Browsing by Author "Guerchet M"

Now showing 1 - 7 of 7
  • Thumbnail Image
    Item
    Associations between social connections and cognition: a global collaborative individual participant data meta-analysis
    (Elsevier B.V, 2022-11) Samtani S; Mahalingam G; Lam BCP; Lipnicki DM; Lima-Costa MF; Blay SL; Castro-Costa E; Shifu X; Guerchet M; Preux P-M; Gbessemehlan A; Skoog I; Najar J; Rydberg Sterner T; Scarmeas N; Kim K-W; Riedel-Heller S; Röhr S; Pabst A; Shahar S; Numbers K; Ganguli M; Jacobsen E; Hughes TF; Crowe M; Ng TP; Maddock J; Marseglia A; Mélis R; Szcześniak D; Wiegelmann H; Vernooij-Dassen M; Jeon Y-H; Sachdev PS; Brodaty H; SHARED consortium for the Cohort Studies of Memory in an International Consortium (COSMIC)
    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.
  • Thumbnail Image
    Item
    Estimating prevalence of subjective cognitive decline in and across international cohort studies of aging: a COSMIC study
    (BioMed Central Ltd, 2020-12-18) Röhr S; Pabst A; Riedel-Heller SG; Jessen F; Turana Y; Handajani YS; Brayne C; Matthews FE; Stephan BCM; Lipton RB; Katz MJ; Wang C; Guerchet M; Preux P-M; Mbelesso P; Ritchie K; Ancelin M-L; Carrière I; Guaita A; Davin A; Vaccaro R; Kim KW; Han JW; Suh SW; Shahar S; Din NC; Vanoh D; van Boxtel M; Köhler S; Ganguli M; Jacobsen EP; Snitz BE; Anstey KJ; Cherbuin N; Kumagai S; Chen S; Narazaki K; Ng TP; Gao Q; Gwee X; Brodaty H; Kochan NA; Trollor J; Lobo A; López-Antón R; Santabárbara J; Crawford JD; Lipnicki DM; Sachdev PS; for Cohort Studies of Memory in an International Consortium (COSMIC)
    Background Subjective cognitive decline (SCD) is recognized as a risk stage for Alzheimer’s disease (AD) and other dementias, but its prevalence is not well known. We aimed to use uniform criteria to better estimate SCD prevalence across international cohorts. Methods We combined individual participant data for 16 cohorts from 15 countries (members of the COSMIC consortium) and used qualitative and quantitative (Item Response Theory/IRT) harmonization techniques to estimate SCD prevalence. Results The sample comprised 39,387 cognitively unimpaired individuals above age 60. The prevalence of SCD across studies was around one quarter with both qualitative harmonization/QH (23.8%, 95%CI = 23.3–24.4%) and IRT (25.6%, 95%CI = 25.1–26.1%); however, prevalence estimates varied largely between studies (QH 6.1%, 95%CI = 5.1–7.0%, to 52.7%, 95%CI = 47.4–58.0%; IRT: 7.8%, 95%CI = 6.8–8.9%, to 52.7%, 95%CI = 47.4–58.0%). Across studies, SCD prevalence was higher in men than women, in lower levels of education, in Asian and Black African people compared to White people, in lower- and middle-income countries compared to high-income countries, and in studies conducted in later decades. Conclusions SCD is frequent in old age. Having a quarter of older individuals with SCD warrants further investigation of its significance, as a risk stage for AD and other dementias, and of ways to help individuals with SCD who seek medical advice. Moreover, a standardized instrument to measure SCD is needed to overcome the measurement variability currently dominant in the field.
  • Thumbnail Image
    Item
    Estimating prevalence of subjective cognitive decline in and across international cohort studies of aging: A COSMIC study
    (BioMed Central Ltd, 2020-05-26) Röhr S; Pabst A; Riedel-Heller SG; Jessen F; Turana Y; Handajani YS; Brayne C; Matthews FE; Stephan BCM; Lipton RB; Katz MJ; Wang C; Guerchet M; Preux P-M; Mbelesso P; Ritchie K; Ancelin M-L; Carrière I; Guaita A; Davin A; Vaccaro R; Kim KW; Han JW; Suh SW; Shahar S; Din NC; Vanoh D; van Boxtel M; Köhler S; Ganguli M; Jacobsen EP; Snitz BE; Anstey KJ; Cherbuin N; Kumagai S; Chen S; Narazaki K; Ng TP; Gao Q; Gwee X; Brodaty H; Kochan NA; Trollor J; Lobo A; López-Antón R; Santabárbara J; Crawford JD; Lipnicki DM; Sachdev PS; for Cohort Studies of Memory in an International Consortium (COSMIC)
    Background Subjective cognitive decline (SCD) is recognized as a risk stage for Alzheimer’s disease (AD) and other dementias, but its prevalence is not well known. We aimed to use uniform criteria to better estimate SCD prevalence across international cohorts. Methods We combined individual participant data for 16 cohorts from 15 countries (members of the COSMIC consortium) and used qualitative and quantitative (Item Response Theory/IRT) harmonization techniques to estimate SCD prevalence. Results The sample comprised 39,387 cognitively unimpaired individuals above age 60. The prevalence of SCD across studies was around one quarter with both qualitative harmonization/QH (23.8%, 95%CI = 23.3–24.4%) and IRT (25.6%, 95%CI = 25.1–26.1%); however, prevalence estimates varied largely between studies (QH 6.1%, 95%CI = 5.1–7.0%, to 52.7%, 95%CI = 47.4–58.0%; IRT: 7.8%, 95%CI = 6.8–8.9%, to 52.7%, 95%CI = 47.4–58.0%). Across studies, SCD prevalence was higher in men than women, in lower levels of education, in Asian and Black African people compared to White people, in lower- and middle-income countries compared to high-income countries, and in studies conducted in later decades. Conclusions SCD is frequent in old age. Having a quarter of older individuals with SCD warrants further investigation of its significance, as a risk stage for AD and other dementias, and of ways to help individuals with SCD who seek medical advice. Moreover, a standardized instrument to measure SCD is needed to overcome the measurement variability currently dominant in the field.
  • Thumbnail Image
    Item
    Lifestyle and incident dementia: A COSMIC individual participant data meta-analysis
    (Wiley Periodicals LLC on behalf of Alzheimer's Association, 2024-06-16) Van Asbroeck S; Köhler S; van Boxtel MPJ; Lipnicki DM; Crawford JD; Castro-Costa E; Lima-Costa MF; Blay SL; Shifu X; Wang T; Yue L; Lipton RB; Katz MJ; Derby CA; Guerchet M; Preux P-M; Mbelesso P; Norton J; Ritchie K; Skoog I; Najar J; Sterner TR; Scarmeas N; Yannakoulia M; Dardiotis T; Rolandi E; Davin A; Rossi M; Gureje O; Ojagbemi A; Bello T; Kim KW; Han JW; Oh DJ; Trompet S; Gussekloo J; Riedel-Heller SG; Röhr S; Pabst A; Shahar S; Rivan NFM; Singh DKA; Jacobsen E; Ganguli M; Hughes T; Haan M; Aiello AE; Ding D; Zhao Q; Xiao Z; Narazaki K; Chen T; Chen S; Ng TP; Gwee X; Gao Q; Brodaty H; Trollor J; Kochan N; Lobo A; Santabárbara J; Gracia-Garcia P; Sachdev PS; Deckers K; for Cohort Studies of Memory in an International Consortium (COSMIC)
    INTRODUCTION: The LIfestyle for BRAin Health (LIBRA) index yields a dementia risk score based on modifiable lifestyle factors and is validated in Western samples. We investigated whether the association between LIBRA scores and incident dementia is moderated by geographical location or sociodemographic characteristics. METHODS: We combined data from 21 prospective cohorts across six continents (N = 31,680) and conducted cohort-specific Cox proportional hazard regression analyses in a two-step individual participant data meta-analysis. RESULTS: A one-standard-deviation increase in LIBRA score was associated with a 21% higher risk for dementia. The association was stronger for Asian cohorts compared to European cohorts, and for individuals aged ≤75 years (vs older), though only within the first 5 years of follow-up. No interactions with sex, education, or socioeconomic position were observed. DISCUSSION: Modifiable risk and protective factors appear relevant for dementia risk reduction across diverse geographical and sociodemographic groups. HIGHLIGHTS: - A two-step individual participant data meta-analysis was conducted. - This was done at a global scale using data from 21 ethno-regionally diverse cohorts. - The association between a modifiable dementia risk score and dementia was examined. - The association was modified by geographical region and age at baseline. - Yet, modifiable dementia risk and protective factors appear relevant in all investigated groups and regions.
  • Thumbnail Image
    Item
    Sex differences in dementia risk and risk factors: Individual-participant data analysis using 21 cohorts across six continents from the COSMIC consortium.
    (John Wiley and Sons, Inc., 2023-08-01) Gong J; Harris K; Lipnicki DM; Castro-Costa E; Lima-Costa MF; Diniz BS; Xiao S; Lipton RB; Katz MJ; Wang C; Preux P-M; Guerchet M; Gbessemehlan A; Ritchie K; Ancelin M-L; Skoog I; Najar J; Sterner TR; Scarmeas N; Yannakoulia M; Kosmidis MH; Guaita A; Rolandi E; Davin A; Gureje O; Trompet S; Gussekloo J; Riedel-Heller S; Pabst A; Röhr S; Shahar S; Singh DKA; Rivan NFM; Boxtel MV; Köhler S; Ganguli M; Chang C-C; Jacobsen E; Haan M; Ding D; Zhao Q; Narazaki K; Chen T; Chen S; Ng TP; Gwee X; Numbers K; Mather KA; Scazufca M; Lobo A; De-la-Cámara C; Lobo E; Sachdev PS; Brodaty H; Hackett ML; Peters SAE; Woodward M
    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.
  • Thumbnail Image
    Item
    Social connections and risk of incident mild cognitive impairment, dementia, and mortality in 13 longitudinal cohort studies of ageing.
    (Wiley Periodicals LLC on behalf of Alzheimer’s Association., 2023-11) Mahalingam G; Samtani S; Lam BCP; Lipnicki DM; Lima-Costa MF; Blay SL; Castro-Costa E; Shifu X; Guerchet M; Preux P-M; Gbessemehlan A; Skoog I; Najar J; Sterner TR; Scarmeas N; Yannakoulia M; Dardiotis T; Kim K-W; Riedel-Heller S; Röhr S; Pabst A; Shahar S; Numbers K; Ganguli M; Hughes TF; Chang C-CH; Crowe M; Ng TP; Gwee X; Chua DQL; Rymaszewska J; Wolf-Ostermann K; Welmer A-K; Stafford J; Mélis R; Vernooij-Dassen M; Jeon Y-H; Sachdev PS; Brodaty H; SHARED consortium for the Cohort Studies of Memory in an International Consortium (COSMIC)
    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. 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.
  • Thumbnail Image
    Item
    Trajectory of Cognitive Decline Before and After Stroke in 14 Population Cohorts
    (American Medical Association, 2024-10-02) Lo JW; Crawford JD; Lipnicki DM; Lipton RB; Katz MJ; Preux P-M; Guerchet M; d'Orsi E; Quialheiro A; Rech CR; Ritchie K; Skoog I; Najar J; Sterner TR; Rolandi E; Davin A; Rossi M; Riedel-Heller SG; Pabst A; Röhr S; Ganguli M; Jacobsen E; Snitz BE; Anstey KJ; Aiello AE; Brodaty H; Kochan NA; Chen Y-C; Chen J-H; Sanchez-Juan P; Del Ser T; Valentí M; Lobo A; De-la-Cámara C; Lobo E; Sachdev PS
    IMPORTANCE: Poststroke cognitive impairment is common, but the cognitive trajectory following a first stroke, relative to prestroke cognitive function, remains unclear. OBJECTIVE: To map the trajectory of cognitive function before any stroke and after stroke in global cognition and in 4 cognitive domains, as well as to compare the cognitive trajectory prestroke in stroke survivors with the trajectory of individuals without incident stroke over follow-up. DESIGN, SETTING, AND PARTICIPANTS: The study used harmonized and pooled data from 14 population-based cohort studies included in the Cohort Studies of Memory in an International Consortium collaboration. These studies were conducted from 1993 to 2019 across 11 countries among community-dwelling older adults without a history of stroke or dementia. For this study, linear mixed-effects models were used to estimate trajectories of cognitive function poststroke relative to a stroke-free cognitive trajectory. The full model adjusted for demographic and vascular risk factors. Data were analyzed from July 2022 to March 2024. EXPOSURE: Incident stroke. MAIN OUTCOMES AND MEASURES: The primary outcome was global cognition, defined as the standardized average of 4 cognitive domains (language, memory, processing speed, and executive function). Cognitive domain scores were formed by selecting the most commonly administered test within each domain and standardizing the scores. RESULTS: The study included 20 860 participants (12 261 [58.8%] female) with a mean (SD) age of 72.9 (8.0) years and follow-up of 7.51 (4.2) years. Incident stroke was associated with a substantial acute decline in global cognition (-0.25 SD; 95% CI, -0.33 to -0.17 SD), the Mini-Mental State Examination, and all cognitive domains (ranging from -0.17 SD to -0.22 SD), as well as accelerated decline in global cognition (-0.038 SD per year; 95% CI, -0.057 to -0.019 SD per year) and all domains except memory (ranging from -0.020 to -0.055 SD per year), relative to a stroke-free cognitive trajectory. There was no significant difference in prestroke slope in stroke survivors compared with the rate of decline in individuals without stroke in all cognitive measures. The mean rate of decline without a previous stroke was -0.049 SD per year (95% CI, -0.051 to -0.047 SD) in global cognition. CONCLUSIONS AND RELEVANCE: In this cohort study using pooled data from 14 cohorts, incident stroke was associated with acute and accelerated long-term cognitive decline in older stroke survivors.