Comparative study of machine learning methods for modeling associations between risk factors and future dementia cases.

A substantial portion of dementia risk can be attributed to modifiable risk factors that can be affected by lifestyle changes. Identifying the contributors to dementia risk could prove valuable. Recently, machine learning methods have been increasingly applied to healthcare data. Several studies have attempted to predict dementia progression by using such techniques. This study aimed to compare the performance of different machine-learning methods in modeling associations between known cognitive risk factors and future dementia cases. A subset of the AGES-Reykjavik Study dataset was analyzed using three machine-learning methods: logistic regression, random forest, and neural networks. Data were collected twice, approximately five years apart. The dataset included information from 1,491 older adults who underwent a cognitive screening process and were considered to have healthy cognition at baseline. Cognitive risk factors included in the models were based on demographics, MRI data, and other health-related data. At follow-up, participants were re-evaluated for dementia using the same cognitive screening process. Various performance metrics for all three machine learning algorithms were assessed. The study results indicate that a random forest algorithm performed better than neural networks and logistic regression in predicting the association between cognitive risk factors and dementia. Compared to more traditional statistical analyses, machine-learning methods have the potential to provide more accurate predictions about which individuals are more likely to develop dementia than others.

Development of soft tissue asymmetry indicators to characterize aging and functional mobility.

Introduction: The aging population poses significant challenges to healthcare systems globally, necessitating a comprehensive understanding of age-related changes affecting physical function. Age-related functional decline highlights the urgency of understanding how tissue composition changes impact mobility, independence, and quality of life in older adults. Previous research has emphasized the influence of muscle quality, but the role of tissue composition asymmetry across various tissue types remains understudied. This work develops asymmetry indicators based on muscle, connective and fat tissue extracted from cross-sectional CT scans, and shows their interplay with BMI and lower extremity function among community-dwelling older adults. Methods: We used data from 3157 older adults from 71 to 98 years of age (mean: 80.06). Tissue composition asymmetry was defined by the differences between the right and left sides using CT scans and the non-Linear Trimodal Regression Analysis (NTRA) parameters. Functional mobility was measured through a 6-meter gait (Normal-GAIT and Fast-GAIT) and the Timed Up and Go (TUG) performance test. Statistical analysis included paired t-tests, polynomial fitting curves, and regression analysis to uncover relationships between tissue asymmetry, age, and functional mobility. Results: Findings revealed an increase in tissue composition asymmetry with age. Notably, muscle and connective tissue width asymmetry showed significant variation across age groups. BMI classifications and gait tasks also influenced tissue asymmetry. The Fast-GAIT task demonstrated a substantial separation in tissue asymmetry between normal and slow groups, whereas the Normal-GAIT and the TUG task did not exhibit such distinction. Muscle quality, as reflected by asymmetry indicators, appears crucial in understanding age-related changes in muscle function, while fat and connective tissue play roles in body composition and mobility. Discussion: Our study emphasizes the importance of tissue asymmetry indicators in understanding how muscle function changes with age in older individuals, demonstrating their role as risk factor and their potential employment in clinical assessment. We also identified the influence of fat and connective tissue on body composition and functional mobility. Incorporating the NTRA technology into clinical evaluations could enable personalized interventions for older adults, promoting healthier aging and maintaining physical function.

Predicting stroke, neurological and movement disorders using single and dual-task gait in Korean older population.

BACKGROUND: Single and motor or cognitive dual-gait analysis is often used in clinical settings to evaluate older adults affected by neurological and movement disorders or with a stroke history. Gait features are frequently investigated using Machine Learning (ML) with significant results that can help clinicians in diagnosis and rehabilitation. The present study aims to classify patients with stroke, neurological and movement disorders using ML to analyze gait characteristics and to understand the importance of the single and dual-task features among Korean older adults. METHODS: A cohort of 122 non-hospitalized Korean older adult participated in a single and a cognitive dual-task gait performance analysis. The extracted temporal and spatial features, together with clinical data, were used as input for the binary classification using tree-based ML algorithms. A repeated-stratified 10-fold cross-validation was performed to better evaluate multiple classification metrics with a final feature importance analysis. RESULTS AND SIGNIFICANCE: The best accuracy - maximum >90 % - for gait and neurological disorders classification was obtained with Random Forest. In the stroke classification a 91.7 % of maximum accuracy was reached, with a significant recall of 92 %. The feature importance analysis showed a substantial balance between single and dual-task, while clinical data did not show elevated importance. The current findings indicate that a cognitive dual-task gait performance is highly recommendable together with a single-task in the analysis of older population, particularly for patients with a history of stroke. The results could be useful to medical professionals in treating and diagnosing motor and neurological disorders, and to improve rehabilitation strategies for stroke patients. Furthermore, the results confirm the proficiency of the tree-based ML algorithms in biomedical data analysis. Finally, in the future, this research could be replicated with a non-Asian population dataset to deepen the understanding of gait differences between Asian-Korean population and other ethnicities.

Exposure factors associated with dementia among older adults in Iceland: the AGES-Reykjavik study.

The study aimed to assess whether factors related to cognitive performance were associated with the development of dementia. Additionally, the study aimed to establish whether cognitive performance at baseline or change in cognition between baseline and follow-up (five-year period) had a stronger association with whether an individual would fulfill a dementia criterion at follow-up. The data was collected from 2002 to 2011. Logistic regression was applied to the AGES-Reykjavik Study epidemiological data. The analysis, which builds upon previous data analyses of the same dataset, included 1,491 participants between the ages of 66 and 90. All those included were considered to have normal cognition at baseline; 8.2% (n = 123) of them fulfilled a dementia criterion at follow-up five years later. The study's results indicated that being high on cognitive reserve factors reduced the risk of developing dementia. Compared to other known dementia risk factors, cognitive reserve factors (education level, participation in leisure activities, and self-reported health) were more likely than others to have an association with dementia. Additionally, the study's findings showed that cognitive performance at baseline, rather than change in cognition between baseline and follow-up five years later, had a stronger association with dementia at the follow-up assessment. Together, these findings support the notion that promoting high cognitive reserve throughout the lifespan and reaching high cognitive performance is important in reducing dementia risk.

Trends in the use of home care services among Norwegians 70+ and projections towards 2050: The HUNT study 1995-2017.

BACKGROUND: Life expectancy (LE) is increasing worldwide, while there is lack of information on how this affects older individuals' use of formal home care services. AIM: We aimed to decompose LE into years with and without home care services and estimate projected number of users towards 2050 in Norway for people 70 years or older. METHODS: This study is based on a sample of 25,536 participants aged 70 years and older in the Trøndelag Health Study (HUNT) survey 2 (1995-1997), 3 (2006-2008), or 4 (2017-2019) linked with national data on mortality. Prevalence of home care services was standardised to the Norwegian population by age and sex. The Sullivan method was used to estimate expected years with and without home help services and nursing services for the years 1995, 2006 and 2016. Data from HUNT4 and Statistics Norway were used to estimate projected use of these services between 2020 and 2050. RESULTS: During 1995-2017, the use of home help services decreased from 22.6% to 6.2% (p < 0.001), and from 6.4% to 5.5% (p = 0.004) for home nursing services. Adjusted for age and sex, the use of home help services decreased significantly over time (p < 0.001), while home nursing services were stable (p = 0.69). LE at age 70 increased from 11.9 to 15.3 years in men (p < 0.05) during 1995-2017, and from 14.7 to 17.1 in women (p < 0.05). In the same period, the expected years receiving home help decreased from 2.6 to 1.1 in men (p < 0.05), and from 4.4 to 2.1 in women (p < 0.05). The expected years receiving home nursing increased from 0.6 to 0.9 in men (p < 0.05), and from 1.3 to 1.7 in women (p < 0.05). Projected numbers of people 70+ in Norway in need of either of these services were estimated to rise from 64,000 in 2020 to 160,000 in 2050. CONCLUSION: While overall life expectancy increased, the expected years receiving home help have decreased and home nursing slightly increased among the Norwegian population aged 70 years and older during 1995-2017. However, the substantial increase in the projected number of older adults using home care services in the future is an alert for the current health care planners.

Cognition and brain health among older adults in Iceland: the AGES-Reykjavik study.

The paper aimed to compare how factors previously identified as predictive factors for cognitive decline and dementia related to cognitive performance on the one hand and brain health on the other. To that aim, multiple linear regression was applied to the AGES-Reykjavik study epidemiological data. Additionally, a regression analysis was performed for change in cognition over 5 years, using the same exposure factors. The study ran from 2002 to 2011, and the sample analyzed included 1707 participants between the ages of 66 and 90. The data contains MR imaging, cognitive testing, background data, and physiological measurements. Overall, we conclude that risk factors linked to dementia relate differently to cognition and brain health. Mobility, physical strength, alcohol consumption, coronary artery disease, and hypertension were associated with cognition and brain volume. Smoking, depression, diabetes, and body fat percentage were only associated with brain volume, not cognitive performance. Modifiable factors previously linked to cognitive reserve, such as educational attainment, participation in leisure activities, multilingualism and good self-reported health, were associated with cognitive function but did not relate to brain volume. These findings show that, within the same participant pool, cognitive reserve proxy variables have a relationship with cognitive performance but have no association with relative brain volume measured simultaneously.

Social network and the risk for developing mild cognitive impairment and dementia among older adults.

BACKGROUND: This study aimed to investigate the longitudinal associations between social network (SN) and the risk of lower cognitive function, mild cognitive impairment (MCI), and dementia among cognitively normal individuals 65 years and older. METHODS: Data from the Age, Gene/Environment Susceptibility (AGES) Reykjavik Study on 2816 participants (aged 65 to 96 years) were used to examine the associations using multiple logistic and linear regression models. SN included questions on frequency of contact with family and friends as well as information on marital status, resulting in a score ranging from 0 (poor social network) to 3 (good social network). Cognitive function outcomes included the speed of processing (SP), executive function (EF) and memory function (MF). MCI and dementia were diagnosed using a detailed assessment according to international guidelines. RESULTS: At baseline 0.5, 7.0, 41.7 and 50.8% reported a score of 0, 1, 2 and 3, respectively. During a mean follow-up time of 5.2 years, 7.1% (n = 188) of cognitively intact participants developed MCI and 3.0% (n = 79) developed dementia. Longitudinal analyses demonstrated that participants who had low SN were significantly more likely to have declines in MF (ß = - 0.533, P = 0.014) compared to high SN. Social networks were not independently associated with the decline of SP and EF during follow-up. According to fully adjusted models using logistic regression, SN was significantly associated with incidence risk of MCI (OR = 2.030, P = 0.014 and OR = 1.847 P = 0.001). These associations were largely independent of other lifestyle factors, depression and genetic disposition. CONCLUSIONS: Community-dwelling older adults who have poor social networks have a higher risk of declining memory function as well as a higher risk of mild cognitive impairment than older adults who have a higher social network. This study included numbers of relevant covariates in the study analysis, thereby significantly contributing to the literature on cognitive aging.

A poor appetite or ability to eat and its association with physical function amongst community-dwelling older adults: age, gene/environment susceptibility-Reykjavik study.

A poor appetite or ability to eat and its association with physical function have not been explored considerably amongst community-dwelling older adults. The current study examined whether having an illness or physical condition affecting one's appetite or ability to eat is associated with body composition, muscle strength, or physical function amongst community-dwelling older adults. This is a secondary analysis of cross-sectional data from the age, gene/environment susceptibility-Reykjavik study (n = 5764). Illnesses or physical conditions affecting one's appetite or ability to eat, activities of daily living, current level of physical activity, and smoking habits were assessed with a questionnaire. Fat mass, fat-free mass, body mass index, knee extension strength, and grip strength were measured, and the 6-m walk test and timed up-and-go test were administered. Individuals who reported illnesses or physical conditions affecting their appetite or ability to eat were considered to have a poor appetite. The associations of appetite or the ability to eat with body composition and physical function were analysed with stepwise linear regression models. A total of 804 (14%) individuals reported having conditions affecting their appetite or ability to eat and had a significantly lower fat-free mass and body mass index, less grip strength, and poorer physical function than did those without any conditions affecting their appetite or ability to eat. Although the factors reported to affect one's appetite or ability to eat are seldom considered severe, their strong associations with physical function suggest that any condition affecting one's appetite or ability to eat requires attention.

Body weight changes and longitudinal associations with cognitive decline among community-dwelling older adults.

INTRODUCTION: We aim to investigate the longitudinal associations between changes in body weight (BW) and declines in cognitive function and risk of mild cognitive impairment (MCI)/dementia among cognitively normal individuals 65 years or older. METHODS: Data from the Age Gene/Environment Susceptibility-Reykjavik Study (AGES-Reykjavik Study) including 2620 participants, were examined using multiple logistic regression models. Cognitive function included speed of processing (SP), executive function (EF), and memory function (MF). Changes in BW were classified as; weight loss (WL), weight gain (WG), and stable weight (SW). RESULTS: Mean follow-up time was 5.2 years and 61.3% were stable weight. Participants who experienced WL (13.4%) were significantly more likely to have declines in MF and SP compared to the SW group. Weight changes were not associated with EF. WL was associated with a higher risk of MCI, while WG (25.3%) was associated with a higher dementia risk, when compared to SW. DISCUSSION: Significant BW changes in older adulthood may indicate impending changes in cognitive function.

Preserving Mobility in Older Adults with Physical Frailty and Sarcopenia: Opportunities, Challenges, and Recommendations for Physical Activity Interventions.

One of the most widely conserved hallmarks of aging is a decline in functional capabilities. Mobility loss is particularly burdensome due to its association with negative health outcomes, loss of independence and disability, and the heavy impact on quality of life. Recently, a new condition, physical frailty and sarcopenia, has been proposed to define a critical stage in the disabling cascade. Physical frailty and sarcopenia are characterized by weakness, slowness, and reduced muscle mass, yet with preserved ability to move independently. One of the strategies that have shown some benefits in combatting mobility loss and its consequences for older adults is physical activity. Here, we describe the opportunities and challenges for the development of physical activity interventions in people with physical frailty and sarcopenia. The aim of this article is to review age-related physio(patho)logical changes that impact mobility in old age and to provide recommendations and procedures in accordance with the available literature.

The effect of cognitive function on mobility improvement among community-living older adults: A 12-week resistance exercise intervention study.

The purpose of the study was to investigate the association between baseline cognitive function and improvement in mobility after 12 weeks of resistance training (3 times/week; 3 sets, 6-8 repetitions at 75-80% of the 1-repetition maximum) among community-dwelling older adults in Iceland (N=205, 73.5±5.7 years, 57.0% female). Body composition, physical activity status, cardiovascular risk factors, 6-minute walk test (6MWT), and Mini-Mental State Examination (MMSE) were measured. The linear regression model was used to examine the association between baseline MMSE and mobility improvement. Mean distance of 6MWT was 462.8±71.6 meter at baseline and mean change after the exercise intervention was 33.7±34.9 meter. The mean MMSE score at baseline was 27.6±1.9. After adjusting for baseline covariates, we found that baseline MMSE score was significantly associated with improvement in mobility among older adults after the exercise intervention. Cognitive function strongly influences the effect of exercise intervention on mobility among older adults.

Associations between education and need for care among community dwelling older adults in Iceland.

BACKGROUND: Older adults in Iceland have good access to social services that support them in maintaining an independent life, although receiving informal care is common for community living older adults in Iceland. The aim of this study was to examine whether the need for care as well as receiving formal and informal care is associated with education among older adults in Iceland. METHODS: Among a national sample of 782 Icelandic community dwelling old adults (mean age 76.9 ± 7.4 years, 55% women), a telephone survey was conducted. The survey included questions on: socioeconomic status, social network, health status, activities of daily living and formal/informal care. RESULTS: A full data set was available for 720 subjects and among these, 349 (48.5%) had no need for care, 197 (27.4%) received informal care only, 31 (4.3%) received formal care only, and 143 (19.9%) received both type of care. Participants with higher education were significantly less likely to need care (OR 0.67, 95% CI, 0.47-0.97, p = 0.031) when compared with those who had primary education. Categorisation by age showed that this difference was only significant in participants younger than 80 years. Education was not related to formal care, but adults with higher education were less likely to receive informal care compared with older adults who had primary education (OR: 0.65, 95%CI: 0.46, 0.93, p = 0.018). CONCLUSIONS: People with higher education were significantly less likely to need care and this association was mainly present among those aged below 80 years. Further, in participants that needed care, the likelihood of receiving informal care was lower in highly educated participants, but no differences in formal care were observed between educational levels.

Ageing populations in the Nordic countries: Mortality and longevity from 1990 to 2014.

Aims: Cross-country comparisons of mortality and longevity patterns of Nordic populations could contribute with novel insights into the compositional changes of these populations. We investigated three metrics of population ageing: the proportion of the population aged 75+ and 90+ years, the proportion of birth cohorts reaching 75 and 90 years, and life expectancy (LE) at age 75 and 90 years in Sweden, Norway, Iceland, Denmark and Finland, in the period 1990-2014. Methods: Demographic information was collected from national statistical databases and the Human Mortality Database. Results: All metrics on population ageing increased during the study period, but there were some cross-country variations. Finland experienced a notably steep increase in the proportion of 75+ and 90+ year olds compared to the other countries. Regarding the proportion reaching old ages, the Finnish lagged behind from the beginning, but females decreased this difference. The Danes were more similar to the other countries at the beginning, but did not experience the same increase over time. Gender-specific LE at age 75 and 90 years was similar overall in the five countries. Conclusions: Developments in cross-country variation suggest that survival until old age has become more similar for Finnish females and more different for Danish males and females compared with the other countries in recent decades. This provides perspectives on the potential to improve longevity in Denmark and Finland. Similarities in LE in old age suggest that expected mortality in old age has been more similar throughout the study period.

Discriminatory Power of Women's Handball Game-Related Statistics at the Olympic Games (2004-2016).

Sports performance analysis has been a growing field of study in the last decade. However, the number of studies in handball is small. The aims of this present study were (i) to compare handball game-related statistics by the match outcome (winning and losing teams) and (ii) to identify characteristics that discriminated performance in elite women's handball. The game-related statistics of the 236 matches played in the last four Olympic Games (Athens, Greece, 2004; Beijing, China, 2008; London, United Kingdom, 2012; and Rio de Janeiro, Brazil, 2016) were analysed. Differences between match outcomes (winning or losing teams) were determined using the chi-squared statistic, also calculating the effect sizes of the differences. A discriminant analysis was then performed applying the sample-splitting method according to match outcomes. The results showed the differences between winning and losing teams were red cards and assists. Also, the discriminant analysis selected five variables (shots, goalkeeper-blocked shots, technical fouls, steals, and goalkeeper-blocked fast-break shots) that classified correctly 83% of matches. The selected variables included offensive and defensive predictors. Coaches and players can use these results as a reference against which to assess their performance and plan training.

The Association Between Midlife Physical Activity and Depressive Symptoms in Late Life: Age Gene/Environment Susceptibility-Reykjavik Study.

BACKGROUND: There is little evidence on the long-term association between physical activity (PA) and depressive symptoms in old age. We examined the association of midlife PA and depressive symptoms in late life. METHODS: A large community-based population residing in Reykjavik, Iceland, participated in a longitudinal study with an average of 25 years of follow up. Midlife PA was categorized as active and inactive groups (n = 4,140, Active = 1,292, Inactive = 2,848, mean age 52±7 years). The main outcome had six or higher depressive symptoms assessed by the 15-item Geriatric Depression scale. Participants who had a history of depression (n = 226), and were diagnosed with dementia (n = 393), and had incomplete cognitive data (n = 595) and incomplete analytical data (n = 422) were excluded. Level of weekly PA was ascertained by a questionnaire at midlife. Depressive symptoms were assessed on average 25 (±4) years later. RESULTS: After controlling for demographic and health-related risk factors, those who were active at midlife were less likely to have high level of depressive symptomatology (6 or higher Geriatric Depression scale scores, odds ratio = 0.58, 95% confidence interval: 0.41-0.83, p < .005) compared with those who were inactive in midlife. After full adjustment of three domains of late-life cognitive function the results remained significant (odds ratio = 0.61, 95% confidence interval: 0.43-0.86, p = .005). CONCLUSION: Our study shows that midlife PA is associated with lower depressive symptoms 25 years later. Participating in regular PA in midlife may improve mental health in late life.

Overweight and Obesity in Midlife and Brain Structure and Dementia 26 Years Later: The AGES-Reykjavik Study.

High adiposity in midlife might increase risk for late-life brain pathology, including dementia. Using data from the prospective Age, Gene/Environment Susceptibility-Reykjavik Study of men and women (born 1907-1935), we studied the associations of overweight and obesity at midlife (mean age, 50 (standard deviation, 4.7) years) with 1.5-T brain magnetic resonance imaging measures of infarct-like brain lesions, cerebral microbleeds, total brain volume, and white matter lesions volume, as well as dementia, in late life (mean age, 76 (standard deviation, 5.2) years). We used linear and Poisson models to estimate associations in 3,864 persons after adjustment for sociodemographic, health, and lifestyle characteristics. In midlife, the prevalence of overweight was 39% and that of obesity was 8%. After a mean follow-up of 26.2 (standard deviation, 4.9) years, midlife overweight and obesity were not associated with infarct-like brain lesions (relative risk (RR) = 0.82, 95% confidence interval (CI): 0.61, 1.10), cerebral microbleeds (RR = 0.69, 95% CI: 0.37, 1.32), total brain volume (ß = 0.05, 95% CI: -0.34, 0.45), white matter lesions volume (ß = -0.10, 95% CI: -0.20, 0.01), or dementia (RR = 0.91, 95% CI: 0.49, 1.72) compared with normal weight. These findings do not support the hypothesis that high body mass index in midlife modulates the risk for dementia.

Spousal loss and cognitive function in later life: a 25-year follow-up in the AGES-Reykjavik study.

The aim of this study was to investigate the associations between loss of a life partner and the development of dementia and decline in cognitive function in later life. We used an Icelandic cohort of 4,370 participants in the Age, Gene/Environment Susceptibility-Reykjavik Study who were living as married in 1978 (born in 1907-1935) and were either still married (unexposed cohort) or widowed (exposed cohort) at follow-up (in 2002-2006). We ascertained history of marital status and spouse's death by record linkage to the Registry of the Total Population, Statistics Iceland. The outcome measures were as follows: 1) dementia and mild cognitive impairment; and 2) memory, speed of processing, and executive function. During the observation period, 3,007 individuals remained married and 1,363 lost a spouse through death. We did not find any significant associations between loss of a spouse and our outcome variables, except that widowed women had poorer executive function (mean = -0.08) during the first 2 years after their husbands' deaths compared with still-married women (mean = 0.09). Our findings do not support the notion that the risk of dementia is increased following the loss of a spouse, yet women demonstrate a seemingly temporary decline in executive function following the death of a partner.

Midlife physical activity preserves lower extremity function in older adults: age gene/environment susceptibility-Reykjavik study.

OBJECTIVES: To examine the long-term association between midlife physical activity (PA) and lower extremity function (LEF) in late life. DESIGN: Longitudinal study with an average of 25 years of follow-up. SETTING: Community-dwelling old population in Reykjavik, Iceland. PARTICIPANTS: Four thousand seven hundred fifty-three community-dwelling men and women (mean age 76 ± 6) in Reykjavik, Iceland. MEASUREMENTS: On the basis of weekly hours of regular PA reported at the midlife examination, participants were classified as active or inactive. Measures of LEF in late life were gait speed on a 6-m walk, Timed Up and Go (TUG), and knee extension (KE) strength tests. Linear regression analysis was used to examine the association. RESULTS: Participants who were active in midlife had significantly better LEF (faster gait speed, ß = 0.50, P ≤ .001; faster TUG time, ß = -0.53 P ≤ .001; stronger KE strength, ß = 1.3, P ≤ .001) in late life than those who were not active in midlife after adjusting for sociodemographic and cardiovascular risk factors. After adjustment for cognitive function in late life (speed of processing, memory, and executive function), participants who were active in midlife had significantly faster gait speed (ß = 0.04, P ≤ .001), faster TUG time (ß = -0.34, P ≤ .001), and greater KE strength (ß = 0.87, P ≤ .001) in old age than those who were not active in midlife. CONCLUSION: Regular PA in midlife is associated with better performance of LEF in later life, even after controlling for late-life cognitive function.

The effect of midlife physical activity on cognitive function among older adults: AGES--Reykjavik Study.

BACKGROUND: There are few studies on the long-term associations of physical activity (PA) to cognition. Here, we examine the association of midlife PA to late-life cognitive function and dementia. METHODS: The sample consisted of a population-based cohort of men and women (born in 1907-1935) participating in the Age Gene/Environment Susceptibility-Reykjavik Study. The interval between the midlife ascertainment of PA and late-life cognitive function was 26 years. Composite scores of speed of processing, memory, and executive function were assessed with a battery of neuropsychological tests, and dementia was diagnosed according to international guidelines. There were 4,761 nondemented participants and 184 (3.7%) with a diagnosis of dementia, with complete data for the analysis. RESULTS: Among the participants, no midlife PA was reported by 68.8%, ≤ 5 hours PA by 26.5%, and >5 hours PA by 4.5%. Excluding participants with dementia compared with the no PA group, both PA groups had significantly faster speed of processing (≤ 5 hours, ß = .22; >5 hours, ß = .32, p trend < .0001), better memory (≤ 5 hours, ß = .15; >5 hours, ß = .18, p trend < .0001), and executive function (≤ 5 hours, ß = .09; >5 hours, ß = .18, p trend< .0001), after controlling for demographic and cardiovascular factors. The ≤ 5 hours PA group was significantly less likely to have dementia in late life (odds ratio: 0.6, 95% confidence interval: 0.40-0.88) after adjusting for confounders. CONCLUSION: Midlife PA may contribute to maintenance of cognitive function and may reduce or delay the risk of late-life dementia.

An association between incident disability and depressive symptoms over 3 years of follow-up among older women: the Women's Health and Aging Study.

BACKGROUND AND AIMS: To examine the impact of new disability on the incidence of depressive symptoms, with 3-year biannual data from The Woman's Health and Aging Study. METHODS: Subjects (n=671) were selected if they were independent at baseline in 5 basic activities of daily living (ADLs) and were not depressed [scored <14 on the Geriatric Depression Scale (GDS; range 0 to 30)]. During the follow-ups, worsening of ADL disability (needed help on an increased number of ADLs) and onset of depressive symptoms (GDS score > or =14) were defined. For each pair of consecutive interviews in which depressive symptoms were not present in the first interview in the pair, we assessed incidence of worsening disability and depressive symptoms in the second interview of the pair. We also summarized the incidence of depressive symptoms 6 months later among the people who did not develop depressive symptoms at the time they reported a new disability. RESULTS: Compared with those not developing disability, after adjusting for demographic characteristics, number of diseases, and ADL difficulty level at the moment of onset of the disability, the odds ratio (OR) for developing depressive symptoms at disability onset was 2.2 (95% Confidence Interval (CI) 1.1-4.3). For those developing new disability without depressive symptoms, the adjusted OR for developing depressive symptoms 6 months later was 1.7 (CI 0.6-4.8). CONCLUSION: Onset of new disability in basic ADLs had a significant impact on the development of depressive symptoms at the moment of onset. Our results demonstrate that clinicians should carefully evaluate depressive symptoms in patients with new onset of disability.