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- Gong, J., et al.
(author)
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Sex differences in dementia risk and risk factors: Individual-participant data analysis using 21 cohorts across six continents from the COSMIC consortium
- 2023
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In: Alzheimers & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 19:8, s. 3365-3378
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Journal article (peer-reviewed)abstract
- IntroductionSex differences in dementia risk, and risk factor (RF) associations with dementia, remain uncertain across diverse ethno-regional groups. MethodsA 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. ResultsIncident 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. DiscussionDementia 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.
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- Mahalingam, G., et al.
(author)
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Social connections and risk of incident mild cognitive impairment, dementia, and mortality in 13 longitudinal cohort studies of ageing
- 2023
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In: Alzheimers & Dementia. - 1552-5260. ; 19:11, s. 5114-5128
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Journal article (peer-reviewed)abstract
- IntroductionPrevious 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. MethodsWe used individual participant data (N = 39271, M-age = 70.67 (40-102), 58.86% female, M-education = 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. ResultsWe 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. DiscussionDifferent aspects of social connections - structure, function, and quality - are associated with benefits for healthy aging internationally. HighlightsSocial 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.
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- Samtani, S., et al.
(author)
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Associations between social connections and cognition: a global collaborative individual participant data meta-analysis
- 2022
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In: The Lancet Healthy Longevity. - 2666-7568. ; 3:11
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Journal article (peer-reviewed)abstract
- 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.
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- Matison, Annabel P., et al.
(author)
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Associations between fruit and vegetable intakes and incident depression in middle-aged and older adults from 10 diverse international longitudinal cohorts
- 2024
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In: JOURNAL OF AFFECTIVE DISORDERS. - 0165-0327 .- 1573-2517. ; 359, s. 373-381
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Journal article (peer-reviewed)abstract
- Background: Emerging observational evidence supports a role for higher fruit and vegetable intake in protecting against the development of depression. However, there is a scarcity of research in older adults or in low- to middle -income countries (LMICs). Methods: Participants were 7801 community -based adults (mean age 68.6 +/- 8.0 years, 55.8 % female) without depression, from 10 diverse cohorts, including four cohorts from LMICs. Fruit and vegetable intake was selfreported via comprehensive food frequency questionnaire, short food questionnaire or diet history. Depressive symptoms were assessed using validated measures, and depression defined applying validated cut-offs. The associations between baseline fruit and vegetable intakes and incident depression over a follow-up period of three to nine years were examined using Cox regression. Analyses were performed by cohort with results metaanalysed. Results: There were 1630 cases of incident depression (21 % of participants) over 40,258 person -years of followup. Higher intake of fruit was associated with a lower risk of incident depression (HR 0.87, 95%CI [0.77, 0.99], I 2 = 4 %). No association was found between vegetable intake and incident depression (HR 0.93, 95%CI [0.84, 1.04], I 2 = 0 %).
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5. |
- Van Asbroeck, Stephanie, et al.
(author)
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Lifestyle and incident dementia: A COSMIC individual participant data meta-analysis
- 2024
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In: ALZHEIMERS & DEMENTIA. - 1552-5260 .- 1552-5279. ; 20:6, s. 3972-3986
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Journal article (peer-reviewed)abstract
- INTRODUCTIONThe 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. METHODSWe 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. RESULTSA 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. DISCUSSIONModifiable 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.
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