Walnut Consumption and Diabetes Risk

July 19, 2017 updated by: Lenore Arab, PhD, University of California, Los Angeles

Association Between Walnut Consumption and Diabetes Risk in NHANES May be Gender Sex Specific

Multiple NHANES surveys were combined and weighted to evaluate relationships between walnut consumption and type 2 diabetes mellitus using various independent measures of diabetes status and risk. After risks were ascertained, interactions with gender were analyzed.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Background. Dietary interventions and cohort studies of tree nuts lowering glucose levels for diabetes suggest a possible effect with walnuts. Objective. To examine the associations between walnut consumption and diabetes risk through data from the National Health and Nutrition Examination Survey (NHANES). Methods. NHANES survey data for 1999 through 2014 was pooled for adults with 24 hour recall dietary data. Risk of diabetes was based on self-report, medication use, fasting plasma glucose levels, and hemoglobin A1c (HbA1c) levels. Individuals were characterized as reporting consumption of walnuts, mixed 'nuts', or no nuts.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
34121

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

  • United States
    • California
      • Los Angeles, California, United States, 90095
        • University of California Los Angeles

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

The National Health and Nutrition Examination Survey (NHANES) is a cross-sectional, probability survey administered to the US civilian population aged from 0 to 85 years. This study used continuous NHANES data collected from 1999 to 2014, covering eight cycles of data collection (N=82,091). Participants were excluded from analysis for being under 18 (N=34,735) and not having data on either day of the 24-hour food intake (N=6,533). In an attempt to have a control group free of nut consumers, individuals who consumed peanuts, but not other nuts on the day of recall, were excluded from the analysis (N=6,702). After exclusions, our analytic sample N was 34,121, representing a population size of approximately 176 million individuals.

Description

Inclusion Criteria:

  • NHANES data from 1999-2014 with food recalls and dietary food intake

Exclusion Criteria:

  • not having data on either day of the 24-hour food intake
  • individuals who consumed peanuts, but not other nuts on the day of recall, were excluded from the analysis

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

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
No Nuts
All other foods that did not include walnuts or other nuts were classified as "no nuts" (NN).
Diagnostic test: Diabetes Outcome
based on self report definition, fasting plasma glucose, and hemoglobin A1c
Other Nuts
Foods codes describing nuts that are not walnuts (i.e. cashew nuts, pistachios, etc.) or nut-containing foods that do not commonly contain walnuts (e.g. granola) were classified as "other nuts" (ON).
Diagnostic test: Diabetes Outcome
based on self report definition, fasting plasma glucose, and hemoglobin A1c
Walnuts with other nuts
food codes describing nut mixes and foods that commonly include walnuts were classified as "walnuts with other nuts" (WwON)
Diagnostic test: Diabetes Outcome
based on self report definition, fasting plasma glucose, and hemoglobin A1c
Walnuts with high certainty
Foods consisting entirely or mostly of walnuts were classified as "walnuts with high certainty" (WwHC)
Diagnostic test: Diabetes Outcome
based on self report definition, fasting plasma glucose, and hemoglobin A1c

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Diabetes Outcome- self report
Time Frame: 1999-2014
Based on self-report as told by a doctor
1999-2014
Diabetes Outcome- Fasting Plasma Glucose
Time Frame: 1999-2014
Based on FPG levels
1999-2014
Diabetes Outcome- Hemoglobin A1c
Time Frame: 1999-2014
Based on HbA1c levels
1999-2014
Diabetes Outcome- Combined Definition
Time Frame: 1999-2014
Based on both FPG and HbA1c levels
1999-2014

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Sex Interaction
Time Frame: 1999-2014
based on the previously stated definition outcomes
1999-2014

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of California, Los Angeles

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
California Walnut Commission

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Lenore Arab, MSc, PhD, David Geffen School of Medicine

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 1, 2015

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 30, 2017

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 30, 2017

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 15, 2017

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 19, 2017

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 21, 2017

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 21, 2017

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 19, 2017

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2017

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • WALNUT6DIABETES

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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