Key Concepts About How the Environmental Chemical Data Fit into the NHANES Data Structure


Continuous NHANES data are released in two-year cycles beginning with NHANES 1999-2000 (See the "Overview of NHANES Survey Design and Weights" module for information about the reasons for this policy.)  Some survey topic areas are included in all survey cycles, whereas others are included in selected cycles.


The data for each survey cycle are composed of four sections:  Demographics, Examination, Laboratory, and Questionnaire. 

Each section contains groups of related variables, packaged in one or more data files for each two-year cycle.  This organization scheme allows for efficiency in posting data to the website, downloading data, and analyzing data.  Environmental analytes data can be found in the Laboratory section.

For each two-year cycle of continuous NHANES, the 1999-2010 Survey Contents Brochure provides:


The Survey Contents brochure [PDF - 1.4 MB] ]also lists the different classes of environmental chemicals measured and the years in which they were collected.

close window icon Close Window