MIND not Mediterranean diet related to 12-year incidence of cognitive impairment in an Australian longitudinal cohort study.

INTRODUCTION: Associations between the Mediterranean-DASH diet Intervention for Neurological Delay (MIND) diet and incidence of cognitive impairment have not been evaluated outside the United States. METHODS: We investigated MIND and Mediterranean diet relations with 12-year incidence of Alzheimer's disease/Vascular dementia (National Institute of Neurological Disorders criteria) and mild cognitive impairment (Winbald criteria) in the Personality and Total Health (PATH) Through Life cohort (n = 1220) set in Canberra, Australia: wave-1 2001-2002; wave-2 2005-2006; wave-3 2009-2010; and wave-4 2013-2014. MIND diet and two alternate Mediterranean diet scores were calculated from the baseline food frequency questionnaire responses. Higher dietary scores signified greater adherence. RESULTS: In adjusted logistic regression models, MIND diet (OR = 0.47, 95% CI 0.24, 0.91), but not Mediterranean diet, was associated with reduced odds of 12-year cognitive impairment. DISCUSSION: Preliminary evidence suggests that protective effects of the MIND diet are geographically generalizable. Additional prospective studies are needed in diverse samples to determine the relative effects of the MIND and the Mediterranean diets against cognitive decline.

Informant-Reported Cognitive Decline and Activity Engagement across Four Years in a Community Sample.

BACKGROUND: Subtle age-related cognitive decline may be associated with the capacity to remain engaged in mental, physical, and social activities. Informant reports of cognitive decline potentially provide additional information to psychometric tests on change in everyday cognitive function relevant to activity engagement. OBJECTIVE: To investigate relations between decline in everyday cognitive function as assessed by informant report and activity engagement in community-dwelling older adults. METHODS: A sample of cognitively normal older adults was drawn from the 2 latest waves of the PATH Through Life Study (n = 1,391; mean age 74.5 ± 1.5, 48.4% female). PATH is a 16-year longitudinal cohort study set in the Canberra/Queanbeyan district, Australia. Assessments were carried out at baseline, and at 3 subsequent time-points 4 years apart. At wave-4, the IQCODE, an informant measure of 4-year cognitive decline was provided by a spouse, family member, or friend of each participant. Activity engagement was assessed by the abbreviated RIASEC Mental Activity List, self-reported frequency and duration of physical activity (Whitehall Questionnaire) and the Lubben Social Network Scale that assessed interaction with family/friends. Participants provided demographic information, self-reported health status (SF-12), and responses to the Goldberg Depression Scale. The Symbol Digit Modalities Test (SDMT) and California Verbal Learning Test (CVLT) were used to measure objective 4-year cognitive change. Those with MMSE score of ≤27 were excluded. RESULTS: IQCODE score predicted disengagement from mental activities over 4 years in cognitively healthy adults (ß = -0.056, standard error [SE] = 0.019, p = 0.004). This association was robust to covariate control and change on the SDMT which was also significantly related to mental activity disengagement. In models adjusted for change scores on the SDMT and the CVLT, the IQCODE was associated with less physical (ß = -0.692, SE = 0.24, p = 0.004) and social engagement (ß -0.046, SE = 0.021, p = 0.032), but relationships were attenuated with the inclusion of covariates. CONCLUSION: Informant-reported cognitive decline in a non-clinical sample was linked to activities that support cognitive health. Associations were robust to adjustment for cognitive change scores. Utilising informant reports prior to the manifestation of clinically relevant decline may identify those who would benefit most from personalised activity interventions.

The Economics of Cognitive Impairment: Volunteering and Cognitive Function in the HILDA Survey.

BACKGROUND: The economic impact of older-age cognitive impairment has been estimated primarily by the direct and indirect costs associated with dementia care. Other potential costs associated with milder cognitive impairment in the community have received little attention. OBJECTIVE: To quantify the cost of nonclinical cognitive impairment in a large population-based sample in order to more fully inform cost-effectiveness evaluations of interventions to maintain cognitive health. METHODS: Volunteering by seniors has economic value but those with lower cognitive function may contribute fewer hours. Relations between hours volunteering and cognitive impairment were assessed using the Household, Income and Labour Dynamics in Australia (HILDA) survey data. These findings were extrapolated to the Australian population to estimate one potential cost attributable to nonclinical cognitive impairment. RESULTS: In those aged ≥60 years in HILDA (n = 3,127), conservatively defined cognitive impairment was present in 3.8% of the sample. Impairment was defined by performance ≥1 standard deviation below the age- and education-adjusted mean on both the Symbol Digit Modalities Test and Backwards Digit Span test. In fully adjusted binomial regression models, impairment was associated with the probability of undertaking 1 h 9 min less volunteering a week compared to being nonimpaired (ß = -1.15, 95% confidence interval -1.82 to -0.47, p = 0.001). In the population, 3.8% impairment equated to probable loss of AUD 302,307,969 per annum estimated by hours of volunteering valued by replacement cost. CONCLUSION: Nonclinical cognitive impairment in older age impacts upon on the nonmonetary economy via probable loss of volunteering contribution. Valuing loss of contribution provides additional information for cost-effectiveness evaluations of research and action directed toward maintaining older-age cognitive functioning.

Cognitive performance in older adults is inversely associated with fish consumption but not erythrocyte membrane n-3 fatty acids.

Higher n-3 (ω-3) polyunsaturated fatty acids (PUFAs) and fish intake may help maintain cognitive function in older age. However, evidence is inconsistent; few studies have examined the relation in cognitively healthy individuals across numerous cognitive domains, and none to our knowledge have considered lifetime fish intake. We examined associations between multiple domains of cognition and erythrocyte membrane n-3 PUFA proportions and historical and contemporary fish intake in 390 normal older adults, analyzing baseline data from the Older People, Omega-3, and Cognitive Health trial. We measured n-3 PUFA in erythrocyte membranes, and we assessed historical and contemporary fish intake by food-frequency questionnaires. We assessed cognitive performance on reasoning, working memory, short-term memory, retrieval fluency, perceptual speed, simple/choice reaction time, speed of memory-scanning, reasoning speed, inhibition, and psychomotor speed. Cognitive outcomes for each construct were factor scores from confirmatory factor analysis. Multiple linear regression models controlled for a number of potential confounding factors, including age, education, sex, apolipoprotein E-ε 4 allele, physical activity, smoking, alcohol intake, socioeconomic variables, and other health-related variables. Higher erythrocyte membrane eicosapaentonoic acid proportions predicted slower perceptual and reasoning speed in females, which was attenuated once current fish intake was controlled. No other associations were present between n-3 PUFA proportions and cognitive performance. Higher current fish consumption predicted worse performance on several cognitive speed constructs. Greater fish consumption in childhood predicted slower perceptual speed and simple/choice reaction time. We found no evidence to support the hypothesis that higher proportions of long-chain n-3 fatty acids or fish intake benefits cognitive performance in normal older adults.

Retrospective lifetime dietary patterns predict cognitive performance in community-dwelling older Australians.

Dietary intake is a modifiable exposure that may have an impact on cognitive outcomes in older age. The long-term aetiology of cognitive decline and dementia, however, suggests that the relevance of dietary intake extends across the lifetime. In the present study, we tested whether retrospective dietary patterns from the life periods of childhood, early adulthood, adulthood and middle age predicted cognitive performance in a cognitively healthy sample of 352 older Australian adults >65 years. Participants completed the Lifetime Diet Questionnaire and a battery of cognitive tests designed to comprehensively assess multiple cognitive domains. In separate regression models, lifetime dietary patterns were the predictors of cognitive factor scores representing ten constructs derived by confirmatory factor analysis of the cognitive test battery. All regression models were progressively adjusted for the potential confounders of current diet, age, sex, years of education, English as native language, smoking history, income level, apoE ɛ4 status, physical activity, other past dietary patterns and health-related variables. In the adjusted models, lifetime dietary patterns predicted cognitive performance in this sample of older adults. In models additionally adjusted for intake from the other life periods and mechanistic health-related variables, dietary patterns from the childhood period alone reached significance. Higher consumption of the 'coffee and high-sugar, high-fat extras' pattern predicted poorer performance on simple/choice reaction time, working memory, retrieval fluency, short-term memory and reasoning. The 'vegetable and non-processed' pattern negatively predicted simple/choice reaction time, and the 'traditional Australian' pattern positively predicted perceptual speed and retrieval fluency. Identifying early-life dietary antecedents of older-age cognitive performance contributes to formulating strategies for delaying or preventing cognitive decline.

Retrospective lifetime dietary patterns are associated with demographic and cardiovascular health variables in an older community-dwelling Australian population.

Dietary patterns derived from factor analytic procedures have been demonstrated to predict demographic and health outcomes across a wide range of populations. To examine the potential utility of long-term dietary recall, in the present study, we examined associations between dietary patterns from across the lifespan and demographic and later-life cardiovascular-related health variables, using the Lifetime Diet Questionnaire (LDQ). The LDQ is a self-administered, non-quantitative, retrospective FFQ designed to assess dietary intake from childhood to older age. Participants (n 352) from the Older People, Omega-3 and Cognitive Health trial, aged 65-91 years, completed the LDQ. Exploratory factor analysis was conducted on the LDQ and plausible dietary patterns were derived. As a result, three patterns were extracted from each life period, with five distinct patterns overall; these were 'traditional Australian' and 'non-traditional Australian', 'high-sugar and high-fat', 'vegetable' and 'fruit and vegetable' patterns. In separate adjusted regression models, age, sex, education, income, parental background and childhood physical activity all significantly predicted dietary patterns across the lifespan. A 'traditional Australian' pattern in childhood predicted higher HDL-cholesterol levels and lower odds of cholesterol medication use; lower HDL-cholesterol levels were predicted by the adult 'processed, high-sugar and high-fat' pattern, and higher intake of a 'non-traditional Australian' pattern in adulthood also predicted lower odds of using cardiac medications. Lifetime dietary recall, as instantiated by the LDQ, provides a hitherto untapped source of long-term dietary information in older adults that may contribute to greater understanding of the impact exerted by early-life and cumulative dietary choices on later-life health.

Assessing lifetime diet: reproducibility of a self-administered, non-quantitative FFQ.

OBJECTIVE: To demonstrate test-retest reliability (reproducibility) of a new self-administered lifetime diet questionnaire, with a focus on foods relevant to cognitive health in older age. DESIGN: The reproducibility of dietary recall over four or five life periods was assessed by administering the questionnaire at two time points to an older cohort. The period between questionnaire administrations was 7 weeks. Polychoric correlations measured the association between recall at time 1 and time 2 and the weighted κ statistic measured the level of recall agreement for food groups across the two administrations of the questionnaire. SETTING: Adelaide, South Australia. SUBJECTS: Fifty-two cognitively healthy, older-age, community-dwelling adults completed the Lifetime Diet Questionnaire; mean age 81·8 (SD 4·4) years, range 70-90 years. RESULTS: The questionnaire showed very good reproducibility in this sample with a mean polychoric correlation coefficient of 0·81 between administration at time 1 and time 2, and an average weighted κ of 0·49 for the level of recall agreement between food groups. CONCLUSIONS: The demonstrated reliability of this lifetime diet questionnaire makes it a useful tool to assess potential relationships between long-term dietary intake and later-age cognitive outcomes.

Physical activity for older Australians with mild cognitive impairment or subjective cognitive decline - A narrative review to support guideline development.

OBJECTIVES: This review informed development of the first national Physical Activity (PA) Guidelines for Older Australians with Mild Cognitive Impairment (MCI) or Subjective Cognitive Decline (SCD) (http://www.dementiaresearch.org.au/images/dcrc/output-files/1567-pa_guidelines_for_mci_or_scd_full_report_final.pdf). These guidelines are directed at healthcare professionals and aim to encourage older adults with SCD/MCI to engage in PA to enhance cognitive, mental and physical health. DESIGN: A narrative review was undertaken to inform the guideline adaptation process. METHODS: A systematic search of existing PA guidelines for older adults was performed and evaluated using the Appraisal of Guidelines for Research and Evaluation II Instrument. The guideline assessed as most appropriate was adapted to the population with SCD/MCI using the Guideline Adaptation Resource Toolkit, supported by the narrative review. RESULTS: The search for existing PA guidelines for older adults yielded 22 guidelines, none of which specifically considered older adults with SCD/MCI. The Canadian Physical Activity Guidelines for Older Adults were selected for adaptation to the population with SCD/MCI. The narrative review found 24 high-quality randomised controlled trials and 17 observational studies. These supported the four guideline recommendations that address aerobic PA, progressive resistance training, balance exercises and consultation with healthcare professionals to tailor PA to the individual. CONCLUSIONS: This review found evidence to support the four guideline recommendations. These recommendations provide specific guidance for older adults with SCD/MCI, their families, health professionals, community organisations and government to obtain benefits from undertaking PA. The review also highlights important future research directions, including the need for targeted translation and implementation research for diverse consumers.

More evidence is needed. Iron, incident cognitive decline and dementia: a systematic review.

BACKGROUND: Our aim was to systematically review the relationship between iron and incident cognitive decline or dementia from midlife onwards. METHODS: Systematic review of eligible studies using Medline, Embase and PsycINFO® for the period from 1 January 1986 to 2 December 2016 (CRD42016023800), where study populations had a mean age of over 50 years and were free of cognitive impairment or dementia at baseline. Two authors independently extracted data according to eligibility criteria and assessed study characteristics, quality and outcomes. Disagreement was resolved by discussion. RESULTS: A total of 1185 relevant records were identified with 12 full-text articles eligible for review. Six studies were excluded, leaving six texts to be included. Sample size ranged from 90 to 7173, with an average follow up of approximately 11.5 years. Baseline iron measures included brain iron (n = 2), iron-related biomarkers in blood and plasma (n = 2), and iron intake estimates from dietary records (n = 2). Outcomes were dementia incidence (n = 2) and longitudinal outcomes on neuropsychological tests (n = 4). Bias was evident across studies in one or more of the following: recruitment, iron exposure, outcome assessments, potential confounders, missing data or attrition. CONCLUSIONS: Diversity across the small number of identified studies precludes conclusions regarding the role of iron in cognitive decline or dementia. Our review highlights substantial gaps in the evidence base and the need for more comprehensive, higher quality studies in this area.

An 18-mo randomized, double-blind, placebo-controlled trial of DHA-rich fish oil to prevent age-related cognitive decline in cognitively normal older adults.

Background: Fish oil trials in cognitively healthy older adults have yielded inconsistent results. Supplementation may differentially affect the domains that underpin cognitive performance, and effects may differ across sex or genotype. Objective: The aim of this study was to test whether docosahexaenoic acid (DHA)-rich fish oil slows 18-mo cognitive decline in cognitively healthy elders. Design: In a double-blind, randomized, placebo-controlled, parallel-group trial, cognitively healthy Australian community-dwelling adults (aged 65-90 y) consumed either 1720 mg DHA and 600 mg eicosapentaenoic acid or low-polyphenolic olive oil daily, as capsules, for 18 mo. Groups were allocated by permuted-block randomization and stratified by age. Cognitive assessment was conducted at baseline and then every 6 mo. Primary analyses tested the difference between groups in the rate of 18-mo cognitive change via latent growth curve models on any of the following: reasoning, working memory, short-term memory, retrieval fluency, and cognitive speed-related constructs. Treatment interactions with sex and APOE-ε4 were tested. Secondary outcomes were self-reported changes in well-being and everyday functioning, blood pressure, biomarkers of n-3 (ω-3) long-chain polyunsaturated fatty acids (LC PUFAs), lipids, glucose metabolism, inflammation, oxidative stress, DNA damage, and Mini-Mental State Examination. Results: A total of 403 people were randomly assigned. Data from those who completed baseline were analyzed (n = 390; intervention n = 194, control n = 196). Daily supplementation with 2.3 g DHA-rich fish oil for 18 mo did not maintain or improve cognitive performance. A small negative main effect was found on psychomotor speed (intervention = -0.02, 95% CI: -0.04 to 0.00; d = 0.24, P = 0.03). Treatment effects differed according to sex on retrieval fluency and some speed-based domains, including psychomotor speed, and according to APOE-ε4 carrier status on reaction time and reasoning. For secondary outcomes, treatment was associated with increased perceived cognitive mistakes (d = 0.24; P = 0.003), increased oxidative stress, and expected changes in fatty acid metabolism. Conclusions: Findings do not support supplementing older adults with fish oil to prevent cognitive decline. Treatment interactions with sex and APOE-ε4 carrier status warrant further investigation. This trial was registered at the Australia and New Zealand Clinical Trials Register (ANZCTR) as ACTRN12607000278437.

The epidemiology of driving in later life: Sociodemographic, health and functional characteristics, predictors of incident cessation, and driving expectations.

AIM: To describe population-level characteristics of drivers and non-drivers in a cohort of older Australians and identify predictors of driving cessation and expectations. METHODS: The sample comprised the oldest cohort of the PATH Through Life project who were assessed 4 times between 2001 and 2013. At waves 3 and 4 questions on driving were included in the study interview. Data were also collected on health, physical and cognitive function and psychosocial wellbeing. Descriptive analyses compared drivers and non-drivers on sociodemographic, health and functional variables and regression models identified predictors of cessation and driving expectations. RESULTS: 92.5% of the sample were current drivers. They reported better physical, mental and cognitive health than non-drivers. Drivers expected to drive for another 12.6 years, the majority drove 6+ days per week. Four percent of the sample ceased driving over the four year follow-up. Predictors of cessation were financial problems, driving expectations and driving fewer kilometres per week. Predictors of expectations were poorer self-rated health, mastery, difficulties reading maps, self-rated visual function, years of driving experience, and fewer kilometres driven per week. CONCLUSION: Driving is normative for many older Australians in their 70s. Similar factors are associated with actual cessation and expectation of driving suggesting that older adults do have a sense of their expected driving life.

An Australian survey of cognitive health beliefs, intentions, and behaviours through the adult life course.

OBJECTIVE: Information is required regarding cognitive health beliefs and behaviours from across the life in order to inform the design of interventions to optimise cognitive health and reduce the risk of cognitive impairment. METHODS: A survey of Australian adults aged 20-89 was administered via Computer Assisted Telephone Interviewing (CATI) software to respondents recruited by random digit dialling (N = 900). Socio-demographic and self-reported health information was collected to investigate associations with cognitive health responses. RESULTS: Alcohol abuse was nominated by the highest proportion of respondents (34.3%) as detrimental for brain health. Fewer than 5% nominated elevated cholesterol, blood pressure, obesity, poor education, or ageing. The most frequently endorsed protective activity was socialising (70%). Socio-demographic factors predicted responses. Age-group differences were apparent in the proportions nominating alcohol (X(2) = 24.2; p < .001), drugs (X(2) = 56.8; p < .001), smoking (X(2) = 13.1; p = .001), nutrition (X(2) = 20.4; p < .001), and mental activity (X(2) = 12.8; p = .002) as relevant to brain health. Activities undertaken for cognitive benefit also differed by age. Across all ages the perceived benefit of activities was not supported by intentions to undertake activities. CONCLUSIONS: Interventions are needed to inform and motivate people across the life-course to undertake behaviours specifically to optimise their cognitive health.

Bridging the Translation Gap: From Dementia Risk Assessment to Advice on Risk Reduction.

Dementia risk reduction is a global health and fiscal priority given the current lack of effective treatments and the projected increased number of dementia cases due to population ageing. There are often gaps among academic research, clinical practice, and public policy. We present information on the evidence for dementia risk reduction and evaluate the progress required to formulate this evidence into clinical practice guidelines. This narrative review provides capsule summaries of current evidence for 25 risk and protective factors associated with AD and dementia according to domains including biomarkers, demographic, lifestyle, medical, and environment. We identify the factors for which evidence is strong and thereby especially useful for risk assessment with the goal of personalising recommendations for risk reduction. We also note gaps in knowledge, and discuss how the field may progress towards clinical practice guidelines for dementia risk reduction.