Self-reported sleep fragmentation and sleep duration and their association with cognitive function in PROTECT, a large digital community-based cohort of people over 50.

OBJECTIVE: Sleep is vital for normal cognitive function in daily life, but is commonly disrupted in older adults. Poor sleep can be detrimental to mental and physical health, including cognitive function. This study assessed the association between self-reported short (<6 h) and long (>9 h) sleep duration and sleep fragmentation (3≥ nightly awakenings) in cognitive function. METHODS: Cross-sectional data from 8508 individuals enroled in the PROTECT study aged 50 and above formed the basis of the univariate linear regression analysis conducted on four cognitive outcomes assessing visuospatial episodic memory (VSEM), spatial working memory, verbal working memory (VWM), and verbal reasoning (VR). RESULTS: Short (ß = -0.153, 95% CI [-0.258, -0.048], p = 0.004) and long sleep duration (ß = -0.459, 95% CI [-0.826, -0.091], p = 0.014) were significantly associated with poorer cognitive performance in VWM. Long sleep duration (ß = -2.986, 95% CI [-5.453, -0.518], p = 0.018) was associated with impaired VR. Short sleep (ß = -0.133, 95% CI [-0.196, -0.069], p = <0.001) and sleep fragmentation (ß = -0.043, 95% CI [-0.085, -0.001], p = 0.043) were associated with reduced VSEM. These associations remained significant when including other established risk factors for dementia and cognitive decline (e.g., depression, hypertension). CONCLUSIONS: Our findings suggest that short and long sleep durations and fragmented sleep, may be risk factors for a decline in cognitive processes such as working memory, VR and episodic memory thus might be potential targets for interventions to maintain cognitive health in ageing.

Awareness of age-related changes in Norwegian individuals 50+. Short form questionnaire validation.

Background: A questionnaire assessing awareness of positive and negative age-related changes (AARC gains and losses) was developed in the US and Germany, and validated for the UK and Brazilian populations. In this study, we validated the short-form measure (AARC-10 SF) in the Norwegian population aged 50 and over. In addition, the relationship between cognitive variables and AARC was examined. Methods: Cross-sectional analyses of data from 1,510 participants in the ongoing online PROTECT Norge study were used to explore and confirm the two-factor structure of AARC gains and AARC losses; reliability; measurement invariance across different population groups defined by sex, education level, employment, and in middle age, early old age, and advanced old age. We explored the relationship between AARC and demographic variables (defined in the same way as the population groups). Results: We confirmed the two-factor structure (gains and losses) of the Norwegian translation of the AARC-10 SF. We did not find mutual correlations between related items in gains and losses, except for the physical health item from the gains dimension, which was positively correlated with all items of the losses dimension. Age, sex, marital status, employment, and university education predicted AARC gains and losses. Conclusion: The Norwegian translation of the AARC-10 SF captures individuals' positive and negative self-perceptions of age-related changes in their mental, physical, and cognitive health.