Table of Contents

Component Description

Aldehydes are formed as thermal degradation byproducts released into the atmosphere from the burning of organic matter such as gasoline, food flavorants, and tobacco. Aldehydes are potentially carcinogenic and mutagenic; therefore, exposure to aldehydes has raised concerns about adverse health effects in humans.

Eligible Sample

Examined participants aged 12 years and older from a one-third subsample were eligible.

Description of Laboratory Methodology

An automated analytical method was developed using solid phase microextraction (SPME) gas chromatography (GC) and high-resolution mass spectrometry (HRMS) with selected ion mass detection and isotope-dilution techniques. This analytical method quantifies trace levels of 12 aldehydes from protein adducts in human serum.

Because aldehydes have the tendency to react with biological molecules to form various products, including Schiff base protein adducts, free aldehydes released into the headspace of biological samples from the Schiff base protein adducts at low pH (~3) are analyzed. The method reproducibly hydrolyzes aldehyde adducts covalently bound to proteins, using automation to individually incubate samples prior to analysis with hydrochloric acid (Yeo 2004). Free aldehydes are captured by the SPME fiber; desorbed into the heated GC injector; and extracted aldehydes are focused at the head of the GC column using a cryogenically cooled trap (Cryo-trap). Analytes are then separated in a capillary column and quantified using multiple ion detection (MID) with mass spectrometry. This method employs isotope dilution to quantify precisely trace amounts of aldehydes with limits of detection in the low parts per trillion range. The linear calibration curve spanned over three orders of magnitude.

Refer to the Laboratory Method Files section for a detailed description of the laboratory methods used.

This is a new component in the NHANES 2013-2014 cycle.

Laboratory Method Files

Serum Aldehydes Laboratory Procedure Manual (April 2019)

Laboratory Quality Assurance and Monitoring

Serum samples were processed, stored, and shipped to the Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA for analysis.

Detailed instructions on specimen collection and processing are discussed in the NHANES Laboratory Procedures Manual (LPM). Vials are stored under appropriate refrigerated (2-8°C) conditions until they are shipped to the National Center for Environmental Health for testing.

The NHANES quality assurance and quality control (QA/QC) protocols meet the 1988 Clinical Laboratory Improvement Act mandates. Detailed QA/QC instructions are discussed in the NHANES LPM.

Mobile Examination Centers (MECs)

Laboratory team performance is monitored using several techniques. NCHS and contract consultants use a structured competency assessment evaluation during visits to evaluate both the quality of the laboratory work and the quality-control procedures. Each laboratory staff member is observed for equipment operation, specimen collection and preparation; testing procedures and constructive feedback are given to each staff member. Formal retraining sessions are conducted annually to ensure that required skill levels were maintained.

Analytical Laboratories

NHANES uses several methods to monitor the quality of the analyses performed by the contract laboratories. In the MEC, these methods include performing blind split samples collected during “dry run” sessions. In addition, contract laboratories randomly perform repeat testing on 2% of all specimens.

NCHS developed and distributed a quality control protocol for all CDC and contract laboratories, which outlined the use of Westgard rules (Westgard, et al., 1981) when running NHANES specimens. Progress reports containing any problems encountered during shipping or receipt of specimens, summary statistics for each control pool, QC graphs, instrument calibration, reagents, and any special considerations are submitted to NCHS quarterly. The reports are reviewed for trends or shifts in the data. The laboratories are required to explain any identified areas of concern.

All QC procedures recommended by the manufacturers were followed. Reported results for all assays meet the Division of Laboratory Sciences’ quality control and quality assurance performance criteria for accuracy and precision, similar to the Westgard rules (Caudill, et al., 2008).

Data Processing and Editing

The data were reviewed. Incomplete data or improbable values were sent to the performing laboratory for confirmation.

Analytic Notes

Refer to the 2013-2014 Laboratory Data Overview for general information on NHANES laboratory data.

Subsample Weights

Serum aldehydes were measured in a one-third subsample of participants 12 years and older. Special 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.

Demographic and Other Related Variables

The analysis of NHANES laboratory data must be conducted using the appropriate survey design and demographic variables. The NHANES 2013-2014 Demographics File contains demographic data, health indicators, and other related information collected during household interviews as well as the sample design variables. The recommended procedure for variance estimation requires use of stratum and PSU variables (SDMVSTRA and SDMVPSU, respectively) in the demographic data file.

The Fasting Questionnaire File includes auxiliary information such as fasting status, the length of fast, and the time of venipuncture.

This laboratory data file can be linked to the other NHANES data files using the unique survey participant identifier (i.e., SEQN).

Detection limits

The detection limits were constant for all of the analytes in the data set. Two variables are provided for each of these analytes. The variable name ending in “LC” (ex., LBD4ALLC) 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 lower limit of detection (ex., LBD4ALLC=1), an imputed fill value was placed in the analyte results field. This value is the lower limit of detection divided by square root of 2 (LLOD/sqrt [2]). The other variable prefixed LBX (ex., LBX4AL) provides the analytic result for that analyte.

The lower limit of detection (LLOD, in ng/mL) for serum aldehydes:

VARIABLE NAME

SAS LABEL

LLOD

LBXBZAL

Benzaldehyde (ng/mL)

0.461

LBXCRAL

Crotonaldehyde (ng/mL)

0.147

LBXI5AL

Isopentanaldehyde (ng/mL)

0.316

LBXTLAL

o-Tolualdehyde (ng/mL)

0.142

LBX3AL

Propanaldehyde (ng/mL)

1.16

LBX4AL

Butyraldehyde (ng/mL)

0.313

LBX5AL

Pentanaldehyde (ng/mL)

0.316

LBX6AL

Hexanaldehyde (ng/mL)

0.693

LBX7AL

Heptanaldehyde (ng/mL)

0.312

LBX8AL

Octanaldehyde (ng/mL)

0.66

LBX9AL

Nonanaldehyde (ng/mL)

2.63

LBX10AL

Decanaldehyde (ng/mL)

3.9

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.

References

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
Target:
Both males and females 12 YEARS - 150 YEARS

WTALD2YR - Two Year Aldehyde Subsample Weights

Variable Name:
WTALD2YR
SAS Label:
Two Year Aldehyde Subsample Weights
English Text:
Two Year Aldehyde Subsample Weights
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
22540.35398 to 595728.72529 Range of Values 1843 1843
0 No Lab Result 481 2324
. Missing 0 2324

LBXBZAL - Benzaldehyde (ng/mL)

Variable Name:
LBXBZAL
SAS Label:
Benzaldehyde (ng/mL)
English Text:
Benzaldehyde (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.326 to 28.2 Range of Values 1468 1468
. Missing 856 2324

LBDBZLC - Benzaldehyde Comment Code

Variable Name:
LBDBZLC
SAS Label:
Benzaldehyde Comment Code
English Text:
Benzaldehyde Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 1391 1391
1 Below lower detection limit 77 1468
2 Detectable result and exceeds the calibrated range of assay 0 1468
. Missing 856 2324

LBX4AL - Butyraldehyde (ng/mL)

Variable Name:
LBX4AL
SAS Label:
Butyraldehyde (ng/mL)
English Text:
Butyraldehyde (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.221 to 3.49 Range of Values 1740 1740
. Missing 584 2324

LBD4ALC - Butyraldehyde Comment Code

Variable Name:
LBD4ALC
SAS Label:
Butyraldehyde Comment Code
English Text:
Butyraldehyde Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 1372 1372
1 Below lower detection limit 368 1740
2 Detectable result and exceeds the calibrated range of assay 0 1740
. Missing 584 2324

LBXCRAL - Crotonaldehyde (ng/mL)

Variable Name:
LBXCRAL
SAS Label:
Crotonaldehyde (ng/mL)
English Text:
Crotonaldehyde (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.104 to 2.44 Range of Values 1733 1733
. Missing 591 2324

LBDCRLC - Crotonaldehyde Comment Code

Variable Name:
LBDCRLC
SAS Label:
Crotonaldehyde Comment Code
English Text:
Crotonaldehyde Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 582 582
1 Below lower detection limit 1151 1733
2 Detectable result and exceeds the calibrated range of assay 0 1733
. Missing 591 2324

LBX10AL - Decanaldehyde (ng/mL)

Variable Name:
LBX10AL
SAS Label:
Decanaldehyde (ng/mL)
English Text:
Decanaldehyde (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2.76 to 13.3 Range of Values 1411 1411
. Missing 913 2324

LBD10ALC - Decanaldehyde Comment Code

Variable Name:
LBD10ALC
SAS Label:
Decanaldehyde Comment Code
English Text:
Decanaldehyde Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 11 11
1 Below lower detection limit 1400 1411
2 Detectable result and exceeds the calibrated range of assay 0 1411
. Missing 913 2324

LBX7AL - Heptanaldehyde (ng/mL)

Variable Name:
LBX7AL
SAS Label:
Heptanaldehyde (ng/mL)
English Text:
Heptanaldehyde (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.221 to 3.83 Range of Values 1527 1527
. Missing 797 2324

LBD7ALC - Heptanaldehyde Comment Code

Variable Name:
LBD7ALC
SAS Label:
Heptanaldehyde Comment Code
English Text:
Heptanaldehyde Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 1407 1407
1 Below lower detection limit 120 1527
2 Detectable result and exceeds the calibrated range of assay 0 1527
. Missing 797 2324

LBX6AL - Hexanaldehyde (ng/mL)

Variable Name:
LBX6AL
SAS Label:
Hexanaldehyde (ng/mL)
English Text:
Hexanaldehyde (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.49 to 62.1 Range of Values 1571 1571
. Missing 753 2324

LBD6ALC - Hexanaldehyde Comment Code

Variable Name:
LBD6ALC
SAS Label:
Hexanaldehyde Comment Code
English Text:
Hexanaldehyde Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 1532 1532
1 Below lower detection limit 39 1571
2 Detectable result and exceeds the calibrated range of assay 0 1571
. Missing 753 2324

LBXI5AL - Isopentanaldehyde (ng/mL)

Variable Name:
LBXI5AL
SAS Label:
Isopentanaldehyde (ng/mL)
English Text:
Isopentanaldehyde (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.13 to 4.57 Range of Values 1798 1798
. Missing 526 2324

LBDI5ALC - Isopentanaldehyde Comment Code

Variable Name:
LBDI5ALC
SAS Label:
Isopentanaldehyde Comment Code
English Text:
Isopentanaldehyde Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 1783 1783
1 Below lower detection limit 15 1798
2 Detectable result and exceeds the calibrated range of assay 0 1798
. Missing 526 2324

LBX9AL - Nonanaldehyde (ng/mL)

Variable Name:
LBX9AL
SAS Label:
Nonanaldehyde (ng/mL)
English Text:
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.86 to 39.8 Range of Values 1534 1534
. Missing 790 2324

LBD9ALC - Nonanaldehyde Comment Code

Variable Name:
LBD9ALC
SAS Label:
Nonanaldehyde Comment Code
English Text:
Nonanaldehyde Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 572 572
1 Below lower detection limit 962 1534
2 Detectable result and exceeds the calibrated range of assay 0 1534
. Missing 790 2324

LBX8AL - Octanaldehyde (ng/mL)

Variable Name:
LBX8AL
SAS Label:
Octanaldehyde (ng/mL)
English Text:
Octanaldehyde (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.467 to 3.61 Range of Values 1456 1456
. Missing 868 2324

LBD8ALC - Octanaldehyde Comment Code

Variable Name:
LBD8ALC
SAS Label:
Octanaldehyde Comment Code
English Text:
Octanaldehyde Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 226 226
1 Below lower detection limit 1230 1456
2 Detectable result and exceeds the calibrated range of assay 0 1456
. Missing 868 2324

LBXTLAL - o-Tolualdehyde (ng/mL)

Variable Name:
LBXTLAL
SAS Label:
o-Tolualdehyde (ng/mL)
English Text:
o-Tolualdehyde (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 2.38 Range of Values 1561 1561
. Missing 763 2324

LBDTLALC - o-Tolualdehyde Comment Code

Variable Name:
LBDTLALC
SAS Label:
o-Tolualdehyde Comment Code
English Text:
o-Tolualdehyde Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 63 63
1 Below lower detection limit 1498 1561
2 Detectable result and exceeds the calibrated range of assay 0 1561
. Missing 763 2324

LBX5AL - Pentanaldehyde (ng/mL)

Variable Name:
LBX5AL
SAS Label:
Pentanaldehyde (ng/mL)
English Text:
Pentanaldehyde (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.223 to 6.61 Range of Values 1768 1768
. Missing 556 2324

LBD5ALC - Pentanaldehyde Comment Code

Variable Name:
LBD5ALC
SAS Label:
Pentanaldehyde Comment Code
English Text:
Pentanaldehyde Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 592 592
1 Below lower detection limit 1176 1768
2 Detectable result and exceeds the calibrated range of assay 0 1768
. Missing 556 2324

LBX3AL - Propanaldehyde (ng/mL)

Variable Name:
LBX3AL
SAS Label:
Propanaldehyde (ng/mL)
English Text:
Propanaldehyde (ng/mL)
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.82 to 8.39 Range of Values 1714 1714
. Missing 610 2324

LBD3ALC - Propanaldehyde Comment Code

Variable Name:
LBD3ALC
SAS Label:
Propanaldehyde Comment Code
English Text:
Propanaldehyde Comment Code
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above detection limit 1513 1513
1 Below lower detection limit 201 1714
2 Detectable result and exceeds the calibrated range of assay 0 1714
. Missing 610 2324