Up to speed: Birth cohort effects observed for speed of processing in older adults: Data from the Good Ageing in Skåne population study

Excessive sleep is associated with worse cognition, cognitive decline, and dementia in mild cognitive impairment

INTRODUCTION

This study examines the link between daytime and nighttime excessive sleep and cognition, cognitive decline, and dementia in individuals with existing mild cognitive impairment (MCI).

METHODS

Using data from the Swedish longitudinal study Good Aging in Skåne, participants aged 60-102 years were retrospectively classified as MCI based on cognitive testing. The average follow-up time was 6.59 years. Mixed linear models assessed cross-sectional and longitudinal associations between excessive sleep patterns (napping ≥2 h or nighttime sleep ≥9 h) and multiple cognitive domains. Cox regressions estimated dementia risk for excessive sleep.

RESULTS

Of 4930 participants, 2052 (41%) had MCI. Excessive daytime napping and nighttime sleep were associated with worse cognition and cognitive decline. Excessive napping and nighttime sleep were also linked to higher dementia risk (hazard ratios: 1.75 and 1.86, respectively).

DISCUSSION

These findings suggest that excessive sleep in MCI is associated with further cognitive decline and dementia.

Highlights

Excessive daytime napping and nighttime sleep are linked cognitive decline for those with MCI.Excessive sleep during the day or at night heighten dementia risk.Worse test scores across multiple cognitive domains were observed for excessive daytime nappers.Excessive sleep in MCI may be a warning sign for further cognitive decline.

The Association between Physical Frailty and Cognitive Performance in Older Adults Aged 60 to 96 Years: Data from the "Good Aging in Skåne" (GÅS) Swedish Population Study

BACKGROUND

The association between physical frailty and performance in different cognitive domains in the absence of cognitive disorders is poorly understood. Hence, we aimed to explore the associations between frailty levels based on the Fried Physical Frailty Phenotype and performance of different cognitive domains. We also aimed to examine the associations between cognitive function and each criterion in the Fried Frailty Scale using the same cognitive domains in a non-dementia population aged 60-96 years.

METHODS

This cross-sectional study included 4,329 participants aged 60-96 years, drawn from the "Good Aging in Skåne" population study. Frailty indices included handgrip strength, physical endurance, body mass index (BMI), physical activity, and walking speed. Cognitive function was assessed across eight domains: episodic memory, processing speed, semantic memory, verbal fluency, working memory, attention, executive function, and visual perception. We constructed adjusted multiple linear regression models for each cognitive domain, with the frailty levels as the independent variable. Likewise, we constructed linear regression models with each cognitive domain as the dependent variable and frailty criteria as independent variables.

RESULTS

Physical frailty was associated with poor performance in episodic memory, processing speed, semantic memory, verbal fluency, working memory, attention, and executive functions (p<0.001 for all associations). Weaker hand grip strength was independently associated with poorer performance in all cognitive domains (p < 0.015).

CONCLUSION

Higher levels of frailty were associated with poorer performance in all cognitive domains except visual perception. Describing frailty by considering cognitive functioning may provide a better understanding of frailty.

Cognitive decline and risk of dementia in older adults after diagnosis of chronic obstructive pulmonary disease

Cognitive screening has been proposed for older adults diagnosed with chronic obstructive pulmonary disease (COPD). Therefore, we examined the change over time in cognitive function and the risk of incident dementia in older adults after COPD diagnosis. A sample of 3,982 participants from the population-based cohort study Good Aging in Skåne was followed for 19 years, and 317 incident COPD cases were identified. The cognitive domains of episodic memory, executive function, and language were assessed using neuropsychological tests. Mixed models for repeated measures and a Cox model were implemented. Participants performed, on average, worse over time on all neuropsychological tests after COPD diagnosis in comparison to those without COPD, although statistical significance differences were only observed for episodic memory and language. The groups had a comparable risk of developing dementia. In conclusion, our results indicate that cognitive screening in the early stages of COPD may be of limited clinical relevance.

Mild Cognitive Impairment, Reversion Rates, and Associated Factors: Comparison of Two Diagnostic Approaches

BACKGROUND

As mild cognitive impairment (MCI) is typically used to identify prodromal stages of dementia, it is essential to identify MCI criteria with high diagnostic stability and prediction of dementia. Moreover, further investigation into pinpointing key factors for reversion is required to foresee future prognosis of MCI patients accurately.

OBJECTIVE

To explore disparities in diagnostic stability by examining reversion rates produced by two operationalizations of the MCI definition: the widely applied Petersen criteria and a version of the Neuropsychological (NP) criteria and to identify cognitive, lifestyle, and health related factors for reversion.

METHODS

MCI was retrospectively classified in a sample from the Swedish community-based study Good Aging in Skåne with the Petersen criteria (n = 744, median follow-up = 7.0 years) and the NP criteria (n = 375, median follow-up, 6.7 years), respectively. Poisson regression models estimated the effect of various factors on the likelihood of incident reversion.

RESULTS

Reversion rates were 323/744 (43.4%, 95% confidence intervals (CI): 39.8; 47.0) and 181/375 (48.3% 95% CI: 43.2; 53.5) for the Petersen criteria and NP criteria, respectively. Participants with impairment in a single cognitive domain, regular alcohol consumption, living with someone, older age, and lower body mass index had a higher likelihood of reverting to normal.

CONCLUSION

Reversion rates were similar for Petersen and NP criteria indicating that one definition is not superior to the other regarding diagnostic stability. Additionally, the results highlight important aspects such as multiple domain MCI, cohabitation, and the role of alcohol on predicting the trajectory of those diagnosed with MCI.

Secular Trends in Dementia Free Cognitive Function in Older Adults: A Systematic Review

BACKGROUND

Although numerous studies have reported a decrease in dementia risk in the last two decades, it is unclear whether dementia-free cognitive function is also changing across generations.

OBJECTIVE

The objective was to systematically evaluate the published data on generational differences in cognitive function in the older population.

METHODS

Searches were performed on PubMed, Embase, and PsychInfo for articles published in English before 20 June 2021. Included studies were from population-based samples that reported generational differences in cognition in individuals without dementia, aged ≥60 years.

RESULTS

28,101 studies were identified and 15 selected covering the period from 1971 to 2015: including studies from China, Europe, and the USA. The results show generally consistent findings of improvements or stability in dementia free cognitive function in later versus earlier born generations, but not for all cognitive domains. Prevalence of mild cognitive impairment and cognitive impairment no dementia has remained stable in the USA, UK, and China over the last two decades.

RESULTS

Prevalence of vascular related mild cognitive impairment has increased in China. Improvements in cognition may only partially be explained by increased educational attainment across generations.

CONCLUSION

This review provides evidence for generational effects in dementia-free cognitive function, predominately stability or improvements in performance, in later compared to earlier born individuals across different world regions. There is an urgent need to determine the factors driving such changes and whether they are being experienced in all world regions, particularly low- and middle-income countries where the burden of cognitive impairment is greatest and rising.

Secular trends in prevalent mild cognitive impairment: Data from the Swedish population-based study Good Aging in Skåne

Background

Research suggests that incident dementia is decreasing, yet research on secular trends of prodromal dementia such as mild cognitive impairment (MCI) is lacking.

Methods

To determine change of MCI prevalence over time and potential explanatory factors, four baseline samples (years 2001-2020) of Swedish participants (n = 3910) aged 60 and 81 at examination were compared.

Results

An overall drop of 9 to 10 percentage points in MCI prevalence between 2001 and 2020 was observed, with lower odds ratios (OR) for MCI in the latest birth cohorts compared to earliest (e.g., ORs for 60-year-olds in latest born = 0.53; 95% confidence interval [CI] 0.37-0.76). Adjustments for sociodemographic (e.g., education), lifestyle, vascular and metabolic health and depression could not fully explain the observed MCI decline (e.g., 60-year-olds, OR = 0.59; 95% CI 0.40-0.88).

Discussion

Studies like this are imperative as even a slight postponement in the onset of dementia could have a substantial impact on future public health burden.

Prevalence and Incidence of Mild Cognitive Impairment across Subtypes, Age, and Sex

OBJECTIVE

The purpose of this study was to report on the prevalence and incidence of mild cognitive impairment (MCI) across age, sex, and subtypes according to various criteria in a population-based sample.

METHODS

The sample was drawn from the Swedish Good Aging in Skåne (GÅS) population study, and data from 3,752 participants aged 60 years and more were used to calculate the MCI prevalence. The incidence was calculated using 2,093 participants with 6-year follow-up data. MCI was defined according to the expanded Mayo Clinic criteria: cognitive complaint, objective cognitive impairment (two different criteria depending on the severity of impairment), preserved functional abilities, and no dementia.

RESULTS

The prevalence estimates ranged from 5.13 to 29.9% depending on age and severity of impairment. The incidence rates of overall MCI were 22.6 (95% confidence interval [CI]: 19.6-25.9) and 8.67 (95% CI: 7.0-10.7) per 1,000 person-years for less severe and severe cognitive impairment, respectively. The highest prevalence and incidence estimates were found for "non-amnestic MCI single domain." The older age groups had a higher prevalence, and no sex or age differences in MCI incidence were detected.

CONCLUSION

Our findings concur with previous research advocating that MCI is a heterogeneous concept, since the prevalence and incidence estimates differed substantially according to age, MCI subtype, and severity of cognitive impairment.