Genetic risk for Alzheimer’s disease and adherence to the Mediterranean diet: results from the HELIAD study

ABSTRACT

Obejctives: The aim of the current study was to investigate whether genetic risk factors may moderate the association between adherence to the Mediterranean diet and AD incidence.

Mehtods: The sample was drawn from the HELIAD study, a longitudinal study with a follow-up interval of 3 years. In total 537 older adults without dementia or AD at baseline were included. Adherence to the Mediterranean diet was assessed at baseline and AD diagnosis was determined at both visits. A Polygenic Index for late onset AD (PGI-AD) was constructed. Cox proportional hazard models adjusted for age, sex, education, baseline Global cognition score and APOE e-4 genotype were employed to evaluate the association between PGI-AD and Mediterranean diet with AD incidence. Next, we examined the association between adherence to the Mediterranean diet and AD risk over time across participants stratified by low and high PGI-AD.

Results: Twenty-eight participants developed AD at follow-up. In fully adjusted models both the PGI-AD and the adherence to the Mediterranean diet were associated with AD risk (p < 0.05 for both). In the low PGI-AD group, those with a low adherence had a 10-fold higher risk of developing AD per year of follow-up, than did the participants with a high adherence to the Mediterranean diet (p = 0.011), whereas no such association was found for participants in the high PGI-AD group.

Discussion: The association of Mediterranean diet with AD risk is more prominent in the group of older adults with a low polygenic risk for developing AD. Our findings suggest that genetic risk factors should be taken into account when planning interventions aiming to improve cognitive health.

KEYWORDS:

• Nutrition
• dementia
• cognitive health
• elderly
• PRS
• PGI
• APOE

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author, NS, upon reasonable request.

Additional information

Funding

This work was supported by the grants: IIRG-09-133014 from the Alzheimer’s Association [grant 189 10276/8/9/2011]; the ESPA-EU program Excellence Grant (ARISTEIA); the Ministry for Health and Social Solidarity (Greece) [grant ΔΥ2β/οικ.51657/14.4.2009]. The funders had no role in the design, execution, analysis and interpretation of data, or writing of the study.

Notes on contributors

Eirini Mamalaki

Eirini Mamalaki is a Dietician-Nutritionist and a Research Assistant in Eginition Hospital. Her research interest focus on the investigation of lifestyle and cognitive health of older people.

Sokratis Charisis

Sokrates Charissis, neurology resident at UT Health San Antonio, and a postdoctoral research fellow at the Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases. His research is focused on the investigation of imaging, metabolic, and genetic biomarkers in neurodegenerative diseases and healthy aging.

Niki Mourtzi

Niki Mourtzi, PhD on genetics. Her research focus on genetic and non-genetic factors associated with neurological disorders.

Alexandros Hatzimanolis

Alexandros Hatzimanolis, assistant professor of behavioural neuroscience and psychiatric genetics. A human geneticist with a research focus on the investigation of the genomic and environmental underpinnings of cognitive ability, psychosocial functioning and psychiatric disorders.

Eva Ntanasi

Eva Ntanasi, is a Psychologist and a Research Assistant in Eginition Hospital, specialized in Clinical Neuropsychology. Her research interests lie in the investigation of cognitive health and dementias.

Mary H. Kosmidis

Mary H. Kosmidis is a professor of neuropsychological assessment and explores predictive and protective factors related to dementia and cognitive decline, as well as pitfalls and challenges in working cross-culturally with low (or no) educated older individuals.

Vasilios C. Constantinides

Vasilios C. Constantinides is a neurologist with special interest in the neurodegenerative diseases and especially dementias.

Georgios Pantes

Georgios Pantes MD, PhD, is a Clinical and Research Associate at 1st Neurology Department at Aiginition Hospital. Field of interest and publications include Memory, Dementia and interaction of medical approach and social welfare (functionality and disability).

Dimitra Kolovou

Dimitra Kolovou, is a general neurologist with interest in prognosis, diagnosis and therapeutic options for Alzheimer's disease and other dementias. Efthimios Dardiotis is an Associate Professor and his major research interest lie in the epidemiology of various neurological diseases.

Georgios Hadjigeorgiou

Georgios Hadjigeorgiou is a Professor of Neurology.

Paraskevi Sakka

Paraskevi Sakka is a neurologist. Her research interests include pharmacological and nonpharmacological treatments of dementia. She has founded the Athens Alzheimer Association.

Yian Gu

Yian Gu, an epidemiologist aiming to understand what, when, and why nutrients and diet can help prevent Alzheimer's disease and cognitive decline.

Mary Yannakoulia

Mary Yannakoulia, a professor of nutrition, is interested in the investigation of factors that influence human eating behavior and adherence to diet and lifestyle interventions, as well as the connection between diet and aging.

Nikolaos Scarmeas

Nikolaos Scarmeas is a Professor of Neurology. His research interests include cognitive reserve, and he has extensively investigated the contribution of diet (in particular dietary patterns such as a Mediterranean-type diet and others) in relation to dementias, Alzheimer's disease, cognitive and other aspects of aging.