Vegetarian Diet and Chronic Degenerative Diseases

September 8, 2025 updated by: Dalin Tzu Chi General Hospital

Vegetarian Diet and Chronic Degenerative Diseases in the Tzu Chi Health Study (TCHS) and the Tzu Chi Vegetarian Study (TCVS)

To investigate the prospective association between a vegetarian diet and chronic degenerative diseases in two cohorts of Taiwanese Buddhists

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The Tzu Chi Vegetarian Study (TCVS) recruited 12062 community volunteers of the Buddhists Tzu Chi Foundation throughout Taiwan in the year 2005. All participants completed a self-administered questionnaire on basic information, medical history, lifestyle, and diet.

The Tzu Chi Health Study (TCHS) recruited 6002 participants who came to the Buddhist Tzu Chi Dalin General Hospital for health examination. All participants were interviewed on basic information, medical history, lifestyle, and diet. Biochemical and anthropometric data was collected through a health examination:

Biochemical variables: CBC, fasting glucose, lipid profile (TCH, LDL, HDL, TG), BUN, Cr, ALT, AST, and UA. In addition, homocysteine, serum vitamin B12, folate, and C-reactive protein (CRP) are available for 1500 subjects.

Blood: Extra blood samples have been obtained and stored for 3500 subjects and will be available for future investigation.

Anthropometric variables: body weight, height, waist circumference, % body fat (with BIA), blood pressure, pulse wave velocity, bone mineral density through DXA (at spine for female and hip for male), lung function test (spirometric), abdominal sonography, colonoscopy, esophageal-gastro-duodenal-scopy, chest X-ray, KUB.

Follow-up: Individual baseline data were linked to the National Health Insurance Database and the National Death Registry to ascertain disease outcomes at the Health and Welfare Data Science Center.

Study Type

Observational

Enrollment (Actual)

18064

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Taiwan
      • Chiayi City, Taiwan
        • Dalin Tzu Chi Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Participants in the Tzu Chi Vegetarian Study were all certified volunteers of the Buddhist Tzu Chi Foundation. Participants of the Tzu Chi Health Study were the ones who came to the Dalin Tzu Chi Hospital for health examination and agree to join the cohort study (77% were certified Tzu Chi volunteers). About 1/3 of both cohorts were vegetarians at enrollment.

Description

Inclusion Criteria:

  • Participants who consent to be followed.

Exclusion Criteria:

  • Participants with inaccurate ID which make linkage to NHIRD impossible.
  • Participants already with study outcome (disease) prior to enrollment in the study.
  • Participants with missing covariates

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Tzu Chi Vegetarian Study
12062 Tzu Chi volunteers of the Buddhist Tzu Chi Foundation recruited throughout communities in Taiwan in the year 2005. All participants filled out a self-administered questionnaire on basic information, medical history, lifestyle, and diet. Diet exposure: 1/3 vegetarians, 2/3 nonvegetarians.
Other: Diet Exposure
Vegetarian diet vs nonvegetarian diet
Tzu Chi Health Study
6002 participants who came for health examination at the Dalin Tzu Chi Hospital between the years 2007 to 2009. 77% were Tzu Chi volunteers. All participants were interviewed on a structured questionnaire including basic information, medical history, lifestyle, and diet, and received a comprehensive health examination. Diet exposure: 1/3 vegetarians, 2/3 nonvegetarians.
Other: Diet Exposure
Vegetarian diet vs nonvegetarian diet

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Gout
Time Frame: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Incidence of gout are ascertained by linking individual participants' baseline data to the the National Health Insurance Database. Cases of gout are identified using ICD-9 code: 274.
From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Stroke
Time Frame: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Incidence of stroke are ascertained by linking individual participants' baseline data to the the National Health Insurance Database. Cases of stroke are identified using ICD-9 code: 430-438, where hemorrhagic stroke is defined by ICD9 430-432 and ischemic stroke is defined by ICD9 433-434.
From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Cataract
Time Frame: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Incidence of cataract are ascertained by linking individual participants' baseline data to the the National Health Insurance Database. Cases of cataract are identified using ICD-9 code: 366.
From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Gallstone disease
Time Frame: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Incidence of gallstone disease are ascertained by linking individual participants' baseline data to the the National Health Insurance Database. Cases of gallstone diseases are identified using ICD-9 code: 574.
From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Dementia and mild cognitive impairment
Time Frame: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Incidence of dementia are ascertained by linking individual participants' baseline data to the the National Health Insurance Database. Cases of dementia and mild cognitive impairment are identified using ICD-9 code: 290.0, 290.1,290.4, 331.0, 331.1, 331.82, 331.83.
From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Depression
Time Frame: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Incidence of depression are ascertained by linking individual participants' baseline data to the the National Health Insurance Database. Cases of depression and are identified using ICD-9 code: 296.2, 296.3, 300.4 and 311.
From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Urinary tract infections (UTI)
Time Frame: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Incidence of UTI are ascertained by linking individual participants' baseline data to the the National Health Insurance Database. Cases of UTI are identified using ICD-9 code: 599.0, 595, 590.
From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Medical expenditures
Time Frame: From enrollment to December 31st 2014.
Actual medical expenditure associated with different dietary patterns are analyzed. Medical expenditures are obtained and computed from the National Health Insurance Database claim data for outpatient treatment, inpatient treatment, and dental treatment. This also includes costs associated with laboratory work and medication prescription.
From enrollment to December 31st 2014.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Dalin Tzu Chi General Hospital

Investigators

  • Study Chair: Chin-Lon Lin, MD, Dalin Tzu Chi General Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 1, 2005

Primary Completion (Actual)

December 30, 2005

Study Completion (Actual)

December 31, 2014

Study Registration Dates

First Submitted

March 12, 2018

First Submitted That Met QC Criteria

March 18, 2018

First Posted (Actual)

March 20, 2018

Study Record Updates

Last Update Posted (Estimated)

September 12, 2025

Last Update Submitted That Met QC Criteria

September 8, 2025

Last Verified

March 1, 2018

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • TCHS-02

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The disease outcome data from the National Health Insurance Database belongs to the Ministry of Health in Taiwan. Access to these data requires permission and formal application to the Health and Welfare Data Science Center, Ministry of Health in Taiwan. This is regulated by local law and regulation to protect individual personal information. Our research team does not have the right to release any data other than summarized results in the forms of peer-reviewed publications, for noncommercial purposes.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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