Polygenic risk scores for Alzheimer's disease in relation to cognitive change: A representative sample from the general population followed over 16 years.

BACKGROUND: Polygenic risk scores for Alzheimer's disease (AD-PRSs) have been associated with cognition. However, few studies have examined the effect of AD-PRS beyond the APOE gene, and the influence of genetic variants related to level of cognitive ability (COG-PRS) on cognitive performance over time in the general older population. METHOD: A population-based sample of 965 individuals born in 1930, with genetic and standardized cognitive data on six psychometric tests (Thurstone's picture memory, immediate recall of 10 words, Block design, word fluency, figure identification, delayed recall of 12 items), were examined at age 70, 75, 79, and 85 years. Non-APOE AD-PRSs and COG-PRSs (P < 5e-8, P < 1e-5, P < 1e-3, P < 1e-1) were generated from recent genome-wide association studies. Linear mixed effect models with random intercepts and slope were used to analyze the effect of APOE ε4 allele, AD-PRSs, and COG-PRSs, on cognitive performance and rate of change. Analyses were repeated in samples excluding dementia. RESULTS: APOE ε4 and AD-PRS predicted change in cognitive performance (APOE ε4*age: ß = -0.03, P < 0.0001 and AD-PRS *age: ß = -0.01, P = 0.02). The results remained similar in the sample excluding those with dementia. COG-PRS predicted level of cognitive performance, while APOE ε4 and AD-PRS did not. COG-PRSs did not predict change in cognitive performance. CONCLUSION: We found that genetic predisposition of AD predicted cognitive decline among 70-year-olds followed over 16 years, regardless of dementia status, while polygenic risk for general cognitive performance did not.

Preventive interventions for children of parents with depression, anxiety, or bipolar disorder: A quasi-experimental clinical trial.

AIM: To investigate the effectiveness of preventive interventions for 8-17-year-old children of patients diagnosed with depression, anxiety, or bipolar disorder. METHODS: Sixty-two families including 89 children received either the more extensive Family Talk Intervention (FTI; n = 35), the brief Let's Talk about Children (LTC; n = 16), or Interventions as Usual (IAU; n = 38) in routine care in adult psychiatry. Parent-rated questionnaire data were collected at baseline, after 6 and 12 months. We used growth curve models to investigate the effect of intervention on child mental health problems (SDQ-P Total Difficulties) and perceived parental control of child behaviour (PLOC-PPC). RESULTS: Parents in the FTI and LTC groups, versus the IAU group, reported more favourable development in terms of preventing increase in child mental health problems with standardised intervention effects of d = -0.86 and -0.88 respectively, by study end, and reported improved perceived parental control, d = 1.08 and 0.71, respectively, by study end. No significant differences in effect were found when FTI and LTC were compared. CONCLUSIONS: The results support continued use of FTI and LTC in adult psychiatry, and since LTC is a brief intervention, it might be useful as a minimum-level preventive intervention.

The Gothenburg H70 Birth cohort study 2014-16: design, methods and study population.

To improve health care for older persons, we need to learn more about ageing, e.g. identify protective factors and early markers for diseases. The Gothenburg H70 Birth Cohort Studies (the H70 studies) are multidisciplinary epidemiological studies examining representative birth cohorts of older populations in Gothenburg, Sweden. So far, six birth cohorts of 70-year-olds have been examined over time, and examinations have been virtually identical between studies. This paper describes the study procedures for the baseline examination of the Birth cohort 1944, conducted in 2014-16. In this study, all men and women born 1944 on specific dates, and registered as residents in Gothenburg, were eligible for participation (n = 1839). A total of 1203 (response rate 72.2%; 559 men and 644 women; mean age 70.5 years) agreed to participate in the study. The study comprised sampling of blood and cerebrospinal fluid, psychiatric, cognitive, and physical health examinations, examinations of genetics and family history, use of medications, social factors, functional ability and disability, physical fitness and activity, body composition, lung function, audiological and ophthalmological examinations, diet, brain imaging, as well as a close informant interview, and qualitative studies. As in previous examinations, data collection serves as a basis for future longitudinal follow-up examinations. The research gained from the H70 studies has clinical relevance in relation to prevention, early diagnosis, clinical course, experience of illness, understanding pathogenesis and prognosis. Results will increase our understanding of ageing and inform service development, which may lead to enhanced quality of care for older persons.

Parenting programs during adolescence: Outcomes from universal and targeted interventions offered in real-world settings.

The aim of this naturalistic study was to explore short and long-term outcomes of five different group-based parenting programs offered to parents of 10 to 17-year-olds. Three hundred and fifteen parents (277 mothers and 38 fathers) who had enrolled in a parenting program (universal: Active Parenting, COPE; Connect; targeted: COMET; Leadership training for parents of teenagers [LFT]) answered questionnaires at three measurement waves (baseline, post-measurement, and one-year follow-up). The questions concerned parenting style, parental mental health, family climate and adolescent mental health. Results revealed small to moderate changes in almost all outcome variables and in all parenting programs. Overall, parents in COMET reported the largest short and long-term changes. No substantial differences in change were seen between the other programs. The results support the general effectiveness of parenting programs for parents of adolescents.

Impact of stroke on cognition in old age: Comparison of two population-based cohorts, born up to 30 years apart and followed from age 70 to 85.

Little is known about birth cohort differences in the impact of stroke on cognitive aging. Given improved poststroke rehabilitation and better treatments for vascular health risk, we may expect a reduction in the stroke impact in later-born cohorts. We tested this prediction using data from two cohorts, born in 1901-1907 (n = 1,155) and 1930 (n = 919), identified from the same city population at the same age of 70 and subsequently measured on the same cognitive outcomes (i.e., spatial ability, perceptual-motor speed, and reasoning) at ages 70, 75, 79, and 85. We fitted multiple-group second-order latent growth curve models to the data, regressing the first-order cognitive factor on the time-varying stroke variable and controlling for relevant covariates. Findings revealed moderate to large average cognitive decline (d = -.45) following stroke, and the impact was relatively similar across cohorts (1901-1907: d = -.52; 1930: d = -.39). However, there was a stroke by age by cohort interaction, implying that the stroke impact increased with age in the 1901-1907 cohort (dage ≤ 75 = -.42; dage ≥ 79 = -.70) but decreased in the 1930 cohort (dage ≤ 75 = -.53; dage ≥ 79 = -.17). We found no evidence for lagged effect of stroke beyond the impact on measures following the incidence. Our hypothesis was only partially supported, as the impact of stroke was reduced in the later-born cohort but solely at higher ages. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Future time perspective and personality trait change during the retirement transition: Insights from a six-wave longitudinal study in Sweden.

The present study examined associations between two future time perspective (FTP) dimensions (perceived opportunities and perceived time) and the Big Five personality traits during older adulthood, a developmental period that has received limited attention in personality development. Specifically, it tested whether FTP dimensions were cross-sectionally associated with personality traits, as well as if they predicted changes on those traits during a time when participants were transitioning to retirement. Participants from the Health, Ageing and Retirement Transitions in Sweden (HEARTS) study (N = 5,913, Mage = 63.09 years) reported on their FTP at the initial assessment and on their Big Five personality traits on six assessments 1 year apart. Latent growth curve models were fit to examine FTP as a predictor of level and change in the Big Five traits over time, with perceived time and opportunities included as unique predictors. Results found that broader FTP was associated with higher extraversion, agreeableness, openness to experience, and conscientiousness, but lower neuroticism initially. However, results indicated associations were stronger and sometimes only significant for perceived opportunities not time. Regarding FTP as a predictor of personality trait change, modest evidence was found that perceived opportunities predicted changes in neuroticism and openness over time. The present study extends past work by showing the importance of capturing different components of FTP when examining personality traits during older adulthood. Research needs to further explore the longitudinal predictive effects of FTP, focusing on more proximal assessments and how FTP changes during retirement. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Onset and rate of cognitive change before dementia diagnosis: findings from two Swedish population-based longitudinal studies.

We used data from two population-based longitudinal studies to estimate time of onset and rate of accelerated decline across cognitive domains before dementia diagnosis. The H70 includes an age-homogeneous sample (127 cases and 255 non-cases) initially assessed at age 70 with 12 follow-ups over 30 years. The Kungsholmen Project (KP) includes an age-heterogeneous sample (279 cases and 562 non-cases), with an average age of 82 years at initial assessment, and 4 follow-ups spanning 13 years. We fit mixed linear models to the data and determined placement of change points by a profile likelihood method. Results demonstrated onset of accelerated decline for fluid (speed, memory) versus crystallized (verbal, clock reading) abilities occurring approximately 10 and 5 years before diagnosis, respectively. Although decline before change points was greater for fluid abilities, acceleration was more pronounced for crystallized abilities after the change points. This suggests that onset and rate of acceleration vary systematically along the fluid-crystallized ability continuum. There is early onset in fluid abilities, but these changes are difficult to detect due to substantial age-related decline. Onset occurred later and acceleration was greater in crystallized abilities, suggesting that those markers may provide more valid identification of cases in later stages of the prodromal phase.

What Matters and What Matters Most for Survival After age 80? A Multidisciplinary Exploration Based on Twin Data.

Given research and public interest for conditions related to an extended lifespan, we addressed the questions of what matters and what matters most for subsequent survival past age 80. The data was drawn from the population-based and multidisciplinary Swedish OCTO Twin Study, in which a sample (N = 699) consisting of identical and same-sex fraternal twin pairs, followed from age 80 until death, provided detailed data on health, physical functioning, life style, personality, and sociodemographic conditions. Information concerning date of birth and death were obtained from population census register. We estimated heritability using an ACE model and evaluated the role of multiple predictors for the mortality-related hazard rate using Cox regression. Our findings confirmed a low heritability of 12%. As expected, longer survival was associated with being a female, an apolipoprotein E (APOE) e4 allele non-carrier, and a non-smoker. Several diseases were found to be associated with shorter survival (cerebrovascular, dementia, Parkinson's, and diabetes) as well as certain health conditions (high diastolic blood pressure, low body mass index, and hip fracture). Stronger grip and better lung function, as well as better vision (but not hearing), and better cognitive function (self-evaluated and measured) was related to longer survival. Social embeddedness, better self-evaluated health, and life-satisfaction were also significantly associated with longer survival. After controlling for the impact of comorbidity, functional markers, and personality-related predictors, we found that sex, cerebrovascular diseases, compromised cognitive functioning, self-related health, and life-satisfaction remained as strong predictors. Cancer was only associated with the mortality hazard when accounting for other co-morbidities. The survival estimates were mostly in anticipated directions and contained effect sizes within the expected range. Noteworthy, we found that some of the so-called "soft-markers" remained strong predictors, despite a control for other factors. For example, self-evaluation of health and ratings of life-satisfaction provide additional and valuable information.

Memory in individuals with mild cognitive impairment in relation to APOE and CSF Abeta42.

BACKGROUND: The epsilon4 allele of the apolipoprotein E (APOE) gene and low levels of cerebrospinal fluid (CSF) amyloid beta-proteins 42 (Abeta) have previously been associated with increased risk of cognitive decline in old age. In this study we examine the interaction of these markers with episodic memory in a sample identified as having mild cognitive impairment (MCI). METHODS: The sample (N = 149) was drawn from the Gothenburg MCI study and measured according to three free recall tests on three occasions spanning over four years. Second-order Latent Curve Models (LCM) were fitted to the data. RESULTS: Analyses accounting for age, gender, education, APOE, Abeta42, and interaction between APOE and Abeta42 revealed that the epsilon4 allele was significantly associated with level of memory performance in the presence of low Abeta42 values (< or = 452 ng/L). Associations between memory performance and Abeta42 were significant among the epsilon4 carriers but not among the non-carriers. The Abeta42 marker was, however, significantly associated with changes in memory over the study time period in the total sample. CONCLUSION: The findings support the hypothesis of an interactive effect of APOE and Abeta42 for memory decline in MCI patients.

Cholesterol and cognitive aging: Between-person and within-person associations in a population-based representative sample not on lipid-lowering medication.

Previous studies suggest that cholesterol metabolic dysregulation, characterized by abnormally low or high serum total cholesterol (TC) values, constitutes a risk for pronounced cognitive decline in old age. We tested this prediction using a population-based representative Swedish sample (N = 382), born in 1901-1902, and subsequently assessed on TC and 3 cognitive outcomes (verbal ability, spatial ability, and perceptual-motor-speed) at ages 70, 75, 79, 85, 88, and 90. None of the participants were on lipid-lowering medication, as prescription availability for these medications were not initiated in Sweden until the mid-1990s. We used a 3-level hierarchical model, with cognitive tests nested within time, nested within individuals. Estimates from this model revealed a nonlinear between-person association between TC and cognition, indicating that low, and to some degree high, TC values were associated with poorer cognition. This association was stronger among nondementia-cases (n = 255). Among subsequent dementia cases (n = 127), the data suggested a linear trend, indicating that lower TC values were associated with poorer cognition. TC levels declined over time in the vast majority (96%), and the steepness of this decline was associated with the rate of cognitive decline. This within-person association was particularly strong among incident dementia cases with low TC values. Our findings indicate an optimal range of TC values associated with better cognition in old age and that the within-person association between TC and cognition is related to dementia pathologies. Further, our findings demonstrate the need to separate between-person from within-person associations when evaluating the relation between TC and cognition in old age. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Child maltreatment and substance-use-related negative consequences: Longitudinal trajectories from early to mid adolescence.

BACKGROUND: Child maltreatment is associated with adult substance use disorders (i.e. alcohol and/or illicit drug use). Little is known about the behavioral pathways characterizing adolescent substance users who were subjected to childhood maltreatment. Here, we investigate the longitudinal trajectories of substance-use-related negative consequences (SURNCs) in adolescence in relation to childhood maltreatment. METHOD: We drew the data (N = 1515) from the longitudinal multidisciplinary research program LoRDIA (Longitudinal Research on Development In Adolescence), of which 406 reported substance use and were included in the presented analyses. The data were collected via self-report questionnaires in classroom settings at three time points (mean age: 13.5, 14.4 and 15.0). We obtained information for childhood maltreatment using the Childhood Trauma Questionnaire-Short Form (CTQ-SF) and data of frequencies of SURNC with a questionnaire scale. RESULTS: Estimates from zero-inflated Poisson growth curve model revealed no baseline differences in SURNCs across children reporting none, single, or multiple maltreatment before the age of twelve. However, children experiencing multiple maltreatment displayed a greater increase in the frequency of SURNCs during the transition from early to mid adolescence than did those reporting no maltreatment. These estimates were only partly influenced by the inclusion of frequency of alcohol and substance drug use to the model. CONCLUSIONS: These findings imply that children suffering maltreatment are at a higher risk of experiencing SURNCs, a factor known to elevate the risk of substance use disorders later in life, as they transition from early to mid adolescence.

The pattern of cognitive symptoms predicts time to dementia onset.

BACKGROUND: Few studies have examined whether cognitive symptom patterns differ by age and length of time before dementia onset. Our objective was to investigate whether different patterns of cognitive symptoms at ages 70, 75, and 79 years predict short-term (< or =5 years) and long-term (>5 years) dementia onset. METHODS: A representative sample of 382 nondemented 70-year-olds from Gothenburg, Sweden was examined periodically up to age 90 years. Information on dementia in those lost to follow-up was obtained from medical records. Cognitive assessments at ages 70, 75, and 79 years included psychiatric and psychometric examinations. Four patterns of cognitive performance were examined in relation to dementia onset: (1) unimpaired cognition, (2) isolated low memory, (3) low non-memory, and (4) global low cognitive performance. RESULTS: Short-term onset was predicted by global low performance at ages 70, 75, and 79 years and by low non-memory performance at ages 70 and 75. Isolated low memory was not a short-term predictor at any examination, but it predicted long-term onset at ages 70 and 75 years. CONCLUSIONS: A global pattern of low cognitive performance predicts short-term but not long-term onset of dementia, whereas isolated low memory performance predicts dementia only in the long-term. Our findings also suggest that preclinical symptoms of dementia might differ by age.

Do later-born birth cohorts of septuagenarians sleep better? A prospective population-based study of two birth cohorts of 70-year-olds.

Study Objectives: To investigate birth cohort differences in the prevalence of insomnia from ages 70 to 79. Methods: Data were drawn from population-based samples of two cohorts of septuagenarians; the early-born 1901-07-cohort, who took part in psychiatric examinations between 1971 and 1986 (n = 681), and the later-born 1930-cohort examined between 2000 and 2010 (n = 943). Examinations were conducted at ages 70, 75, and 79. Criteria for insomnia were identical across cohorts and included sleep dissatisfaction accompanied with complaints of difficulty initiating or maintaining sleep. Associations were analyzed with logistic growth curve models. Results: The later-born cohort had lower odds for insomnia at age 70 (OR = 0.52, 95% CI: 0.32-0.87) compared with the earlier born cohort. Age was not related to insomnia as a main effect but we found an interaction between age and birth cohort (OR = 1.14, 95% CI: 1.08-1.21); insomnia increased with age in the later but not in the early-born cohort. Women had higher odds for insomnia compared with men (OR = 3.10, 95% CI: 2.02-4.74), and there was an interaction between sex and birth cohort (OR = 0.51, 95% CI: 0.30-0.88; there were larger cohort differences among women than among men and less sex differences in the later than in the earlier born cohort. Also, there were no significant differences between the cohorts in taking sleep medications. Conclusions: Our findings provide evidence of improved self-reported sleep in later-born cohorts of septuagenarians, but the difference diminished with age. The prevalence of self-reported insomnia was greater in women than in men, but sex differences were less pronounced in the later-born cohort.

Association of IL1RAP-related genetic variation with cerebrospinal fluid concentration of Alzheimer-associated tau protein.

A possible involvement of the gene IL1RAP (interleukin-1 receptor-associated protein) in the pathogenesis of Alzheimer's disease (AD) has been suggested in GWASs of cerebrospinal fluid (CSF) tau levels and longitudinal change in brain amyloid burden. The aim of this study was to examine previously implicated genetic markers in and near IL1RAP in relation to AD risk, CSF tau and Aß biomarkers, as well as cognitive decline, in a case (AD)-control study and an age homogenous population-based cohort. Genotyping of IL1RAP-related single nucleotide polymorphisms (SNPs), selected based on previous GWAS results, was performed. 3446 individuals (1154 AD cases and 2292 controls) were included in the analyses of AD risk, 1400 individuals (cognitively normal = 747, AD = 653) in the CSF biomarker analyses, and 861 individuals in the analyses of cognitive decline. We found no relation between IL1RAP-related SNPs and AD risk. However, CSF total-tau and phospho-tau were associated with the SNP rs9877502 (p = 6 × 10-3 and p = 5 × 10-4). Further, nominal associations (p = 0.03-0.05) were found between three other SNPs and CSF biomarker levels, or levels of cognitive performance and decline in a sub-sample from the general population. These results support previous studies suggesting an association of IL1RAP with disease intensity of AD.

IQ as moderator of terminal decline in perceptual and motor speed, spatial, and verbal ability: Testing the cognitive reserve hypothesis in a population-based sample followed from age 70 until death.

Terminal decline (TD) refers to acceleration in within-person cognitive decline prior to death. The cognitive reserve hypothesis postulates that individuals with higher IQ are able to better tolerate age-related increase in brain pathologies. On average, they will exhibit a later onset of TD, but once they start to decline, their trajectory is steeper relative to those with lower IQ. We tested these predictions using data from initially nondemented individuals (n = 179) in the H70-study repeatedly measured at ages 70, 75, 79, 81, 85, 88, 90, 92, 95, 97, 99, and 100, or until death, on cognitive tests of perceptual-and-motor-speed and spatial and verbal ability. We quantified IQ using the Raven's Coloured Progressive Matrices (RCPM) test administrated at age 70. We fitted random change point TD models to the data, within a Bayesian framework, conditioned on IQ, age of death, education, and sex. In line with predictions, we found that 1 additional standard deviation on the IQ scale was associated with a delay in onset of TD by 1.87 (95% highest density interval [HDI; 0.20, 4.08]) years on speed, 1.96 (95% HDI [0.15, 3.54]) years on verbal ability, but only 0.88 (95% HDI [-0.93, 3.49]) year on spatial ability. Higher IQ was associated with steeper rate of decline within the TD phase on measures of speed and verbal ability, whereas results on spatial ability were nonconclusive. Our findings provide partial support for the cognitive reserve hypothesis and demonstrate that IQ can be a significant moderator of cognitive change trajectories in old age. (PsycINFO Database Record

Better Cognition in New Birth Cohorts of 70 Year Olds, But Greater Decline Thereafter.

OBJECTIVES: To evaluate birth cohort differences in level of cognition and rate of change in old age. METHODS: Data were drawn from three population-based Swedish samples including age-homogenous cohorts born 1901/02, 1906/07, and 1930, and measured on the same cognitive tests at ages 70, 75, and 79 as part of the Gerontological and Geriatric Populations Studies in Gothenburg (H70). We fitted growth curve models to the data using a Bayesian framework and derived estimates and inferences from the marginal posterior distributions. RESULTS: We found moderate to large birth cohort effects in level of performance on all cognitive outcomes. Later born cohorts, however, showed steeper linear rate of decline on reasoning, spatial ability, and perceptual- and motor-speed, but not on picture recognition memory and verbal ability. DISCUSSION: These findings provide strong evidence for substantial birth cohort effects in cognition in older ages and emphasize the importance of life long environmental factors in shaping cognitive aging trajectories. Inferences from cognitive testing, and standardization of test scores, in elderly populations must take into account the substantial birth cohort differences.

Psychological Health in the Retirement Transition: Rationale and First Findings in the HEalth, Ageing and Retirement Transitions in Sweden (HEARTS) Study.

From an aging research and life-course perspective, the transition to retirement marks a significant life-event and provides a unique opportunity to study psychological health and coping during a period of substantial change in everyday life. The aim of the present paper is to: (a) outline the rationale of the HEalth, Ageing and Retirement Transitions in Sweden (HEARTS) study, (b) describe the study sample, and (c) to present some initial results from the two first waves regarding the association between retirement status and psychological health. The HEARTS study is designed to annually study psychological health in the years before and following retirement, and to examine change and stability patterns related to the retirement event. Among a representative Swedish population-based sample of 14,990 individuals aged 60-66 years, 5,913 completed the baseline questionnaire in 2015. The majority of the participants (69%) completed a web-based survey, and the rest (31%) completed a paper version. The baseline HEARTS sample represents the general population well in terms of gender and age, but is more highly educated. Cross-sectional findings from the first wave showed that retired individuals demonstrated better psychological health compared to those who were still working. Longitudinal results from the first and second waves showed that individuals who retired between waves showed more positive changes in psychological health compared with those still working or previously retired.

A Longitudinal Study of the Mini-Mental State Examination in Late Nonagenarians and Its Relationship with Dementia, Mortality, and Education.

OBJECTIVES: To examine level of and change in cognitive status using the Mini-Mental State Examination (MMSE) in relation to dementia, mortality, education, and sex in late nonagenarians. DESIGN: Three-year longitudinal study with examinations at ages 97, 99, and 100. SETTING: Trained psychiatric research nurses examined participants at their place of living. PARTICIPANTS: A representative population-based sample of 97-year-old Swedes (N = 591; 107 men, 484 women) living in Gothenburg, Sweden. MEASUREMENTS: A Swedish version of the MMSE was used to measure cognitive status. Geriatric psychiatrists diagnosed dementia according to the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised. Mixed models were fitted to the data to model the longitudinal relationship between MMSE score and explanatory variables. RESULTS: Individuals with dementia between age 97 and 100 had lower mean MMSE scores than those without dementia. Those who died during the 3-year follow-up had lower MMSE scores than those who survived. MMSE scores at baseline did not differ between those without dementia and those who developed dementia during the 3-year follow-up. Participants with more education had higher MMSE scores, but there was no association between education and linear change. CONCLUSION: MMSE score is associated with dementia and subsequent mortality even in very old individuals, although the preclinical phase of dementia may be short in older age. Level of education is positively associated with MMSE score but not rate of decline in individuals approaching age 100.

Effects of repeated testing in a longitudinal age-homogeneous study of cognitive aging.

Estimates of gains related to repeated test exposure (retest effects) and within-person cognitive changes are confounded in most longitudinal studies because of the nonindependent time structures underlying both processes. Recently developed statistical approaches rely on between-person age differences to estimate effects of repeated testing. This study, however, demonstrates how retest effects can be evaluated at the group level in an age-homogeneous population-based study by use of a sampling-based design approach in which level and change of cognitive performance of previous participants, measured at ages 70, 75, 79, 81, 85, 88, 90, 92, 95, 97, and 99 years, were compared with performances of survivors of a representative sample identified and drawn from the same original population cohort but invited for the first time at age 85 with subsequent measurements at ages 88, 90, 92, 95, 97, and 99. The comparisons revealed a trend toward retest effects on two out of five cognitive measurements. The study demonstrates how a design-based approach can provide valuable insights into continuous learning processes embedded in population average aging trajectories that are not confounded with cohort and mortality-related selective attrition.

Birth cohort differences in fluid cognition in old age: comparisons of trends in levels and change trajectories over 30 years in three population-based samples.

Later-born cohorts of older adults tend to outperform earlier born on fluid cognition (i.e., Flynn effect) when measured at the same chronological ages. We investigated cohort differences in level of performance and rate of change across three population-based samples born in 1901, 1906, and 1930, drawn from the Gerontological and Geriatric Population Studies in Gothenburg, Sweden (H70), and measured on tests of logical reasoning and spatial ability at ages 70, 75, and 79 years. Estimates from multiple-group latent growth curve models (LGCM) revealed, in line with previous studies, substantial differences in level of performance where later-born cohorts outperformed earlier born cohorts. Somewhat surprisingly, later-born cohorts showed, on average, a steeper decline than the earlier-born cohort. Gender and education only partially accounted for observed cohort trends. Men outperformed women in the 1906 and 1930 cohorts but no difference was found in the 1901 cohort. More years of education was associated with improved performance in all three cohorts. Our findings confirm the presence of birth cohort effects also in old age but indicate a faster rate of decline in later-born samples. Potential explanations for these findings are discussed.