Table of Contents

Component Description

Users of the 2013-2014 dual-energy X-ray absorptiometry whole body data (DXX_H) are encouraged to read the documentation before accessing the data file.

Dual-energy x-ray absorptiometry (DXA) is the most widely accepted method of measuring body composition due in part to its speed, ease of use, and low radiation exposure (Baran, 1997; Genant, 1996; Heymsfield, 1989; and Njeh, 1999). Whole body DXA scans were administered from 1999-2006 and 2011-2014. The NHANES DXA examination provides nationally representative data on body composition (bone and soft tissue), overall, and for age, gender, and race/ethnic groups, to study the association between body composition and other health conditions and risk factors, such as cardiovascular disease, diabetes, hypertension, and physical activity and dietary intake patterns.

The DXA scans provide bone and soft tissue measurements for the total body, for both arms and both legs, the trunk, and the head. Bone measurements also were obtained for the pelvis, left and right ribs, thoracic spine, and lumbar spine. Values for the total body and regions include:

Eligible Sample

Participants aged 8-59 years were eligible. Pregnant females were excluded from the DXA examination. Participants who were excluded from the DXA examination for reasons other than pregnancy were considered to be eligible nonrespondents. Reasons for exclusion from the DXA examination were as follows:

The variable DXAEXSTS indicates the examination status for the whole body scan. The codes for DXAEXSTS are as follows:

DXAEXSTS – whole body scan examination status variable
1 = Whole body scan completed, and all regions are valid
2 = Whole body scan completed, but one or more regions are invalid
3 = Whole body not scanned, pregnancy
4 = Whole body not scanned, weight > 450 lbs
5 = Whole body not scanned, height > 6’5”
6 = Whole body not scanned, other reason

The main reasons for completed, but invalid, whole body scans were an insufficient scan area or partial scan. The “Not scanned, other reason” code includes no time to complete the examination, pregnancy test not completed, and participant refusal, as well as exclusion for reasons other than pregnancy, such as a medical test.

Protocol and Procedure

The whole body scans were acquired on the Hologic Discovery model A densitometers (Hologic, Inc., Bedford, Massachusetts), using software version Apex 3.2. The radiation exposure from DXA whole body scans is extremely low at less than 20 uSv. All scans in the DXX_H file were analyzed with Hologic APEX version 4.0 software with NHANES BCA option.

The DXA examinations were administered by trained and certified radiology technologists. Further details of the DXA examination protocol are documented in the Body Composition Procedures Manual located on the NHANES website.

Quality Assurance & Quality Control

A high level of quality control was maintained throughout the DXA data collection and scan analysis, including a rigorous phantom scanning schedule.

Monitoring of Field Staff and Densitometers
Staff from the National Center for Health Statistics (NCHS) and the NHANES data collection contractor monitored technologist acquisition performance through in-person observations in the field. Retraining sessions were conducted with the technologists annually and as needed to reinforce correct techniques and appropriate protocol. In addition, technologist performance codes were recorded by the NHANES quality control center at the University of California, San Francisco (UCSF), Department of Radiology, during review of participant scans. The codes documented when the technologist deviated from acquisition procedures and where scan quality could have been improved. The performance codes were tracked for each technologist individually and a summary was reported to NCHS on a quarterly basis. Additional feedback on technologist performance was provided by the UCSF when problems were noted during review of the scans. Ongoing communication was maintained throughout the year among the UCSF, the NCHS, and the data collection contractor regarding any issues that arose.

Hologic service engineers performed all routine densitometer maintenance and repairs. Copies of all reports completed by the manufacturer’s service engineers were sent to the UCSF when the scanners were serviced or repaired so any changes in measurement, as a result of the work, was assessed.

Scan Analysis
Each participant scan and phantom scan was reviewed and analyzed by the UCSF using standard radiologic techniques and study-specific protocols developed for NHANES. The Hologic software, APEX v4.0 (Hologic) was used to analyze whole body scans acquired in 2013-14. Expert review was conducted by the UCSF on 100% of analyzed participant scans to verify the accuracy and consistency of the results.

Invalidity Codes
Invalidity codes were applied by the UCSF to indicate the reasons that regions of the body could not be analyzed accurately. The invalidity codes are provided in the data file (see the Data Processing and Editing section for a more detailed description of the invalidity codes).

Quality Control Scans
The quality control phantoms were scanned according to a predetermined schedule. The Hologic Anthropomorphic Spine Phantom that traveled with each MEC was scanned daily, as required by the manufacturer, to ensure accurate calibration of the densitometer. Other MEC-specific phantoms, such as the Hologic Whole Body Slim-line Phantom and Hologic Tissue Step Phantom, were scanned 1 to 3 times weekly. A Hologic Spine (HSP-Q96) Phantom, Hologic Block, and Hologic whole body Phantoms circulated among the MECs and were scanned at the start of operations at each survey site.

Air scans, phantom-less scans using the whole body scan mode, were used to describe and monitor the systems’ radiographic uniformity across the entire scan field. Poor uniformity may be caused by poor aperture alignment, incorrect gantry rotation, non-uniform gain in detectors, etc., that result in localized inaccuracies in the attenuation values.

The complete phantom scanning schedule is described in the Body Composition Procedures Manual located on the NHANES website.

In 2013-2014, longitudinal monitoring was conducted through daily spine phantom scans as required by the manufacturer, whole body slim-line phantom scans and air scans in order to correct any scanner-related changes in participant data were conducted 3 times per week. The circulating HSP-Q96, block and whole body phantoms, which were scanned at the start of operations at each site, provided additional data for use in longitudinal monitoring and cross calibration.

The UCSF used the Cumulative Statistics method (CUSUM) and the MEC-specific phantom data to determine breaks in the calibration of the densitometers over the course of the survey (Lu, 1996). Multiplicative correction factors were used to correct the phantom data back to the baseline calibration. The type, frequency, and magnitude of calibration problems detected in the NHANES data were similar to those in other studies using stationary densitometers that were being monitored by UCSF.

After applying the correction factors developed by UCSF from the cross-calibration and longitudinal phantom data to the NHANES participant data, the adjusted participant data were compared to unadjusted data. The magnitude of the changes and reduction in standard errors between the adjusted and unadjusted data were found to be small and correction of the participant data not required.

A number of data quality issues were addressed through the quality control program. Direct feedback given to the technologists regarding acquisition problems affecting the quality of the scans and yearly refresher training resulted in improved technologist performance. The rigorous schedule of quality control scans provided continuous monitoring of machine performance. The expert review procedures helped to ensure that scan analysis was accurate and consistent.

Data Processing and Editing

During the editing process, data were reviewed for completeness, consistency, and outliers. Back-end edits of the data were performed when errors were identified. The NHANES BCA option was enabled for whole body scan analysis, this option adds 5% of lean mass to the fat mass. The correction is based on the results of an analysis of QDR-4500A DXA data from seven research laboratories indicating that the QDR-4500A algorithm underestimated fat mass and overestimated lean mass (Schoeller, 2005).

Invalidity Codes
Invalidity codes were included in the data file to indicate the reasons that regions of the body could not be analyzed accurately. Invalidity codes were applicable to completed scans only (DXAEXSTS= 1 or 2). If a participant was not scanned, all invalidity codes are missing.

The invalidity codes are provided in the data file as follows:

Invalidity codes
DXAHEBV = head bone
DXAHETV = head tissue
DXALABV = left arm bone
DXALATV = left arm tissue
DXALLBV = left leg bone
DXALLTV = left leg tissue
DXARABV = right arm bone
DXARATV = right arm tissue
DXARLBV = right leg bone
DXARLTV = right leg tissue
DXATRBV = trunk bone, includes thoracic and lumbar spine, left and right ribs, and pelvis
DXATRTV = trunk tissue

Values for invalidity codes DXAHEBV and DXAHETV:
0 = Valid data
1 = Removable or non-removable objects
5 = Body parts out of scan region
6 = Positioning problem
7 = Other

Values for invalidity codes DXALABV, DXALATV, DXARABV, DXARATV, DXALLBV, DXALLTV, DXARLBV and DXARLTV:
0 = Valid data
1 = Removable or non-removable objects
4 = Arm/leg overlap
5 = Body parts out of scan region
6 = positioning problem
7 = Other

Values for invalidity codes DXATRBV and DXATRTV:
0 = Valid data
1 = Removable or non-removable objects
3 = Excessive x-ray noise due to morbid obesity
4 = Arm/leg overlap
5 = Body parts out of scan region
6 = positioning problem
7 = Other

If any region was coded as invalid all bone and soft tissue measurements for that region were set to missing.

The percentage of eligible survey participants in 2013-2014 with 100% valid data (all analyzed regions were valid) is shown by age group in Table 1. The percentage of participants with valid data decreases with increasing age. The decrease in valid data with age was due primarily to an increase in the number of participants with implants, such as stents and hip replacements and higher rates of obesity resulting in invalid truncal data from “obesity noise.” The percentage of participants with 100% valid data also decreases with increasing BMI due to weight over 450 pounds and “obesity noise” (Table 2).

Table 1. Percentages of interviewed and examined participants 8-59 years of age with valid DXA data by age group, NHANES 2013-14.
Age group (years) Interviewed and Examined (N)* Eligible for DXA (N) † Eligible for DXA (%) † 100% valid DXA data (N) ‡ 100% valid DXA data (%) ‡
8-11  839  839  100  746  89
12-15  713  713  100  621  87
16-19  678  678  100  575  85
20-29  919  876  95  749  86
30-39  961  942  98  773  82
40-49  1007  1004  99  865  86
50-59  916  916  100  727  79
Total  6033  5968  99  5056  85

* The number interviewed and examined is the total number of participants in the data file with a SEQN variable. This number includes pregnant women.
†The total number eligible for DXA does not include pregnant women.
‡ Of those eligible for DXA who successfully completed a scan..

Table 2. Percentages of participants 20 years and older with valid DXA data by body mass index (BMI) * category, NHANES 2013-14.
BMI group Interviewed and Examined (N) Eligible for DXA (N) † Eligible for DXA (%) † 100% valid DXA data (N) ‡ 100% valid DXA data (%) ‡
< 18 41 41 100 33 80
18-24.9 1155 1131 98 967 85
25-29.9 1138 1120 98 979 87
30-34.9 760 746 98 623 84 
35-39.9 359 356  99  294 83
> 40 318 312  98  207  66
Total 3803 3738 98 3114 83

*Measured weight in kilograms divided by measured height in meters squared.
†The total number eligible for DXA does not include pregnant women.
‡ Of those eligible for DXA who successfully completed a scan.

Analytic Notes

The NHANES examination sample weights should be used for any analyses using the DXX_G data. 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. Both of these are available on the NHANES website.

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 8 YEARS - 59 YEARS

DXAEXSTS - Exam Status

Variable Name:
DXAEXSTS
SAS Label:
Exam Status
English Text:
Exam Status
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Whole body scan completed 5446 5446
2 Whole body scan completed, but invalid 2 5448
3 Whole body not scanned, pregnancy 65 5513
4 Whole body not scanned, weight > 450 lbs 2 5515
5 Whole body not scanned, height > 6'5 7 5522
6 Whole body not scanned, other reason 511 6033
. Missing 0 6033

DXAHEBV - Head Bone Invalidity Code

Variable Name:
DXAHEBV
SAS Label:
Head Bone Invalidity Code
English Text:
Head Bone Invalidity Code
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Valid data 5379 5379
1 Removable or non-removable objects 45 5424
5 Body parts out of scan region 14 5438
6 Positioning problem 8 5446
7 Other 0 5446
. Missing 587 6033

DXXHEA - Head Area (cm^2)

Variable Name:
DXXHEA
SAS Label:
Head Area (cm^2)
English Text:
Head Area (cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
164.36 to 289.21 Range of Values 5379 5379
. Missing 654 6033

DXXHEBMC - Head Bone Mineral Content (g)

Variable Name:
DXXHEBMC
SAS Label:
Head Bone Mineral Content (g)
English Text:
Head Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
168.37 to 888.47 Range of Values 5379 5379
. Missing 654 6033

DXXHEBMD - Head Bone Mineral Density (g/cm^2)

Variable Name:
DXXHEBMD
SAS Label:
Head Bone Mineral Density (g/cm^2)
English Text:
Head Bone Mineral Density (grams/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.891 to 3.759 Range of Values 5379 5379
. Missing 654 6033

DXAHETV - Head Tissue Invalidity Code

Variable Name:
DXAHETV
SAS Label:
Head Tissue Invalidity Code
English Text:
Head Tissue Invalidity Code
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Valid data 5379 5379
1 Removable or non-removable objects 45 5424
5 Body parts out of scan region 14 5438
6 Positioning problem 8 5446
7 Other 1 5447
. Missing 586 6033

DXXHEFAT - Head Fat (g)

Variable Name:
DXXHEFAT
SAS Label:
Head Fat (g)
English Text:
Head Fat (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
686.9 to 2089.8 Range of Values 5379 5379
. Missing 654 6033

DXDHELE - Head Lean excl BMC (g)

Variable Name:
DXDHELE
SAS Label:
Head Lean excl BMC (g)
English Text:
Head Lean excl Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1901.2 to 5016.9 Range of Values 5379 5379
. Missing 654 6033

DXXHELI - Head Lean incl BMC (g)

Variable Name:
DXXHELI
SAS Label:
Head Lean incl BMC (g)
English Text:
Head Lean incl Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2152.5 to 5601.7 Range of Values 5379 5379
. Missing 654 6033

DXDHETOT - Head Total (g)

Variable Name:
DXDHETOT
SAS Label:
Head Total (g)
English Text:
Head Total (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2840.9 to 7475.1 Range of Values 5379 5379
. Missing 654 6033

DXDHEPF - Head Percent Fat

Variable Name:
DXDHEPF
SAS Label:
Head Percent Fat
English Text:
Head Percent Fat
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
22.2 to 29.5 Range of Values 5379 5379
. Missing 654 6033

DXALABV - Left Arm Bone Invalidity Code

Variable Name:
DXALABV
SAS Label:
Left Arm Bone Invalidity Code
English Text:
Left Arm Bone Invalidity Code
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Valid data 5347 5347
1 Removable or non-removable objects 59 5406
4 Arm/leg overlap 17 5423
5 Body parts out of scan region 16 5439
6 Positioning problem 7 5446
7 Other 0 5446
. Missing 587 6033

DXXLAA - Left Arm Area (cm^2)

Variable Name:
DXXLAA
SAS Label:
Left Arm Area (cm^2)
English Text:
Left Arm Area (cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
54.36 to 382.31 Range of Values 5347 5347
. Missing 686 6033

DXXLABMC - Left Arm BMC (g)

Variable Name:
DXXLABMC
SAS Label:
Left Arm BMC (g)
English Text:
Left Arm Body Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
25.39 to 408.54 Range of Values 5347 5347
. Missing 686 6033

DXXLABMD - Left Arm BMD (g/cm^2)

Variable Name:
DXXLABMD
SAS Label:
Left Arm BMD (g/cm^2)
English Text:
Left Arm Body Mineral Density (grams/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.313 to 1.496 Range of Values 5347 5347
. Missing 686 6033

DXALATV - Left Arm Tissue Invalidity Code

Variable Name:
DXALATV
SAS Label:
Left Arm Tissue Invalidity Code
English Text:
Left Arm Tissue Invalidity Code
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Valid data 5348 5348
1 Removable or non-removable objects 59 5407
4 Arm/leg overlap 16 5423
5 Body parts out of scan region 16 5439
6 Positioning problem 7 5446
7 Other 0 5446
. Missing 587 6033

DXXLAFAT - Left Arm Fat (g)

Variable Name:
DXXLAFAT
SAS Label:
Left Arm Fat (g)
English Text:
Left Arm Fat (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
178.8 to 7248 Range of Values 5348 5348
. Missing 685 6033

DXDLALE - Left Arm Lean excl BMC (g)

Variable Name:
DXDLALE
SAS Label:
Left Arm Lean excl BMC (g)
English Text:
Left Arm Lean excl Body Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
485.2 to 7790.2 Range of Values 5348 5348
. Missing 685 6033

DXXLALI - Left Arm Lean incl BMC (g)

Variable Name:
DXXLALI
SAS Label:
Left Arm Lean incl BMC (g)
English Text:
Left Arm Lean incl BMC (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
521.9 to 8139.2 Range of Values 5347 5347
. Missing 686 6033

DXDLATOT - Left Arm Total (g)

Variable Name:
DXDLATOT
SAS Label:
Left Arm Total (g)
English Text:
Left Arm Total (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
829.2 to 12134.5 Range of Values 5347 5347
. Missing 686 6033

DXDLAPF - Left Arm Percent Fat

Variable Name:
DXDLAPF
SAS Label:
Left Arm Percent Fat
English Text:
Left Arm Percent Fat
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
11.3 to 70 Range of Values 5348 5348
. Missing 685 6033

DXALLBV - Left Leg Bone Invalidity Code

Variable Name:
DXALLBV
SAS Label:
Left Leg Bone Invalidity Code
English Text:
Left Leg Bone Invalidity Code
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Valid data 5299 5299
1 Removable or non-removable objects 80 5379
4 Arm/leg overlap 15 5394
5 Body parts out of scan region 43 5437
6 Positioning problem 9 5446
7 Other 0 5446
. Missing 587 6033

DXXLLA - Left Leg Area (cm^2)

Variable Name:
DXXLLA
SAS Label:
Left Leg Area (cm^2)
English Text:
Left Leg Area(cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
157.46 to 543.85 Range of Values 5299 5299
. Missing 734 6033

DXXLLBMC - Left Leg BMC (g)

Variable Name:
DXXLLBMC
SAS Label:
Left Leg BMC (g)
English Text:
Left Leg Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
88.1 to 865.04 Range of Values 5299 5299
. Missing 734 6033

DXXLLBMD - Left Leg BMD (g/cm^2)

Variable Name:
DXXLLBMD
SAS Label:
Left Leg BMD (g/cm^2)
English Text:
Left Leg Bone Mineral Density (grams/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.47 to 1.812 Range of Values 5299 5299
. Missing 734 6033

DXALLTV - Left Leg Tissue Invalidity Code

Variable Name:
DXALLTV
SAS Label:
Left Leg Tissue Invalidity Code
English Text:
Left Leg Tissue Invalidity Code
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Valid data 5290 5290
1 Removable or non-removable objects 80 5370
4 Arm/leg overlap 15 5385
5 Body parts out of scan region 52 5437
6 Positioning problem 9 5446
7 Other 0 5446
. Missing 587 6033

DXXLLFAT - Left Leg Fat (g)

Variable Name:
DXXLLFAT
SAS Label:
Left Leg Fat (g)
English Text:
Left Leg Fat (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
446 to 18238.2 Range of Values 5290 5290
. Missing 743 6033

DXDLLLE - Left Leg Lean excl BMC (g)

Variable Name:
DXDLLLE
SAS Label:
Left Leg Lean excl BMC (g)
English Text:
Left Leg Lean excl Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1618.4 to 18375.8 Range of Values 5290 5290
. Missing 743 6033

DXXLLLI - Left Leg Lean incl BMC (g)

Variable Name:
DXXLLLI
SAS Label:
Left Leg Lean incl BMC (g)
English Text:
Left Leg Lean incl Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1713.2 to 19065 Range of Values 5299 5299
. Missing 734 6033

DXDLLTOT - Left Leg Total (g)

Variable Name:
DXDLLTOT
SAS Label:
Left Leg Total (g)
English Text:
Left Leg Total (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2613.8 to 34055 Range of Values 5289 5289
. Missing 744 6033

DXDLLPF - Left Leg Percent Fat

Variable Name:
DXDLLPF
SAS Label:
Left Leg Percent Fat
English Text:
Left Leg Percent Fat
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
11.1 to 62.7 Range of Values 5290 5290
. Missing 743 6033

DXARABV - Right Arm Bone Invalidity Code

Variable Name:
DXARABV
SAS Label:
Right Arm Bone Invalidity Code
English Text:
Right Arm Bone Invalidity Code
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Valid data 5347 5347
1 Removable or non-removable objects 42 5389
4 Arm/leg overlap 23 5412
5 Body parts out of scan region 25 5437
6 Positioning problem 9 5446
7 Other 0 5446
. Missing 587 6033

DXXRAA - Right Arm Area (cm^2)

Variable Name:
DXXRAA
SAS Label:
Right Arm Area (cm^2)
English Text:
Right Arm Area (cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
71.97 to 382.31 Range of Values 5347 5347
. Missing 686 6033

DXXRABMC - Right Arm BMC (g)

Variable Name:
DXXRABMC
SAS Label:
Right Arm BMC (g)
English Text:
Right Arm Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
28.67 to 394.21 Range of Values 5347 5347
. Missing 686 6033

DXXRABMD - Right Arm BMD (g/cm^2)

Variable Name:
DXXRABMD
SAS Label:
Right Arm BMD (g/cm^2)
English Text:
Right Arm Bone Mineral Density (grams/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.302 to 1.258 Range of Values 5347 5347
. Missing 686 6033

DXARATV - Right Arm Tissue Invalidity Code

Variable Name:
DXARATV
SAS Label:
Right Arm Tissue Invalidity Code
English Text:
Right Arm Tissue Invalidity Code
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Valid data 5348 5348
1 Removable or non-removable objects 42 5390
4 Arm/leg overlap 22 5412
5 Body parts out of scan region 25 5437
6 Positioning problem 9 5446
7 Other 0 5446
. Missing 587 6033

DXXRAFAT - Right Arm Fat (g)

Variable Name:
DXXRAFAT
SAS Label:
Right Arm Fat (g)
English Text:
Right Arm Fat (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
163.3 to 7248 Range of Values 5348 5348
. Missing 685 6033

DXDRALE - Right Arm Lean excl BMC (g)

Variable Name:
DXDRALE
SAS Label:
Right Arm Lean excl BMC (g)
English Text:
Right Arm Lean excl Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
614.7 to 7790.2 Range of Values 5348 5348
. Missing 685 6033

DXXRALI - Right Arm Lean incl BMC (g)

Variable Name:
DXXRALI
SAS Label:
Right Arm Lean incl BMC (g)
English Text:
Right Arm Lean incl Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
657.5 to 8139.2 Range of Values 5347 5347
. Missing 686 6033

DXDRATOT - Right Arm Total (g)

Variable Name:
DXDRATOT
SAS Label:
Right Arm Total (g)
English Text:
Right Arm Total (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
914.4 to 12134.5 Range of Values 5347 5347
. Missing 686 6033

DXDRAPF - Right Arm Percent Fat

Variable Name:
DXDRAPF
SAS Label:
Right Arm Percent Fat
English Text:
Right Arm Percent Fat
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
10.1 to 65.7 Range of Values 5348 5348
. Missing 685 6033

DXARLBV - Right Leg Bone Invalidity Code

Variable Name:
DXARLBV
SAS Label:
Right Leg Bone Invalidity Code
English Text:
Right Leg Bone Invalidity Code
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Valid data 5295 5295
1 Removable or non-removable objects 74 5369
4 Arm/leg overlap 25 5394
5 Body parts out of scan region 43 5437
6 Positioning problem 9 5446
7 Other 0 5446
. Missing 587 6033

DXXRLA - Right Leg Area (cm^2)

Variable Name:
DXXRLA
SAS Label:
Right Leg Area (cm^2)
English Text:
Right Leg Area (cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
158.26 to 544.44 Range of Values 5295 5295
. Missing 738 6033

DXXRLBMC - Right Leg BMC (g)

Variable Name:
DXXRLBMC
SAS Label:
Right Leg BMC (g)
English Text:
Right Leg Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
77.97 to 915.52 Range of Values 5295 5295
. Missing 738 6033

DXXRLBMD - Right Leg BMD(g/cm^2)

Variable Name:
DXXRLBMD
SAS Label:
Right Leg BMD(g/cm^2)
English Text:
Right Leg Bone Mineral Density (grams/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.482 to 2.91 Range of Values 5295 5295
. Missing 738 6033

DXARLTV - Right Leg Tissue Invalidity Code

Variable Name:
DXARLTV
SAS Label:
Right Leg Tissue Invalidity Code
English Text:
Right Leg Tissue Invalidity Code
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Valid data 5296 5296
1 Removable or non-removable objects 74 5370
4 Arm/leg overlap 24 5394
5 Body parts out of scan region 43 5437
6 Positioning problem 9 5446
7 Other 0 5446
. Missing 587 6033

DXXRLFAT - Right Leg Fat (g)

Variable Name:
DXXRLFAT
SAS Label:
Right Leg Fat (g)
English Text:
Right Leg Fat (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
497.7 to 18974.4 Range of Values 5296 5296
. Missing 737 6033

DXDRLLE - Right Leg Lean excl BMC (g)

Variable Name:
DXDRLLE
SAS Label:
Right Leg Lean excl BMC (g)
English Text:
Right Leg Lean excl Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1646.1 to 18101.4 Range of Values 5296 5296
. Missing 737 6033

DXXRLLI - Right Leg Lean incl BMC (g)

Variable Name:
DXXRLLI
SAS Label:
Right Leg Lean incl BMC (g)
English Text:
Right Leg Lean incl Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1738.4 to 18825.3 Range of Values 5295 5295
. Missing 738 6033

DXDRLTOT - Right Leg Total (g)

Variable Name:
DXDRLTOT
SAS Label:
Right Leg Total (g)
English Text:
Right Leg Total (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2929.4 to 36954.9 Range of Values 5295 5295
. Missing 738 6033

DXDRLPF - Right Leg Percent Fat

Variable Name:
DXDRLPF
SAS Label:
Right Leg Percent Fat
English Text:
Right Leg Percent Fat
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
11.8 to 61 Range of Values 5296 5296
. Missing 737 6033

DXXLRA - Left Ribs Area (cm^2)

Variable Name:
DXXLRA
SAS Label:
Left Ribs Area (cm^2)
English Text:
Left Ribs Area(cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
44.77 to 203.85 Range of Values 5294 5294
. Missing 739 6033

DXXLRBMC - Left Ribs BMC (g)

Variable Name:
DXXLRBMC
SAS Label:
Left Ribs BMC (g)
English Text:
Left Ribs Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
17.07 to 167.72 Range of Values 5294 5294
. Missing 739 6033

DXXLRBMD - Left Ribs BMD (g/cm^2)

Variable Name:
DXXLRBMD
SAS Label:
Left Ribs BMD (g/cm^2)
English Text:
Left Ribs Bone Mineral Density (grams/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.336 to 0.983 Range of Values 5294 5294
. Missing 739 6033

DXXRRA - Right Ribs Area (cm^2)

Variable Name:
DXXRRA
SAS Label:
Right Ribs Area (cm^2)
English Text:
Right Ribs Area (cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
44.77 to 236.01 Range of Values 5294 5294
. Missing 739 6033

DXXRRBMC - Right Ribs BMC (g)

Variable Name:
DXXRRBMC
SAS Label:
Right Ribs BMC (g)
English Text:
Right Ribs Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
17.67 to 185.35 Range of Values 5294 5294
. Missing 739 6033

DXXRRBMD - Right Ribs BMD (g/cm^2)

Variable Name:
DXXRRBMD
SAS Label:
Right Ribs BMD (g/cm^2)
English Text:
Right Ribs Bone Mineral Density (grams/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.349 to 0.984 Range of Values 5294 5294
. Missing 739 6033

DXXTSA - Thoracic Spine Area (cm^2)

Variable Name:
DXXTSA
SAS Label:
Thoracic Spine Area (cm^2)
English Text:
Thoracic Spine Area (cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
44.37 to 226.65 Range of Values 5294 5294
. Missing 739 6033

DXXTSBMC - Thoracic Spine BMC (g)

Variable Name:
DXXTSBMC
SAS Label:
Thoracic Spine BMC (g)
English Text:
Thoracic Spine Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
19 to 257.54 Range of Values 5294 5294
. Missing 739 6033

DXXTSBMD - Thoracic Spine BMD (g/cm^2)

Variable Name:
DXXTSBMD
SAS Label:
Thoracic Spine BMD (g/cm^2)
English Text:
Thoracic Spine Bone Mineral Density (grams/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.363 to 1.334 Range of Values 5294 5294
. Missing 739 6033

DXXLSA - Lumbar Spine Area (cm^2)

Variable Name:
DXXLSA
SAS Label:
Lumbar Spine Area (cm^2)
English Text:
Lumbar Spine Area (cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
12.09 to 88.34 Range of Values 5294 5294
. Missing 739 6033

DXXLSBMC - Lumbar Spine BMC (g)

Variable Name:
DXXLSBMC
SAS Label:
Lumbar Spine BMC (g)
English Text:
Lumbar Spine Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8.12 to 123.64 Range of Values 5294 5294
. Missing 739 6033

DXXLSBMD - Lumbar Spine BMD (g/cm^2)

Variable Name:
DXXLSBMD
SAS Label:
Lumbar Spine BMD (g/cm^2)
English Text:
Lumbar Spine Bone Mineral Density (grams/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.47 to 1.738 Range of Values 5294 5294
. Missing 739 6033

DXXPEA - Pelvis Area (cm^2)

Variable Name:
DXXPEA
SAS Label:
Pelvis Area (cm^2)
English Text:
Pelvis Area (cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
67.09 to 360.66 Range of Values 5294 5294
. Missing 739 6033

DXXPEBMC - Pelvis BMC (g)

Variable Name:
DXXPEBMC
SAS Label:
Pelvis BMC (g)
English Text:
Pelvis Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
49.2 to 681.41 Range of Values 5294 5294
. Missing 739 6033

DXXPEBMD - Pelvis BMD (g/cm^2)

Variable Name:
DXXPEBMD
SAS Label:
Pelvis BMD (g/cm^2)
English Text:
Pelvis Bone Mineral Density (grams/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.524 to 2.073 Range of Values 5294 5294
. Missing 739 6033

DXATRBV - Trunk Bone Invalidity Code

Variable Name:
DXATRBV
SAS Label:
Trunk Bone Invalidity Code
English Text:
Trunk Bone Invalidity Code
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Valid data 5294 5294
1 Removable or non-removable objects 147 5441
3 Excessive x-ray noise due to morbid obesity 0 5441
4 Arm/leg overlap 0 5441
5 Body parts out of scan region 5 5446
6 Positioning problem 0 5446
7 Other 0 5446
. Missing 587 6033

DXDTRA - Trunk Bone area (cm^2)

Variable Name:
DXDTRA
SAS Label:
Trunk Bone area (cm^2)
English Text:
Trunk Bone area (cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
277.02 to 991.42 Range of Values 5297 5297
. Missing 736 6033

DXDTRBMC - Trunk BMC (g)

Variable Name:
DXDTRBMC
SAS Label:
Trunk BMC (g)
English Text:
Trunk Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
138.84 to 1313.21 Range of Values 5294 5294
. Missing 739 6033

DXDTRBMD - Trunk Bone BMD (g/cm^2)

Variable Name:
DXDTRBMD
SAS Label:
Trunk Bone BMD (g/cm^2)
English Text:
Trunk Bone BMD (g/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.432 to 1.929 Range of Values 5297 5297
. Missing 736 6033

DXATRTV - Trunk Tissue Invalidity Code

Variable Name:
DXATRTV
SAS Label:
Trunk Tissue Invalidity Code
English Text:
Trunk Tissue Invalidity Code
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Valid data 5288 5288
1 Removable or non-removable objects 147 5435
3 Excessive x-ray noise due to morbid obesity 0 5435
4 Arm/leg overlap 0 5435
5 Body parts out of scan region 11 5446
6 Positioning problem 0 5446
7 Other 0 5446
. Missing 587 6033

DXXTRFAT - Trunk Fat (g)

Variable Name:
DXXTRFAT
SAS Label:
Trunk Fat (g)
English Text:
Trunk Fat (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1170.2 to 49425.8 Range of Values 5288 5288
. Missing 745 6033

DXDTRLE - Trunk Lean excl BMC (g)

Variable Name:
DXDTRLE
SAS Label:
Trunk Lean excl BMC (g)
English Text:
Trunk Lean excl Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5434.2 to 56813.7 Range of Values 5288 5288
. Missing 745 6033

DXXTRLI - Trunk Lean incl BMC (g)

Variable Name:
DXXTRLI
SAS Label:
Trunk Lean incl BMC (g)
English Text:
Trunk Lean incl Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5606.9 to 57666.7 Range of Values 5294 5294
. Missing 739 6033

DXDTRTOT - Trunk Total (g)

Variable Name:
DXDTRTOT
SAS Label:
Trunk Total (g)
English Text:
Trunk Total (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
6911.6 to 100254.5 Range of Values 5288 5288
. Missing 745 6033

DXDTRPF - Trunk Percent Fat

Variable Name:
DXDTRPF
SAS Label:
Trunk Percent Fat
English Text:
Trunk Percent Fat
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
10.3 to 55.1 Range of Values 5288 5288
. Missing 745 6033

DXDSTA - Subtotal Area (cm^2)

Variable Name:
DXDSTA
SAS Label:
Subtotal Area (cm^2)
English Text:
Subtotal Area (cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
821.46 to 2739.79 Range of Values 4992 4992
. Missing 1041 6033

DXDSTBMC - Subtotal BMC (g)

Variable Name:
DXDSTBMC
SAS Label:
Subtotal BMC (g)
English Text:
Subtotal Bone Mineral Content (grams)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
365.36 to 3689.24 Range of Values 4992 4992
. Missing 1041 6033

DXDSTBMD - Subtotal BMD (g/cm^2)

Variable Name:
DXDSTBMD
SAS Label:
Subtotal BMD (g/cm^2)
English Text:
Subtotal Bone Mineral Density (grams/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.423 to 1.435 Range of Values 4992 4992
. Missing 1041 6033

DXDSTFAT - Subtotal Fat (g)

Variable Name:
DXDSTFAT
SAS Label:
Subtotal Fat (g)
English Text:
Subtotal Fat (g)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2641.9 to 90439.9 Range of Values 5110 5110
. Missing 923 6033

DXDSTLE - Subtotal Lean excl BMC (g)

Variable Name:
DXDSTLE
SAS Label:
Subtotal Lean excl BMC (g)
English Text:
Subtotal Lean excl BMC (g)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
11085.6 to 100464.1 Range of Values 5110 5110
. Missing 923 6033

DXDSTLI - Subtotal Lean incl BMC (g)

Variable Name:
DXDSTLI
SAS Label:
Subtotal Lean incl BMC (g)
English Text:
Subtotal Lean incl BMC (g)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
11530.7 to 103279.6 Range of Values 4983 4983
. Missing 1050 6033

DXDSTTOT - Subtotal (Total excl Head) (g)

Variable Name:
DXDSTTOT
SAS Label:
Subtotal (Total excl Head) (g)
English Text:
Subtotal (Total excl Head) (g)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
14216.3 to 175121.2 Range of Values 5110 5110
. Missing 923 6033

DXDSTPF - Subtotal Percent Fat

Variable Name:
DXDSTPF
SAS Label:
Subtotal Percent Fat
English Text:
Subtotal Percent Fat
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
11.9 to 56.1 Range of Values 5110 5110
. Missing 923 6033

DXDTOA - Total Area (cm^2)

Variable Name:
DXDTOA
SAS Label:
Total Area (cm^2)
English Text:
Total Area (cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1023.09 to 2981.1 Range of Values 5068 5068
. Missing 965 6033

DXDTOBMC - Total Bone Mineral Content (g)

Variable Name:
DXDTOBMC
SAS Label:
Total Bone Mineral Content (g)
English Text:
Total Bone Mineral Content (g)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
602.95 to 4365.07 Range of Values 5068 5068
. Missing 965 6033

DXDTOBMD - Total Bone Mineral Density (g/cm^2)

Variable Name:
DXDTOBMD
SAS Label:
Total Bone Mineral Density (g/cm^2)
English Text:
Total Bone Mineral Density (g/cm^2)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.559 to 1.548 Range of Values 5068 5068
. Missing 965 6033

DXDTOFAT - Total Fat (g)

Variable Name:
DXDTOFAT
SAS Label:
Total Fat (g)
English Text:
Total Fat (g)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3328.8 to 91731.8 Range of Values 5056 5056
. Missing 977 6033

DXDTOLE - Total Lean excl BMC (g)

Variable Name:
DXDTOLE
SAS Label:
Total Lean excl BMC (g)
English Text:
Total Lean excl BMC (g)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
12986.8 to 104820.7 Range of Values 5110 5110
. Missing 923 6033

DXDTOLI - Total Lean incl BMC (g)

Variable Name:
DXDTOLI
SAS Label:
Total Lean incl BMC (g)
English Text:
Total Lean incl BMC (g)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
13764.1 to 108116 Range of Values 5056 5056
. Missing 977 6033

DXDTOTOT - Total Lean+Fat (g)

Variable Name:
DXDTOTOT
SAS Label:
Total Lean+Fat (g)
English Text:
Total Lean+Fat(g)
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
17092.9 to 180764.5 Range of Values 5056 5056
. Missing 977 6033

DXDTOPF - Total Percent Fat

Variable Name:
DXDTOPF
SAS Label:
Total Percent Fat
English Text:
Total Percent Fat
Target:
Both males and females 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
12.7 to 54.8 Range of Values 5056 5056
. Missing 977 6033