UMIN-ICDS Clinical Trial

Public title

Systematic review and meta-analysis of the association between the Japanese diet or Japanese dietary pattern and all-cause mortality

Acronym

Japanese diet and all-cause mortality systematic review

Scientific Title

Systematic review and meta-analysis of the association between the Japanese diet or Japanese dietary pattern and all-cause mortality

Scientific Title:Acronym

Japanese diet mortality meta-analysis

Region

Japan

Condition

Not applicable
This study focuses on all-cause mortality in the general adult population.

Classification by specialty

Not applicable

Classification by malignancy

Others

Genomic information

NO

Narrative objectives1

The objective of this study is to examine the association between the Japanese diet or Japanese dietary pattern and all-cause mortality as a health outcome through a systematic review and meta-analysis of observational studies.

Basic objectives2

Others

Basic objectives -Others

Evaluation of the association between the Japanese diet or Japanese dietary pattern and all-cause mortality

Trial characteristics_1

Others

Trial characteristics_2

Others

Developmental phase

Not applicable

Primary outcomes

All-cause mortality
Adjusted effect estimates (risk ratios [RRs], hazard ratios [HRs], or odds ratios [ORs]) and their 95% confidence intervals for all-cause mortality will be extracted for comparisons between higher and lower adherence to the Japanese diet or Japanese dietary pattern, or across categories based on Japanese dietary pattern scores.

Key secondary outcomes

Study type

Others,meta-analysis etc

Basic design

Randomization

Randomization unit

Blinding

Control

Stratification

Dynamic allocation

Institution consideration

Blocking

Concealment

No. of arms

Purpose of intervention

Type of intervention

Interventions/Control_1

Interventions/Control_2

Interventions/Control_3

Interventions/Control_4

Interventions/Control_5

Interventions/Control_6

Interventions/Control_7

Interventions/Control_8

Interventions/Control_9

Interventions/Control_10

Age-lower limit

18

years-old

<=

Age-upper limit

Not applicable

Gender

Male and Female

Key inclusion criteria

Studies meeting the following criteria will be included:
1. Observational studies.
2. Studies conducted in the general adult population.
3. Cohort studies or similar follow-up studies examining the association between dietary exposure and mortality.
4. Studies assessing the intake status of the Japanese diet or Japanese dietary pattern using a Japanese dietary pattern index.
5. Studies in which the Japanese dietary pattern index is based on multiple food groups constituting the Japanese diet, such as rice, miso soup, fish, vegetables, and green tea.
6. Studies reporting all-cause mortality as an outcome.
7. Studies reporting adjusted effect estimates (RRs, HRs, or ORs) and 95% confidence intervals for all-cause mortality, or sufficient information to estimate them.

Key exclusion criteria

The following studies will be excluded:
1. Cross-sectional studies, case-control studies, intervention studies, case reports, reviews, narrative reviews, commentaries, animal studies, and in vitro studies.
2. Studies in which the study population consists exclusively of patients with a specific disease.
3. Studies evaluating only a single food or food component rather than the Japanese diet or Japanese dietary pattern.
4. Studies not using a Japanese dietary pattern index.
5. Studies not reporting all-cause mortality.
6. Studies reporting only cause-specific mortality, such as cardiovascular disease mortality, cancer mortality, or stroke mortality.
7. Studies without sufficient effect estimates or information required to estimate them.
8. Conference abstracts, proceedings, and non-peer-reviewed articles.

Target sample size

Name of lead principal investigator

1st name	Norikazu
Middle name
Last name	Watanabe

Organization

Yokohama University of Pharmacy

Division name

Department of Health Pharmacy / Laboratory of Food Chemistry

Zip code

245-0066

Address

601 Matano-cho, Totsuka-ku, Yokohama-shi, Kanagawa-ken 245-0066, Japan

TEL

045-859-1300

Email

260201_iv@yok.hamayaku.ac.jp

Name of contact person

1st name	Norikazu
Middle name
Last name	Watanabe

Organization

Yokohama University of Pharmacy

Division name

Department of Health Pharmacy / Laboratory of Food Chemistry

Zip code

245-0066

Address

601 Matano-cho, Totsuka-ku, Yokohama-shi, Kanagawa-ken 245-0066, Japan

TEL

045-859-1300

Homepage URL

Email

260201_iv@yok.hamayaku.ac.jp

Institute

Yokohama University of Pharmacy
Department of Health Pharmacy / Laboratory of Food Chemistry
Norikazu Watanabe

Institute

Department

Personal name

Organization

None

Organization

Division

Category of Funding Organization

Self funding

Nationality of Funding Organization

Co-sponsor

Name of secondary funder(s)

Organization

Not applicable

Address

Not applicable

Tel

-

Email

-

Secondary IDs

NO

Study ID_1

Org. issuing International ID_1

Study ID_2

Org. issuing International ID_2

IND to MHLW

Institutions

Date of disclosure of the study information

2026

Year

06

Month

15

Day

URL releasing protocol

Publication of results

Unpublished

URL related to results and publications

Number of participants that the trial has enrolled

Results

Results date posted

Results Delayed

Results Delay Reason

Date of the first journal publication of results

Baseline Characteristics

Participant flow

Adverse events

Outcome measures

Plan to share IPD

IPD sharing Plan description

Recruitment status

Preinitiation

Date of protocol fixation

2026

Year

06

Month

08

Day

Date of IRB

Anticipated trial start date

2026

Year

06

Month

15

Day

Last follow-up date

2026

Year

07

Month

31

Day

Date of closure to data entry

Date trial data considered complete

Date analysis concluded

Other related information

In this study, we will examine the association between the intake status of the Japanese diet or Japanese dietary pattern and all-cause mortality. The exposure will be the intake status of the Japanese diet or Japanese dietary pattern assessed using a Japanese dietary pattern index, such as the Japanese Diet Index, which scores the consumption of food groups constituting the Japanese diet, including rice, miso soup, fish, vegetables, and green tea.

The comparison will be between groups with higher and lower intake status of the Japanese diet or Japanese dietary pattern, or between groups categorized according to scores of the Japanese dietary pattern index. The primary outcome will be all-cause mortality.

Adjusted effect estimates, including risk ratios [RRs], hazard ratios [HRs], or odds ratios [ORs], and their 95% confidence intervals for all-cause mortality will be extracted from each study. When multiple adjusted models are reported, the estimate from the model with the greatest adjustment for potential confounders will be used in principle.

As an exploratory analysis, associations between individual food groups constituting the Japanese dietary pattern index and all-cause mortality will also be examined for food groups for which data are available within the included studies.

Registered date

2026

Year

06

Month

15

Day

Last modified on

2026

Year

06

Month

13

Day

Link to view the page

Value
https://center6.umin.ac.jp/cgi-open-bin/icdr_e/ctr_view.cgi?recptno=R000070821