Table of Contents

Locator Record

Title: Body Measures (BMX_E )
Contact Number: 1-866-441-NCHS
Years of Content: 2007 - 2008
First Published: September, 2009
Revised: April, 2011
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:Body measurement component of the NHANES health examination. Height, Weight, Arm Circumference, BMI.
Record Source: NHANES 2007 - 2008
Survey Methodology: NHANES 2007 - 2008 is a stratified multistage probability sample of the civilian non-institutionalized population of the U.S.
Medium: NHANES Web site; SAS transport files

Component Description

NHANES body measurement data are used to monitor trends in infant and child growth, to estimate the prevalence of overweight and obesity in the U.S. population, and to examine the associations between body weight and the health and nutritional status of the U.S. population. The target age groups for the NHANES 2007-2008 body measurement component are as follows:

Head circumference: birth through 6 months of age
Mid-upper arm circumference: 2 months of age and older
Recumbent length: birth through 47 months
Standing height: 2 years and older
Subscapular skin fold: 2 months of age and older
Triceps skin fold: 2 months of age and older
Upper arm length: 2 months of age and older
Upper leg length: 8 years and older
Waist circumference: 2 years of age and older
Weight: All ages

Eligible Sample

All survey participants were eligible for the body measurement component. There were no medical, safety, or other exclusions for the body measurements protocol. The health technicians used their discretion to obtain as many measures as practical for persons who used a wheelchair. Maximal calf and mid-thigh circumference measurements were discontinued after the NHANES 2005-2006 data collection cycle was completed.

Protocol and Procedure

The body measurement data were collected by trained health technicians. The health technician was assisted by a recorder during the body measurement examination. The respondent’s age at the time of the screening interview determined the body measurement examination protocol for survey participants. In some instances the age at screening interview and age at the time of the health examination differed by several weeks. The Demographics data file includes variables for age at screening (RIDAGEYR and RIDAGEMN) and age at examination (RIDAGEEX).

Arm and leg measurements were made on the right side of the body. If an examinee had an amputation, medical condition, or medical appliance, such as a cast, that prevented measurements from being taken on the right side of the body, the examiner took measurements on the left side. The body measurements file does not identify persons who had amputations because the information might be considered identifiable and pose a disclosure concern. The body weight data for individuals who had limb amputations were set to missing.

This data file includes body measurements for women who were pregnant at the time of their health examination. Pregnancy status at the time of the health examination is indicated by the Demographic file variable, RIDEXPRG - pregnancy status at the time of the health examination. RIDEXPRG values are reported for women 20-44 years of age. RIDEXPRG for several pregnant women who were outside of this age range are not reported due to disclosure concerns. The body measures data for these individuals are not reported.

For general guidelines on the body measurement procedures, please refer to the Anthropometric Standardization Reference Manual (Lohman et al, 1988).

The NHANES III Anthropometric Procedures Video (Centers for Disease Control and Prevention) illustrates the NHANES III anthropometry methodology. The same methods have been used in each of the continuous NHANES cycles. The NHANES III anthropometry component included several measurements that are no longer part of the anthropometry protocol. The NHANES III video is available in VHS and DVD format upon request and may also be viewed on the NHANES website.
The NHANES 2007-2008 Body Measurement Procedures Manual is posted on the NHANES 2007-2008 website. The manual provides descriptions of the NHANES protocol, survey equipment, and quality control procedures.

Quality Assurance & Quality Control

The NHANES health technicians completed a 2-day training program with survey staff and an expert anthropometrist. The training included an overview of the component, using the NHANES III anthropometry video, and demonstrations conducted by the expert examiner with volunteer subjects. The expert examiner reviewed and demonstrated the proper technique to use for each measurement. Supervised practice exercises followed, conducted with several volunteer subjects, including infants, children, and adults. The chief health technician, at each of the mobile examination centers, monitored staff performance in the field. Health technician performance was also monitored using direct observation, data reviews, and periodic expert examiner (gold standard comparison) evaluations.

The body measurement examination rooms in each of the mobile examination centers were identical with respect to layout and equipment. Scheduled equipment calibration was performed by the health technicians and verified by supervisory staff. The Body Measures Procedures Manual includes detailed descriptions of the quality assurance and quality control measures that are used in NHANES.

Data Processing and Editing

The 2007-2008 data were reviewed for unusual and erroneous values. Review criteria, based on NHANES III and NHANES 1999–2006 body measures data, were used for the initial data reviews. Range checks for infants under 2 months of were based on NHANES 1999–2006 body measurement data. During the data review, values that were above the 99th percentile or below the 1st percentile, for a particular age or age-gender group, were flagged for review. When records were flagged, the entire body measurements record was reviewed for reasonableness. Subject characteristics such as height, weight, age and gender were taken into consideration. Values that were determined to be unrealistic were deleted from the file. None of the original body measures data were changed and there are no imputed values in this file.

Analytic Notes

Component status code: A final body measures component status code (BMDSTAT) provides analysts with a quick method of identifying survey participants with complete or partial body measurement data.

Unusual values: Unusual body measurement values were noted during the review of the data. Typically, unusual values occurred when a subject was extremely short, tall, overweight or underweight. Analysts should examine the distributions of the body measurements carefully. In particular, the upper arm length (BMXARML) and upper leg length (BMXLEG) values are affected by extreme amounts of adipose tissue. Skinfold measurements were not obtained for many obese subjects because the amount of adipose tissue exceeded the limits of the caliper, or the technician was not able to grasp a double thickness of tissue.

Comment Codes: Comment codes were added by the health technicians, during data collection, to document problems or situations that arose during the body measurement examination. For example, the variable BMIWT is a comment code for the body weight measurement. If a subject did not change into the NHANES exam gown, a code of BMIWT of ‘3’ denoting ‘clothing worn’ was made in the record. Analysts should review the comment code information for each of the body measures prior to data analysis.

Sample Weights: The NHANES examination sample weights should be used to analyze the body measurement data. Please refer to the Analytic Guidelines for further details on the use of sample weights and other analytic issues. The Analytic Guidelines 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 0 YEARS - 150 YEARS

BMDSTATS - Body Measures Component Status Code

Variable Name:
BMDSTATS
SAS Label:
Body Measures Component Status Code
English Text:
Body Measures Component status Code
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Complete data for age group 8088 8088
2 Partial: Height and weight obtained 241 8329
3 Other partial exam 1322 9651
4 No body measures exam data 111 9762
. Missing 0 9762

BMXWT - Weight (kg)

Variable Name:
BMXWT
SAS Label:
Weight (kg)
English Text:
Weight (kg)
Target:
Both males and females 0 YEARS - 150 YEARS
Hard Edits:
0.0000 to 440.0000
Code or Value Value Description Count Cumulative Skip to Item
3.1 to 218.2 Range of Values 9631 9631
. Missing 131 9762

BMIWT - Weight Comment

Variable Name:
BMIWT
SAS Label:
Weight Comment
English Text:
Weight Comment
Target:
Both males and females 0 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Could not obtain 28 28
2 Exceeds capacity 0 28
3 Clothing 292 320
4 Medical appliance 19 339
. Missing 9423 9762

BMXRECUM - Recumbent Length (cm)

Variable Name:
BMXRECUM
SAS Label:
Recumbent Length (cm)
English Text:
Recumbent Length (cm)
Target:
Both males and females 0 MONTHS - 47 MONTHS
Hard Edits:
16.0000 to 119.3000
Code or Value Value Description Count Cumulative Skip to Item
49.1 to 116.6 Range of Values 1194 1194
. Missing 8568 9762

BMIRECUM - Recumbent Length Comment

Variable Name:
BMIRECUM
SAS Label:
Recumbent Length Comment
English Text:
Recumbent Length Comment
Target:
Both males and females 0 MONTHS - 47 MONTHS
Code or Value Value Description Count Cumulative Skip to Item
1 Could not obtain 17 17
2 Exceeds capacity 0 17
3 Not straight 1 18
. Missing 9744 9762

BMXHEAD - Head Circumference (cm)

Variable Name:
BMXHEAD
SAS Label:
Head Circumference (cm)
English Text:
Head Circumference (cm)
Target:
Both males and females 0 MONTHS - 6 MONTHS
Hard Edits:
00.0000 to 99.9999
Code or Value Value Description Count Cumulative Skip to Item
33.5 to 47.4 Range of Values 260 260
. Missing 9502 9762

BMIHEAD - Head Circumference Comment

Variable Name:
BMIHEAD
SAS Label:
Head Circumference Comment
English Text:
Head Circumference Comment
Target:
Both males and females 0 MONTHS - 6 MONTHS
Code or Value Value Description Count Cumulative Skip to Item
1 Could not obtain 0 0
2 Exceeds capacity 0 0
3 Not straight 0 0
. Missing 9762 9762

BMXHT - Standing Height (cm)

Variable Name:
BMXHT
SAS Label:
Standing Height (cm)
English Text:
Standing Height (cm)
Target:
Both males and females 2 YEARS - 150 YEARS
Hard Edits:
70.0000 to 208.4000
Code or Value Value Description Count Cumulative Skip to Item
81.5 to 203.8 Range of Values 8873 8873
. Missing 889 9762

BMIHT - Standing Height Comment

Variable Name:
BMIHT
SAS Label:
Standing Height Comment
English Text:
Standing Height Comment
Target:
Both males and females 2 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Could not obtain 50 50
2 Exceeds capacity 0 50
3 Not straight 259 309
. Missing 9453 9762

BMXBMI - Body Mass Index (kg/m**2)

Variable Name:
BMXBMI
SAS Label:
Body Mass Index (kg/m**2)
English Text:
Body Mass Index (kg/m**2)
Target:
Both males and females 2 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
12.5 to 73.43 Range of Values 8861 8861
. Missing 901 9762

BMXLEG - Upper Leg Length (cm)

Variable Name:
BMXLEG
SAS Label:
Upper Leg Length (cm)
English Text:
Upper Leg Length (cm)
Target:
Both males and females 8 YEARS - 150 YEARS
Hard Edits:
0.0000 to 200.0000
Code or Value Value Description Count Cumulative Skip to Item
22.1 to 55.5 Range of Values 7304 7304
. Missing 2458 9762

BMILEG - Upper Leg Length Comment

Variable Name:
BMILEG
SAS Label:
Upper Leg Length Comment
English Text:
Upper Leg Length Comment
Target:
Both males and females 8 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Could not obtain 324 324
. Missing 9438 9762

BMXARML - Upper Arm Length (cm)

Variable Name:
BMXARML
SAS Label:
Upper Arm Length (cm)
English Text:
Upper Arm Length (cm)
Target:
Both males and females 2 MONTHS - 150 YEARS
Hard Edits:
0.0000 to 200.0000
Code or Value Value Description Count Cumulative Skip to Item
9 to 47.7 Range of Values 9276 9276
. Missing 486 9762

BMIARML - Upper Arm Length Comment

Variable Name:
BMIARML
SAS Label:
Upper Arm Length Comment
English Text:
Upper Arm Length Comment
Target:
Both males and females 2 MONTHS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Could not obtain 299 299
. Missing 9463 9762

BMXARMC - Arm Circumference (cm)

Variable Name:
BMXARMC
SAS Label:
Arm Circumference (cm)
English Text:
Arm Circumference (cm)
Target:
Both males and females 2 MONTHS - 150 YEARS
Hard Edits:
0.0000 to 200.0000
Code or Value Value Description Count Cumulative Skip to Item
9.6 to 59.4 Range of Values 9281 9281
. Missing 481 9762

BMIARMC - Arm Circumference Comment

Variable Name:
BMIARMC
SAS Label:
Arm Circumference Comment
English Text:
Arm Circumference Comment
Target:
Both males and females 2 MONTHS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Could not obtain 302 302
. Missing 9460 9762

BMXWAIST - Waist Circumference (cm)

Variable Name:
BMXWAIST
SAS Label:
Waist Circumference (cm)
English Text:
Waist Circumference (cm)
Target:
Both males and females 2 YEARS - 150 YEARS
Hard Edits:
0.0000 to 200.0000
Code or Value Value Description Count Cumulative Skip to Item
37.8 to 178.2 Range of Values 8538 8538
. Missing 1224 9762

BMIWAIST - Waist Circumference Comment

Variable Name:
BMIWAIST
SAS Label:
Waist Circumference Comment
English Text:
Waist Circumference Comment
Target:
Both males and females 2 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Could not obtain 369 369
. Missing 9393 9762

BMXTRI - Triceps Skinfold (mm)

Variable Name:
BMXTRI
SAS Label:
Triceps Skinfold (mm)
English Text:
Triceps Skinfold (mm)
Target:
Both males and females 2 MONTHS - 150 YEARS
Hard Edits:
0.0000 to 45.0000
Code or Value Value Description Count Cumulative Skip to Item
3 to 41.4 Range of Values 8944 8944
. Missing 818 9762

BMITRI - Triceps Skinfold Comment

Variable Name:
BMITRI
SAS Label:
Triceps Skinfold Comment
English Text:
Triceps Skinfold Comment
Target:
Both males and females 2 MONTHS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Could not obtain 442 442
2 Exceeds capacity 199 641
3 Hard to obtain 0 641
. Missing 9121 9762

BMXSUB - Subscapular Skinfold (mm)

Variable Name:
BMXSUB
SAS Label:
Subscapular Skinfold (mm)
English Text:
Subscapular Skinfold (mm)
Target:
Both males and females 2 MONTHS - 150 YEARS
Hard Edits:
0.0000 to 45.0000
Code or Value Value Description Count Cumulative Skip to Item
3 to 44 Range of Values 8213 8213
. Missing 1549 9762

BMISUB - Subscapular Skinfold Comment

Variable Name:
BMISUB
SAS Label:
Subscapular Skinfold Comment
English Text:
Subscapular Skinfold Comment
Target:
Both males and females 2 MONTHS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Could not obtain 1232 1232
2 Exceeds capacity 140 1372
3 Hard to obtain 0 1372
. Missing 8390 9762