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Background Semi-competing risks arise when interest lies in the time-to-event for some non-terminal event, the observation of which is subject to some terminal event. One approach to assessing the impact of covariates on semi-competing risks data is through the illness-death model with shared frailty, where hazard regression models are used to model the effect of covariates on the endpoints. The shared frailty term, which can be viewed as an individual-specific random effect, acknowledges dependence between the events that is not accounted for by covariates. Although methods exist for fitting such a model to right-censored semi-competing risks data, there is currently a gap in the literature for fitting such models when a flexible baseline hazard specification is desired and the data are left-truncated, for example when time is on the age scale. We provide a modeling framework and openly available code for implementation. Methods We specified the model and the likelihood function that accounts for left-truncated data, and provided an approach to estimation and inference via maximum likelihood. Our model was fully parametric, specifying baseline hazards via Weibull or B-splines. Using simulated data we examined the operating characteristics of the implementation in terms of bias and coverage. We applied our methods to a dataset of 33,117 Kaiser Permanente Northern California members aged 65 or older examining the relationship between educational level (categorized as: high school or less; trade school, some college or college graduate; post-graduate) and incident dementia and death. Results A simulation study showed that our implementation provided regression parameter estimates with negligible bias and good coverage. In our data application, we found higher levels of education are associated with a lower risk of incident dementia, after adjusting for sex and race/ethnicity. Conclusions As illustrated by our analysis of Kaiser data, our proposed modeling framework allows the analyst to assess the impact of covariates on semi-competing risks data, such as incident dementia and death, while accounting for dependence between the outcomes when data are left-truncated, as is common in studies of aging and dementia.

Childhood socioeconomic status (cSES) is a powerful predictor of adult health, but its operationalization and measurement varies across studies. Using Health and Retirement Study data (HRS, which is nationally representative of community-residing United States adults aged 50+ years), we specified theoretically-motivated cSES measures, evaluated their reliability and validity, and compared their performance to other cSES indices. HRS respondent data (N = 31,169, interviewed 1992-2010) were used to construct a cSES index reflecting childhood social capital (cSC), childhood financial capital (cFC), and childhood human capital (cHC), using retrospective reports from when the respondent was <16 years (at least 34 years prior). We assessed internal consistency reliability (Cronbach's alpha) for the scales (cSC and cFC), and construct validity, and predictive validity for all measures. Validity was assessed with hypothesized correlates of cSES (educational attainment, measured adult height, self-reported childhood health, childhood learning problems, childhood drug and alcohol problems). We then compared the performance of our validated measures with other indices used in HRS in predicting self-rated health and number of depressive symptoms, measured in 2010. Internal consistency reliability was acceptable (cSC = 0.63, cFC = 0.61). Most measures were associated with hypothesized correlates (for example, the association between educational attainment and cSC was 0.01, p < 0.0001), with the exception that measured height was not associated with cFC (p = 0.19) and childhood drug and alcohol problems (p = 0.41), and childhood learning problems (p = 0.12) were not associated with cHC. Our measures explained slightly more variability in self-rated health (adjusted R2 = 0.07 vs. <0.06) and number of depressive symptoms (adjusted R2 > 0.05 vs. < 0.04) than alternative indices. Our cSES measures use latent variable models to handle item-missingness, thereby increasing the sample size available for analysis compared to complete case approaches (N = 15,345 vs. 8,248). Adopting this type of theoretically motivated operationalization of cSES may strengthen the quality of research on the effects of cSES on health outcomes.

Positive childhood experiences (PCEs) have unknown effects on late life cognition and Alzheimer’s Disease biomarkers. We examined 406 Asian, 1179 Black, 349 Latinx, and 498 White KHANDLE and STAR study participants with data on PCEs, longitudinal cognitive measures, MRI (n = 560), and amyloid PET (n = 281). We conducted mediation and multigroup models within the structural equation modeling framework allowing us to examine the direct association of PCEs with episodic memory level and change as well as the indirect effects of PCEs through education. We additionally conducted linear regressions examining the association of PCEs with MRI and amyloid PET outcomes. Average participant age was 74 (53–90) and 62% were female. Overall, PCEs were positively associated with memory intercept and change. Education significantly mediated the association between PCEs and memory intercept. PCEs were not associated with hippocampal volume or amyloid burden in the combined sample or across individual ethnocultural groups. PCEs are positively related to episodic memory through the promotion of educational attainment.

ObjectivesTo evaluate how insurance influences the risk of a dementia diagnosis among a large, diverse cohort of US civilian adults with traumatic brain injury (TBI) over a 22-year period.DesignThis is a retrospective cohort study involving individuals diagnosed with TBI.SettingThe study used the Merative MarketScan Research Database, specifically drawing from the Commercial Claims and Encounters, Medicare Supplemental and Medicaid databases, from 2000 to 2022 in the USA. These databases provide comprehensive insights into healthcare services received by enrollees, including inpatient and outpatient services, outpatient prescription claims, clinical utilisation records and healthcare expenditures.Participants267 473 adults aged 55 and older who were diagnosed with a TBI between 1 January 2000 and 31 December 2022. Individuals with unknown TBI severity and dementia claims 2 years preceding TBI were excluded. TBI and dementia diagnoses were identified using International Classification of Disease 9th and 10th editions codes from inpatient and outpatient admission records.InterventionsNone.Primary and secondary outcome measuresWe compared the incidence of all-cause dementia across different insurance types to assess potential disparities in diagnosis following TBI. Cox proportional hazards models, with age as the time scale, were used to study the association between insurance type and dementia diagnosis following a TBI. Models were adjusted for key demographic variables, medical comorbidities and psychiatric conditions to account for potential confounding.ResultsOf the 267 473 individuals with TBI, 12.7% were diagnosed with dementia over a mean follow-up period of 40 months (SD of 42 months). Dementia incidence differed significantly by insurance type, with 18.2% for Medicaid recipients, 17.3% for Medicare beneficiaries and only 2.3% among individuals with commercial insurance. The adjusted HR for dementia was notably higher among individuals enrolled on Medicaid (HR 2.9, 95% CI: 2.8 to 3.1) and Medicare (HR 2.1, 95% CI: 2.0 to 2.2), when compared with those with commercial insurance.ConclusionsIndividuals with TBI covered by Medicaid and Medicare are significantly more likely to be diagnosed with dementia, with a 2.9-fold and 2.1-fold increase risk, respectively, compared with those with commercial insurance. Addressing insurance-related disparities in dementia diagnosis is crucial for building a more equitable healthcare system. It is essential that individuals with TBI cases, regardless of their insurance type, have access to comprehensive care and preventive interventions to achieve the best possible long-term outcomes.

ObjectivesEvidence on adverse childhood experiences (ACEs) and late-life cognitive outcomes is inconsistent, with little research among diverse racial/ethnic groups. We investigated whether ACE exposures were associated with worse late-life cognition for all racial/ethnic groups and at different ages of exposure.DesignCovariate-adjusted mixed-effects linear regression models estimated associations of: (1) total number of ACEs experienced, (2) earliest age when ACE occurred and (3) type of ACE with overall cognition.SettingKaiser Permanente Northern California members aged 65 years and older, living in Northern California.ParticipantsKaiser Healthy Aging and Diverse Life Experiences study baseline participants, aged 65 years and older (n=1661; including 403 Asian-American, 338 Latino, 427 Black and 493 white participants).ResultsMost respondents (69%) reported one or more ACE, most frequently family illness (36%), domestic violence (23%) and parental divorce (22%). ACE count was not adversely associated with cognition overall (β=0.01; 95% CI −0.01 to 0.03), in any racial/ethnic group or for any age category of exposure. Pooling across all race/ethnicities, parent’s remarriage (β=−0.11; 95% CI −0.20 to −0.03), mother’s death (β=−0.18; 95% CI −0.30 to −0.07) and father’s death (β=−0.11; 95% CI −0.20 to −0.01) were associated with worse cognition.ConclusionAdverse childhood exposures overall were not associated with worse cognition in older adults in a diverse sample, although three ACEs were associated with worse cognitive outcomes.

Background Low socioeconomic status (SES) in early and late life has been associated with lower late-life cognition. Less is known about how changes in SES from childhood to late life are associated with late-life cognition, especially among diverse populations of older adults. Methods In a multi-ethnic sample ( n  = 1353) of older adults, we used linear regression to test associations of change in comprehensive measures of SES (financial, cultural, and social domains) from childhood to late life with semantic memory, episodic memory, and executive function. We tested whether the association between SES trajectory and late-life cognition differed by populations who resided in the U.S. during childhood or immigrated to the U.S. as adults. Results Participants with low childhood/high late-life financial capital had better semantic memory (β = 0.18; 95% CI: 0.04, 0.32) versus those with low financial capital in both childhood and late life, regardless of childhood residence. We observed a significant interaction in the association of verbal episodic memory and cultural capital by childhood residence ( p  = 0.08). Participants with a foreign childhood residence had higher verbal episodic memory if they had low childhood/high late-life cultural capital (β = 0.32; 95% CI: 0.01, 0.63), but lower verbal episodic memory if they had high childhood/low late-life cultural capital (β = − 0.40; 95% CI: − 0.94, 0.13). Having high lifecourse social capital was associated with better verbal episodic memory scores among those with a U.S. childhood (β = 0.34; 95% CI: 0.14, 0.55), but lower verbal episodic memory among those with a foreign childhood (β = − 0.10; 95% CI: − 0.51, 0.31). Conclusions High financial and cultural capital in late life is associated with better cognition, regardless of early childhood SES or childhood residence.

ObjectivesAdverse childhood experiences (ACEs) are associated with higher risk of chronic disease, but little is known about the association with late life cognitive decline. We examined the longitudinal association between ACEs and late-life cognitive decline in the Study of Healthy Aging in African Americans (STAR).DesignLinear mixed models with random intercepts and slope examined the association of individual and composite ACEs with cognitive change adjusting for years from baseline (timescale), baseline age, sex, parental education, childhood socioeconomic status and childhood social support. Participants reported whether they had experienced nine types of ACEs. Executive function and verbal episodic memory were measured up to three times over a 3-year period using the Spanish and English Neuropsychological Assessment Scales.SettingsKaiser Permanente Northern California members living in the Bay Area.ParticipantsSTAR is a cohort study of cognitive ageing launched in 2018 that has enrolled 764 black Americans ages ≥50 years (mean age=67.5; SD=8.5).ResultsTwenty-one per cent of participants reported no ACEs, 24% one ACE, 20% two ACEs, 17% three ACEs and 17% four or more ACEs. Compared with no ACEs, two ACEs (β=0.117; 95% CI 0.052 to 0.182), three ACEs (β=0.075; 95% CI 0.007 to 0.143) and four or more ACEs (β=0.089; 95% CI 0.002 to 0.158) were associated with less decline in executive function. There were no significant associations between number of ACEs and baseline or longitudinal verbal episodic memory or between individual ACEs and executive function or verbal episodic memory.ConclusionIn this cohort of older black Americans, there was no association between ACEs and baseline cognition or cognitive change in verbal episodic memory; however, experiencing ≥ 2 ACEs was associated with less decline in executive function. These results may indicate that participants who survived to age 50+ and experienced ACEs may have cognitive resilience that warrants further investigation.

The relation between TV viewing and posttraumatic stress disorder (PTSD) is controversial; prior work focused exclusively on whether TV viewing of disaster events constitutes a traumatic stressor that causes PTSD. This study evaluates a possible bidirectional relation between PTSD and TV viewing in community-dwelling women. Data are from the PTSD subsample of the Nurses' Health II study, an ongoing prospective study of women aged 24-42 years at enrollment and who have been followed biennially (N = 50,020). Trauma exposure and PTSD symptoms (including date of onset) were assessed via the Brief Trauma Questionnaire and the Short Screening Scale for DSM-IV PTSD. Average TV viewing was reported at 5 times over 18 years of follow-up. Linear mixed models assessed differences in TV viewing patterns by trauma/PTSD status. Among women with trauma/PTSD onset during follow-up (N = 14,374), linear spline mixed models assessed differences in TV viewing patterns before and after PTSD onset. Women with high PTSD symptoms reported more TV viewing (hours/wk) compared to trauma-unexposed women at all follow-up assessments (β = 0.14, SE = 0.01, p < .001). Among the women who experienced trauma during follow-up, significant increases in TV viewing (hours/day) prior to onset of high PTSD symptom levels were evident (β = 0.15, SE = 0.02, p < .001). TV viewing following trauma exposure may be a marker of vulnerability for developing PTSD and also a consequence of having PTSD. High TV viewing levels may be linked with ineffective coping strategies or social isolation, which increase risk of developing PTSD.

ObjectiveThe role of spousal education on dementia risk and how it may differ by gender or race/ethnicity is unknown. This study examines the association between one’s own education separate from and in conjunction with spousal education and risk of dementia.DesignCohort.SettingKaiser Permanente Northern California (KPNC), an integrated health care delivery system.Participants8835 members of KPNC who were aged 40–55, married and reported own and spousal education in 1964–1973.Primary outcome measureDementia cases were identified through medical records from 1 January 1996 to 30 September 2017.MethodsOwn and spousal education was self-reported in 1964–1973 and each was classified as four indicator variables (≤high school, trade school/some college, college degree and postgraduate) and as ≥college degree versus

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