Kaiser Healthy Aging And Diverse Life Experiences Research Articles

The relationships of grip strength and gait speed with cognitive function in a diverse cohort: Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study

AbstractBackgroundGrip strength and gait speed, indicators of frailty, have been associated with poor cognitive outcomes. Whether there are differences in these associations by race/ethnicity is unknown. In the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study, we examined the cross‐sectional associations of grip strength and gait speed with cognition.MethodKHANDLE aimed to evaluate how race/ethnicity and life‐course health influence late‐life brain health among community‐dwelling adults ages 65+ living in Northern California. Analysis included 1,353 Asian (24%), Black (26%), Latino (18%), and White (32%) participants. Grip strength (kg) was measured using a hand‐held dynamometer and gait speed measured a timed 4‐meter walk (m/s). Cognitive domains of verbal episodic memory, semantic memory, and executive function were measured using the Spanish and English Neuropsychological Assessment Scales (SENAS). Z‐standardized test scores were averaged for a global z‐score. Linear regression was used to assess the associations of grip strength and gait speed with cognition. Models were adjusted for demographic (age, education, income), physical (waist circumference), and behavioral risk factors (physical activity, smoking status, alcohol consumption). Gender and race/ethnicity interactions were tested separately.ResultParticipants had a mean age of 76 (SD=7) years and 58% were women. The associations of grip strength and gait speed with cognition did not differ by gender. A standard deviation (SD) increase in grip strength was associated with better global cognition [β=0.11(0.06, 0.15)]. This association did not differ by race/ethnicity and was similar across cognitive domains [executive β=0.07(0.03, 0.12); semantic β=0.12(0.07, 0.17); verbal β=0.06(0.01, 0.11)]. A SD decrease in gait speed was associated with worse global cognition [β=‐0.09(‐0.12, ‐0.06)] and associations were consistent across domains [executive β=‐0.08(‐0.11, ‐0.05); semantic β=‐0.08(‐0.11, ‐0.05); verbal β=‐0.06(‐0.09, ‐0.02)]. There were significant race/ethnicity interactions on the associations of gait speed with global cognition (p=0.001), executive function (p=0.02), and semantic memory (p=0.0004). Decreased gait speed was associated with worse cognition in these domains for Asians, Latinos, and Whites, but not associated in Blacks.ConclusionGrip strength and gait speed were cross‐sectionally associated with cognition. There were race/ethnicity differences in the association of gait speed with executive function, semantic memory, as well as global cognition.

Sensory impairments and cognition in a diverse cohort: Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study

AbstractBackgroundSensory impairments have been associated with poor cognition in primarily non‐Latino White cohorts. We used the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study to examine racial/ethnic differences in the association between sensory impairments and cognition.MethodKHANDLE includes diverse, community‐dwelling adults ages 65+ living in North California and aims to evaluate how race/ethnicity influence brain health. Analysis included 1,623 Asian (24%), Black (26%), Latino (18%), and White (32%) individuals. Participants rated their hearing and vision and were classified as impaired (self‐report of “Fair” or “Poor”) or not impaired (“Excellent,” “Very Good,” or “Good”) in hearing, vision, or both. Cognition was measured using the Spanish and English Neuropsychological Assessment Scales (SENAS). Cognitive test scores for executive function, semantic memory, and verbal episodic memory were z‐standardized and averaged for a global z‐score. Linear regression was used to estimate the associations between sensory impairments and cognition, adjusted for age, gender, race, education, income, waist circumference, physical activity, alcohol consumption, and ever smoking tobacco. Race/ethnicity interaction terms were tested.ResultParticipants had a mean age of 76 (SD=7). Whites (23.9%) were the most likely to report hearing impairment followed by Latinos (19.4%), Asians (18.0%), and Blacks (11.6%). Latinos (13.2%) were the most likely to report vision impairment followed by Blacks (12.5%), Asians (10.3%), and Whites (8.6%). Blacks (16.0%) were the most likely to report concurrent vision and hearing impairment followed by Latinos (11.8%), Asians (11.3%), and Whites (9.8%). Associations between sensory impairments and cognition did not differ by race/ethnicity. Associations remained consistent across the cognitive domains but were strongest for semantic memory. Hearing impairment was not associated with global cognition [β(95% CI):‐0.04(‐0.12, 0.05)]. Participants with visual impairments had worse global cognition than those without visual impairment [β:‐0.18(‐0.27, ‐0.09)]. Compared to those with no impairments, global cognition did not differ for participants with one impairment [β:‐0.03(‐0.12, 0.05)], but was significantly worse in those with dual sensory impairments [β:‐0.20(‐0.33, ‐0.08)].ConclusionWe found no racial/ethnic differences in the association between sensory impairments and cognition. Self‐reported vision impairment was associated with poor cognition, but self‐reported hearing impairment was not.

Head injury at different ages and cognitive performance in a diverse cohort: Findings from the KHANDLE Study

AbstractBackgroundEvidence is limited on the impact of a head injury and the role of age at injury on different cognitive domains, particularly among in diverse cohorts.MethodsThe Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) study examines cognitive aging across four racial/ethnic groups (29% White, 26% Black, 24% Asian, & 20% Latino). Head injury was determined by asking: “Have you ever had a head injury where you lost consciousness or for which you received medical care?” Age at first injury was grouped as 0‐15, 16‐29, 30‐64 and 65+ years. Education was coded as college graduate or more and less than college graduate. Z‐standardized measures of verbal episodic memory, semantic memory, and executive function were assess using the Spanish and English Neuropsychological Assessment Scales (SENAS). The association between head injury and cognitive domains were analyzed with adjustment for age, sex, race, and education using multivariable linear regression models.ResultsAmong the analytic sample of 1,666 participants, 392 (22.9%) reported history of a head injury. Exposure to head injury was not associated with deficits in executive function (β=0.04, 95% CI: −0.05, 0.14), verbal episodic memory (β=‐0.09, 95% CI: −0.02, 0.10), or semantic memory (β=0.07, 95% CI: −0.02, 0.16). Among those reporting a head injury, 77.1% experienced one injury, 15.5% 2 injuries, 4.6% 3 injuries, and 6.7% participants reported 4+ injuries. The median (interquartile range) age at first head injury was 24 (13‐60) years, and time since first head injury was 48 (14‐61) years. Age at first head injury was not associated with cognitive function when compared to individuals without a head injury (Table 1A). Among those with a history of head injury, age at first injury was not associated with executive function (65+ vs. 0‐15 years: β=‐0.25, 95% CI: −0.50, 0.01), verbal episodic memory (65+ vs. 0‐15 years: β=0.21, 95% CI: −0.05, 0.47), or semantic memory (65+ vs. 0‐15 years: β=‐0.09, 95% CI: −0.32, 0.13) (Table 1B).ConclusionParticipants who reported a head injury did not exhibit worse cognition compared to those without history of injury nor was age at first head injury associated with any cognitive domain.

Relationship between MRI and amyloid PET measures with cognition in the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) study

AbstractBackgroundThe U.S. population is aging and becoming more diverse. The Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study enrolled 1,712 participants with the aim of evaluating how race/ethnicity and life‐course factors influence late‐life brain health. We examined the association between brain images and cognition in this cohort.MethodTo date, 164 participants have received MRI and PET imaging (25% Asian, 20% Black, 25% Latino, and 30% White). MRI analyses included regional gray matter, cerebrospinal fluid, and white matter hyperintensity (WMH) volumes. Amyloid PET used AV45 and standard SUVR analysis with cerebellar gray matter as the reference region. Participants underwent neuropsychologic testing and received diagnoses of cognitively normal or impaired (syndrome). Cognitive domains of verbal episodic memory, working memory, and executive function were measured using the Spanish and English Neuropsychological Assessment Scales (SENAS). Linear and logistic regressions were used to assess associations between imaging measures with cognition. Race/ethnicity interactions were tested (significant interaction p<0.10).ResultParticipants had a mean age of 75 (SD=6) years. Verbal memory was positively associated with hippocampal volume [β(95% CI):0.16(0.03, 0.28)] and negatively associated with amyloid burden [β:‐0.20(‐0.33, ‐0.06)]. Cerebral and parietal cortex volumes were associated with better working memory [cerebral β:0.21(0.07, 0.35); parietal β:0.15(0.03, 0.28)] and executive function [cerebral β:0.25(0.11, 0.38); parietal β:0.17(0.05, 0.30)]. Lateral and third ventricle volumes were negatively associated with working memory [lateral ventricle β:‐0.17(0.30, ‐0.04); third ventricle β:‐0.22(‐0.34, ‐0.10)] and executive function [lateral ventricle β:‐0.15(0.28, ‐0.02); third ventricle β:‐0.16(‐0.29, ‐0.04)]. Odds of syndrome were lower in those with greater cerebrum gray matter [OR:0.54(0.32, 0.90)], hippocampal [OR:0.27(0.14, 0.52)], and temporal cortex [OR:0.61(0.38, 0.98)] volumes. The positive associations of hippocampal (interaction p=0.08) and occipital cortex (p=0.02) volumes with verbal memory were significant for Asians and Latinos. Cerebrum gray matter (p=0.06) and parietal cortex (p=0.07) volumes were positively associated with working memory in Blacks. Occipital cortex volume (p=0.07) was positively associated with executive function in Asians. Racial/ethnic differences were seen in the relationship of WMH (p=0.07) and amyloid burden (p=0.04) with syndrome, but small numbers prevented race‐stratification.ConclusionRegional MRI and amyloid burden were associated with cognition and there were significant racial/ethnic differences.

Young adulthood cardiovascular risk and MRI and amyloid PET in late‐life in a diverse cohort: The Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study

AbstractBackgroundMid‐life cardiovascular (CVD) risk factors have been associated with cognitive impairment, but CVD risk factors in young adulthood are not well characterized. We evaluated how young adulthood CVD factors influence late‐life brain health in The Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) cohort.MethodKHANDLE is a multi‐ethnic study of 1,712 long‐term Kaiser Permanente North California members ages 65 and older. To date, 165 participants (25% Asian, 21% Black, 24% Latino, and 30% White) received MRI and PET imaging as part of an imaging sub‐study. MRI analyses included regional gray matter and total WMH volumes. Amyloid PET used AV45 and standard SUVR analysis with cerebellar gray matter as the reference region. Participants underwent neuropsychologic testing and received diagnoses of cognitively normal or dementia/mild cognitive impairment (MCI). CVD risk factors were measured during Multiphasic Health Checkups (MHC) between 1964‐1992 where body mass index (BMI), blood pressure, and total cholesterol were measured. The association of young adulthood CVD factors with imaging measures and syndrome were assessed using linear and logistic regressions with adjustment for age, years since MHC, gender, education and race/ethnicity.ResultParticipants had a mean age of 31+6 at MHC and 75+6 at KHANDLE. Being overweight or obese at MHC was negatively associated with hippocampal volume [β:‐0.42(‐0.81, ‐0.03)] and marginally associated with cerebral gray matter [β:‐0.37(‐0.75, 0.01)] and temporal cortex [β: ‐0.39(‐0.78, 0.01)] volumes. Continuous BMI was negatively associated with cerebral gray [β:‐0.07(‐0.14, ‐0.01)], hippocampal [β:‐0.07(‐0.14, ‐0.01)], and temporal cortex [β:‐0.39(‐0.78, 0.01)] volumes. Hypertension at MHC was negatively associated with cerebral [β:‐0.34(‐0.61, ‐0.06)] and occipital cortex [β:‐0.36(‐0.66, ‐0.06)] volumes. Hypercholesteremia at MHC was negatively associated with cerebral volume [β:‐0.50(‐0.81, ‐0.19)] and hippocampal volume [β:‐0.36(‐0.72, ‐0.01)]. A standard deviation increase in total cholesterol was negatively associated with hippocampal volume [β:‐0.16(‐0.31, ‐0.01)] and associated with greater amyloid burden [β:0.19(0.02, 0.36)].ConclusionCVD risk factors of overweight/obesity, hypertension, and hypercholesteremia in young adulthood were negatively associated with measures of late‐life brain health in this diverse cohort of community‐dwelling older adults.

Conceptualizing the relationship between parental education and own cognition in the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) study

AbstractBackgroundFew studies have considered how parental education influences late‐life cognition; those that have often focus on maternal and not paternal influences or as part of a broader SES index, which does not allow us to understand the functional form of the relationship between parental education and cognition. We assessed whether mother’s education dichotomized at 8th grade, a commonly used cutoff among similarly aged older adults to our sample, sufficiently captured effects of parental education by systematically evaluating conceptualizations of parental education.MethodsKaiser Healthy Aging and Diverse Life Experiences (KHANDLE) study baseline participants, aged 65 years plus (n=1,633), self‐reported own and parents’ education at baseline. Parental education was operationalized separately as (1) mother’s only, (2) father’s only, (3) mother and father together; each operationalization was considered as categorical (missing, <=8th grade, incomplete high school, high school diploma, postsecondary education), as >8th grade (with missingness indicator and with missing included in “low”), and as high school completion (with and without missingness indicator). Parental (4) concordance (both high, high mother, high father, both low), (5) highest parental level, and (6) lowest parental level were also evaluated. Verbal episodic memory (VEM), semantic memory (SEM), and executive functioning (EF) from the Spanish and English Neuropsychological Assessment Scales (SENAS) were considered separately in covariate‐adjusted linear models. The lowest Bayesian Information Criterion (BIC) model was considered to provide the best fit.ResultsAcross all parental education operationalizations, 8th grade cut‐offs performed best; categorical (5‐level) parent education performed the worst. Semantic memory was best predicted by the referent measure of mother’s education >8th (B̂: 0.33; 95% CI: 0.25, 0.42); however verbal memory was best predicted by mother’s education >8th grade (B̂: 0.14; 95% CI: 0.03, 0.24) plus missing indicator (B̂: ‐0.24; 95% CI: ‐0.37, ‐0.10) and executive function by both mother’s (B̂: 0.22; 95% CI: 0.12, 0.31) and father’s (B̂: 0.18; 95% CI: 0.09, 0.28) >8th together.ConclusionThe preferable performance of parental education as >8th grade likely reflects historical education trends when KHANDLE participants’ parents were educated; whether preference for dichotomized measures over full categories reflects uncertainties in recall of parental education remains unclear.

Racial/Ethnic Differences in Sleep Quality among Older Adults: Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study.

We assessed cross-sectional differences in sleep quality and risk factors among Asian, Black, Latino, and White participants in the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study. KHANDLE enrolled community-dwelling adults aged ≥65 years living in northern California. Participants completed a modified Pittsburgh Sleep Quality Index to measure six sleep components and a global sleep score (scored 0-24). Covariates included age, sex, central adiposity, education, income, alcohol consumption, ever smoking, physical activity, and depression. Ordinal logistic regression was used to model sleep component scores across race/ethnic groups. Linear regression was used to assess racial/ethnic differences in global sleep score and the association between risk factors and global sleep score. 1,664 participants with a mean age of 76 (SD=7) and mean global sleep score of 6 (SD=4) were analyzed. Using Latinos as reference (highest average sleep score), Blacks had an average .96 (.37, 1.54) unit higher global sleep score (worse sleep) while Asians [β: .04 (-.56, .63)] and Whites [β: .28 (-.29, .84)] did not significantly differ. Compared with Latinos, Blacks and Asians had greater odds of a worse score on the sleep duration component; Blacks and Whites had greater odds of a worse score on the sleep disturbances component; and, Whites had greater odds of a worse score on the medication component. Risk factors for poor sleep did not differ by race/ethnicity except alcohol consumption (interaction P=.04), which was associated with poor sleep in Blacks only. In this cohort, racial/ethnic differences in sleep quality were common.

Association Between Cognitive Test Performance and Subjective Cognitive Decline in a Diverse Cohort of Older Adults: Findings From the KHANDLE Study.

Subjective cognitive decline (SCD) may represent a low-burden indicator of dementia risk. The value of SCD as a proxy marker, however, depends on the consistency of associations between subjective and objective cognitive measures across sociodemographic and psychological factors. We evaluated baseline data from the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) study (n=1615). SCD was measured using the 12-item Everyday Cognition (ECog) scale. Using linear regression models with interaction terms, we evaluated 6 potential modifiers (age, sex, race/ethnicity, educational attainment, family history of dementia, and depressive symptoms) of the association between cognitive performance (episodic memory, executive function) and SCD. Lower episodic memory and executive function scores were associated with higher log(ECog scores) (more SCD). Older age and elevated depressive symptoms were associated with higher log(ECog scores). Age (interaction P=0.002) and education (interaction P=0.01) modified the association between executive function and log(ECog scores). Specifically, associations between executive function and log(ECog scores) were stronger among participants with more education and less pronounced among older participants. The association between cognitive performance and log(ECog scores) differed little across sociodemographic and psychological factors. SCD as measured by the ECog may be a valuable proxy for cognitive performance in diverse older adults.

Differences in association of leisure time activities and cognition in a racially/ethnically diverse cohort of older adults: Findings from the KHANDLE study

IntroductionLeisure time activity is associated with better cognitive function but has not been well studied in racially/ethnically diverse cohorts, who may have different access to activities.MethodsFrequency of participation in 10 leisure time activities (eg, reading, attending cultural events) and cognition (executive function, semantic memory, and verbal episodic memory) were assessed at Wave 1 in the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) study, a prospective cohort initiated in 2017. Linear regression models adjusted for sociodemographics and depression estimated cross‐sectional associations between leisure time activity variety and frequency and cognitive domains overall and by race/ethnicity. Logistic regression models estimated odds of cognitive impairment among those in the lowest quartiles of activity variety and frequency. All models controlled for age, sex, education, income, retirement status, and depression.ResultsHigher leisure time activity variety was significantly associated with better cognition for all, except for verbal episodic memory among Asians (β = 0.05, 95% confidence interval [CI]: −0.004, 0.11) and semantic memory among Latinos (β = 0.04, 95% CI: −0.01, 0.08). Low activity variety was associated with nearly three‐fold increased odds of cognitive impairment (adjusted odds ratio [OR] = 2.87, 95% CI: 1.77, 4.64). Activity frequency was associated with higher executive function only among whites (β = 0.10, 95% CI: 0.02, 0.18). Patterns by race/ethnicity were not explained by education.DiscussionEngaging in a wider variety of leisure time activities may be more important than frequently participating in fewer activities for cognitive aging in racially/ethnically diverse cohorts.

USING RACIAL/ETHNIC COMPARISONS TO EVALUATE UNMEASURED CONFOUNDING: CHILDHOOD DISADVANTAGE AND COGNITIVE RESERVE IN LATE LIFE IN THE MULTI-ETHNIC KHANDLE COHORT

Numerous indicators of childhood disadvantage predict dementia risk and cognitive reserve. Evaluating whether specific types of disadvantage are causal for late life cognitive outcomes is challenging due to numerous unmeasured potential confounders. Triangulating associations across racial/ethnic groups with different confounding patterns may help evaluate whether any specific measure is causal or merely proxies for general disadvantage. We hypothesized that childhood experience of a traumatic event, specifically death of a child in the immediate family (e.g., a sibling), would predict cognitive reserve similarly for four racial/ethnic groups, despite different patterning of this social exposure. At baseline, 250 Asian, 189 Latino, 251 African-American, and 348 white Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) cohort participants (average age=70.3 years; standard deviation=6.8) reported on childhood social experiences, including whether a child in their immediate family died (child death). We Z-scored a composite of verbal memory, episodic memory, and executive function as an indicator of cognitive reserve and estimated linear regressions for whether child death predicted cognitive reserve differentially by race/ethnicity. Child death was common for Asian (22.4%), African-American (17.5%) and Latino (19.1%) participants, but less frequent for white (8.6%) participants (p<.01 for racial/ethnic differences). Child death was associated with lower maternal (bwhite=−1.8 years difference; bLatino=-1.4) and paternal (bwhite=−1.4; bLatino=-1.5) education for whites and Latinos, but not associated with paternal education for Asians (bAsian=0.1) or maternal education for African-Americans (bAfrican-American=0.1). In age and sex adjusted models, child death predicted lower cognitive reserve similarly for whites (bwhite=−.44; 95% CI: −.76, −.13) and Latinos (bLatino=−.49; 95% CI: −.78, −.19); the association was weaker among African-American (bAfrican-American =−.22; 95% CI: −.48, .03) and not present among Asian (bAsian=−.02; 95% CI: −.28, .24) participants. Contrary to our hypothesis, childhood exposure to death of a child was associated with lower cognitive reserve only in racial/ethnic groups for whom exposure was correlated with other indicators of childhood disadvantage. Childhood exposure to death of a child may be relevant as a marker of general disadvantage rather than causal in and of itself. Multi-ethnic research studies provide opportunities to triangulate evidence on risk factors with complex, unmeasured confounders.