Giorgos M. Hadjigeorgiou

Mediterranean diet and cognitive health: Initial results from the Hellenic Longitudinal Investigation of Ageing and Diet

Background The Mediterranean dietary pattern has been associated with a decreased risk of many degenerative diseases and cognitive function in particular; however, relevant information from Mediterranean regions, where the prototype Mediterranean diet is typically adhered to, have been very limited. Additionally, predefined Mediterranean diet (MeDi) scores with use of a priori cut-offs have been used very rarely, limiting comparisons between different populations and thus external validity of the associations. Finally, associations between individual components of MeDi (i.e., food groups, macronutrients) and particular aspects of cognitive performance have rarely been explored. We evaluated the association of adherence to an a priori defined Mediterranean dietary pattern and its components with dementia and specific aspects of cognitive function in a representative population cohort in Greece. Methods Participants from the Hellenic Longitudinal Investigation of Ageing and Diet (HELIAD), an on-going population-based study, exploring potential associations between diet and cognitive performance in a representative sample from Greek regions, were included in this analysis. Diagnosis of dementia was made by a full clinical and neuropsychological evaluation, while cognitive performance was assessed according to five cognitive domains (memory, language, attention-speed, executive functioning, visuospatial perception) and a composite cognitive score. Adherence to MeDi was evaluated by an a priori score (range 0–55), derived from a detailed food frequency questionnaire. Results Among 1,865 individuals (mean age 73±6 years, 41% male), 90 were diagnosed with dementia and 223 with mild cognitive impairment. Each unit increase in the Mediterranean dietary score (MedDietScore) was associated with a 10% decrease in the odds for dementia. Adherence to the MeDi was also associated with better performance in memory, language, visuospatial perception and the composite cognitive score; the associations were strongest for memory. Fish consumption was negatively associated with dementia and cognitive performance positively associated with non-refined cereal consumption. Conclusions Our results suggest that adherence to the MeDi is associated with better cognitive performance and lower dementia rates in Greek elders. Thus, the MeDi in its a priori constructed prototype form may have cognitive benefits in traditional Mediterranean populations.

Sleep quality and duration in relation to memory in the elderly: Initial results from the Hellenic Longitudinal Investigation of Aging and Diet

Background: Sleep is crucial for cognition, particularly for memory, given its complex association with neurodegenerative processes. The aim of the present study was to examine the association between sleep quality as well as sleep duration and memory performance in a Greek elderly population. Setting: Cross‐sectional design in the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD), a population representative study of Greek elderly (65 years or older). Methods: Data from 1589 participants free of sleep medication were included. Sleep quality was estimated by using the Sleep Scale from the Medical Outcomes Study. An extensive neuropsychological assessment examining memory was administered to each participant. Linear regression analyses were used to examine whether sleep quality (higher score, poor quality) and/or sleep duration were associated with memory expressed in the form of a z‐score. Age, sex, education, and body mass index were included as covariates. The main analyses were conducted first on the total sample, then with the exclusion of demented participants, and finally with the exclusion of both demented and participants with Mild Cognitive Impairment (MCI). We then conducted further analyses on the non‐demented, non‐MCI group, initially stratified by Apolipoprotein E‐&egr;4 gene. We further examined the role of co‐morbidities, as well as the association between sleep duration groups and memory. We also explored any interaction effect between sex and sleep quality/duration on memory. We then examined the associations between components of sleep measures and memory scores. Lastly, we examined the associations between sleep quality/duration and verbal/non‐verbal memory separately. Results: In the total sample, we noted significant associations between sleep duration and memory (B = −0.001, p ≤ 0.0001), but not for sleep quality and memory (B = −0.038, p = 0.121). After excluding the demented participants, the associations were significant for: sleep quality and memory (B = −0.054, p = 0.023), and sleep duration and memory (B = −0.001, p ≤ 0.0001). After excluding both the MCI and the demented subjects, the associations between sleep quality and memory (B = −0.065, p = 0.006), and sleep duration and memory (B = −0.001, p = 0.003) were still significant. The association between the sleep duration groups and memory function was also significant, such that poor memory performance was associated with the longer sleep duration group. The results remained significant even after controlling for the co‐morbidities, as well as after adding in the model anxiety and depression as covariates. Associations between sleep quality and memory, and sleep duration and memory were present in the ApoE‐&egr;4 non‐carriers. The individual sleep questions that were probably shown to be driving the associations between sleep and memory were: time to fall asleep, sleep not quiet, getting enough sleep to feel rested upon waking in the morning, and getting the amount of sleep needed. Sleep duration was associated with both verbal and non‐verbal memory, while sleep quality was only associated with verbal memory. Conclusion: Poor sleep quality and longer sleep duration were linked to low memory performance, independent of demographic and clinical factors, in a large sample of cognitively healthy older Greek adults. Other parameters than sleep and memory measurements could play an important role on the association. Levels of melatonin, or circadian rhythms dysregulation might play a crucial role in the above associations. HIGHLIGHTSPoor sleep quality, low memory in the elderly.Longer sleep, low memory in the elderly.No sex differences between sleep quality/duration and memory.

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]

Associations between the mediterranean diet and sleep in older adults: Results from the hellenic longitudinal investigation of aging and diet study

Although there is some evidence of the relationships between sleep duration/quality and nutrient and/or food intake, the associations between sleep and dietary patterns have been poorly explored. The aim of the present study was to evaluate sleep duration and quality in relation to adherence to the Mediterranean diet (MeDi), and to investigate the sex‐ and age‐specific associations in a population‐representative cohort of older adults.

Mediterranean Lifestyle in Relation to Cognitive Health: Results from the HELIAD Study

Many lifestyle factors have been linked to cognitive function but little is known about their combined effect. An overall lifestyle pattern for people living in the Mediterranean basin has been proposed, including diet, but also physical activity, sleep and daily living activities with social/intellectual aspects. We aimed to examine the associations between a combination of these lifestyle factors and detailed cognitive performance. A total of 1716 participants from the Hellenic Longitudinal Investigation of Ageing and Diet (HELIAD), a population-based study of participants ≥65 years, were included in this analysis. Lifestyle factors were evaluated using standard, validated questionnaires and a Total Lifestyle Index (TLI) was constructed. Cognitive outcomes included mild cognitive impairment (MCI) diagnosis, a composite z-score (either continuous or with a threshold at the 25th percentile) and z-scores for five cognitive domains. A higher TLI was associated with 65% reduced odds for MCI in the non-demented individuals and 43% reduced odds for low global cognition when MCI participants were excluded, a risk reduction equivalent to 9 and 2.7 fewer years of ageing, respectively. Each lifestyle factor was differentially associated with domain-specific cognitive performance. Our results suggest that a TLI, more so than single lifestyle parameters, may be related to cognitive performance.

Differential effects of completed and incomplete pregnancies on the risk of Alzheimer disease

Objective To investigate the effects of completed pregnancy with childbirth and incomplete pregnancy without childbirth on the late-life cognition and the risk of Alzheimer disease (AD) in women. Methods Using the pooled data of 3,549 women provided by 2 population-based cohort studies, we conducted logistic regression analyses to examine retrospectively the associations of completed and incomplete pregnancy with the risks of mild cognitive impairment and AD. For women without dementia, we also conducted analyses of covariance to examine the associations of completed and incomplete pregnancy with Mini-Mental State Examination (MMSE) score. Results Grand multiparous women who experienced ≥5 completed pregnancies showed an ≈1.7-fold higher risk of AD than those who experienced 1 to 4 completed pregnancies (odds ratio [OR] 1.68, 95% confidence interval [CI] 1.04–2.72), while those who had incomplete pregnancies showed half the level of AD risk compared with those who never experienced an incomplete pregnancy (OR 0.43, 95% CI 0.24–0.76 for 1 incomplete pregnancy; OR 0.56, 95% CI 0.34–0.92 for ≥2 incomplete pregnancies). In women without dementia, the grand multiparous had worse MMSE scores than those with 1 to 4 completed pregnancies (p < 0.001), while those who experienced ≥1 incomplete pregnancies had better MMSE scores than those who never experienced an incomplete pregnancy (p = 0.008). Conclusions Grand multiparity was associated with high risk of AD, while incomplete pregnancy was associated with low risk of AD in late life.

IMPACT OF COMPLETED AND INCOMPLETE PREGNANCIES ON THE RISK OF ALZHEIMER’S DISEASE

Laurel Beckett, Charlie S. DeCarli, University of California, San Francisco, San Francisco, CA, USA; University of California-Davis, Sacramento, CA, USA; UC Davis, Davis, CA, USA; University of California Davis, Sacramento, CA, USA; University of California, Davis, Davis, CA, USA; University of California, Davis, Sacramento, CA, USA; University of California Davis Alzheimer’s Center, Davis, CA, USA; University of California-Davis, Davis, CA, USA. Contact e-mail: Teresa. Filshtein@ucsf.edu