Development and assessment of analytic methods to improve the measurement of cognition in longitudinal studies of aging through the use of substudies with comprehensive neuropsychological testing

INTRODUCTION

The Health and Retirement Study International Partner Surveys (HRS IPS) have rich longitudinal data, but the brevity of cognitive batteries is a limitation.

METHODS

We used data from a substudy of the English Longitudinal Study of Ageing (ELSA) administering detailed cognitive assessments with the Harmonized Cognitive Assessment Protocol (ELSA-HCAP) (N = 1273) to inform approaches for estimating cognition in ELSA (N = 11,213). We compared two novel approaches: confirmatory factor analysis (CFA)- and regression-based prediction.

RESULTS

Compared to estimates from the full HCAP battery, estimated cognitive functioning derived using regression models or CFA had high correlations (regression: r = 0.85 [95% confidence interval [CI]: 0.83 to 0.87]; CFA: r = 0.83 [95% CI: 0.81 to 0.85]) and reasonable mean squared error (regression: 0.25 [0.22 to 0.27]; CFA: 0.29 [0.26 to 0.32]) in held-out data. The use of additional items from waves 7 to 9 improved performance.

DISCUSSION

Both approaches are recommended for future research; the similarity in approaches may be due to the brevity of available cognitive assessments in ELSA.

HIGHLIGHTS

Estimates of cognitive functioning informed by English Longitudinal Study of Ageing-Harmonized Cognitive Assessment Protocol (ELSA-HCAP) data had an adequate performance. Standard errors were smaller for associations with example risks when using measures informed by ELSA-HCAP. Performance was better when including additional cognitive measures available in waves 7 to 9. Conceptual advantages to the confirmatory factor analysis (CFA) approach were not important in practice due to the brevity of the ELSA cognitive battery.

Exploring factors associated with self-rated health in individuals with diabetes and its impact on quality of life: Evidence from the Survey of Health, Ageing, and Retirement in Europe

BACKGROUND

Self-rated health (SRH), a measure of self-reported general health, is a robust predictor of morbidity and mortality in various populations, including people with diabetes. Diabetes is negatively associated with SRH and quality of life (QoL). Little is known about how people with diabetes rate their health and which aspects influence the rating. Also, the predictive value of SRH on future QoL has not yet been evaluated.

METHODS

We analyzed data from 46 592 participants of the Survey of Health, Ageing and Retirement in Europe (SHARE). Using linear regression, we aimed to determine which sociodemographic, socioeconomic, medical, social, mental, and health behavior factors determine SRH in people with diabetes. In addition, we analyzed the predictive value of SRH on future QoL using the generalized estimating equations procedure.

RESULTS

We determined that country, current job situation, hospitalization, pain, polypharmacy, memory, eyesight, activities of daily living, number of chronic diseases, and depression are all linked to SRH. Together these variables explained 38% of the SRH's variance, whereas depression, pain, and memory had the greatest influence on SRH of people with diabetes. We also found that SRH independently predicted future QoL, supported by a regression coefficient of β = -1.261 (Wald chi-square test, χ2 = 22.097, df = 1, p < .05).

CONCLUSIONS

As SRH is linked to future QoL, we conclude that incorporating SRH assessment into medical evaluations can help health care professionals gaining a more comprehensive understanding of an individual's health trajectory and supporting patients to enhance their QoL.

The association between self-rated health, number of family members, and cognitive function in community-dwelling older adults: Mediating role of depression

With the increasing number of older adults, research on cognitive function has expanded. However, studies examining the mediating effect of depression on the association between complex factors and cognitive function in older adults are still insufficient. Additionally, there is a lack of studies that have investigated these relationships by integrating multiple factors related to the cognitive function of older adults. Therefore, our study investigated the association between the number of family members, self-rated health, depression, and cognitive function in community-dwelling older adults and highlighted the mediating role of depression in these relationships. We used data from 218 older adults aged over 65 collected in a previous study. The independent variables were the number of family members and self-rated health, and the dependent variable was cognitive function measured by the cognitive impairment screening test (CIST). The mediation variable was depression measured by the Patient Health Questionnaire-9 (PHQ-9). Structural equation modeling was used to examine the association between the independent, dependent, and mediation variable. The mean ages of the participants were 81.71 (standard deviation [SD] = 6.00) years, with 198 females (90.83%) and 20 males (9.17%). The structural equation model demonstrated a good model fit (chi-square value = 33.375; degrees of freedom = 24; p-value = 0.0964; RMSEA = 0.042; CFI = 0.970; TLI = 0.956; SRMR = 0.042). Self-rated health and the number of family members were not directly associated with cognitive function; however, depression had significant indirect effects (self-rated health to cognitive function: coefficient = -0.023, p-value = 0.017; number of family members and cognitive function: coefficient = 0.012, p-value = 0.030). Our findings indicated that depression plays a crucial mediating role between self-rated health, number of family members, and cognitive function. The results highlight the need for comprehensive strategies for mental health care to support cognitive health in older adults.

Age and Sex Differences in the Genetic Architecture of Measures of Subjective Health: Relationships With Physical Health, Depressive Symptoms, and Episodic Memory

OBJECTIVES

Subjective health (SH) is not just an indicator of physical health, but also reflects active cognitive processing of information about one's own health and has been associated with emotional health measures, such as neuroticism and depression. Behavior genetic approaches investigate the genetic architecture of SH, that is, genetic and environmental influences on individual differences in SH and associations with potential components such as physical, cognitive, and emotional health. Previous twin analyses have been limited by sex, sample size, age range, and focus on single covariates.

METHODS

The current analysis used data from 24,173 adults ranging in age from 40 to 90 years from the international Interplay of Genes and Environment across Multiple Studies consortium to investigate the genetic architecture of 3 measures of SH: self-rated health, health compared to others, and impact of health on activities. Independent pathways model of SH included physical health, depressive symptoms, and episodic memory, with age, sex, and country included as covariates.

RESULTS

Most or all of the genetic variance for SH measures were shared with physical health, depressive symptoms, and episodic memory. Genetic architecture of SH differed across measures, age groups (40-65, 66-90), and sexes. Age comparisons indicated stronger correlations with all 3 covariates in older adults, often resulting from greater shared genetic variance.

DISCUSSION

The predictive value of SH has been amply demonstrated. The higher genetic contributions to associations between SH and its components in older adults support the increasing conceptualization with age of SH as an intuitive summation of one's vital reserve.

The role of family support in the self-rated health of older adults in eastern Nepal: findings from a cross-sectional study

BACKGROUND

Nepal's low fertility rate and increasing life expectancy have resulted in a burgeoning older population. For millennia, filial piety shaped family cohesion and helped Nepali older adults achieve positive outcomes, but recently, it has been eroding. Furthermore, there are not enough institutional support options or alternatives to family-based care to deal with the biosocial needs of older adults. This study explored the association between family support and self-rated health among Nepali older adults.

METHODS

A community-based cross-sectional survey in eastern Nepal's two districts, Sunsari and Morang, interviewed 847 older adults (≥ 60 years). The final analytical sample was 844. Participants were asked whether they received assistance with various aspects of daily life and activities of daily living from their families. Multivariable logistic regression examined the association between family support and self-rated health.

RESULTS

Participants who received support with various aspects of daily life had 43% higher odds of good health, but after adjusting for control variables, the result only approached statistical significance (p = 0.087). Those who received family assistance with activities of daily living had nearly four times higher odds (OR: 3.93; 95% CI: 2.58 - 5.98) of reporting good health than participants who lacked this support.

CONCLUSIONS

Given the important role of family support in Nepali older adults' health, government programs and policies should create a conducive environment to foster family-based care until more comprehensive policies for older adults' care can be put into effect. The results of this study can also help shape the global aging environment by highlighting the need for family support in older care, particularly in low-income nations with declining traditional care systems and weak social security policies.

Impact of hearing loss on cognitive function in community-dwelling older adults: serial mediation of self-rated health and depressive anxiety symptoms

Background

Hearing loss can exacerbate cognitive decline; therefore, exploring the mechanisms through which hearing loss affects cognitive function is crucial. The current study aimed to investigate the impact of hearing loss on cognitive function and the mediating role played by self-rated health and depressive anxiety symptoms.

Methods

Using stratified whole-group random sampling, the study employed a cross-sectional design and included 624 participants aged ≥65 years from three communities in Urumqi, China. Cognitive function was assessed using the Mini-Mental State Examination. Hearing function and self-rated health were determined by self-report. The 15-item Geriatric Depression Scale and the 7-item Generalized Anxiety Disorder Scale were used to assess depressive anxiety symptoms. Serial mediation analysis was performed using AMOS 26.0.

Results

Hearing loss can not only negatively affect cognitive function in older adults directly (direct effect = -0.106; SE = 0.045; 95% confidence interval (CI): -0.201 to -0.016), but also indirectly affect the relationship between hearing loss and cognitive function through self-rated health and depressive anxiety symptoms. The results of the serial mediation analysis showed that the total indirect effect of self-rated health and depressive anxiety symptoms was -0.115 (95% CI: -0.168 to -0.070), and the total effect of the model was -0.221 (95% CI: -0.307 to -0.132), with the total indirect effect accounting for 52.04% of the total effect of the model.

Conclusion

Our study discovered that there is a partial mediation of the relationship between hearing loss and cognitive function by self-rated health and depressive anxiety symptoms. It is suggested that by enhancing self-rated health and ensuring good mental health, the decline in cognitive function among older adults with hearing loss can be delayed.

Determinants of semantic and episodic memory decline among older adults in Ghana: Evidence from the WHO study on global AGEing and adult health Ghana wave 2

Objective

Determined factors associated with semantic (SM) and episodic memory (EM) among older adults aged 50 years and older in Ghana.

Methods

Data from WHO Study on Global AGEing and Adult Health (SAGE) Ghana Wave 2 was used for this study. Semantic memory (SM) and Episodic memory (EM) were the main study outcomes separately. The study employed Nested Ordinary Least Square regression analysis by sequentially adding 6 blocks of variables and comparison tests between the nested models.

Results

The study involved 3575 adult Ghanaians aged 50 years and older with a mean ± standard deviation of 62.6 ± 18.4 years. The overall mean ± SD of EM and SM were 5.86 ± 2.51 and 11.69 ± 8.59 respectively. Overall, analysis from block 6 showed a significant variation in SM by approximately 16.9%(ΔR2 = 1.17%) where increasing age, never married (β = -1.55; 95% CI = -2.41-0.69), being resident in Greater Accra (regional disparity) (β = -3.45; 95% CI = -4.73-2.20), underweight (β = -0.81;95% CI = -1.34-0.27), and moderate self-rated health (SRH) (β = -0.98; 95% CI = -1.52-0.45) significantly decreased SM. Similarly, increasing age, separated/divorced (β = -0.22; 95% CI = -0.35-0.87), being resident in Greater Accra (β = -0.53; 95% CI = -0.80-0.26), and moderate SRH (β = -0.20; 95% CI = -0.36--0.04) significantly decrease EM with an overall significant variation of approximately 22.9%(ΔR2 = 2.7%).

Conclusions

Increasing age, sex, marital status, regional disparity, and poor SRH significantly decreased both Semantic memory and Episodic memory. Higher educational attainment and life satisfaction significantly influenced SM and EM. These provide pointers to important socio-demographic determinants of SM and EM with implications for the implementation of the Ghana national ageing policy 2010, 'ageing with security and dignity', and as a key consideration for healthy ageing towards 2030.

Self-rated health (SRH) partially mediates and associations between personality traits and life satisfaction in older adults

It is established that personality traits contribute to life satisfaction but why they are connected are far less understood. This research report tested if self-rated health (SRH) which is one's subjective ratings of their health and has a high predictivity of actual health mediates the associations between the Big Five model of personality and life satisfaction in a cohort (N = 5,845) of older adults from the UK. By using Pearson's correlation analysis and mediation analysis, the current research reported positive correlations between Agreeableness, Openness, Conscientiousness, and Extraversion, SRH, and life satisfaction. However, Neuroticism was negatively correlated with SRH and life satisfaction. The main findings were that SRH partially mediates the associations between all traits in the Big Five and life satisfaction in older adults. This study began novel exploration on if SRH could explain the connections between the Big Five and life satisfaction. Results revealed SRH could partially explain these associations in all traits. These results may offer additional support to recently developed integrated account of life satisfaction, which argues that there are no single determinants of life satisfaction. Rather, life satisfaction is made up by many factors including but not limited to personality and health.

Personality predicts self-rated health: considering age differences

Self-rated health (SRH) refers to the subjective evaluation of one's own health. Big Five personality traits including Neuroticism, Agreeableness, Openness, Conscientiousness, and Extraversion have been consistently found as significant predictors of SRH. In addition, SRH declines with age, and personality traits change with age. Thus, it is reasonable to speculate that age might moderate the associations between personality traits and SRH. The current study analyzed data from 33,256 participants with a mean age of 45.78 years old and 55.92% females. The current study found that age significantly moderates the associations between Agreeableness, Openness, and Conscientiousness and SRH after controlling for demographic covariates. The current study implies that personality traits relate to SRH differently at different ages. Thus, studies regarding the associations between personality traits and SRH must take the interactions between age and personality traits into account.

Grip Strength Trajectories and Cognition in English and Chilean Older Adults: A Cross-Cohort Study

Growing evidence about the link between cognitive and physical decline suggests the early changes in physical functioning as a potential biomarker for cognitive impairment. Thus, we compared grip-strength trajectories over 12-16 years in three groups classified according to their cognitive status (two stable patterns, normal and impaired cognitive performance, and a declining pattern) in two representative UK and Chilean older adult samples. The samples consisted of 7069 UK (ELSA) and 1363 Chilean participants (ALEXANDROS). Linear Mixed models were performed. Adjustments included socio-demographics and health variables. The Declined and Impaired group had significantly lower grip-strength at baseline when compared to the Non-Impaired. In ELSA, the Declined and Impaired showed a faster decline in their grip strength compared to the Non-Impaired group but differences disappeared in the fully adjusted models. In ALEXANDROS, the differences were only found between the Declined and Non-Impaired and they were partially attenuated by covariates. Our study provides robust evidence of the association between grip strength and cognitive performance and how socio-economic factors might be key to understanding this association and their variability across countries. This has implications for future epidemiological research, as hand-grip strength measurements have the potential to be used as an indicator of cognitive performance.

Relationships of Illness Perceptions with Depression and Anxiety in People Who Live with HIV/AIDS in a High-prevalence Ethnic Autonomous Region of Sichuan, China

Poor mental health challenges outcomes and treatment of people living with HIV/AIDS (PLWHA) and may be related to illness perceptions. To investigate if depression and anxiety were associated with illness perceptions, we drew a random sample of 729 PLWHA from 13 administrative units in Liangshan Prefecture, Sichuan, China. Among the PLWHA surveyed, 222 and 175 had probable anxiety or depression. In mixed-effects logistic regression, negative illness perceptions were associated with increased odds of anxiety/depression. In linear mixed-effects quantile regression, the relationship of more negative illness perceptions with more severe and frequent symptoms of anxiety/depression grew stronger in the upper quantiles of the GAD-7 and PHQ-9 distributions, well beyond scale cut-offs for probable clinical relevance. We hypothesize that negative illness perceptions of HIV/AIDS and severity of depression and anxiety symptoms may mutually reinforce each other. Illness perceptions are a promising intervention target for improving the mental health of PLWHA.

Cognition in informal caregivers: evidence from an English population study

BACKGROUND AND OBJECTIVES

The relationship between caregiving and cognition remains unclear. We investigate this association comparing four cognitive tasks and exploring the role of potential explanatory pathways such as healthy behaviours (healthy caregiver hypothesis) and depression (stress process model).

RESEARCH DESIGN AND METHODS

Respondents were from English Longitudinal Study of Ageing (ELSA) (N = 8910). Cognitive tasks included immediate and delayed word recall, verbal fluency and serial 7 subtraction. Series of hierarchical linear regressions were performed. Adjustments included socio-demographics, health related variables, health behaviours and depression.

RESULTS

Being a caregiver was positively associated with immediate and delayed recall, verbal fluency but not with serial 7. For immediate and delayed recall, these associations were partially attenuated when adjusting for health behaviours, and depression. For verbal fluency, associations were partially attenuated when adjusting for depression but fully attenuated when adjusting for health behaviours. No associations were found for serial 7.

DISCUSSION AND IMPLICATIONS

Our findings show that caregivers have higher level of memory and executive function compared to non-caregivers. For memory, we found that although health behaviours and depression can have a role in this association, they do not fully explain it. However, health behaviours seem to have a clear role in the association with executive function. Public health and policy do not need to target specifically cognitive function but other areas as the promotion of healthy behaviours and psychological adjustment such as preventing depression and promoting physical activity in caregivers.

Age- and time-varying associations between subjective health and episodic memory in older adults

OBJECTIVE

There are positive correlations between subjective health reports and episodic memory performance in older adults. However, previous studies have not evaluated the scope of such complex relationships, nor the potentially nonlinear magnitude of these correlations across age and time. We employed multiple subjective heath indices to evaluate the scope and nonlinearity of such relationships with memory performance.

METHOD

We utilized a cross-sectional (N = 2,783 at baseline) and longitudinal sample (N = 311) of healthy older adults aged 65 and older from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study. We used time-varying effects modeling (TVEM) to assess potential differences in relationship magnitudes between memory and three subjective health subscales (general health, role physical function, and physical function, from the Short Form Health Survey; SF-36) across five years.

RESULTS

Episodic memory positively predicted all subjective health measures cross-sectionally and longitudinally in our sample. TVEM revealed the relationships between all subjective health measures and episodic memory were stable across age. While role physical function and physical function maintained stable relationships with episodic memory across time, general health became increasingly coupled with memory five years following baseline.

DISCUSSION

Together, our findings highlight stable and varying relationships between episodic memory and multiple subjective health indicators across metrics of time in older adults.

Predictors of Subjective Cognitive Decline Among People With Diabetes: Data From the Behavioral Risk Factor Surveillance System

PURPOSE

The purpose of this study was to examine the prevalence of subjective cognitive decline (SCD) and SCD-related functional limitations among people with diabetes and to identify socioeconomic and comorbidity risk factors associated with SCD.

METHODS

This study analyzed data from the 2017 Behavioral Risk Factor Surveillance System (BRFSS) with background variables (race, gender, education, and age), health-related factors (self-rated health, BMI, insurance, and comorbid conditions), and health behaviors (smoking, exercise, alcohol consumption) entered simultaneously to estimate logistic regression models of SCD.

RESULTS

Within the sample (n = 5263 adults with diabetes), 48% were age ≥65 years; 50% were male; 55% were non-Hispanic White; and of the 15% who reported having SCD, 57% had functional limitations. Increased odds of reporting SCD were observed among individuals who were Hispanic (odds ratio [OR] = 2.21, P < .001), male (OR = 1.47, P < .01), depressed (OR = 3.85, P < .001), or had arthritis (OR = 1.43, P < .03). Participants with better self-rated health had a reduced likelihood of SCD (OR = 0.51, P < .001).

CONCLUSIONS

Health care providers should assess high-risk patients for self-rated cognitive dysfunction and offer early interventions.

Trajectories of Multiple Behavioral Risk Factors and Their Associations With Cognitive Function Trajectories Among Older African Americans and White Americans

Objectives: This study examined the joint trajectories of behavioral risk factors (smoking, alcohol drinking, and body mass index) and their associations with cognitive function trajectories among older African Americans and white Americans. Methods: Data from the Health and Retirement Study (1998-2014) were used. Group-based mixture modeling and multinomial logistic regression analysis were performed. Results: Three joint trajectories of behavioral risk factors (overweight, smoking and drinking, and drinking and overweight) and three cognitive function trajectories (low, moderate, and high) were identified. A significantly higher percentage of African Americans were in the "overweight," "smoking and drinking," and "low" cognitive functioning groups as measured by the total cognition composite score compared to white Americans. After accounting for covariates, the "drinking and overweight" group was associated with the "moderate" or "high" cognitive functioning group. Discussion: Future interventions targeting the combinations of behavioral risk factors are needed to promote healthy aging among high-risk populations.

Changes in trust and trait anxiety: The mediating role of changes in self-rated health among older adults in Taiwan

AIM

This study examined whether changes in generalized trust and bonding trust are related to changes in trait anxiety, and whether changes in self-rated health mediate the relationship between changes in two types of trust and trait anxiety among older Taiwanese adults.

METHODS

A hierarchical regression model and a mediation model were separately used to analyze two-wave panel data on 763 older adults from the Panel Study of Family Dynamics in Taiwan.

RESULTS

Our findings show that changes in bonding trust (but not changes in generalized trust) are associated with changes in trait anxiety. The results show that sustaining a high level of bonding trust is associated with consistently good health, which in turn decreases anxiety. The relationship between changes in bonding trust and trait anxiety was found to be partially mediated by changes in self-rated health among older people.

CONCLUSIONS

The results suggest that bonding trust is more beneficial for the promotion of self-rated health and reducing trait anxiety than generalized trust in a given context. Policies aiming to ameliorate anxiety among older adults should take into consideration the importance of the developing bonding trust and promoting health in Chinese societies. Geriatr Gerontol Int 2020; 20: 833-838.

Health Burden, Support Adequacy, and Depressive Symptoms in Older Men With HIV

BACKGROUND AND OBJECTIVES

Older adults with HIV face greater health burden than HIV-uninfected counterparts. Little is known about resources that might mediate the influence of physiological health burden on psychological well-being. Informed by the stress process model, we assessed the influence of multifaceted health burden indicators on depressive symptoms and evaluated the mediating effects of social support adequacy.

RESEARCH DESIGN AND METHODS

This cross-sectional study used structural equation modeling with data from 640 older men who participated in the Research on Older Adults with HIV study in the United States. Health burden assessment included number of age-related chronic conditions, multiple HIV-related chronic conditions, and self-rated health. Perceptions of instrumental and emotional support adequacy measured support as a coping resource. Depressed mood as assessed by the 10-item Center for Epidemiologic Studies Depression Scale was the indicator of psychological well-being.

RESULTS

Higher incidence of age-related conditions and worse self-rated health was significantly associated with more depressed mood. Self-rated health and HIV-related conditions showed a significant indirect effect on depressed mood via emotional support adequacy.

DISCUSSION AND IMPLICATIONS

Each dimension of health burden demonstrated a distinct pathway to psychological well-being for men with HIV, which should be considered when prioritizing care plans. Complementing research on medical interventions for people with HIV, these findings suggest that nonpharmacological interventions may be important for improving overall well-being.

Evaluations of a Previous Day as a Pathway Between Personality and Healthy Cognitive Aging

Objective: To examine the association between Five-Factor Model personality traits and how individuals evaluate a recent day in their lives (yesterday) and whether these evaluations mediate personality and cognitive function over time. Methods: Participants were a subsample from the Health and Retirement Study who completed personality measures in 2008/2010, the day evaluation in 2011, and cognitive tasks in 2012 (N = 3,454). Results: Lower Neuroticism and Higher Extraversion, Openness, Agreeableness, and Conscientiousness were associated with a more engaging day, fewer negative feelings, better subjective health, and less time spent alone. Active engagement and subjective health were associated with cognitive function and mediated the prospective associations between Neuroticism, Openness, and Conscientiousness and cognitive function. Discussion: Personality is associated with how individuals evaluated their previous day, which contributes to cognition over time. The present research contributes to a mechanistic model that aims to identify pathways through which personality contributes to cognitive aging.

Sleep and Self-Rated Health in an Aging Workforce

The labor force participation rate for adults aged 55 years and older has increased nearly 10% over the past two and a half decades. As workers age, they frequently experience increased chronic health conditions and impaired sleep, which may negatively influence their self-rated health (SRH) and work performance. This study aimed to examine the associations between nonrestorative sleep (NRS) and work performance (i.e., difficulty concentrating or having lower productivity at work) and associations between demographic and sleep characteristics with SRH in middle-aged workers. We conducted a secondary data analysis among working middle-aged adults 50 to 65 years of age ( N = 392) from the 2008 Sleep in America Poll. Respondents frequently reported impaired sleep such as frequent insomnia symptoms, NRS, and short sleep duration. Nonrestorative sleep was associated with decreased work performance such as trouble organizing work, doing work over due to mistakes, and lower productivity. Nonrestorative sleep and short sleep duration were significantly associated with lower SRH. Strategies for the early detection of impaired sleep and implementation of interventions to improve sleep may improve SRH and work performance in working middle-aged adults.

Measurement matters: higher waist-to-hip ratio but not body mass index is associated with deficits in executive functions and episodic memory

Background

The current study aimed to reconcile the inconsistent findings between obesity, executive functions, and episodic memory by addressing major limitations of previous studies, including overreliance on body mass index (BMI), small sample sizes, and failure to control for confounds.

Methods

Participants consisted of 3,712 midlife adults from the Cognitive Project of the National Survey of Midlife Development. Executive functions and episodic memory were measured by a battery of cognitive function tests.

Results

We found that higher waist-to-hip ratio was associated with deficits in both executive functions and episodic memory, above and beyond the influence of demographics, comorbid health issues, health behaviors, personality traits, and self-perceived obesity. However, higher BMI was not associated with deficits in executive functions and episodic memory. More importantly, these differential associations were robust and stable across adulthood.

Discussion

Our findings confirm the association between obesity and episodic memory while highlighting the need for better measures of obesity when examining its associations with individual differences in cognitive functions.

The ACTIVE conceptual framework as a structural equation model

Background/Study Context: Conceptual frameworks are analytic models at a high level of abstraction. Their operationalization can inform randomized trial design and sample size considerations.

METHODS

The Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) conceptual framework was empirically tested using structural equation modeling (N=2,802). ACTIVE was guided by a conceptual framework for cognitive training in which proximal cognitive abilities (memory, inductive reasoning, speed of processing) mediate treatment-related improvement in primary outcomes (everyday problem-solving, difficulty with activities of daily living, everyday speed, driving difficulty), which in turn lead to improved secondary outcomes (health-related quality of life, health service utilization, mobility). Measurement models for each proximal, primary, and secondary outcome were developed and tested using baseline data. Each construct was then combined in one model to evaluate fit (RMSEA, CFI, normalized residuals of each indicator). To expand the conceptual model and potentially inform future trials, evidence of modification of structural model parameters was evaluated by age, years of education, sex, race, and self-rated health status.

RESULTS

Preconceived measurement models for memory, reasoning, speed of processing, everyday problem-solving, instrumental activities of daily living (IADL) difficulty, everyday speed, driving difficulty, and health-related quality of life each fit well to the data (all RMSEA < .05; all CFI > .95). Fit of the full model was excellent (RMSEA = .038; CFI = .924). In contrast with previous findings from ACTIVE regarding who benefits from training, interaction testing revealed associations between proximal abilities and primary outcomes are stronger on average by nonwhite race, worse health, older age, and less education (p < .005).

CONCLUSIONS

Empirical data confirm the hypothesized ACTIVE conceptual model. Findings suggest that the types of people who show intervention effects on cognitive performance potentially may be different from those with the greatest chance of transfer to real-world activities.