Sleep disturbances and change in multiple cognitive domains among older adults: a multicenter study of five Nordic cohorts.

STUDY OBJECTIVES: We examined and compared cross-sectional and longitudinal associations between self-reported sleep disturbances and various cognitive domains in five separate Nordic European longitudinal aging studies (baseline N = 5631, mean age = 77.7, mean follow-up = 4.16 years). METHODS: Comparable sleep parameters across studies included reduced sleep duration/quality, insomnia symptoms (sleep latency, waking up at night, and early awakenings), short and long sleep duration, and daytime napping. The cognitive domains were episodic memory, verbal fluency, perceptual speed, executive functioning, and global cognition (aggregated measure). A series of mixed linear models were run separately in each study and then compared to assess the level and rate of change in cognitive functioning across each sleep disturbance parameter. Models were adjusted for age, sex, education, hypnotic usage, depressive symptoms, lifestyle factors, cardiovascular, and metabolic conditions. By using a coordinated analytic approach, comparable construct-level measurements were generated, and results from identical statistical models were qualitatively compared across studies. RESULTS: While the pattern of statistically significant results varied across studies, subjective sleep disturbances were consistently associated with worse cognition and steeper cognitive decline. Insomnia symptoms were associated with poorer episodic memory and participants sleeping less or more than 7-8 hours had a steeper decline in perceptual speed. In addition, daytime napping (>2 hours) was cross-sectionally and longitudinally associated with all examined cognitive domains. Most observed associations were study-specific (except for daytime napping), and a majority of association estimates remained significant after adjusting for covariates. CONCLUSION: This rigorous multicenter investigation further supports the importance of sleep disturbance, including insomnia, long and short sleep duration, and daytime napping on baseline cognitive functioning and rate of change among older adults. These sleep factors may be targeted in future lifestyle interventions to reduce cognitive decline.

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.

Conditions for uptake of evidence-based knowledge in municipal care for older people in Sweden: a developmental evaluation.

OBJECTIVE: The objective of this paper is to describe the initial phase of a long-term collaboration initiative between a municipality and the Faculty of Medicine at a university in Sweden. The overall ambition of the collaboration is to strengthen the quality of care for older people. The concrete goal is to equip academically trained registered health care professionals (HCP) with tools for transferring evidence-based knowledge into practice. As municipal healthcare for older people is mainly carried out by staff lacking academic education, reg. HCP are key actors to bring in and consolidate an evidence-based approach in this setting. Developmental evaluation (DE) has been used to evaluate four separate activities in the initial phase. The activities where sequenced in a cumulative design to provide knowledge for further development of adequate tools. RESULTS: The cumulative design originally planned did not fit the internal logic of the municipality. Therefore, workflow and pace adjustments were made to proceed towards the joint ambition; the creation of fruitful conditions for the uptake of evidence-based knowledge. Long-term collaboration between academia and organizations outside academia demands a sensitive and flexible research approach, recognizing that collaboration implies mutuality and restricts the sovereignty of academia in designing research.

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.

Impaired kidney function is associated with lower cognitive function in the elder general population. Results from the Good Aging in Skåne (GÅS) cohort study.

BACKGROUND: A possible connection on vascular basis between impaired kidney function and cognitive dysfunction has been suggested in previous studies. Contradictory results regarding specific cognitive domains have been reported. The aim for this study was to investigate the association between kidney function and specific cognitive domains. METHODS: In this cross-sectional design, data from the general population based cohort study "Good aging in Skåne" (GÅS) was used. The sample included 2931 subjects ages 60 to 93 randomly selected from the southern part of Sweden. Estimated glomerular filtration rate (eGFR) for both creatinine and cystatine C was calculated using the chronic kidney disease epidemiology collaboration (CKD-EPI) equation. The subjects underwent a test battery of neuropsychological tests assessing global cognitive function, learning and memory, language, complex attention, executive function, perceptual motor and meta-memory. Adjustments were made for age, sex, education and country of origin. RESULTS: After adjustment for demographic variables, impaired kidney function was associated with 0.41 points worse result in MMSE, 0.56 points worse result in recognition, 0.66 points worse result in word fluency, 0.45 points worse result in digit cancellation, 0.99 points worse result in pattern comparison, and 3.71 s longer time to finish TMT B-A. Associations to cognitive function was also noted for mildly impaired kidney function defined as eGFR 45- < 60 ml/min/1,73m2. No association was found between kidney function and meta-memory. CONCLUSIONS: Impaired kidney function as well as the severity of impaired kidney function is associated with impairment in learning and memory, language, complex attention, executive function and global cognitive function, but not meta-memory.

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.

Diagnostic Stability of Mild Cognitive Impairment, and Predictors of Reversion to Normal Cognitive Functioning.

OBJECTIVE: Studies that investigate predictive factors for spontaneous recovery (reversion) from mild cognitive impairment (MCI) are only beginning to emerge, and the long-term course of MCI is not properly understood. We aimed to investigate stability of the MCI diagnosis, predictors for reversion, as well as the trajectory of MCI over the course of 12 years. MATERIALS AND METHODS: Data were drawn from the Swedish population study: Good Aging in Skåne with MCI defined according to the expanded Mayo Clinic criteria. A total of 331 participants, aged 60-95 years with MCI, were used to investigate 6-year MCI stability and reversion, and 410 participants were used to inspect 12-year MCI trajectory. Predictors for reversion included demographical factors, psychological status, and factors tied to the cognitive testing session and the operationalization of the MCI criteria. RESULTS: Over half (58%, 95% CI 52.7-63.3) of the participants reverted back to normal cognitive functioning at 6-year follow-up. Of those with stable MCI, 56.5% (95% CI 48.2-64.8) changed subtype. A total of 23.9% (95% CI 13.7-34.1) of the 6-year follow-up reverters re-transitioned back to MCI at 12-year follow-up. ORs for reversion were significantly higher in participants with lower age (60-year-olds: OR 2.19, 95% CI 1.08-4.43, 70-year-olds: OR 3.11, 95% CI 1.27-7.62), better global cognitive functioning (OR 1.15, 95% CI 1.03-1.29), good concentration (OR 2.53, 95% CI 1.06-6.05), and single-domain subtype (OR 2.68, 95% CI 1.51-4.75). CONCLUSION: Our findings provide further support that MCI reversion to normal cognitive functioning as well as re-transitioning to MCI is fairly common, suggesting that the MCI trajectory does not necessarily lead straight to dementia. Additionally, assessment of factors associated with reversion can aid clinicians to make accurate MCI progression prognosis.