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
Factors affecting serum zinc concentrations in the U.S. population: National Health and Nutrition Examination Survey (2011-2014)
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.
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
Observational epidemiological study
Primary study design
Secondary study design
Patient information sheet
Not available in web format, please use the contact details to request a patient information sheet
Serum zinc concentration
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.
Primary outcome measures
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
Overall trial end date
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
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
Recruitment end date
Countries of recruitment
United States of America
Trial participating centre
U.S. Army Research Institute of Environmental Medicine
Medical Research and Materiel Command
U.S. Army Medical Research and Materiel Command, US Army Medical Research and Materiel Command, MRMC, USAMRMC
Funding Body Type
Funding Body Subtype
United States of America
Department of Defense Center Alliance for Nutrition and Dietary Supplement Research
Funding Body Type
Funding Body Subtype
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
Participant level data
Stored in repository
Results - basic reporting