Risk factors and cognitive correlates of white matter hyperintensities in ethnically diverse populations without dementia: The COSMIC consortium.

INTRODUCTION: White matter hyperintensities (WMHs) are an important imaging marker for cerebral small vessel diseases, but their risk factors and cognitive associations have not been well documented in populations of different ethnicities and/or from different geographical regions. METHODS: We investigated how WMHs were associated with vascular risk factors and cognition in both Whites and Asians, using data from five population-based cohorts of non-demented older individuals from Australia, Singapore, South Korea, and Sweden (N = 1946). WMH volumes (whole brain, periventricular, and deep) were quantified with UBO Detector and harmonized using the ComBat model. We also harmonized various vascular risk factors and scores for global cognition and individual cognitive domains. RESULTS: Factors associated with larger whole brain WMH volumes included diabetes, hypertension, stroke, current smoking, body mass index, higher alcohol intake, and insufficient physical activity. Hypertension and stroke had stronger associations with WMH volumes in Whites than in Asians. No associations between WMH volumes and cognitive performance were found after correction for multiple testing. CONCLUSION: The current study highlights ethnic differences in the contributions of vascular risk factors to WMHs.

Reduced skeletal muscle mass to visceral fat area ratio is independently associated with reduced cognitive function in type 2 diabetes mellitus.

AIM: Skeletal muscle mass to visceral fat area ratio (SVR) has been recognised as an index of sarcopenic obesity. SVR is associated with type 2 diabetes mellitus (T2DM), metabolic syndrome and arterial stiffness which are known risk factors for cognitive dysfunction. We aimed to investigate association between SVR and cognitive function in patients with T2DM. METHODS: This was a cross-sectional study of 1326 patients with T2DM and mean age 61.3 ± 8.0 years. SVR was assessed based on bioelectrical impedance measurements of muscle mass and visceral fat area (VFA). Cognitive function was assessed using Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Linear regression was used to examine the association between SVR in quartiles and RBANS score, adjusting for demographics, education, presence of depressive symptoms, clinical covariates and medications. RESULTS: The lower SVR quartiles were negatively associated with RBANS total score in the unadjusted analysis. The corresponding coefficients for Quartiles 1 and 2 SVR were -3.79 (95 % CI -5.39 to -2.19; p < 0.001) and -1.47 (95 % CI -2.86 to -0.07; p = 0.039) in fully adjusted analysis. The negative association between Quartile 1 SVR and RBANS score was evident in immediate memory, delayed memory, visuo-spatial construction, language and attention domains. Muscle mass and VFA alone had weaker associations with RBANS scores. CONCLUSION: Our study demonstrated, for the first time, an independent association between reduced SVR and lower cognitive function. This is evident in global and multiple cognitive domains. The synergistic effects of reduced muscle mass and visceral obesity may be more pronounced than their independent effects on cognitive function.

Digits in noise testing in a multilingual sample of Asian adults.

OBJECTIVE: Appropriate speech-in noise assessment is challenging in multilingual populations. This study aimed to assess whether first preferred language affected performance on an English Digits-in-noise (DIN) test in the local Asian multilingual population, controlling for hearing threshold, age, sex, English fluency and educational status. A secondary aim was to determine the association between DIN test scores and hearing thresholds. DESIGN: English digit-triplets in noise testing and pure-tone audiometry were conducted. Multiple regression analysis was performed with DIN scores and hearing thresholds as dependent variables. Correlation analysis was performed between DIN-SRT and hearing thresholds. STUDY SAMPLE: 165 subjects from the Singapore Longitudinal Ageing Study, a population-based longitudinal study of community-dwellers over 55 years of age. RESULTS: Mean DIN speech reception threshold (DIN-SRT) was -5.7 dB SNR (SD 3.6; range 6.7 to -11.2). Better ear pure tone average and English fluency were significantly associated with DIN-SRT. CONCLUSIONS: DIN performance was independent of first preferred language in a multilingual ageing Singaporean population after adjusting for age, gender and education. Those with poorer English fluency had a significantly lower DIN-SRT score. The DIN test has the potential to provide a quick, uniform method of testing speech in noise in this multilingual population.

Curcumin-rich curry consumption and life expectancy: Singapore longitudinal ageing study.

The therapeutic potential of curcumin for many diseases are intensively investigated. However, real-world observational data documenting health and longevity effects associated with dietary curcumin in turmeric from consuming curry in food is lacking. A prospective cohort study of 4551 adults aged 55 + assessed curry consumption (never or < once/year, ≥ once/year to < once/month, ≥ once/month to < once/week, ≥ once/week to < daily, ≥ once daily), prevalent health conditions, blood biomarker indexes of atherogenicity, insulin resistance, and inflammation at baseline, and mean (SD) 11.6 (3.8) year follow up of all-cause, CVS and cancer mortality. There were linear positive associations of increasing curry consumption with waist circumference, fasting blood glucose, TyG, AIP, CRI-1, CRI-2, central obesity and diabetes prevalence, and inverse association with eGFR. There were non-linear associations with FEV1/height2 and COPD prevalence, GDS score and depression, MMSE score and cognitive impairment, comorbidity count, serum albumin and haemoglobin, being most favourable with moderate consumption. The levels of NLR, PLR and SII indices of systemic and immune inflammation decreased linearly with curry consumption. Total mortality HR adjusted for baseline co-variables, decreased across curry consumption, 0.68 (95%CI 0.56-0.82), 0.54 (95%CI 0.43-0.69), 0.70 (0.52-0.93), and 0.62 (0.41-0.95), being lowest in the middle categories. Among participants with cardio-metabolic and vascular diseases (CMVD), at least occasional curry consumption was associated with decreased mortality risk by 39%, and increased life expectancy by 1.0 years. Among those without CMVD, the associated life expectancy increase was 1.9 years. Moderate curry consumption may confer meaningful longevity benefits.

Risk factors and cognitive correlates of white matter hyperintensities in ethnically diverse populations without dementia: the COSMIC consortium.

INTRODUCTION: White matter hyperintensities (WMH) are an important imaging marker for cerebral small vessel diseases, but their risk factors and cognitive associations have not been well-documented in populations of different ethnicities and/or from different geographical regions. METHOD: Magnetic resonance imaging data of five population-based cohorts of non-demented older individuals from Australia, Singapore, South Korea, and Sweden (N = 1,946) were examined for WMH and their associations with vascular risk factors and cognition. RESULT: Factors associated with larger whole brain WMH volumes included diabetes, hypertension, stroke, current smoking, body mass index, higher alcohol intake and insufficient physical activity. Participants with moderate or higher physical activity had less WMH than those who never exercised, but the former two groups did not differ. Hypertension and stroke had stronger associations with WMH volumes in the White, compared to Asian subsample. DISCUSSION: The current study highlighted the ethnic differences in the contributions of vascular risk factors to WMH.

Use of Antihypertensives, Blood Pressure, and Estimated Risk of Dementia in Late Life: An Individual Participant Data Meta-Analysis.

Importance: The utility of antihypertensives and ideal blood pressure (BP) for dementia prevention in late life remains unclear and highly contested. Objectives: To assess the associations of hypertension history, antihypertensive use, and baseline measured BP in late life (age >60 years) with dementia and the moderating factors of age, sex, and racial group. Data Source and Study Selection: Longitudinal, population-based studies of aging participating in the Cohort Studies of Memory in an International Consortium (COSMIC) group were included. Participants were individuals without dementia at baseline aged 60 to 110 years and were based in 15 different countries (US, Brazil, Australia, China, Korea, Singapore, Central African Republic, Republic of Congo, Nigeria, Germany, Spain, Italy, France, Sweden, and Greece). Data Extraction and Synthesis: Participants were grouped in 3 categories based on previous diagnosis of hypertension and baseline antihypertensive use: healthy controls, treated hypertension, and untreated hypertension. Baseline systolic BP (SBP) and diastolic BP (DBP) were treated as continuous variables. Reporting followed the Preferred Reporting Items for Systematic Review and Meta-Analyses of Individual Participant Data reporting guidelines. Main Outcomes and Measures: The key outcome was all-cause dementia. Mixed-effects Cox proportional hazards models were used to assess the associations between the exposures and the key outcome variable. The association between dementia and baseline BP was modeled using nonlinear natural splines. The main analysis was a partially adjusted Cox proportional hazards model controlling for age, age squared, sex, education, racial group, and a random effect for study. Sensitivity analyses included a fully adjusted analysis, a restricted analysis of those individuals with more than 5 years of follow-up data, and models examining the moderating factors of age, sex, and racial group. Results: The analysis included 17 studies with 34 519 community dwelling older adults (20 160 [58.4%] female) with a mean (SD) age of 72.5 (7.5) years and a mean (SD) follow-up of 4.3 (4.3) years. In the main, partially adjusted analysis including 14 studies, individuals with untreated hypertension had a 42% increased risk of dementia compared with healthy controls (hazard ratio [HR], 1.42; 95% CI 1.15-1.76; P = .001) and 26% increased risk compared with individuals with treated hypertension (HR, 1.26; 95% CI, 1.03-1.53; P = .02). Individuals with treated hypertension had no significant increased dementia risk compared with healthy controls (HR, 1.13; 95% CI, 0.99-1.28; P = .07). The association of antihypertensive use or hypertension status with dementia did not vary with baseline BP. There was no significant association of baseline SBP or DBP with dementia risk in any of the analyses. There were no significant interactions with age, sex, or racial group for any of the analyses. Conclusions and Relevance: This individual patient data meta-analysis of longitudinal cohort studies found that antihypertensive use was associated with decreased dementia risk compared with individuals with untreated hypertension through all ages in late life. Individuals with treated hypertension had no increased risk of dementia compared with healthy controls.

The Healthy Ageing Questionnaire Index: Validation in the Singapore Longitudinal Ageing Study.

INTRODUCTION: Healthy ageing (HA) indices typically use full questionnaire, performance- or blood-based assessment of functional ability which are time-consuming and resource-intensive. We developed and validated a simple and brief Healthy Ageing Questionnaire (HAQ) index with comparable measurement accuracy. METHODS: The 15-item HAQ (scored 0-100) was developed using data of 500 participants in the Singapore Study of Successful Ageing (SSOSA), a sub-cohort of the Singapore Longitudinal Ageing Study (SLAS-2). Its construct, concurrent, and predictive validity were evaluated in 2,161 participants in the SLAS-2 who were non-participants of the SSOSA. RESULTS: The HAQ index (mean = 64.0, SD = 11.8) showed a coherent 3-factor structure (Cronbach's alpha = 0.735). HAQ scores were higher among participants who were female, highly educated, not living alone, non-smoking, non-alcohol drinkers, not at risk of malnutrition, were robust or pre-frail, not disabled, had no or <5 medical conditions, and no recent fall or hospitalization. It was positively correlated with Mini-Mental State Examination and life satisfaction, and negatively correlated with age, logMAR vision, 5 times sit-and-stand, and timed-up-and-go. The HAQ index was significantly correlated but showed modest concordance with the Rowe-Kahn SA index. Increasing HAQ index quintiles were associated with decreased mortality risks from 40.6 to 9.7 deaths per 1,000 person-years; covariate-adjusted hazard ratio for the highest Q5 levels (HAQ score >70) was 0.44 (95% CI = 0.28-0.67). Using receiver operating characteristics analysis of predictive accuracy for survival, the area under the curve of HAQ was 0.675, and Rowe-Kahn SA index was 0.660 (p = 0.361). CONCLUSION: The HAQ is a brief and accurate HA index that is potentially useful across diverse settings and purposes in research, healthcare, and policy-making.

Happy people live longer because they are healthy people.

OBJECTIVES: Higher levels of happiness are associated with longer life expectancy. Our study assessed the extent to which various factors explain the protective effect of happiness on all-cause mortality risk, and whether the association differs between older men and women. METHODS: Using data from the Singapore Longitudinal Aging Studies (N = 6073) of community-dwelling older adults aged ≥ 55 years, we analyzed the association of baseline Likert score of happiness (1 = very sad to 5 = very happy) and mortality from mean 11.7 years of follow up. Cox regression models were used to assess the extent to which confounding risk factors attenuated the hazard ratio of association in the whole sample and sex-stratified analyses. RESULTS: Happiness was significantly associated with lower mortality (p < .001) adjusted for age, sex and ethnicity: HR = 0.85 per integer score and HR = 0.57 for fairly-or-very happy versus fairly-or-very sad. The HR estimate (0.90 per integer score) was modestly attenuated (33.3%) in models that included socio-demographic and support, lifestyle or physical health and functioning factor, but remained statistically significant. The HR estimate (0.94 per integer score) was substantially attenuated (60%) and was insignificant in the model that included psychological health and functioning. Including all co-varying factors in the model resulted in statistically insignificant HR estimate (1.04 per integer score). Similar results were obtained for HR estimates for fairly-to-very happy versus fairly-to- very sad). DISCUSSION: Much of the association between happiness and increased life expectancy could be explained by socio-demographic, lifestyle, health and functioning factors, and especially psychological health and functioning factors.

Risk Factors of Progression to Cognitive Frailty: Singapore Longitudinal Ageing Study 2.

INTRODUCTION: Cognitive frailty is associated with higher risk of dementia and adverse health outcomes. However, multidimensional factors that influence cognitive frailty transitions are not known. We aimed to investigate risk factors of incident cognitive frailty. METHODS: Prospective cohort study participants were community-dwelling adults without dementia and other degenerative disorders and baseline and follow-up, including N = 1,054 participants aged ≥55 free of cognitive frailty at baseline, with complete baseline (March 6, 2009, to June 11, 2013) and follow-up data at 3-5 years later (January 16, 2013, to August 24, 2018). Incident cognitive frailty was defined by one or more criteria of the physical frailty phenotype and <26 of Mini-Mental State Examination (MMSE) score. Potential risk factors assessed at baseline included demographic, socioeconomic, medical, psychological and social factors, and biochemical markers. Data were analyzed using least absolute shrinkage selection operator (LASSO) multivariable logistic regression models. RESULTS: A total of 51 (4.8%) participants, including 21 (3.5%) of the cognitively normal and physically robust participants, 20 (4.7%) of the prefrail/frail only, and 10 (45.4%) of cognitively impaired only, transited to cognitive frailty at follow-up. Risk factors for transition to cognitive frailty were having eye problem (OR = 2.6, 95% CI 1.24-5.43) and low HDL cholesterol (OR = 4.1, 95% CI 2.03-8.40), while protective factors for cognitive frailty transition were higher levels of education (OR = 0.3, 95% CI 0.10-0.74) and participation in cognitive stimulating activities (OR = 0.4, 95% CI 0.17-0.82). CONCLUSION: Multi-domain modifiable factors especially related to leisure activities predict cognitive frailty transition and may be targeted for prevention of dementia and associated adverse health outcomes.

Social connections and risk of incident mild cognitive impairment, dementia, and mortality in 13 longitudinal cohort studies of ageing.

INTRODUCTION: Previous meta-analyses have linked social connections and mild cognitive impairment, dementia, and mortality. However, these used aggregate data from North America and Europe and examined a limited number of social connection markers. METHODS: We used individual participant data (N = 39271, Mage  = 70.67 (40-102), 58.86% female, Meducation  = 8.43 years, Mfollow-up  = 3.22 years) from 13 longitudinal ageing studies. A two-stage meta-analysis of Cox regression models examined the association between social connection markers with our primary outcomes. RESULTS: We found associations between good social connections structure and quality and lower risk of incident mild cognitive impairment (MCI); between social structure and function and lower risk of incident dementia and mortality. Only in Asian cohorts, being married/in a relationship was associated with reduced risk of dementia, and having a confidante was associated with reduced risk of dementia and mortality. DISCUSSION: Different aspects of social connections - structure, function, and quality - are associated with benefits for healthy aging internationally. HIGHLIGHTS: Social connection structure (being married/in a relationship, weekly community group engagement, weekly family/friend interactions) and quality (never lonely) were associated with lower risk of incident MCI. Social connection structure (monthly/weekly friend/family interactions) and function (having a confidante) were associated with lower risk of incident dementia. Social connection structure (living with others, yearly/monthly/weekly community group engagement) and function (having a confidante) were associated with lower risk of mortality. Evidence from 13 longitudinal cohort studies of ageing indicates that social connections are important targets for reducing risk of incident MCI, incident dementia, and mortality. Only in Asian cohorts, being married/in a relationship was associated with reduced risk of dementia, and having a confidante was associated with reduced risk of dementia and mortality.

Correlates of Gait Speed Among Older Adults From 6 Countries: Findings From the COSMIC Collaboration.

BACKGROUND: Few studies have compared gait speed and its correlates among different ethnogeographic regions. The goals of this study were to describe usual and rapid gait speed, and identify their correlates across Australian, Asian, and African countries. METHODS: We used data from 6 population-based cohorts of adults aged 65+ from 6 countries and 3 continents (N = 6 472), with samples ranging from 231 to 1 913. All cohorts are members of the Cohort Studies of Memory in an International Consortium collaboration. We investigated whether clinical (body mass index [BMI], hypertension, stroke, apolipoprotein status), psychological (cognition, mood, general health), and behavioral factors (smoking, drinking, physical activity) correlated with usual (N = 4 cohorts) and rapid gait speed (N = 3 cohorts) similarly across cohorts. Regression models were controlled for age, sex, and education, and were sex-stratified. RESULTS: Age- and sex-standardized usual gait speed means ranged from 0.61 to 1.06 m/s and rapid gait speed means ranged from 1.16 to 1.64 m/s. Lower BMI and better cognitive function consistently correlated with faster gait speed in all cohorts. Less consistently, not having hypertension and greater physical activity engagement were associated with faster gait speed. Associations with mood, smoking, and drinking were largely nonsignificant. These patterns were not attenuated by demographics. There was limited evidence that the associations differed by sex, except physical activity, where the greater intensity was associated with usual gait among men but not women. CONCLUSIONS: This study is among the first to describe the usual and rapid gait speeds across older adults in Africa, Asia, and Australia.

Sex differences in dementia risk and risk factors: Individual-participant data analysis using 21 cohorts across six continents from the COSMIC consortium.

INTRODUCTION: Sex differences in dementia risk, and risk factor (RF) associations with dementia, remain uncertain across diverse ethno-regional groups. METHODS: A total of 29,850 participants (58% women) from 21 cohorts across six continents were included in an individual participant data meta-analysis. Sex-specific hazard ratios (HRs), and women-to-men ratio of hazard ratios (RHRs) for associations between RFs and all-cause dementia were derived from mixed-effect Cox models. RESULTS: Incident dementia occurred in 2089 (66% women) participants over 4.6 years (median). Women had higher dementia risk (HR, 1.12 [1.02, 1.23]) than men, particularly in low- and lower-middle-income economies. Associations between longer education and former alcohol use with dementia risk (RHR, 1.01 [1.00, 1.03] per year, and 0.55 [0.38, 0.79], respectively) were stronger for men than women; otherwise, there were no discernible sex differences in other RFs. DISCUSSION: Dementia risk was higher in women than men, with possible variations by country-level income settings, but most RFs appear to work similarly in women and men.

Associations of Inflammatory, Metabolic, Malnutrition, and Frailty Indexes with Multimorbidity Incidence and Progression, and Mortality Impact: Singapore Longitudinal Aging Study.

INTRODUCTION: The detection of systemic risk factors aids in the formulation of strategies to prevent multimorbidity and its associated mortality impact. We aimed to determine the associations of inflammatory, metabolic, malnutrition, and frailty indexes with multimorbidity onset and progression and their predictions of multimorbidity-associated mortality risk. METHODS: A prospective cohort study (Singapore Longitudinal Aging Study [SLAS]) of 5,089 community-dwelling older adults aged ≥55 years in two waves of recruitment (SLAS-1: March 2005-September 2007, SLAS-2: January 2013-August 2018). Baseline variables included inflammatory (neutrophil-lymphocyte ratio (NLR), lymphocyte-monocyte ratio (LMR)) and metabolic profiles (atherogenic index of plasma (AIP), triglyceride-glucose index of insulin resistance (TyG)), physical frailty, and nutritional risk (Mini Nutritional Assessment-Short Form (MNA-SF), Nutritional Screening Initiative (NSI), Elderly Nutritional Indicators for Geriatric Malnutrition Assessment (ENIGMA)). At follow-up, 3-5 years after the baseline interview, incident multimorbidity (≥2 chronic diseases) was determined among multimorbidity-free participants (N = 1,657) and worsening multimorbidity (increase of ≥2 chronic diseases) among participants with baseline multimorbidity (N = 1,207). Mortality in all participants and those with multimorbidity (N = 2,291) was determined up to 31 December, 2016. Odds ratio (OR), hazard ratio (HR), and 95% confidence intervals (95% CI) were estimated in multivariate logistic and Cox regression models, in base model adjustments for age, sex, ethnicity, housing type, smoking, and a number of comorbidities, and further stepwise selection adjustment for other systemic risk indexes. RESULTS: At baseline, NLR, LMR, AIP, TyG, physical frailty, ENIGMA, NSI, and MNA-SF were significantly associated with prevalent multimorbidity (p < 0.001). Among multimorbidity-free participants, LMR, TyG, and ENIGMA were significantly associated with incident multimorbidity in both the base model and further stepwise selection models: LMR (OR = 0.87, 95% CI: 0.81-0.94), TyG (OR = 1.36, 95% CI: 1.06-1.75), and ENIGMA (OR = 1.15, 95% CI: 1.02-1.30). Among participants with baseline multimorbidity, NLR, LMR, and TyG significantly predicted worsened multimorbidity at follow-up in base model analysis, and LMR (OR = 0.72, 95% CI: 0.60-0.86) and TyG (OR = 1.96, 95% CI: 1.24-3.09) remained as independent predictors in further stepwise selection models. Among participants with prevalent multimorbidity, NLR, TyG, frailty, MNA, and ENIGMA were significantly associated with mortality risk with base model adjustments and further stepwise selection models: NLR (HR = 1.20, 95% CI: 1.10-1.32), TyG (HR = 1.27, 95% CI: 1.04-1.54), frailty (HR = 1.22, 95% CI: 1.10-1.36), ENIGMA (HR = 1.13, 95% CI: 1.05-1.22), MNA (HR = 0.91, 95% CI: 0.85-0.97). A combined systemic risk index shows increasing quartiles, adjusted for age, sex, housing, and smoking status, significantly predicting mortality risk. DISCUSSION/CONCLUSION: The onset and progression of multimorbidity and its mortality impact are driven by systemic factors, including inflammation, metabolic dysfunction (insulin resistance), malnutrition, and frailty. The measurement of these systemic factors using simple, inexpensive clinical and blood chemistry tools can help in strategies to prevent and reduce its mortality impact.

Physiological and Cognitive Determinants of Gait Variability of Asian Population: The Yishun Study.

INTRODUCTION: Gait variability is associated with frailty, dementia, and falls. Studies on the association of physiological and cognitive factors with gait variability have seldom included middle-aged adults, even though these adults already experienced loss of muscular strength and postural stability. This study aimed a) to examine and compare the trend of gait variability in men and women, across the adult age spectrum, and b) to identify and compare the contributions of physiological and cognitive factors to gait variability. METHODS: This was a population-based cross-sectional study at a single center. A random sample of 507 community-dwelling, well-functioning adults aged 21-90 years were studied. Cognition was measured using the Repeatable Battery for the Assessment of Neuropsychological Status. Physiological factors examined included visual contrast sensitivity (VCS), postural sway, hand reaction time, handgrip strength (HGS), knee extensor strength, and gait variability (coefficient of variation [CoV]). Multivariable regression models were used to examine the association between physiological and cognitive performance with gait CoV. RESULTS: Women walked with greater stride width CoV (p < 0.01) and double support time (DST) CoV (p < 0.01) than men. The stride width (p = 0.01) and DST variability (p = 0.03) were significantly higher in older men as compared to men in younger age-groups. Gait speed accounted for most of the gait CoV variances and attenuated the effects of physiological performance and/or attention cognition on most gait variability, except for CoV of DST and stride width. Adults with better VCS (ß = -0.19), faster hand reaction (ß = 0.12), and greater HGS (ß = -0.15) had lower variability in step length. CONCLUSION: The trends of stride width CoV and DST CoV across adult age spectrum were different between men and women. Greater stride width variability was partly attributed to greater HGS, possibly to better control lateral stability during walking. Physiological factors outweigh cognition in regulating most of the gait CoV in this study. They are modifiable and potential targets for healthy aging program.

Dose-response relationship between late-life physical activity and incident dementia: A pooled analysis of 10 cohort studies of memory in an international consortium.

INTRODUCTION: Though consistent evidence suggests that physical activity may delay dementia onset, the duration and amount of activity required remains unclear. METHODS: We harmonized longitudinal data of 11,988 participants from 10 cohorts in eight countries to examine the dose-response relationship between late-life physical activity and incident dementia among older adults. RESULTS: Using no physical activity as a reference, dementia risk decreased with duration of physical activity up to 3.1 to 6.0 hours/week (hazard ratio [HR] 0.88, 95% confidence interval [CI] 0.67 to 1.15 for 0.1 to 3.0 hours/week; HR 0.68, 95% CI 0.52 to 0.89 for 3.1 to 6.0 hours/week), but plateaued with higher duration. For the amount of physical activity, a similar pattern of dose-response curve was observed, with an inflection point of 9.1 to 18.0 metabolic equivalent value (MET)-hours/week (HR 0.92, 95% CI 0.70 to 1.22 for 0.1 to 9.0 MET-hours/week; HR 0.70, 95% CI 0.53 to 0.93 for 9.1 to 18.0 MET-hours/week). DISCUSSION: This cross-national analysis suggests that performing 3.1 to 6.0 hours of physical activity and expending 9.1 to 18.0/MET-hours of energy per week may reduce dementia risk.

Lower insulin level is associated with sarcopenia in community-dwelling frail and non-frail older adults.

Background: Sarcopenia is common among older individuals with and without type 2 diabetes mellitus (T2DM). There are conflicting evidence in support of the role of insulin in the development of age-related and T2DM-related sarcopenia. We investigated the relationships between the levels of fasting insulin and other blood biomarkers related to insulin or lipid metabolism with the presence of sarcopenia in two independent studies. Materials and methods: In 246 pre-frail frail older individuals with (n = 41) and without T2DM (n = 205) in the Singapore Frailty Interventional Trial, sarcopenia was defined by low appendicular lean mass (ALM) relative to total body mass (skeletal muscle index, SMI = ALM/height2) and low lower limb strength or gait speed according to the Asian Working Group for Sarcopenia (AWGS) criteria released in 2019, and related to levels of fasting insulin and glucose, C-peptide, IGF-1, leptin, and active ghrelin. This investigation was validated in another independent study sample of 189 robust and pre-frail frail elderly in the Singapore Longitudinal Aging Study Wave 2 (SLAS-2). Results: Compared to non-sarcopenic individuals, those with sarcopenia and possible sarcopenia showed significantly lower fasting insulin (p < 0.05) in pre-frail/frail and non-frail older individuals. Consistent trends of relationships were observed for serum levels of C-peptide, IGF-1, leptin, and active ghrelin. In multivariable logistic regression models, sarcopenia was independently associated with low insulin (p < 0.05). Levels of fasting insulin, C-peptide, and leptin were also significantly associated with BMI, SMI, knee extension strength, gait speed, and physical activity score. Conclusion: Dysregulated insulin secretion in diabetic and non-diabetic older individuals may play an important role in age-related and diabetes-related sarcopenia.

Longitudinal associations of housework with frailty and mortality in older adults: Singapore Longitudinal Ageing Study 2.

BACKGROUND: Housework may provide a sustainable form of physical activity for older adults and improve health and survival outcomes. Longitudinal studies on associations between housework status over time and health outcomes are lacking. We aim to assess the longitudinal association of intensity and duration of housework with frailty and mortality outcomes. METHODS: Among 3270 community-dwelling prospective cohort study participants, aged ≥55 years, data on light housework (N=2996) and heavy housework (N=3022) were available at baseline (March 6, 2009, to June 11, 2013) and follow-up at 3 to 5 years later, (January 16, 2013 to August 24, 2018). Median time spent per week on light (≥420min/week) and heavy (>0min/week) household activities at baseline and follow-up were used to categorise individuals into three groups (i) consistent low levels of housework at both baseline and follow-up, (ii) inconsistent high levels of housework at either baseline or follow-up and (iii) consistent high levels of housework at both baseline and follow-up. Baseline and follow-up frailty index >0.10, and all-cause, cancer and cardiovascular mortality from mean 9.5 years follow-up to March 31, 2021. Effect estimates were adjusted for socio-demographics, nutritional risk, lifestyle and other physical activities. RESULTS: Overall, participants had mean [SD] age, 66.9 [7.8] years; 1916 [62.7%] were female. Participation in high levels of light and heavy housework consistently over time was associated with decreased odds of prefrailty/frailty at follow-up, [OR,0.61;95%CI,0.40-0.94] and [OR,0.56;95%CI,0.34-0.90] respectively, in the older group aged ≥65, compared to participants with consistent low levels of housework at baseline and follow-up. Sex-stratified analysis revealed an association between regular heavy housework participation and lower prevalence of prefrailty/frailty at follow-up in older men but not women [OR,0.31;95%CI,0.13-0.72]. Regular participation in high levels of light housework was associated with 41% lower risk of all-cause mortality [95%CI,0.36-0.96] in women but not in men, and 54% lower risk of cardiovascular mortality [95%CI,0.22-0.96]. CONCLUSIONS: Regular participation in above average levels of light housework is associated with decreased odds of prefrailty/frailty in older adults aged ≥65 years, and all-cause mortality in older women. Heavy housework participation is associated with decreased odds of prefrailty/frailty, especially in older men aged ≥65. Housework may be a meaningful occupation for older adults and should be encouraged for health and wellbeing.

Body composition reference values in Singaporean adults using dual-energy X-ray absorptiometry-The Yishun study.

OBJECTIVES: This study establishes age- and sex-specific reference values for fat mass index (FMI), lean mass index (LMI), appendicular LMI (aLMI), and body fat distribution indices including Android/Gynoid % fat ratio and Trunk/Limb % fat ratio in multi-ethnic Singaporean adults. METHODS: A population-based cross-sectional study using dual-energy X-ray absorptiometry (Hologic Discovery Wi) was carried out to measure whole body and regional fat and lean mass in community-dwelling adults. A total of 537 adults (57.5% women), aged from 21 to 90 years, were recruited from the large north-eastern residential town of Yishun. Age- and sex-specific percentile reference values were generated for FMI, LMI, aLMI, Android/Gynoid % fat ratio and Trunk/Limb % fat ratio using the Lambda-Mu-Sigma method. The relationship between the parameters and age were assessed through the Pearson's correlation coefficient. RESULTS: All parameters demonstrated significant correlation with age (p < 0.05) for both men and women, except for LMI in women, with the strength of r ranging from 0.12 (weak correlation) to 0.54 (strong correlation). LMI (r = -0.45) and appendicular LMI (r = -0.54) were negatively associated with age in men while none (r = -0.06) to weak correlation (r = -0.14) were shown in women for the same parameters respectively. The Android/Gynoid % fat ratio and Trunk/Limb % fat ratio were positively related to age for both men (r = 0.37 & 0.43, p < 0.001) and women (r = 0.52 & 0.48, p < 0.001). CONCLUSION: We have established DXA-based body composition reference data for the Singapore adult population. These reference data will be particularly useful in geriatric, obesity and oncology clinics, enabling the prescription of appropriate therapy to individuals at risk of morbidity from unfavorable body composition phenotypes. It also adds on to the limited reference database on Southeast Asian body composition.

Associations between social connections and cognition: a global collaborative individual participant data meta-analysis.

BACKGROUND: Poor social connections (eg, small networks, infrequent interactions, and loneliness) are modifiable risk factors for cognitive decline. Existing meta-analyses are limited by reporting aggregate responses, a focus on global cognition, and combining social measures into single constructs. We aimed to investigate the association between social connection markers and the rate of annual change in cognition (ie, global and domain-specific), as well as sex differences, using an individual participant data meta-analysis. METHODS: We harmonised data from 13 longitudinal cohort studies of ageing in North America, South America, Europe, Africa, Asia, and Australia. Studies were eligible for inclusion if they had baseline data for social connection markers and at least two waves of cognitive scores. Follow-up periods ranged from 0 years to 15 years across cohorts. We included participants with cognitive data for at least two waves and social connection data for at least one wave. We then identified and excluded people with dementia at baseline. Primary outcomes were annual rates of change in global cognition and cognitive domain scores over time until final follow-up within each cohort study analysed by use of an individual participant data meta-analysis. Linear mixed models within cohorts used baseline social connection markers as predictors of the primary outcomes. Effects were pooled in two stages using random-effects meta-analyses. We assessed the primary outcomes in the main (partially adjusted) and fully adjusted models. Partially adjusted models controlled for age, sex, and education; fully adjusted models additionally controlled for diabetes, hypertension, smoking, cardiovascular risk, and depression. FINDINGS: Of the 40 006 participants in the 13 cohort studies, we excluded 1392 people with dementia at baseline. 38 614 individual participants were included in our analyses. For the main models, being in a relationship or married predicted slower global cognitive decline (b=0·010, 95% CI 0·000-0·019) than did being single or never married; living with others predicted slower global cognitive (b=0·007, 0·002-0·012), memory (b=0·017, 0·006-0·028), and language (b=0·008, 0·000-0·015) decline than did living alone; and weekly interactions with family and friends (b=0·016, 0·006-0·026) and weekly community group engagement (b=0·030, 0·007-0·052) predicted slower memory decline than did no interactions and no engagement. Never feeling lonely predicted slower global cognitive (b=0·047, 95% CI 0·018-0·075) and executive function (b=0·047, 0·017-0·077) decline than did often feeling lonely. Degree of social support, having a confidante, and relationship satisfaction did not predict cognitive decline across global cognition or cognitive domains. Heterogeneity was low (I2=0·00-15·11%) for all but two of the significant findings (association between slower memory decline and living with others [I2=58·33%] and community group engagement, I2=37·54-72·19%), suggesting robust results across studies. INTERPRETATION: Good social connections (ie, living with others, weekly community group engagement, interacting weekly with family and friends, and never feeling lonely) are associated with slower cognitive decline. FUNDING: EU Joint Programme-Neurodegenerative Disease Research grant, funded by the National Health and Medical Research Council Australia, and the US National Institute on Aging of the US National Institutes of Health.