The main objectives of the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD) are to investigate in the Greek population, associations between the Mediterranean-type diet and cognitive dysfunction/age-related neuropsychiatric diseases, and to estimate the prevalence and incidence of Alzheimer’s disease, other dementias, mild cognitive impairment, and other neuropsychiatric conditions of aging.

The study also ascertains several demographic, medical, social, environmental, clinical, nutritional, and neuropsychological determinants and lifestyle activities.

General Design

Study Design Cohort
General Information on Follow Up (profile, frequency)

Follow-ups with face-to-face interviews at 3 year intervals.

Recruitment Target
  • Individuals
Number of Participants


Number of Participants with Biological Samples



Not Applicable
Don't Know
Possible Access to Data

Possible Access to Biosamples


Marker Paper

Dardiotis et al. The Hellenic Longitudinal Investigation of Aging and Diet (HELIAD): Rationale, study design, and cohort description. Neuroepidemiology, 2014;43:9-14.

PUBMED 24993387

Study Timeline

Each colour in the timeline graph below represents a separate Study Population, while each segment in the graph represents a separate Data Collection Event. Clicking on a segment gives more detailed information on a Data Collection Event.


HELIAD - Population

The popluation consists of men and women aged 65 years and over; residents from the city of Larissa in the province of Thessaly, and from Marousi, a suburban city of Athens, Greece.

Sources of Recruitment

General Population
  • Selected sample

Selection Criteria

Age Minimum age 65
Country Greece
Territory Larissa and Marousi
Supplementary Information The study is conducted in Larissa , Thessaly, since 2009, and in Marousi, Athens, since 2013.

Sample Size

Number of Participants


Number of Participants with Biological Samples


Data Collection Events

HELIAD - Baseline

Certified neurologists, trained...


Variables classifications