N,N-diethyl-3-methylbenzamide, commonly known as DEET, has become a widely used insect repellent in the United States. DEET is highly effective against a broad spectrum of insect pests, including potential disease vectors such as mosquitoes, biting flies and ticks (CDC 2015). More than 500 products are currently registered with the Environmental Protection Agency in a variety of liquids, lotions, gels, sprays, sticks and impregnated materials with DEET concentrations ranging from 5 to 98% (EPA 2017). Every year, approximately one-third of the U.S. population uses DEET-containing insect repellents (CDC, 2009), and exposure to DEET is widespread (Calafat 2016). Urinary metabolites of DEET are more sensitive biomarkers of exposure than DEET itself; in fact, relying on DEET as an exposure biomarker can lead to exposure misclassification (Calafat 2016, ATSDR, 2017).
To better understand exposure
to DEET we measured one DEET metabolite, 3-(ethylcarbamoyl)benzoic acid in a one-third subsample of participants 3+ years of age from NHANES
2015-2016.
One-third subsample of participants aged
3+ years from NHANES 2015-2016 with stored urine (N=3,045).
The method uses 0.2 mL urine and is
based on enzymatic hydrolysis of urinary conjugates of the target analytes,
online solid phase extraction, reversed phase high-performance liquid
chromatography separation, and isotope dilution-electrospray ionization tandem
mass spectrometry detection (Baker et al. 2018).
The analytical measurements were conducted following
strict quality control/quality assurance CLIA guidelines. Along with the study
samples, each analytical run included high- and low-concentration quality
control materials (QCs) and reagent blanks to assure the accuracy and
reliability of the data. The concentrations of the high-concentration QCs and
the low-concentration QCs, averaged to obtain one measurement of
high-concentration QC and low-concentration QC for each run, were evaluated
using standard statistical probability rules (Caudill et al. 2008).
Data were received after all analyses were complete. The
data were not edited. Data Access: All
data are publicly available.
Detection Limits
The detection
limits were constant for all of the analytes in the data set. Two variables are
provided for each analyte. The variable name ending in “L” (ex., SSMEAL)
indicates whether the result was below the limit of detection: the value “0”
means that the result was at or above the limit of detection, “1” indicates
that the result was below the limit of detection. For analytes with analytic
results below the limit of detection (ex.,SSMEAL=1), an imputed fill value was
placed in the analyte results field. This value is the limit of detection
divided by square root of 2 (LOD/√2). The other variable prefixed SS (ex., SSMEA)
provides the analytic result for that analyte.
The limit of detection (LOD, in µg/L) for MEA:
|
Variable Name |
SAS Label |
LOD |
|
SSEMEA |
3-(Ethylcarbamoyl)benzoic acid (µg/L) |
0.20 |
Interferences:
Blanks in an analyte results field represent missing values in cases when the presence of interferences precluded obtaining a valid numeric result for a given analyte.
Subsample Weights
Sample weights are required to analyze these data properly. Specific sample weights for this subsample are included in this data file and should be used when analyzing these data. Previous versions of this data file included a sample weight variable (WTSB2YR) but when observations were removed from this data file, a new sample weight was created, and a new sample weight variable was added to this data file (WTSSBI2Y). Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial for further details on the use of sample weights and other analytic issues.
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 11617.110763 to 931491.77436 | Range of Values | 2436 | 2436 | |
| 0 | No lab specimen | 0 | 2436 | |
| . | Missing | 0 | 2436 |
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 0.14 to 17500 | Range of Values | 2386 | 2386 | |
| . | Missing | 50 | 2436 |
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 0 | At or above the detection limit | 1787 | 1787 | |
| 1 | Below lower detection limit | 599 | 2386 | |
| . | Missing | 50 | 2436 |