect is at least as good as the delayed free recall tests in the early detection of AD PURPOSE The Modifiable Activity Question naire ( MAQ ) is a physical activity question naire shown to be both valid and reliable and was initially design ed to be interviewer-administered . After translation and adaptation into French , the objective of the study was to compare past-year physical activity data obtained by self-administration of this question naire and by interviewer-administration . METHODS 84 subjects ( 22 men , 62 women , age 36 - 63 yr ) enrolled in an ongoing prospect i ve study in France ( the SUpplementation en VItamines et Minéraux AntioXydants or SU.VI.MAX study ) completed both versions of the question naire in a r and omized order with a mean ( SD ) delay of 7.9 ( 5.8 ) d between the two modes . Past-year leisure and occupational physical activity were expressed as both h x wk(-1 ) and MET-h x wk(-1 ) of activity , and television watching was expressed as h x d(-1 ) . Analysis of variance on ranks was used to compare activity variables obtained by self-administration and interview . Agreement was assessed by nonparametric intraclass correlation coefficients . RESULTS A significant effect of the mode of administration was found only for past-year leisure physical activity with lower values reported in self-administered conditions compared with interview . However , a high level of concordance between the two modes of administration was observed for all variables as shown by the intraclass correlation coefficients : 0.90 for leisure physical activity ( h x wk(-1 ) ) , 0.82 for occupational activity ( h x wk(-1 ) ) , 0.83 for total ( leisure and occupational combined ) physical activity ( h x wk(-1 ) ) , and 0.97 for television viewing ( h x d(-1 ) ) . CONCLUSIONS The agreement between the two modes of administration of the question naire suggests that the self-administered version of the MAQ is a valuable tool to assess past-year physical activity and inactivity in self-administered conditions . This instrument could be used in large-scale population studies investigating the relationships between physical activity and health outcomes PURPOSE We established accelerometer count ranges for the Computer Science and Applications , Inc. ( CSA ) activity monitor corresponding to commonly employed MET categories . METHODS Data were obtained from 50 adults ( 25 males , 25 females ) during treadmill exercise at three different speeds ( 4.8 , 6.4 , and 9.7 km x h(-1 ) ) . RESULTS Activity counts and steady-state oxygen consumption were highly correlated ( r = 0.88 ) , and count ranges corresponding to light , moderate , hard , and very hard intensity levels were < or = 1951 , 1952 - 5724 , 5725 - 9498 , > or = 9499 cnts x min(-1 ) , respectively . A model to predict energy expenditure from activity counts and body mass was developed using data from a r and om sample of 35 subjects ( r2 = 0.82 , SEE = 1.40 kcal x min(-1 ) ) . Cross validation with data from the remaining 15 subjects revealed no significant differences between actual and predicted energy expenditure at any treadmill speed ( SEE = 0.50 - 1.40 kcal x min(-1 ) ) . CONCLUSIONS These data provide a template on which patterns of activity can be classified into intensity levels using the CSA accelerometer
target: Summary Sedentary behaviour is associated with lower cognitive performance , although the attributable risk of sedentary time to all-cause dementia incidence is unclear .
  Our systematic review provides evidence that limiting sedentary time and concomitantly engaging in regular moderate-to-vigorous physical activity may best promote healthy cognitive ageing
background: Aim The increasing rate of all-cause dementia worldwide and the lack of effective pharmaceutical treatments emphasise the value of lifestyle approaches as prevention strategies .
  Emerging evidence suggests sedentary behaviour is associated with impaired cognitive function .
  A better underst and ing of this association would significantly add to our knowledge of how to best promote healthy cognitive ageing .
  Thus , we conducted a systematic review ascertaining the contribution of sedentary behaviour towards associated changes in cognitive function over the adult lifespan .