Ebetsu Active Future Study (EAFS): cognitive function and physical and mental health in elderly residents of Ebetsu City, Japan – cohort profile

Abstract

Purpose

Ebetsu Active Future Study (EAFS) conducts comprehensive annual surveys of individuals who are independent in activities of daily living (ADLs) to track age-related physical and mental changes. These surveys include a variety of assessments such as cognitive function tests, physical function tests, blood tests, self-administered questionnaires about lifestyle and health, and interviews regarding medical and family history. In addition, serum, plasma and DNA samples from these assessments are stored at −80°C to facilitate future analyses and accommodate the potential addition of new measurement items. The purposes of this study are: (1) to identify potential blood-based biomarkers applicable to the detection of various types of mild cognitive impairment (MCI), (2) to explore diet-based strategies for preventing MCI and the progression of dementia, (3) to examine the relationship between urban characteristics, individual attributes and healthy life expectancy in Ebetsu City and (4) to return the research findings to the city.

Participants

From August to October 2023, EAFS invited Ebetsu residents to participate in the study. As a result, 1340 individuals applied and 1189 residents aged between 55 and 75 years who were independent in ADLs participated in the baseline survey for the first year.

Findings to date

EAFS initiated a follow-up of 1189 participants (38.9% male; 64.5±5.6 years) in the baseline year of 2023 and maintained a high follow-up rate of 98.5% by wave 3 (2025). The Montreal Cognitive Assessment-Japanese demonstrated that 53.6% of the participants had operational MCI. The proportion of participants with operational MCI increased with ageing. Regarding the APOE4 gene, which is associated with an increased risk of Alzheimer’s disease, 1.2% of the total population were homozygous carriers and 22.1% were heterozygous carriers.

Future plans

EAFS will conduct annual follow-up surveys until 2032. In addition to analysing data for each objective, we also plan to perform further analysis of the stored specimens.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• A comprehensive survey, being conducted annually for 10 years, of elderly individuals who were independent in activities of daily living at baseline.

• Standardised testing methods and conditions are maintained because all participants are tested at the same venue within a relatively short period each year.

• Specimens are systematically collected so that new testing methods can be applied in the future.

• The prevalence of possible mild cognitive impairment at baseline and the subsequent follow-up rate were high.

• The sample may not be representative due to a bias in favour of recruitment of individuals with good physical function and high health awareness.

Introduction

As of September 2024, individuals aged 65 years and older accounted for approximately 29.3% of the total population in Japan.¹ According to the United Nations’ World Population Prospects, the 2024 Revision, Japan ranks second in the proportion of its population aged 65 years or older.² Although the importance of extending healthy life expectancy has been recognised for many years, various challenges remain, including the onset of mild cognitive impairment (MCI) and dementia. Ebetsu Active Future Study (EAFS) conducts comprehensive annual surveys of individuals who are independent in activities of daily living (ADLs) to track age-related physical and mental changes. These surveys include a variety of assessments such as cognitive function tests, physical function tests, blood tests, self-administered questionnaires about lifestyle and health, and interviews regarding medical and family history. In addition, serum, plasma and DNA samples are collected and stored at −80°C to facilitate future analyses and accommodate the potential addition of new measurement items. During the follow-up period, mild cognitive decline and age-related challenges in daily living are expected to emerge. We have set three objectives for this study.

The first objective is to identify widely applicable, blood-based biomarkers for the early detection of MCI. Intervening during the MCI stage, the transitional phase before dementia onset,^{3 4} is considered extremely effective for preventing or delaying disease progression. However, MCI is often difficult to detect because it typically does not cause noticeable symptoms in daily life.⁵ Although there are established diagnostic methods, such as positron emission tomography (PET), MRI and cerebrospinal fluid analysis, they are not suitable for large-scale screening or routine checkups due to their high cost, invasiveness and limited accessibility. Blood-based biomarkers, in contrast, offer a highly practical alternative for widespread screening. Furthermore, other types of dementia exist, including Alzheimer’s disease (AD; the most common form), dementia with Lewy bodies and frontotemporal dementia.⁶ Given this diversity, this study aims to establish a high-precision screening method that comprehensively captures various types of degenerative dementia by combining multiple proteins, including amyloid-beta, with various metabolites.

The second objective is to investigate dietary strategies for preventing MCI and slowing the progression of dementia. Previous reports indicate that, although ageing and genetic factors influence the risk of dementia, modifiable risk factors include midlife hypertension, diabetes, obesity, dyslipidaemia, smoking, physical inactivity, depression and diet.⁷ Specifically, regarding previous research on diet, a study conducted in the USA suggests that greater adherence to the Mediterranean–DASH Intervention for Neurodegenerative Delay diet, a hybrid Mediterranean-DASH diet, may be protective against the development of AD.⁸ Additionally, a study conducted in Japan indicates that dietary fibre intake was inversely associated with the risk of disabling dementia in a general Japanese population.⁹ Dietary prevention of dementia is promising as an easily implementable lifestyle modification. However, the inconsistencies among findings from different research groups require further investigation. Furthermore, from the perspective of personalised nutrition, it is reasonable to consider that dietary habits that are risk factors or effective MCI prevention strategies vary among individuals. Utilising validated dietary assessment tools such as the food frequency questionnaire (FFQ), we will evaluate comprehensive dietary intake status and its relationship with biomarkers associated with cognitive function (eg, amyloid β, advanced glycation end products (AGEs)). Findings from these analyses are expected to be used in developing personalised MCI prevention strategies based on individual dietary patterns.

The third objective is to examine the relationship between urban characteristics, individual attributes and healthy life expectancy in Ebetsu City, and to return the research findings to the city. As stated in the Guideline for the Promotion of Health, Medical, and Welfare Town Planning,¹⁰ addressing the challenges of a super-aged society requires creating communities in which older adults can lead active lives and are supported by the broader community. To realise such a society, it is necessary to promote daily activities such as ‘walking around town’ and ‘community activities’. However, when considering this in Ebetsu City, it is important to recognise the city’s climatic background and the diversity of its residential environments. Specifically, Ebetsu City is characterised by harsh winter conditions, with heavy snowfall and severe cold, and a diverse residential environment, including urban areas, residential districts and rural regions. The previous survey¹¹ reported that over half of all age groups in Ebetsu City (including the elderly) answered that they were ‘satisfied’ or ‘mostly satisfied’ with the city’s liveability. The survey also revealed that satisfaction with the efficiency of snow removal on roads and sidewalks was low across all age demographics. Furthermore, satisfaction with public transportation was low among the elderly population. These results demonstrate general trends; however, it is essential to recognise that the impact of Ebetsu City’s geographical and meteorological factors on its residents may not be uniform. In other words, the extent to which these environmental factors influence daily activities is expected to vary significantly depending on interactions with individual attributes such as physical function and lifestyle. Therefore, this study will comprehensively examine the relationships among Ebetsu City’s environmental factors, individual attributes and health status, including cognitive function. Given the absence of comprehensive, long-term studies on the topic in Japan, this research is regarded as having significant academic worth.

Cohort description

Setting

EAFS is a prospective, longitudinal, observational cohort study designed to investigate the risk factors and biomarkers associated with MCI onset in a community setting. This design enables longitudinal evaluation of lifestyle, dietary patterns and biological markers relevant to cognitive health, with specimen collection and comprehensive data acquisition as integral components of the study.

In June 2022, Shimadzu Corporation, Ebetsu City, Hokkaido Information University, National Agriculture and Food Research Organization (NARO) and Self Care Food Council (SCFC) signed a comprehensive partnership agreement. The agreement aims to contribute to the development of a social system that reduces the risk of MCI onset and prevents its occurrence. EAFS is one of the projects conducted as joint research by the five parties based on this agreement. Shimadzu Corporation, Hokkaido Information University and NARO are responsible for collecting and analysing data and specimens, whereas Ebetsu City and SCFC support the smooth implementation of the project. The study is conducted in Ebetsu City, located in Hokkaido, Japan’s northernmost main island, adjacent to Sapporo, the nation’s fourth-largest city by population (approximately 2 million in 2025). For about 50 years, Ebetsu City has experienced the most significant population growth within the commuting and school commuting zone to Sapporo, functioning as a suburban community. Currently, approximately 120 000 people reside there. Similar to many Japanese cities, Ebetsu City is experiencing an ageing population.

Participant enrolment

Participants were fully informed about the aims, methods and schedule of this study and were included only after providing written informed consent.

To recruit participants for EAFS, we adopted the following recruitment strategies to ensure widespread notification throughout Ebetsu City:

• Informing the public through Ebetsu City’s official website, social media, public relations magazine and neighbourhood association circulars.

• Distributing recruitment flyers and application forms at public facilities, Ebetsu City event venues and commercial facilities that offered cooperation.

• Enclosing recruitment flyers and application forms in letters sent by Ebetsu City to its residents.

• Sending letters to volunteer members managed by the Health Information Science Research Center at Hokkaido Information University.

• Requesting coverage in local newspapers.

Since EAFS focuses on the early stages of cognitive decline, participants aged 55–75 with no impairment in ADLs were recruited. The inclusion criteria were: (1) those capable of providing informed consent to participate in the study; (2) those residing in Ebetsu City at the time of the wave 1 survey; and (3) those aged 55–75 years as of 1 April 2023. The exclusion criteria were: (1) those unable to perform basic ADLs independently; (2) those who are non-ambulatory and restricted by a physician in their ADLs (eg, wheelchair users or users of walking aids, such as T-shaped canes); (3) those with visual or hearing impairments that interfere with daily living; (4) those diagnosed with quadriplegia, major depressive disorder, dementia or intractable neurological diseases (eg, Parkinson’s disease, related disorders, amyotrophic lateral sclerosis and neurodegenerative diseases); and (5) those with medical electrical devices, such as pacemakers. Prospective participants self-reported their status regarding these conditions and submitted a participation application form. Participants were enrolled based on their self-reported information. Figure 1 presents a flowchart illustrating the stages of participant recruitment.

Figure 1. Participant flow diagram.

A total of 1340 individuals applied to participate during the recruitment period from August to October 2023. After excluding 23 ineligible applicants, 43 who failed to attend their scheduled examination and 85 who could not be accommodated due to capacity limits, a final total of 1189 individuals participated in the wave 1 survey. All participants provided written informed consent prior to the commencement of the study. Given that 36 947 residents aged 55–75 were registered in Ebetsu City as of 1 April 2023, this sample represents approximately 3% of the target population. Those who completed the wave 1 survey are invited to participate in the survey annually until 2032. Furthermore, regardless of annual survey participation, basic resident information—specifically the long-term care insurance level and resident registration status (as of 1 October)—will be collected longitudinally from all participants by Ebetsu City. By the start of the wave 3 survey, 18 individuals had withdrawn consent, resulting in a follow-up rate of 98.5% at that point.

Participants receive a ¥4000 gift certificate for each survey they complete. Participants are provided with some health survey results (basic body composition, blood pressure, parts of the physical function test, general blood tests and nutritional balance based on self-administered questionnaires) to help maintain their willingness to continue participating. Participants with clinically significant findings are advised to seek medical attention.

Patient and public involvement

The research design, participant recruitment, questionnaire development and specimen collection were planned and implemented without direct input from participants or the general residents. However, given the potential application of the research findings to address challenges faced by Ebetsu City, the questionnaire was developed based on suggestions from the city and its official surveys. Furthermore, with the cooperation of Ebetsu City, we informed the target population widely when recruiting participants. We have also offered opportunities to share information about the research, for example, by holding public lectures for participants.

Data collection and measurements

EAFS schedules 30–40 survey days over a 3- to 4-month period each year. Participants visit Hokkaido Information University at their scheduled appointment time to undergo various examinations and provide specimens. Whereas the FFQ (Kyoiku software, Japan)¹² must be completed at home beforehand, all other examinations are conducted on the survey day. The wave 1 survey was conducted from 12 September to 18 December 2023; the wave 2 survey from 24 May to 27 July 2024; and the wave 3 survey from 17 May to 4 August 2025.

Table 1 lists the measurement items collected annually from wave 1 to wave 3. These items are scheduled to be conducted annually until wave 10. Additionally, brain imaging such as MRI may be added with participants’ supplementary consent. All data will be consolidated at Hokkaido Information University and then shared within the EAFS research institutions.

Table 1. Study measurements.

Measurement	Description
Demographics	Information on participants’ age, gender and years of education is included. Ebetsu City provides information regarding the long-term care insurance level and whether residents are registered each fiscal year
Genotyping	The ApoE genotype can be determined using peripheral blood
Cognitive function*	Cognitive function is evaluated using the MoCA-J26 27
MOCA-J	The MoCA-J is a screening test for MCI that assesses visuospatial skills, executive functions, attention, concentration, calculation, language, abstraction, memory and orientation. It uses three versions in sequence: Versions 8.1, 8.2 and 8.3
Physical function	The examination staff measures the physical functions of the participants using various instruments
Body composition	The measurement of height, weight, BMI, body fat percentage, muscle mass and other relevant metrics is obtained using a body composition analyser (MC-780AN, TANITA, Japan)
Lower extremity muscle strength and body balance	Participants are required to stand up as quickly as possible from a seated position while watching a video. The measurement of lower limb strength and body balance during this movement is obtained using a motion function analysis device (BM-220, TANITA, Japan)
Grip strength	The grip strength of both the right and left hands was measured on separate occasions using a Smedley-type digital grip dynamometer (Grip-D TKK-5401, Takei Kiki Kogyo, Japan)
Timed chair-stand test	The objective of the test is to measure the time taken to perform the action of rising to a standing position from a seated position on a chair as expeditiously as possible, with the test subject repeating this action five times
Gait analysis	Participants are instructed to walk normally over a distance of approximately 10 m. The walking motion captured by cameras is then analysed using Theia3D (Theia Markerless, Canada) and Visual 3D (C-Motion, Bethesda, Maryland, USA), with the objective of quantifying the position of each body part over time. From these measurements, parameters including gait rate are calculated
Vital signs	Blood pressure and pulse rate are measured three times using a blood pressure monitor (TM-2656VPW, A&D, Japan)
Physiological parameters	Physiological status is assessed through blood tests and non-invasive instrument measurements
Blood tests	Peripheral blood is analysed for the following parameters: WBC, RBC, Ht, Hb, Plt, white blood cell differential count, AST, ALT, γ-GTP, ALP, LDH, BUN, CRE, UA, TC, TG, HDL-C, LDL-C, Random BG, HbA1c, Total protein, Alb, Cholinesterase, Na, Cl, Mg, Ca, Fe, High-sensitivity CRP, Aβ composite biomarker, AGEs, sRAGE
Non-invasive measurement	The accumulation of AGEs is measured optically using the AGE sensor (RQ-AG01J, Shimadzu, Japan)
Lifestyle factors and health status	The following items will be collected via self-administered responses. Participants are generally instructed to respond electronically at the venue. As for the FFQ, which is part of the daily diet questions, participants are instructed to complete it on sheets of paper at home. Many of the questionnaires were based on public surveys21 22 28 29 or previously published questionnaires. Some questions were created specifically for this study
Lifestyle	Participants are asked to answer questions regarding their residential area, housing type, cohabitants, experience of major lifestyle changes, possession of a driver’s licence, employment status and economic situation
Basic activity of daily living	Participants are asked about conditions related to activities of basic ADL, such as swallowing, chewing and mobility. The SARC-F30 31 is included in this section. It also includes some questions from KCL32
Instrumental activity of daily living	Participants are asked about conditions related to activities of instrumental ADLs, such as going out, managing daily life and support needed for daily living. JST-IC,33 34 eHEALS35 36 and CCHL37 are included in this section
Physical activities	The participants are asked about the convenience of summer and winter mobility, their exercise habits and whether they eat meals with others. IPAQ38 39 is included in this section
Social activities	The participants are asked to answer questions regarding the frequency and methods of their communication with others
Health behaviours	The participants are asked whether they have undergone regular health check-ups, whether they have undergone regular dental check-ups and about activities they engage in to maintain their health
Daily diets	The participants are asked about their daily intake of major foods, their intake of foods of EAFS interest (such as locally grown crops and foods rich in functional components), drinking habits and smoking habits. DVS19 and the FFQ are included in this section
Comprehensive physical and psychological status	The participants are asked to answer questions regarding subjective health, sense of well-being and feeling of depression. The Japanese version of the three‐item UCLA Loneliness Scale40 41 is included in this section. It also includes the questions necessary to calculate the revised J-CHS42 criteria and from KCL32
Medical status	The participants are asked about any current or residual illnesses (stroke, heart disease, diabetes, hyperlipidaemia, respiratory disease, gastrointestinal/prostate disease, musculoskeletal disease, trauma, cancer, blood/immune disorders, depression, dementia, Parkinson’s disease, eye disease, ear disease), multiple medication use and frequency of hospital visits
Interview	The examination staff ask participants in a face-to-face interview about the status of treatment for chronic conditions, regularly used medications, medical history and whether individual family members have dementia, hypertension, diabetes, etc. Descriptive responses are collected

^*Participants were also assessed using an additional cognitive instrument designed to evaluate orientation to time and place, immediate recall, short-term verbal memory, calculation, language and constructional ability. However, because this instrument lacked formal validation and explicit bibliographic references, it was excluded from the present manuscript and will not be included in future analyses. However, due to domain overlap, it was previously confounded with and reported as the MMSE in an earlier publication.

ADL, basic daily living; AGE, advanced glycation end product; Alb, albumin; ALP, alkaline phosphatase; ALT, alanine aminotransferase; AST, aspartate aminotransferase; Aβ, amyloid β; BG, blood glucose; BMI, body mass index; BUN, blood urea nitrogen; CCHL, Communicative and Critical Health Literacy; CRE, creatinine; CRP, C reactive protein; DVS, dietary variety score; eHEALS, eHealth Literacy Scale; Hb, haemoglobin; HbA1c, glycated haemoglobin; HDL, high-density lipoprotein; Ht, haematocrit; IPAQ, International Physical Activity Questionnaire; JST-IC, JST-Index of Competence; KCL, the Kihon Checklist; LDH, lactate dehydrogenase; LDL-C, low-density lipoprotein; MoCA-J, Montreal Cognitive Assessment-Japanese version; Plt, platelet count; sRAGE, soluble receptor for AGE; TC, total cholesterol; TG, triglyceride; UA, uric acid; WBC, white cell count; γ-GTP, γ-glutamyl transpeptidase.

Biospecimen samples

Participants provided peripheral blood samples. To minimise participant burden, a light meal up to 3 hours prior to testing was permitted. At Shimadzu Techno Research Co., plasma APP669-711, Aβ1-40 and Aβ1-42 were measured using the IP-MS method (immunoprecipitation-mass spectrometry), and the amyloid beta composite biomarker was calculated.¹³ AGEs and soluble receptor for AGE (sRAGE) were measured at NARO.¹⁴ Other biochemical test items were measured at Sapporo Clinical Laboratory (Sapporo, Japan). We are also considering implementing measurements for NFL, tau protein, metabolomics and proteomics. Serum, plasma and DNA samples are stored at −80°C in preparation for the addition of future analysis. In accordance with the research plan that has been granted ethical approval, biological samples collected for this study are to be stored for a minimum of 10 years following the publication of results, and the data are to be stored for a minimum of 5 years after the publication of results.

Statistical analyses

This initial report presents analyses based on data collected during the first year. Descriptive statistics are provided for participants’ demographic characteristics, genotypes, cognitive and physical function, blood parameters, lifestyle factors and overall health status. Descriptive statistics are presented as numbers and percentages for categorical variables, and as mean and SD for continuous variables. Furthermore, the following criteria were applied when categorising continuous variables.

• According to the Asian Working Group for Sarcopenia (AWGS) 2025 criteria,¹⁵ participants with low values for appendicular skeletal muscle (ASM)/height², ASM/body mass index and grip strength were identified. Based on these criteria, individuals with both low muscle mass and low muscle strength were classified as having sarcopenia.

• For grip strength, the higher value of the two measurements obtained from each hand was used.

• Blood pressure was calculated as the average of all recorded measurements.

• The two cut-off values for the Aβ composite marker were determined based on previously reported National Center for Geriatrics and Gerontology and Australian Imaging, Biomarker and Lifestyle Study of Ageing (AIBL) Pittsburgh Compound-B (PIB) datasets: 0.704, for which the positive predictive value was 90% or higher; and 0.166, for which the negative predictive value was 90% or higher.¹³

• ‘Financial stress’ refers to the number of respondents who reported either ‘My household finances are tight, and I am somewhat worried’ or ‘My household finances are difficult, and I am very worried’.

• ‘Non-employment’ refers to respondents who did not report having a job with income. Work hours and employment status were not mentioned.

• The various medical conditions under ‘Medical states’ indicate the number of individuals who self-reported currently receiving treatment or experiencing residual effects.

• ‘Infrequent health check-up participation’ refers to individuals who did not report undergoing regular health check-ups, but instead reported occasional or no participation.

• ‘Polypharmacy’ indicates the number of individuals who self-reported taking five or more medications.

• For other items where general standards are available, such as physical function tests and blood tests, the number of individuals who meet those standards was reported.

Findings to date

Cohort summary

Online supplemental table 1 shows the general information collected during the first year of EAFS. The mean age of the participants was 64.5±5.6 years, as expressed as mean±SD. Participants were distributed as follows: 23.5% in the late 50s, 25.9% in the early 60s, 29.2% in the late 60s and 21.4% in the early 70s. Additionally, 38.9% of the participants were male and 61.1% were female. None of the participants had dementia (AD, etc) or Parkinson’s disease. However, when MCI was operationally defined as a Montreal Cognitive Assessment-Japanese score of ≤25,¹⁶ 53.6% of participants were suspected as MCI. The proportion of individuals with possible MCI increased with ageing in both males and females. The APOE4 allele, which is associated with an increased risk of AD, was present in 1.2% of the population in the homozygous form and in 22.1% in the heterozygous form. Regarding family history, which is debated for its relationship with dementia risk, 28.5% of the total population had a parent with dementia. Based on the Aβ composite biomarker, which has been reported to predict amyloid positivity in brain PET,¹³ 14.4% were positive and 65.7% were negative. Examining other items frequently referred to as risk factors for dementia,¹⁷ 6.4% of participants had abnormal blood glucose levels, 40.1% had hypertension and 12.8% showed signs of depression. Notably, 20.8% reported a history of hypertension, whereas only 0.3% reported a history of depression. For these conditions, there was a discrepancy between the reported rates and those calculated from the survey results. Among other major problems associated with ageing, oral frailty was present in 15.3% of the population, sarcopenia based on AWGS2025 in 4.4%, frailty in 1.3% and pre-frailty in 42.2%.

Early findings on nutrition and longitudinal health outcomes

Using data collected in waves 1 and 2 of the EAFS, we classified dietary patterns using an ordinal latent block model, a model-based clustering approach applied to the FFQ data. We then examined whether the age–health gradient—measured across 33 indicators—differed significantly across the derived dietary habit types, using random effects models. As a result, the dietary habits of the sample under analysis were classified into six distinct types. Furthermore, parameter estimates from the model suggested that the extracted patterns were distributed continuously from low to high dietary diversity. Additionally, regression analysis revealed a negative correlation between age and low-density lipoprotein levels among women with high dietary diversity.¹⁸

Strengths and limitations

The main strengths of the EAFS are: (1) conducting a comprehensive annual survey for 10 years for elderly individuals who are independent in ADLs at baseline. The survey includes cognitive function tests, physical exams, blood tests, self-administered questionnaires about lifestyle factors and health status, and interviews about medical and family history. Notably, the survey includes numerous items related to diet. For dietary assessment, two methods are primarily implemented: the FFQ¹² and the dietary variety score.¹⁹ Both methods have already been used in domestic cohort studies. Furthermore, measurements of AGEs, which are considered to be strongly associated with diet, will be obtained using both blood tests and non-invasive devices. (2) Standardised testing methods and conditions are maintained because all participants are tested at the same venue within a relatively short period each year. (3) The systematic collection of specimens to enable the future application of new testing methods. (4) The prevalence of possible MCI at baseline and the subsequent follow-up rate were high, which is suitable for exploring biomarkers associated with MCI and for investigating dietary strategies for preventing MCI. (5) EAFS is a program that is carried out through a partnership between industry, government and academia. In other words, Ebetsu City cooperates with industry and academic institutions to leverage their expertise and technology. Additionally, (6) it is conducted in a city with distinctive geographical features within Japan.

One limitation of the EAFS is its representativeness. As this study focused on individuals who were independent in ADL at baseline, participants may have been biased towards individuals with higher levels of physical function. The data presented herein demonstrate that the proportion of subjects who have been diagnosed with sarcopenia according to the AWGS2025 criteria does not exhibit an age-related increase. As previously reported, a decline in muscle strength is a precursor to muscle mass loss.²⁰ However, analysis of the first-year EAFS data revealed that, although the proportion meeting the AWGS2025 criteria for ASM increased with age, the proportion meeting the criteria for grip strength, assessed via the handgrip test, did not. The sample may be biased towards individuals with higher motor function, particularly among the older age groups. Furthermore, in this study, participants voluntarily applied to take part in the examinations. Consequently, the participants may exhibit bias towards those with a high interest in health. The data presented in this report show a lower proportion of respondents who reported infrequent health check-ups compared with previous reports.²¹ In addition, in comparison with previous reports,²² it also exhibits the characteristic of a lower proportion of individuals experiencing financial stress. Consequently, when analysing the third objective of this study—regional challenges and healthy life expectancy in Ebetsu City—the background characteristics of the participants need to be considered.

Future plans

EAFS plans to conduct annual follow-up surveys until 2032. In addition to analysing data according to each objective, we also aim to perform further analysis of the stored specimens. With regards to the utilisation of the large-scale longitudinal data accumulated during the follow-up period through 2032, linear mixed-effects models may be employed to assess annual changes in cognitive function and physical function related to ageing. In addition, the utilisation of Cox proportional hazards models, which incorporate baseline biomarkers and dietary patterns as covariates, is expected to facilitate the identification of risk factors associated with the onset of MCI. Moreover, several cohort studies conducted in other regions of Japan, including the Japan Gerontological Evaluation Study,²³ the National Institute for Longevity Sciences-Longitudinal Study of Aging²⁴ and the Hisayama Study,²⁵ include measurement items common to this study. Comparing our findings with those from these cohorts would provide valuable insights.

Collaboration

Original data and specimens are provided to researchers at EAFS collaborating institutions (Shimadzu Corporation, Hokkaido Information University and NARO). Publication of research findings, issuance of publications, acquisition of intellectual property rights and data sharing in this study must comply with EAFS policies. Researchers, including those affiliated with other academic or private institutions, who are interested in using the data may participate by collaborating with the EAFS project and following the appropriate procedures in accordance with the ‘Ethical Guidelines for Medical and Biological Research Involving Human Subjects’ (Public Notice of the MEXT, MHLW and METI No. 1, 23 March 2021). The project is scheduled to continue until 2032. We welcome new proposals that leverage the unique features of this project.

Data availability statement

Data are available upon reasonable request.