Browsing by Author "Thalamuthu A"

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    Determinants of cognitive performance and decline in 20 diverse ethno-regional groups: A COSMIC collaboration cohort study
    (Public Library of Science (PLoS), 2019-07) Lipnicki DM; Makkar SR; Crawford JD; Thalamuthu A; Kochan NA; Lima-Costa MF; Castro-Costa E; Ferri CP; Brayne C; Stephan B; Llibre-Rodriguez JJ; Llibre-Guerra JJ; Valhuerdi-Cepero AJ; Lipton RB; Katz MJ; Derby CA; Ritchie K; Ancelin M-L; Carrière I; Scarmeas N; Yannakoulia M; Hadjigeorgiou GM; Lam L; Chan W-C; Fung A; Guaita A; Vaccaro R; Davin A; Kim KW; Han JW; Suh SW; Riedel-Heller SG; Roehr S; Pabst A; van Boxtel M; Köhler S; Deckers K; Ganguli M; Jacobsen EP; Hughes TF; Anstey KJ; Cherbuin N; Haan MN; Aiello AE; Dang K; Kumagai S; Chen T; Narazaki K; Ng TP; Gao Q; Nyunt MSZ; Scazufca M; Brodaty H; Numbers K; Trollor JN; Meguro K; Yamaguchi S; Ishii H; Lobo A; Lopez-Anton R; Santabárbara J; Leung Y; Lo JW; Popovic G; Sachdev PS; for Cohort Studies of Memory in an International Consortium (COSMIC)
    Background With no effective treatments for cognitive decline or dementia, improving the evidence base for modifiable risk factors is a research priority. This study investigated associations between risk factors and late-life cognitive decline on a global scale, including comparisons between ethno-regional groups. Methods and findings We harmonized longitudinal data from 20 population-based cohorts from 15 countries over 5 continents, including 48,522 individuals (58.4% women) aged 54–105 (mean = 72.7) years and without dementia at baseline. Studies had 2–15 years of follow-up. The risk factors investigated were age, sex, education, alcohol consumption, anxiety, apolipoprotein E ε4 allele (APOE*4) status, atrial fibrillation, blood pressure and pulse pressure, body mass index, cardiovascular disease, depression, diabetes, self-rated health, high cholesterol, hypertension, peripheral vascular disease, physical activity, smoking, and history of stroke. Associations with risk factors were determined for a global cognitive composite outcome (memory, language, processing speed, and executive functioning tests) and Mini-Mental State Examination score. Individual participant data meta-analyses of multivariable linear mixed model results pooled across cohorts revealed that for at least 1 cognitive outcome, age (B = −0.1, SE = 0.01), APOE*4 carriage (B = −0.31, SE = 0.11), depression (B = −0.11, SE = 0.06), diabetes (B = −0.23, SE = 0.10), current smoking (B = −0.20, SE = 0.08), and history of stroke (B = −0.22, SE = 0.09) were independently associated with poorer cognitive performance (p < 0.05 for all), and higher levels of education (B = 0.12, SE = 0.02) and vigorous physical activity (B = 0.17, SE = 0.06) were associated with better performance (p < 0.01 for both). Age (B = −0.07, SE = 0.01), APOE*4 carriage (B = −0.41, SE = 0.18), and diabetes (B = −0.18, SE = 0.10) were independently associated with faster cognitive decline (p < 0.05 for all). Different effects between Asian people and white people included stronger associations for Asian people between ever smoking and poorer cognition (group by risk factor interaction: B = −0.24, SE = 0.12), and between diabetes and cognitive decline (B = −0.66, SE = 0.27; p < 0.05 for both). Limitations of our study include a loss or distortion of risk factor data with harmonization, and not investigating factors at midlife. Conclusions These results suggest that education, smoking, physical activity, diabetes, and stroke are all modifiable factors associated with cognitive decline. If these factors are determined to be causal, controlling them could minimize worldwide levels of cognitive decline. However, any global prevention strategy may need to consider ethno-regional differences.
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    Use of Antihypertensives, Blood Pressure, and Estimated Risk of Dementia in Late Life: An Individual Participant Data Meta-Analysis.
    (American Medical Association, 2023-09-12) Lennon MJ; Lam BCP; Lipnicki DM; Crawford JD; Peters R; Schutte AE; Brodaty H; Thalamuthu A; Rydberg-Sterner T; Najar J; Skoog I; Riedel-Heller SG; Röhr S; Pabst A; Lobo A; De-la-Cámara C; Lobo E; Bello T; Gureje O; Ojagbemi A; Lipton RB; Katz MJ; Derby CA; Kim KW; Han JW; Oh DJ; Rolandi E; Davin A; Rossi M; Scarmeas N; Yannakoulia M; Dardiotis T; Hendrie HC; Gao S; Carrière I; Ritchie K; Anstey KJ; Cherbuin N; Xiao S; Yue L; Li W; Guerchet MM; Preux P-M; Aboyans V; Haan MN; Aiello AE; Ng TP; Nyunt MSZ; Gao Q; Scazufca M; Sachdev PSS
    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.