Dataset on the associations between sleep quality/duration and cognitive performance in cognitively healthy older adults

In the present data, we provide the details of the cross-sectional study examining the associations between sleep quality/sleep duration and cognitive performance. Data are from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD). A total of 1484 older adults (65 y.o. or older) took part in the study. Sleep measurements were drawn from the sleep scale of the Medical Outcomes Study (MOS). Cognition was used as a z-score drawn by different tests. The domains examined were: executive function, visuo-spatial ability, language, attention- speed of processing, as well as the composite z-score of all the cognitive domains (including memory). Linear regression models were conducted to investigate the associations between sleep quality and cognition, and sleep duration and cognition as well. We also conducted linear regression analyses for the associations between sleep quality/duration and cognitive domains/composite cognitive score based on the status of the Apolipoprotein E-ε4 (ApoE-ε4) genotype. Analyses were performed excluding both the demented and the Mild Cognitive Impairment (MCI) participants. Adjustments conducted for multiple covariates. For further analyses and enhanced discussion, see original article: “Sleep quality and duration in relation to memory in the elderly: initial results from the Hellenic Longitudinal Investigation of Aging and Diet” by Tsapanou et al. [1]


a b s t r a c t
In the present data, we provide the details of the cross-sectional study examining the associations between sleep quality/sleep duration and cognitive performance. Data are from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD). A total of 1484 older adults (65 y.o. or older) took part in the study. Sleep measurements were drawn from the sleep scale of the Medical Outcomes Study (MOS). Cognition was used as a z-score drawn by different tests. The domains examined were: executive function, visuo-spatial ability, language, attention-speed of processing, as well as the composite z-score of all the cognitive domains (including memory). Linear regression models were conducted to investigate the associations between sleep quality and cognition, and sleep duration and cognition as well. We also conducted linear Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/dib regression analyses for the associations between sleep quality/ duration and cognitive domains/composite cognitive score based on the status of the Apolipoprotein E-ε4 (ApoE-ε4) genotype. Analyses were performed excluding both the demented and the Mild Cognitive Impairment (MCI) participants. Adjustments conducted for multiple covariates. For further analyses and enhanced discussion, see original article: "Sleep quality and duration in relation to memory in the elderly: initial results from the Hellenic Longitudinal Investigation of Aging and Diet" by Tsapanou et al. [1] & 2017 Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). This data allows other researchers to extend the statistical analyses on longitudinal design studies.

Data
The dataset of this article provides information about the cross-sectional study that examined the association between sleep quality/duration and specific cognitive domains other than memory, in a large group of older adults. We also conducted the above analyses based on the ApoE-ε4 genotype. We provide the results of the different cognitive groups as well as of the composite cognitive score.

Sample collection
Participants were drawn from the HELIAD study. HELIAD is a population-based, multidisciplinary, collaborative study designed to estimate the prevalence and incidence of Mild Cognitive Impairment (MCI), Alzheimer's Disease (AD), other types of dementia, as well as other neuropsychiatric conditions of aging in the Greek population. The study includes several demographic, medical, social, environmental, clinical, nutritional, and neuropsychological determinants as well as the lifestyle activities of each participant. All participants were 65 y.o. or older [1].

Sleep measures
Sleep quality was assessed using the Sleep Scale from the Medical Outcomes Study (MOS). This scale is a self-reported 12-item questionnaire [2]. Based on the manual of the specific scale [3], in the current study, sleep quality was examined by the Sleep Index II (see Appendix).
In order to also examine sleep duration, we used the following question: "On the average, how many hours did you sleep each night during the past 4 weeks? Write in number of hours and minutes per night." The final variable used was the sum of the total duration calculated in minutes.

Analysis
We used general linear models (GLM) with the sleep quality first and then the sleep duration a variable as the predictor, and the different cognitive z-scores as the outcome.
In the model we adjusted for age, sex, education, and sleep medication (Tables 1-4). Table 1 Association between sleep quality and cognitive domains/composite z-score in the non-demented, non-MCI group. Adjusted for age, sex, education, and sleep medication.