DementiaNCT03470584
Vegetarian Diet and Chronic Degenerative Diseases
An observational study of Dementia and Depression, run by Dalin Tzu Chi General Hospital at 1 site in Taiwan.
Trial summary
To investigate the prospective association between a vegetarian diet and chronic degenerative diseases in two cohorts of Taiwanese Buddhists Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Dementia, Depression, Cardiovascular Diseases
- What is being tested?
- Diet Exposure
- How many people
- 18,064 participants
- Where
- 1 siteTaiwan
- Study dates
- 1 Mar 2005to 31 Dec 2014
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
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.
Who may be able to join
- Participants who consent to be followed.
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Official title: 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
Read the 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.
- Conditions
- Dementia, Depression, Cardiovascular Diseases, Stroke, Gout, Cataract
- Being tested
- Diet Exposure
- Keywords
- Diet, vegetarian, Dementia, Depression, Cardiovascular Diseases, Stroke, Gout, Cataract, Gallstone, Urinary Tract Infections
- Medical subject headings
- Dementia, Depression, Cardiovascular Diseases, Stroke, Gout, Cataract, Gallstones, Urinary Tract Infections
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Diet ExposureOther
Vegetarian diet vs nonvegetarian diet
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: Other: Diet Exposure | |
| 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. Receives: Other: Diet Exposure |
What is being measured
The primary outcome is the main question the study is designed to answer.
Gout
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.
Measured: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Stroke
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.
Measured: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Cataract
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.
Measured: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Gallstone disease
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.
Measured: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Dementia and mild cognitive impairment
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.
Measured: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Depression
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.
Measured: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Urinary tract infections (UTI)
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.
Measured: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).
Medical expenditures
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.
Measured: From enrollment to December 31st 2014.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Mar 2018
- Study start1 Mar 2005
- Primary completion30 Dec 2005
- Study completion31 Dec 2014
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (6)Papers the sponsor has linked to this study.
- Other trials for DementiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 18,064 participants (actual)
Sponsor and investigators
- Lead sponsor
- Dalin Tzu Chi General Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Chin-Lon Lin, MD, Study chair, Dalin Tzu Chi General Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03470584
- Sponsor's protocol ID
- TCHS-02
- Status last verified
- Mar 2018
- First submitted
- 12 Mar 2018
- Last updated
- 12 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: 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.
Publications
Chiu THT, Liu CH, Chang CC, Lin MN, Lin CL. Vegetarian diet and risk of gout in two separate prospective cohort studies. Clin Nutr. 2020 Mar;39(3):837-844. doi: 10.1016/j.clnu.2019.03.016. Epub 2019 Mar 27.
PubMed 30955983Chiu THT, Chang HR, Wang LY, Chang CC, Lin MN, Lin CL. Vegetarian diet and incidence of total, ischemic, and hemorrhagic stroke in 2 cohorts in Taiwan. Neurology. 2020 Mar 17;94(11):e1112-e1121. doi: 10.1212/WNL.0000000000009093. Epub 2020 Feb 26.
PubMed 32102976Chiu THT, Chang CC, Lin CL, Lin MN. A Vegetarian Diet Is Associated with a Lower Risk of Cataract, Particularly Among Individuals with Overweight: A Prospective Study. J Acad Nutr Diet. 2021 Apr;121(4):669-677.e1. doi: 10.1016/j.jand.2020.11.003. Epub 2020 Dec 11.
PubMed 33309591Chang CM, Chiu THT, Chang CC, Lin MN, Lin CL. Plant-Based Diet, Cholesterol, and Risk of Gallstone Disease: A Prospective Study. Nutrients. 2019 Feb 4;11(2):335. doi: 10.3390/nu11020335.
PubMed 30720747Lin CL, Wang JH, Chang CC, Chiu THT, Lin MN. Vegetarian Diets and Medical Expenditure in Taiwan-A Matched Cohort Study. Nutrients. 2019 Nov 6;11(11):2688. doi: 10.3390/nu11112688.
PubMed 31698872Chen YC, Chang CC, Chiu THT, Lin MN, Lin CL. The risk of urinary tract infection in vegetarians and non-vegetarians: a prospective study. Sci Rep. 2020 Jan 30;10(1):906. doi: 10.1038/s41598-020-58006-6.
PubMed 32001729
Study at a glance
From the registry record, last updated by the sponsor on 12 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Vegetarian Diet and Chronic Degenerative Diseases in the Tzu Chi Health Study (TCHS) and the Tzu Chi Vegetarian Study (TCVS)
- ClinicalTrials.gov ID
- NCT03470584
- Acronym / sponsor ID
- TCHS-02
- Conditions
- Dementia, Depression, Cardiovascular Diseases, Stroke, Gout, Cataract
- Keywords
- Diet, vegetarian, Dementia, Depression, Cardiovascular Diseases, Stroke, Gout, Cataract, Gallstone
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 18,064 participants (actual)
- Lead sponsor
- Dalin Tzu Chi General HospitalUniversity, hospital or other
- Study start
- 1 Mar 2005 (actual)
- Primary completion
- 30 Dec 2005 (actual)
- Study completion
- 31 Dec 2014 (actual)
- First posted
- 20 Mar 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
To investigate the prospective association between a vegetarian diet and chronic degenerative diseases in two cohorts of Taiwanese Buddhists
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 design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Tzu Chi Vegetarian Study | – | Other: Diet Exposure12062 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. |
| Tzu Chi Health Study | – | Other: Diet Exposure6002 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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- 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.
Key inclusion criteria (1 listed)
- Participants who consent to be followed.
Key exclusion criteria (3 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Diet ExposureVegetarian diet vs nonvegetarian diet | Other | Tzu Chi Health Study, Tzu Chi Vegetarian Study |
Primary outcome
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.
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.
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.
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.
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.
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.
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.
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.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Sep 2025.
- Results publication: PubMed 30955983Chiu THT, Liu CH, Chang CC, Lin MN, Lin CL. Vegetarian diet and risk of gout in two separate prospective cohort studies. Clin Nutr. 2020 Mar;39(3):837-844. doi: 10.1016/j.clnu.2019.03.016. Epub 2019 Mar 27.
- Results publication: PubMed 32102976Chiu THT, Chang HR, Wang LY, Chang CC, Lin MN, Lin CL. Vegetarian diet and incidence of total, ischemic, and hemorrhagic stroke in 2 cohorts in Taiwan. Neurology. 2020 Mar 17;94(11):e1112-e1121. doi: 10.1212/WNL.0000000000009093. Epub 2020 Feb 26.
- Results publication: PubMed 33309591Chiu THT, Chang CC, Lin CL, Lin MN. A Vegetarian Diet Is Associated with a Lower Risk of Cataract, Particularly Among Individuals with Overweight: A Prospective Study. J Acad Nutr Diet. 2021 Apr;121(4):669-677.e1. doi: 10.1016/j.jand.2020.11.003. Epub 2020 Dec 11.
- Results publication: PubMed 30720747Chang CM, Chiu THT, Chang CC, Lin MN, Lin CL. Plant-Based Diet, Cholesterol, and Risk of Gallstone Disease: A Prospective Study. Nutrients. 2019 Feb 4;11(2):335. doi: 10.3390/nu11020335.
- Results publication: PubMed 31698872Lin CL, Wang JH, Chang CC, Chiu THT, Lin MN. Vegetarian Diets and Medical Expenditure in Taiwan-A Matched Cohort Study. Nutrients. 2019 Nov 6;11(11):2688. doi: 10.3390/nu11112688.
- Results publication: PubMed 32001729Chen YC, Chang CC, Chiu THT, Lin MN, Lin CL. The risk of urinary tract infection in vegetarians and non-vegetarians: a prospective study. Sci Rep. 2020 Jan 30;10(1):906. doi: 10.1038/s41598-020-58006-6.
- Individual participant dataSharing planned: No. 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.
Related trials for Dementia
RecruitingPhase 2
Neuroplasticity Enhancement From Cognitive Training Reinforced by Psilocybin
Alzheimer's Disease
Not yet recruiting
Acupressure as Long-term Intervention to Slow the Progression of Early/Mild Alzheimer's Disease
Alzheimer's Disease
RecruitingObservational study
Effectiveness and Safety of Disease-Modifying Therapy for Alzheimer's Disease: A Multicenter Retrospective Study
Alzheimer's Disease (AD)
Not yet recruitingPhase 2
Lisdexamfetamine For the Treatment of Conduct Disorder in Children
Conduct Disorder
RecruitingPhase 3
A Phase 3 Study to Evaluate the Safety and Efficacy of KarXT + KarX-EC for the Treatment of Agitation Associated With Alzheimer's Disease (ADAGIO-1)
Alzheimer Disease
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Chin-Lon Lin, MD study chair
Dalin Tzu Chi General Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Dementia and Depression, run by Dalin Tzu Chi General Hospital at 1 site in Taiwan.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Taiwan. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Gout (time frame: From enrollment to time of disease occurrence, death of any cause, or end of study period (December 31st 2014).). The study lists 8 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03470584, which also lists 6 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Sep 2025.