Condition category
Not Applicable
Date applied
26/12/2017
Date assigned
09/01/2018
Last edited
28/06/2018
Prospective/Retrospective
Retrospectively registered
Overall trial status
Completed
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Zinc is a nutritionally essential trace mineral required for many biological functions. Marginal or moderate zinc deficiency may be widespread and has negative consequences on health. Although serum (blood) zinc is not considered a reliable indicator of the zinc status of an individual, it is the most widely used and available indicator of risk of zinc deficiency in populations. Moreover, serum zinc is the only indicator of zinc status for which adequate reference data and suggested lower cutoff values are available. However, caution is advised when interpreting serum zinc concentrations as many factors have been identified to affect serum zinc independent of an individual’s zinc status, such as meal consumption, time of day, and inflammation and infection. The cutoffs for serum zinc were established based on serum zinc values obtained from the second National Health and Nutrition Examination Survey (NHANES) in the U.S. (1976-1980). In subsequent years serum zinc was excluded from NHANES and was not re-introduced as a biochemical measurement until the 2011-2012 survey cycle. The aim of this study is to re-evaluate serum zinc concentrations in the U.S. population and to find factors affecting serum zinc using data from NHANES 2011-12 and 2013-14.

Who can participate?
Data from people aged 6 and over participating in NHANES, 2011-2014

What does the study involve?
Previously collected data is extracted from the NHANES database. The database is accessible to the public through the Centers for Disease Control website (National Health and Nutrition Examination Survey; http://cdc.gov/NCHS/nhanes.htm) and does not contain any personal identifiers. Serum zinc and dietary zinc intake are determined and factors affecting serum zinc are identified. The prevalence of low serum zinc in the U.S. is calculated.

What are the possible benefits and risks of participating?
This study will provide data on factors that affect serum zinc concentrations and will inform serum zinc reference values.

Where is the study run from?
U.S. Army Research Institute of Environmental Medicine (USA)

When is the study starting and how long is it expected to run for?
January 2011 to December 2014

Who is funding the study?
1. Medical Research and Materiel Command (USA)
2. Department of Defense Center Alliance for Nutrition and Dietary Supplement Research (USA)

Who is the main contact?
Dr Stephen Hennigar

Trial website

Contact information

Type

Scientific

Primary contact

Dr Stephen Hennigar

ORCID ID

Contact details

10 General Greene Ave.
Natick
01760
United States of America

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

R11-01

Study information

Scientific title

Factors affecting serum zinc concentrations in the U.S. population: National Health and Nutrition Examination Survey (2011-2014)

Acronym

Study hypothesis

Serum zinc concentration is frequently used to assess zinc status in populations. Cutoffs for serum zinc were developed based on data from National Health and Nutrition Examination Survey (NHANES) II in 1976-80, but until recently (2011-12) serum zinc was not included in NHANES. The objective of this study was to evaluate serum zinc concentration in the U.S. population and determine factors affecting serum zinc using NHANES 2011-14.

Ethics approval

1. The National Center for Health Statistics Research Ethics Review Board approved the use of human subjects for NHANES studies
2. The USARIEM Human Use Review Committee determined obtaining unidentifiable information did not constitute human subjects research and therefore did not require full human use review on 13/10/2010

Study design

Observational epidemiological study

Primary study design

Observational

Secondary study design

Epidemiological study

Trial setting

Other

Trial type

Other

Patient information sheet

Not available in web format, please use the contact details to request a patient information sheet

Condition

Serum zinc concentration

Intervention

Data were extracted from a preexisting public database – a nationally representative survey of the US population, the National Health and Nutrition Examination Survey (NHANES). All data used have previously been collected. The database is accessible to the public through the Centers for Disease Control website on the World Wide Web (National Health and Nutrition Examination Survey; http://cdc.gov/NCHS/nhanes.htm) and does not contain any personal identifiers. Standard statistical methods for analysis of weighted population NHANES datasets were employed, including multiple regression modeling.

Serum zinc was determined in males and females ≥6 y using NHANES 2011-2014 (n=4,347). Dietary zinc intake was determined and factors affecting serum zinc were identified while controlling for sex, age, fasting status, and time of blood draw. Odds ratios were calculated to identify factors associated with risk of being below the cutoff for serum zinc and the prevalence of low serum zinc in the U.S. was calculated.

Intervention type

Other

Phase

Drug names

Primary outcome measure

Serum zinc concentration in the U.S. population and factors affecting serum zinc using the National Health and Nutrition Examination Survey 2011-2014

Secondary outcome measures

Prevalence of low serum zinc in the U.S. population using serum zinc concentrations from the National Health and Nutrition Examination Survey 2011-2014

Overall trial start date

01/01/2011

Overall trial end date

31/12/2014

Reason abandoned (if study stopped)

Eligibility

Participant inclusion criteria

1. Data from those aged ≥ 6 years participating in NHANES, 2011-2014 with serum zinc values (~1/3 of sample) were used for these analyses
2. Data for pregnant (n=34) or lactating females (n =20) were separated and analyzed separately

Participant type

All

Age group

All

Gender

Both

Target number of participants

The final analytic sample of those aged ≥ 6 years excluding those pregnant/lactating was 4,347 participants

Participant exclusion criteria

Volunteers without a serum zinc value were excluded from this analysis

Recruitment start date

01/01/2011

Recruitment end date

31/12/2014

Locations

Countries of recruitment

United States of America

Trial participating centre

U.S. Army Research Institute of Environmental Medicine
01760
United States of America

Sponsor information

Organisation

U.S. Army Research Institute of Environmental Medicine

Sponsor details

10 General Greene Ave
Natick
01760
United States of America

Sponsor type

Government

Website

Funders

Funder type

Government

Funder name

Medical Research and Materiel Command

Alternative name(s)

U.S. Army Medical Research and Materiel Command, US Army Medical Research and Materiel Command, MRMC, USAMRMC

Funding Body Type

government organisation

Funding Body Subtype

federal/national government

Location

United States of America

Funder name

Department of Defense Center Alliance for Nutrition and Dietary Supplement Research

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Results and Publications

Publication and dissemination plan

The results of this study should be published in a high-visibility peer-reviewed nutrition journal by mid-2018.

IPD sharing statement
De-identified data are available at the participant level for all study participants in a publically available repository (National Health and Nutrition Examination Survey; http://cdc.gov/NCHS/nhanes.htm).

Intention to publish date

01/07/2018

Participant level data

Stored in repository

Basic results (scientific)

Publication list

2018 results in: https://www.ncbi.nlm.nih.gov/pubmed/29947812

Publication citations

Additional files

Editorial Notes

28/06/2018: Publication reference added.