METHODS: Over a one or two-year period, children <5 years hospitalized with CAP were identified using ICD-10 discharge codes. Cases were matched to standardized definitions of suspected (S-CAP), confirmed (C-CAP), or bacterial CAP (B-CAP) used in a pneumococcal conjugate vaccine efficacy study (COMPAS). Median total direct medical costs of CAP-related hospitalizations were calculated.

RESULTS: Vietnam (three centers): 7591 CAP episodes were identified with 4.3% (95% confidence interval 4.2;4.4) S-CAP, 3.3% (3.2;3.4) C-CAP and 1.4% (1.3;1.4) B-CAP episodes of all-cause hospitalization in children aged <5 years. The B-CAP case fatality rate (CFR) was 1.3%. Malaysia (two centers): 1027 CAP episodes were identified with 2.7% (2.6;2.9); 2.6% (2.4;2.8); 0.04% (0.04;0.1) due to S-CAP, C-CAP, and B-CAP, respectively. One child with B-CAP died. Indonesia (one center): 960 CAP episodes identified with 18.0% (17.0;19.1); 16.8% (15.8;17.9); 0.3% (0.2;0.4) due to S-CAP, C-CAP, and B-CAP, respectively. The B-CAP CFR was 20%. Korea (three centers): 3151 CAP episodes were identified with 21.1% (20.4;21.7); 11.8% (11.2;12.3); 2.4% (2.1;2.7) due to S-CAP, C-CAP, and B-CAP, respectively. There were no deaths.

COSTS: CAP-related hospitalization costs were highest for B-CAP episodes: 145.00 (Vietnam) to 1013.3 USD (Korea) per episode.

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.

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.

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.