Cognition-Mortality Associations Are More Pronounced When Estimated Jointly in Longitudinal and Time-to-Event Models

Associations between modifiable risk factors and cognitive function in middle-aged and older Chinese adults: joint modelling of longitudinal and survival data

Background

Stronger associations between modifiable risk factors and cognitive function have been found in younger than older adults. This age pattern may be subject to mortality selection and non-ignorable missingness caused by dropouts due to death, but this remains unclear.

Methods

Longitudinal data from 9,562 adults aged 50 and older from Waves 1-4 (2011-2018) of the China Health and Retirement Longitudinal Study were used. Cognitive function was assessed repeatedly using a battery of cognitive tests. Joint models of longitudinal and survival data were applied to examine the associations of modifiable risk factors with cognitive function and mortality.

Results

Worse cognitive function score was associated with being female (coefficient[β] = -1.669, 95% confidence interval [CI]: -1.830, -1.511, p < 0.001), low education (β = -2.672, 95%CI: -2.813, -2.530, p < 0.001), rural residence (β = -1.204, 95%CI: -1.329, -1.074, p < 0.001), stroke (β = -0.451, 95%CI: -0.857, -0.051, p = 0.030), probable depression (β = -1.084, 95%CI: -1.226, -0.941, p < 0.001), and current smoking (β = -0.284, 95%CI: -0.437, -0.133, p < 0.001); whereas dyslipidaemia (β = 0.415, 95% CI: 0.207, 0.626, p < 0.001), heart disease (β = 0.513, 95% CI: 0.328, 0.698, p < 0.001), overweight (β = 0.365, 95% CI: 0.224, 0.506, p < 0.001) and obesity (β = 0.264, 95% CI: 0.048, 0.473, p = 0.014) were associated with better cognitive function. These associations changed less than 5% when the longitudinal and survival data were modelled separately. An increase in cognitive function over age was associated with reduced mortality risk (hazard ratio: 0.418, 95%CI: 0.333, 0.537, p < 0.001). The association between socioeconomic disadvantage and cognitive function was more evident in women than in men, while the associations of socioeconomic disadvantage and lifestyle with cognitive function increased with age.

Conclusion

Mortality selection and non-ignorable missingness caused by dropouts due to death played a minor role in the associations between modifiable risk factors and cognitive function in middle-aged and older Chinese adults.

Movement Disorders and Mortality in Severely Mentally Ill Patients: The Curacao Extrapyramidal Syndromes Study XIV

BACKGROUND AND HYPOTHESIS

There is a substantial gap in life expectancy between patients with severe mental illness (SMI) and the general population and it is important to understand which factors contribute to this difference. Research suggests an association between tardive dyskinesia (TD) and mortality; however, results are inconclusive. In addition, studies investigating associations between parkinsonism or akathisia and mortality are rare. We hypothesized that TD would be a risk factor for mortality in patients with SMI.

STUDY DESIGN

We studied a cohort of 157 patients diagnosed predominantly with schizophrenia on the former Netherlands Antilles. TD, parkinsonism, and akathisia were assessed with rating scales on eight occasions over a period of 18 years. Twenty-four years after baseline, survival status and if applicable date of death were determined. Associations between movement disorders and survival were analyzed using Cox regression. Sex, age, antipsychotics, antidepressants and benzodiazepines at each measurement occasion were tested as covariates.

STUDY RESULTS

Parkinsonism was a significant risk factor with an HR of 1.02 per point on the motor subscale of the Unified Parkinson's Disease Rating Scale (range 0-56). TD and akathisia were not significantly associated with mortality.

CONCLUSIONS

Parkinsonism may be an important risk factor for mortality in SMI patients. This finding calls for more follow-up and intervention studies to confirm this finding and to explore whether treatment or prevention of parkinsonism can reduce excess mortality.

Associations of Wellbeing Levels, Changes, and Within-Person Variability With Late-Life All-Cause Mortality Across 12 Years: Contrasting Hedonic vs. Eudaimonic Wellbeing Among Very Old Adults

Advanced old age has been characterized as a biologically highly vulnerable life phase. Biological, morbidity-, and cognitive impairment-related factors play an important role as mortality predictors among very old adults. However, it is largely unknown whether previous findings confirming the role of different wellbeing domains for mortality translate to survival among the oldest-old individuals. Moreover, the distinction established in the wellbeing literature between hedonic and eudaimonic wellbeing as well as the consideration of within-person variability of potentially relevant mortality predictors has not sufficiently been addressed in prior mortality research. In this study, we examined a broad set of hedonic and eudaimonic wellbeing indicators, including their levels, their changes, as well as their within-person variability, as predictors of all-cause mortality in a sample of very old individuals. We used data from the LateLine study, a 7-year longitudinal study based on a sample of n = 124 individuals who were living alone and who were aged 87–97 years (M = 90.6, SD = 2.9) at baseline. Study participants provided up to 16 measurement occasions (mean number of measurement occasions per individual = 5.50, SD = 4.79) between 2009 and 2016. Dates of death were available for 118 individuals (95.2%) who had deceased between 2009 and 2021. We ran longitudinal multilevel structural equation models and specified between-person level differences, within-person long-term linear change trends, as well as the “detrended” within-person variability in three indicators of hedonic (i.e., life satisfaction and positive and negative affect) and four indicators of eudaimonic wellbeing (i.e., purpose in life, autonomy, environmental mastery, and self-acceptance) as all-cause mortality predictors. Controlling for age, gender, education, and physical condition and testing our sets of hedonic and eudaimonic indictors separately in terms of their mortality impact, solely one eudaimonic wellbeing indicator, namely, autonomy, showed significant effects on survival. Surprisingly, autonomy appeared “paradoxically” related with mortality, with high individual levels and intraindividual highly stable perceptions of autonomy being associated with a shorter residual lifetime. Thus, it seems plausible that accepting dependency and changing perceptions of autonomy over time in accordance with objectively remaining capabilities might become adaptive for survival in very old age.

Orientation Experiences and Navigation Aid Use: A Self-Report Lifespan Study on the Role of Age and Visuospatial Factors

Spatial orientation is essential for daily life, but it deteriorates with aging. The present study was aimed at investigating age changes across the adult lifespan in the self-reported use of navigation aids and everyday orientation experiences, as well as investigating to what extent these are related to visuospatial working memory (VSWM) and self-reported wayfinding inclinations. A sample of 456 people aged 25–84 years rated how much they use navigation aids (maps, GPS, verbal directions), how much they went out, and how much they reached or lost their way to unfamiliar destinations (in 2016). Then, they performed the jigsaw puzzle test (VSWM) and questionnaires on sense of direction, pleasure in exploring, and spatial anxiety. The results showed that increasing age is related to a lower tendency to go out, fewer experiences of finding one’s way and getting lost, a lower level of GPS use, and increased verbal directions use. After age changes were accounted for, VSWM was related to aid use and orientation experiences (except for losing one’s way), wayfinding inclinations (especially spatial anxiety) to using a map, and orientation experiences. Overall, other than age, VSWM and one’s wayfinding attitudes can play a role–albeit it a modest one–in spatial behaviors.