Table of Contents

Component Description

Spirometry, which means “the measuring of breath,” is a routinely used clinical pulmonary function test. It measures the amount and speed of air that a person can exhale after taking in the deepest possible breath. This allows estimates for lung volume and air flow rates to be made. Results from Spirometry testing are one key element (among others) needed to diagnose respiratory disorders, such as asthma and chronic obstructive pulmonary disease (COPD). These diseases are typically characterized by a reduction in expiratory air flow rates. This is defined in spirometry as a reduction in the ratio of the expiratory volume measured in the 1st second of a forceful exhalation (FEV1) to the total volume of air exhaled in a complete forced expiration (FVC), the FVC being an estimate of the individual's effective lung volume. The "Spirometric Measurements Section" of the NHANES 2011-12 Respiratory Health Spirometry Procedures Manual contains a basic explanation of interpreting spirometry data.

Spirometry is one of two NHANES 2011-12 components on respiratory health sponsored by the National Heart, Lung, and Blood Institute of the National Institute of Health, the Centers for Disease Control and Prevention, National Center for Health Statistics and the National Institute for Occupational Safety and Health (NIOSH). Individual Exhaled Nitrous Oxide (ENO), a marker of airways inflammation, is also measured. The objective of the Spirometry data collection is to provide health examination data to estimate the current prevalence of asthma and COPD in the U.S. population. The data is also intended to help produce updated spirometric reference data for the U.S. population. National-level Spirometry data was collected in NHANES I (1971-1975), NHANES II (1976-1980), NHANES III (1988-1994) and most recently in NHANES 2007-10. Comparisons of the current data with that from previous studies will help to identify trends in respiratory conditions over time.

Eligible participants performed an initial or "baseline" 1st test spirometry examination. Then a selected subsample of participants whose Baseline 1st Test Spirometry results showed a FEV1/FVC ratio below the lower limit of normal and/or below 70% were asked to repeat spirometry after inhaling a β2-adrenergic bronchodilator medication to open up their airways. This helps differentiate asthma from COPD (Pellegrino, Viegi, Brusasco, et al. 2005). Asthma patients usually show improvements in post-bronchodilator spirometry testing, while patients with COPD exhibit little, if any, response to the medication. Spirometric testing using β2-adrenergic bronchodilator is routinely employed by clinicians to diagnose asthma in both children and adults, and current clinical practice guidelines (NHLBI Expert Panel Report, 2007) consider post-bronchodilator spirometry testing is essential for the initial diagnosis of asthma. Second test post bronchodilator spirometry studies had not been performed in previous NHANES surveys.

 

Eligible Sample

Survey participants aged 6 to 79 years were eligible for the Spirometry Component. Specific exclusion criteria used for Baseline Spirometry included criteria employed in earlier NHANES. Excluded from testing were examinees that had current chest pain or a physical problem with forceful expiration, were taking supplemental oxygen, had recent surgery of the eye, chest or the abdomen, heart attack, stroke, tuberculosis exposure, or had recently coughed up blood. Adults with a personal history of detached retina or a collapsed lung and children with painful ear infections were also excluded. In NHANES 2011-12, Baseline (1st test) Spirometry data was collected for 7,173 sample persons.

Participants completing Baseline spirometry were only selected for follow-up Bronchodilator 2nd Test Spirometry if their baseline spirometry values indicated possible airflow obstruction that might indicate the presence of asthma or COPD. The participant's baseline spirometry results were evaluated by a computerized algorithm and examinees with an FEV1/FVC% less than the Lower Limit of Normal (LLN) determined for his or her age, sex, weight, height, and race/ethnicity, or those who had a FEV1/FVC% less than 70% were considered eligible for bronchodilator testing. These two criteria were used so that NHANES data could be compared with previous epidemiology studies that used these two different formulas. For the first criterion the LLN for the FEV1/FVC was calculated based on the sample person's age, gender, height and race/ethnicity in three major groups (non-Hispanic white, non-Hispanic black, Mexican-American). For participants aged 8-79 the FEV1/FVC% LLN was as defined by NHANES III data (Hankinson, Odencrantz, Fedan, 1999) and for children aged 6-7 it was as defined by Wang et al. (1993). The administrative variable SPDBRONC indicates whether the participant was considered eligible for Bronchodilator 2nd Test Spirometry. The variable SPXBSTAT provides the bronchodilator study exam status.

Participants eligible for Bronchodilator 2nd Test Spirometry were referred to the Mobile Examination Center (MEC) Physician for further evaluation as documented in the Respiratory Health Bronchodilator Procedures Manual. The Bronchodilator testing protocol was explained and the participant was further screened for the presence of any exclusion criteria for bronchodilator administration. These included certain cardiovascular conditions (uncontrolled blood pressure, irregular pulse on examination, taking medication for major arrhythmia, having an implanted defibrillator, or history of congenital heart disease) or taking certain prescription medications (a monamine oxidase inhibitor, an anticonvulsant, a tricyclic antidepressant plus current treatment for cardiac disease, potassium lowering drugs). Examinees were also excluded from bronchodilator administration if they had already recently taken a β2-adrenergic bronchodilator, or had a previous adverse reaction to albuterol. Women who were pregnant or breastfeeding were also excluded.

Following eligibility screening, the MEC physician obtained written informed consent and administered two puffs of the β2-adrenergic bronchodilator albuterol. The examinee was then required to wait a minimum of ten minutes before proceeding to the Spirometry exam room to obtain a repeat 2nd Test Bronchodilator spirometry study. In NHANES 2011-12 a total of 457 participants performed Bronchodilator (2nd Test) Spirometry.

 

Protocol and Procedure

Testing procedures met the recommendations of the American Thoracic Society (ATS) (Miller, Hankinson, Brusasco el al. 2005). The protocol was similar to that used in NHANES III (1998-1994); however, there was one change. In NHANES 2011-12 the health Technician's goal was to obtain three acceptable quality spirometry maneuvers, whereas in NHANES III the Technician's goal was to obtain five acceptable maneuvers. To ensure data comparability between NHANES cycles, the same spirometers that were employed for the NHANES III spirometry examination (1988-1994) were used for NHANES 2011-12 data collection. These were Ohio 822/827 dry-rolling seal volume spirometers. The devices were reconditioned for use in the current survey and were maintained by the NIOSH laboratories. In NHANES 2011-12, unlike NHANES III, a new in-line biological filter (A-M Systems PFT Filter Kit B) was fitted to each spirometry hose to minimize infection risks to the participant.

Spirometry was performed in the standing position unless the participant was physically limited. The participant was asked to elevate the chin and extend the neck slightly and place a nose clip on his or her nose during testing, the latter to prevent air leaks. He/she was then instructed to perform a series of maximal forced expiratory maneuvers. In each maneuver, the participant took the deepest breath possible to fill the lungs with air, then put the mouthpiece into his/her mouth making a tight seal and then blew the air out as hard and fast as possible. Participants, aged 6-10 years were asked to blow out the air for a minimum of 3 seconds of exhalation, whereas those aged 11-79 years were asked to blow out the air for a minimum of 6 seconds of exhalation.

Spirometry testing for an individual continued until he/she was able to achieve a reproducible spirogram, or until a maximum of eight spirometry curves had been obtained, or until the participant could not continue. The overall goal was for the participant to achieve three acceptable exhalation maneuvers by ATS criteria in which the two highest values for the FVC and the FEV1 (each taken from an acceptable forced expiratory maneuver) showed minimal variability: i.e. the two largest FVC values taken from 2 acceptable curves should agree within 150 ml, and similarly for the two largest values for the FEV1. The procedure for the Bronchodilator (2nd Test) Spirometry, performed after the participant had taken the β2-adrenergic bronchodilator albuterol, was identical to the procedure for the Baseline 1st test. Please refer to the NHANES 2011-12 Repiratory Health Spirometry Procedure manual for full details on the testing protocol, and for detailed criteria for a reproducible spirogram.

 

Quality Assurance & Quality Control

The NIOSH Division of Respiratory Disease Studies served as the NHANES Spirometry training and quality control consultant. Each MEC Health Technician received formal training and satisfactorily completed the NIOSH-approved spirometry course. Additionally, all NHANES spirometry data were reviewed by expert reviewers at the NIOSH quality control center on an ongoing basis. MEC Technicians received continuous feedback on their performance throughout the survey.

The Respiratory Health Spirometry Procedures Manual provides detailed descriptions of the quality assurance and quality control measures that were used for the NHANES 2011-12 Spirometry examination. The Chief Health Technician at each MEC monitored ongoing staff performance in the field. Health technician performance was also monitored using direct observation at periodic site visits by NIOSH consultants and project officers from Westat (the data collection contractor) and NHANES. Spirometry equipment was calibrated through regularly scheduled quality control checks by the Health Technicians. These were verified by supervisory staff.

 

Data Processing and Editing

All spirometry data collected were reviewed by expert consultants at the NIOSH quality control center where data processing and editing were performed to ensure internal data consistency.

 

Analytic Notes

Summary results datasets are provided for both 1st and 2nd test Spirometry. These give the single best (highest) overall value for the following parameters taken from reproducible curves. Note that in this dataset, an individual best value for a specific variable could be taken from any of the individual acceptable curves that the participant performed. The summary data set format is similar to that previously released for the NHANES III data. The spirometry summary data release variables are:

SPXNFVC FVC: Forced Vital Capacity, ml (estimated lung volume)
SPXNEV EV (ml): Extrapolated Volume, ml.
SPXNFEV5 FEV0.5: Forced Expiratory Volume 1st 1/2 Second
SPXNFEV7 FEV0.75: Forced Expiratory Volume 1st 3/4 Second
SPXNFEV1 FEV1: Forced Expiratory Volume 1st Second
SPXNFEV3 FEV3: Forced Expiratory Volume 1st 3 Seconds
SPXNFEV6 FEV6 (ml): Forced Expiratory Volume 1st 6 Seconds
SPXNPEF PEF: Peak Expiratory Flow Rate, ml/sec
SPXNF257 FEF25-75%: Forced Expiratory Flow Rate, Mid Exhalation, ml/sec
SPXNFET FET: Forced Expiratory Time, sec

In addition, each summary dataset contains the following administrative variables:

The Number of Acceptable Curves
FVC Quality Rating
FEV1 Quality Rating
Examinee Effort Quality Rating

The following administrative variables are provided to support analysis of the summary best-test spirometry datasets.

SPDBRONC: This is an administrative variable indicating whether a participant was considered eligible for bronchodilator and 2nd Test spirometry. The reference values used in determining SPDBRONC were derived from prediction equations (described earlier) based on age, race, gender, and height values available at examination time. As a result of data editing prior to public release some of these values changed. Additionally, when this protocol was developed, specific equations were not available for the non-Mexican American Hispanic population, categorized as “Other Hispanic” in NHANES public release files, and the non-Hispanic, non-black, non-white population, categorized as “Other Race” in NHANES public release files. Using public release values, other prediction equations, and /or alternate race classifications for the prediction equations may result in differences in bronchodilator eligibility.

When using 2nd test spirometry data, analysts may choose to use SPDBRONC, or they may use the publicly-released values for age, race, gender and height. Additionally, analysts can use equations now available and/or other criteria for determining bronchodilator eligibility.

FEV1 and FVC Quality Codes: These variables rate the quality of the summary best-test FEV1 and FVC values. The variables are SPXNQFVC and SPXNQFV1 for 1st Test Spirometry and SPXBQFVC and SPXBQFV1 for 2nd Test Spirometry. Quality of the FEV1 and FVC estimates was rated on a scale from A-F defined as follows:

A= Exceeds ATS data collection standards: 3 acceptable curves present and 2 reproducible curves; 2 observed values within 100 ml.
B= Meets ATS data collection standards: 3 acceptable curves present and 2 reproducible curves; 2 observed values within 150 ml.
C= Potentially usable value, but does not meet all ATS standards. Estimates usually based on 2 curve results with values within 200 ml. of each other.
D= Questionable result, use with caution
F= Results not valid

For those who want to perform analytic studies using data that excludes subjects that may not have perfect data, they should simply use data only with FEV1 and FVC quality grades A and B. Grade C indicates less than a perfect test, for example instances where there are only 2 acceptable curves achieved but where the data most likely represents a value where the subject made a maximal effort. Generally data with quality grades D and F are not used for data analysis. In the NHANES 2011-12 data collection 85% of baseline spirometry summary best-test FVC estimates were of quality A or B, and 95% were of quality A, B, or C. For FEV1, 88% of summary best-test FVC estimates were of quality A or B, and 96% were of quality A, B, or C.

Additional Variables Relating to Data Quality: The summary spirometry datasets also provide a variable for the number of acceptable spirometry curves achieved by the participant judged by ATS criteria. These are the variables SPDNACC for Baseline 1st Test Spirometry and SPDBACC for Bronchodilator 2nd Test Spirometry. Also, data providing a summary rating of the overall spirometry curve quality for the participant are provided by the variables SPXNQEFF and SPXBQEFF.

Spirometry Exam Status Codes:Baseline 1st Test Spirometry has an overall exam status code (SPXNSTAT) which provides analysts with a single variable to identify those survey participants with complete or partial spirometry exams, those who were excluded from spirometry, or those who were eligible for spirometry but for whom the exam was not done. A similar variable (SPXBSTAT) is provided for the subset of participants who were selected for Bronchodilator 2nd Test Spirometry. For these variables a complete exam is defined as one in which both the best-test FEV1 and FVC estimates had quality ratings of A, B, or C. Partial exams are exams with any other spirometry data collected that was of lesser quality.

Spirometry Exam Comment Codes:Comment codes were added by the MEC Health Technicians, during data collection, to document the reasons why it was only possible to collect partial exam data for participants, and to document the reasons why Spirometry exams were not done if a participant was otherwise eligible. The comment code variable for Baseline 1st Test Spirometry is SPXNCMT, and for Bronchodilator 2nd test Spirometry it is SPXBCMT. Analysts may wish to review the comment code information for the Spirometry data prior to specific types of data analysis.

Sample Weights: The NHANES MEC examination sample weights, i.e., the full sample 2-Year MEC Exam Weight (WTMEC2YR), should be used to analyze the 2011-12 spirometry 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.

Additional 2011-12 NHANES Data on Respiratory Health: The raw data for the spirometry curves attempted by each participant in the NHANES 2011-12 Spirometry Component is released in a separate dataset (SPXRAW_G). The raw data permits users to graph a participant's spirometry test curves. It is also intended for the use of data analysts who may want to perform more advanced modeling studies using the raw data. Data files can be combined with the 2007-12 datasets to provide a larger dataset for analysis.

The NHANES 2011-12 Respiratory Health Component also included testing for Exhaled Nitric Oxide (ENX_G), and Household Interview Questionnaire data on a prior diagnosis of asthma and COPD (MCQ_G), recent respiratory symptoms such as cough and wheezing (RDQ_G), data for the participant's current prescription medications (RXQ_RX_G; RXQ_DRUG_G), and data for occupational risk factors for COPD (OCQ_G).

 

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 6 YEARS - 79 YEARS

ENQ010 - Breathing problem require oxygen?

Variable Name:
ENQ010
SAS Label:
Breathing problem require oxygen?
English Text:
{Do you/Does SP} currently have a breathing problem that requires {you/him/her} to use supplemental oxygen during the day? [This is air stored in a tank that you use to help you breathe. Do not include night treatments for sleep apnea.]
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 41 41 SPAENA
2 No 7152 7193
7 Refused 0 7193 SPAENA
9 Don't know 0 7193 SPAENA
. Missing 302 7495

ENQ020 - Problem taking deep breath?

Variable Name:
ENQ020
SAS Label:
Problem taking deep breath?
English Text:
{Do you/Does SP} now have any pain or physical problem that may prevent {you/him/her} from taking a deep breath and exhaling forcefully?
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 66 66 SPAENA
2 No 7084 7150
7 Refused 0 7150 SPAENA
9 Don't know 2 7152 SPAENA
. Missing 343 7495

SPQ010 - Have a current painful ear infection?

Variable Name:
SPQ010
SAS Label:
Have a current painful ear infection?
English Text:
{Do you/Does SP} now have a painful ear infection?
Target:
Both males and females 6 YEARS - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 7 7 SPAENA
2 No 1893 1900
7 Refused 0 1900 SPAENA
9 Don't know 3 1903 SPAENA
. Missing 5592 7495

SPQ020 - Have you/Has SP ever had eye surgery?

Variable Name:
SPQ020
SAS Label:
Have you/Has SP ever had eye surgery?
English Text:
{Have you/Has SURVEY PARTICIPANT} ever had eye surgery? [Do not include cosmetic surgery on the eyelid or skin around the eye]
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 577 577
2 No 6505 7082 SPQ040
7 Refused 0 7082
9 Don't know 1 7083
. Missing 412 7495

SPQ030 - Eye surgery in the last 3 months?

Variable Name:
SPQ030
SAS Label:
Eye surgery in the last 3 months?
English Text:
Was the eye surgery in the last three months?
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 27 27 SPAENA
2 No 551 578
7 Refused 0 578 SPAENA
9 Don't know 0 578 SPAENA
. Missing 6917 7495

SPQ040 - Ever had open chest/abdominal surgery?

Variable Name:
SPQ040
SAS Label:
Ever had open chest/abdominal surgery?
English Text:
{Have you/Has SP} ever had open chest or abdominal surgery?
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 1043 1043
2 No 6013 7056 SPQ060
7 Refused 0 7056
9 Don't know 1 7057
. Missing 438 7495

SPQ050 - Chest/abdominal surgery last 3 months?

Variable Name:
SPQ050
SAS Label:
Chest/abdominal surgery last 3 months?
English Text:
Was the open chest or abdominal surgery in the last three months?
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 34 34 SPAENA
2 No 1010 1044
7 Refused 0 1044 SPAENA
9 Don't know 0 1044 SPAENA
. Missing 6451 7495

SPQ060 - Tuberculosis in last year?

Variable Name:
SPQ060
SAS Label:
Tuberculosis in last year?
English Text:
Did {you/SP} or anyone in {your/his/her} household have tuberculosis in the past year?
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 24 24 SPAENA
2 No 6999 7023
7 Refused 0 7023 SPAENA
9 Don't know 2 7025 SPAENA
. Missing 470 7495

SPQ070a - Ever told had an aneurysm?

Variable Name:
SPQ070a
SAS Label:
Ever told had an aneurysm?
English Text:
Has a doctor or other health professional ever told {you/SP}that {you/he/she} had . . .
English Instructions:
MARK ALL THAT APPLY
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 An aneurysm? 36 36 SPAENA
77 Refused 0 36 SPAENA
99 Don't know 1 37 SPAENA
. Missing 7458 7495

SPQ070b - Ever told had a collapsed lung?

Variable Name:
SPQ070b
SAS Label:
Ever told had a collapsed lung?
English Text:
Has a doctor or other health professional ever told {you/SP}that {you/he/she} had . . .
English Instructions:
MARK ALL THAT APPLY
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2 a collapsed lung? 39 39 SPAENA
. Missing 7456 7495

SPQ070c - Ever told had a detached retina?

Variable Name:
SPQ070c
SAS Label:
Ever told had a detached retina?
English Text:
Has a doctor or other health professional ever told {you/SP}that {you/he/she} had . . .
Target:
Both males and females 16 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3 a detached retina? 38 38 SPAENA
. Missing 7457 7495

SPQ070d - Ever told had a stroke?

Variable Name:
SPQ070d
SAS Label:
Ever told had a stroke?
English Text:
Has a doctor or other health professional ever told {you/SP}that {you/he/she} had . . .
Target:
Both males and females 16 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
4 a stroke? 103 103 SPQ080
. Missing 7392 7495

SPQ070e - Ever told had a heart attack?

Variable Name:
SPQ070e
SAS Label:
Ever told had a heart attack?
English Text:
Has a doctor or other health professional ever told {you/SP}that {you/he/she} had . . .
Target:
Both males and females 16 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5 a heart attack? 110 110 SPQ090
. Missing 7385 7495

SPQ080 - Stroke in the last 3 months?

Variable Name:
SPQ080
SAS Label:
Stroke in the last 3 months?
English Text:
Did this stroke happen in the last three months?
Target:
Both males and females 16 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 6 6 SPAENA
2 No 89 95
7 Refused 0 95 SPAENA
9 Don't know 0 95 SPAENA
. Missing 7400 7495

SPQ090 - Heart attack in last 3 months?

Variable Name:
SPQ090
SAS Label:
Heart attack in last 3 months?
English Text:
Was {your/SP's} heart attack in the last three months?
Target:
Both males and females 16 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 1 1 SPAENA
2 No 93 94
7 Refused 0 94 SPAENA
9 Don't know 0 94 SPAENA
. Missing 7401 7495

SPQ100 - Coughed up blood past month?

Variable Name:
SPQ100
SAS Label:
Coughed up blood past month?
English Text:
In the past month, {have you/has SP} coughed up blood?
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 22 22 SPAENA
2 No 6874 6896
7 Refused 0 6896 SPAENA
9 Don't know 1 6897 SPAENA
. Missing 598 7495

SPAENA - Check item

Variable Name:
SPAENA
SAS Label:
Check item
English Text:
Check item SPAENA
English Instructions:
If answered No in SPQ010, SPQ030, SPQ050, SPQ060, SPQ080, SPQ090, SPQ100, ENQ010, ENQ020, and Missing in SPQ070a, SPQ070b, SPQ070c set Spirometry to eligible, Otherwise set Spirometry Not Done/Safety Exclusion.
Target:
Both males and females 6 YEARS - 79 YEARS

ENQ100 - Had respiratory illness?

Variable Name:
ENQ100
SAS Label:
Had respiratory illness?
English Text:
In the past 7 days, {have you/has SP} had a cough, cold, phlegm, runny nose or other respiratory illness? Do not count allergies or hay fever.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 1299 1299
2 No 5529 6828
7 Refused 0 6828
9 Don't know 4 6832
. Missing 663 7495

SPXNSTAT - Spirometry First Test Status

Variable Name:
SPXNSTAT
SAS Label:
Spirometry First Test Status
English Text:
Spirometry First Test Status (Baseline Spirometry)
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Complete Exam 6344 6344
2 Partial Exam 351 6695
3 Not Done 437 7132
4 Safety Exclusion 363 7495
. Missing 0 7495

SPXNCMT - Spirometry First Test Comment

Variable Name:
SPXNCMT
SAS Label:
Spirometry First Test Comment
English Text:
Spirometry First Test Comment (Baseline Spirometry)
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Safety exclusion 0 0
2 SP refusal 70 70
3 No time 15 85
4 Physical limitation 34 119
5 Communication problem 21 140
6 Equipment failure 3 143
7 SP ill/emergency 14 157
14 Interrupted 1 158
21 Reached maximum number of ENO trials 0 158
51 SP unable to comply 11 169
56 Came late/left early 225 394
72 Error (technician/software/supply) 1 395
84 SP with child 33 428
99 Other 81 509
122 Language barrier 23 532
. Missing 6963 7495

SPXNFVC - Baseline FVC (mL)

Variable Name:
SPXNFVC
SAS Label:
Baseline FVC (mL)
English Text:
Baseline 1st Test Spirometry, Forced Vital Capacity, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
592 to 7863 Range of Values 6652 6652
. Missing 843 7495

SPXNEV - Baseline Extrapolated Volume (mL)

Variable Name:
SPXNEV
SAS Label:
Baseline Extrapolated Volume (mL)
English Text:
Baseline 1st Test Spirometry, Extrapolated Volume, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 285 Range of Values 6650 6650
. Missing 845 7495

SPXNFEV5 - Baseline FEV 0.5 (mL)

Variable Name:
SPXNFEV5
SAS Label:
Baseline FEV 0.5 (mL)
English Text:
Baseline 1st Test Spirometry, Forced Expiratory Volume in the first 0.5 seconds, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
301 to 5633 Range of Values 6652 6652
. Missing 843 7495

SPXNFEV7 - Baseline FEV 0.75 (mL)

Variable Name:
SPXNFEV7
SAS Label:
Baseline FEV 0.75 (mL)
English Text:
Baseline 1st Test Spirometry, Forced Expiratory Volume in the first 0.75 seconds, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
371 to 6537 Range of Values 6652 6652
. Missing 843 7495

SPXNFEV1 - Baseline FEV 1 (mL)

Variable Name:
SPXNFEV1
SAS Label:
Baseline FEV 1 (mL)
English Text:
Baseline 1st Test Spirometry, Forced Expiratory Volume in the first 1.0 second, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
409 to 6923 Range of Values 6652 6652
. Missing 843 7495

SPXNFEV3 - Baseline FEV 3 (mL)

Variable Name:
SPXNFEV3
SAS Label:
Baseline FEV 3 (mL)
English Text:
Baseline 1st Test Spirometry, Forced Expiratory Volume in the first 3.0 seconds, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
560 to 7526 Range of Values 6652 6652
. Missing 843 7495

SPXNFEV6 - Baseline FEV 6 (mL)

Variable Name:
SPXNFEV6
SAS Label:
Baseline FEV 6 (mL)
English Text:
Baseline 1st Test Spirometry, Forced Expiratory Volume in the first 6.0 seconds, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
592 to 7766 Range of Values 6652 6652
. Missing 843 7495

SPXNPEF - Baseline PEF (mL/s)

Variable Name:
SPXNPEF
SAS Label:
Baseline PEF (mL/s)
English Text:
Baseline 1st Test Spirometry, Peak Expiratory Flow Rate, in mL/s.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
901 to 19024 Range of Values 6652 6652
. Missing 843 7495

SPXNF257 - Baseline FEF 25-75% (mL/s)

Variable Name:
SPXNF257
SAS Label:
Baseline FEF 25-75% (mL/s)
English Text:
Baseline 1st Test Spirometry, Forced Expiratory Flow Rate 25-75%, in mL/s.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
124 to 9280 Range of Values 6652 6652
. Missing 843 7495

SPXNFET - Baseline Forced Expiratory Time (s)

Variable Name:
SPXNFET
SAS Label:
Baseline Forced Expiratory Time (s)
English Text:
Baseline 1st Test Spirometry, Forced Expiratory Time, in seconds.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.1 to 28.6 Range of Values 6652 6652
. Missing 843 7495

SPXNQFVC - Baseline FVC Quality Attribute

Variable Name:
SPXNQFVC
SAS Label:
Baseline FVC Quality Attribute
English Text:
Baseline 1st Test Spirometry, Forced Vital Capacity Quality Attribute.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
A Exceeds ATS data collection standards 4104 4104
B Meets ATS data collection standards 1562 5666
C Potentially usable value, but does not meet all ATS standards 718 6384
D Questionable result, use with caution 249 6633
F Results not valid 63 6696
< blank > Missing 799 7495

SPXNQFV1 - Baseline FEV1 Quality Attribute

Variable Name:
SPXNQFV1
SAS Label:
Baseline FEV1 Quality Attribute
English Text:
Baseline 1st Test Spirometry, Forced Expiratory Volume in the first 1.0 second Quality Attribute
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
A Exceeds ATS data collection standards 4267 4267
B Meets ATS data collection standards 1618 5885
C Potentially usable value, but does not meet all ATS standards 547 6432
D Questionable result, use with caution 216 6648
F Results not valid 48 6696
< blank > Missing 799 7495

SPDNACC - Baseline Number of Acceptable Curves

Variable Name:
SPDNACC
SAS Label:
Baseline Number of Acceptable Curves
English Text:
Baseline 1st Test Spirometry, Number of Acceptable Curves Performed (ATS Criteria)
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 12 Range of Values 6696 6696
. Missing 799 7495

SPXNQEFF - Baseline Effort Quality Attribute

Variable Name:
SPXNQEFF
SAS Label:
Baseline Effort Quality Attribute
English Text:
Baseline 1st Test Spirometry, Effort Quality Attribute
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
A All 6 spirometry quality curve attributes are acceptable 6116 6116
B The curves had a large time to peak flow or a non-repeatable peak flow 223 6339
C The curves had either < 6 seconds of exhalation or no plateau 347 6686
D The curves had either a cough or large extrapolated volume 0 6686
< blank > Missing 809 7495

SPDBRONC - Selected for Bronchodilator

Variable Name:
SPDBRONC
SAS Label:
Selected for Bronchodilator
English Text:
Best test FEV1/FVC ratio below Lower Limit of Normal and/or less than 70%
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 842 842
2 No 5853 6695
. Missing 800 7495

SPXBSTAT - Spirometry Second Test Status

Variable Name:
SPXBSTAT
SAS Label:
Spirometry Second Test Status
English Text:
Spirometry Second Test Status (Post-Bronchodilator Spirometry)
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Complete Exam 456 456
2 Partial Exam 1 457
3 Not Done 218 675
4 Safety Exclusion 167 842
. Missing 6653 7495

SPXBCMT - Spirometry Second Test Comment

Variable Name:
SPXBCMT
SAS Label:
Spirometry Second Test Comment
English Text:
Spirometry Second Test Comment (Post-Bronchodilator Spirometry)
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2 SP refusal 115 115
3 No time 4 119
4 Physical limitation 1 120
5 Communication problem 3 123
7 SP ill/emergency 2 125
27 Proxy no information 2 127
51 SP unable to comply 7 134
99 Other 70 204
. Missing 7291 7495

SPXBFVC - 2nd Test FVC (mL)

Variable Name:
SPXBFVC
SAS Label:
2nd Test FVC (mL)
English Text:
Bronchodilator 2nd Test Spirometry, Forced Vital Capacity, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1204 to 6899 Range of Values 457 457
. Missing 7038 7495

SPXBEV - 2nd Test Extrapolated Volume (mL)

Variable Name:
SPXBEV
SAS Label:
2nd Test Extrapolated Volume (mL)
English Text:
Bronchodilator 2nd Test Spirometry, Extrapolated Volume, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
10 to 165 Range of Values 457 457
. Missing 7038 7495

SPXBFEV5 - 2nd Test FEV 0.5 (mL)

Variable Name:
SPXBFEV5
SAS Label:
2nd Test FEV 0.5 (mL)
English Text:
Bronchodilator 2nd Test Spirometry, Forced Expiratory Volume in the first 0.5 seconds, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
574 to 3987 Range of Values 457 457
. Missing 7038 7495

SPXBFEV7 - 2nd Test FEV 0.75 (mL)

Variable Name:
SPXBFEV7
SAS Label:
2nd Test FEV 0.75 (mL)
English Text:
Bronchodilator 2nd Test Spirometry, Forced Expiratory Volume in the first 0.75 seconds, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
677 to 4864 Range of Values 457 457
. Missing 7038 7495

SPXBFEV1 - 2nd Test FEV 1 (mL)

Variable Name:
SPXBFEV1
SAS Label:
2nd Test FEV 1 (mL)
English Text:
Bronchodilator 2nd Test Spirometry, Forced Expiratory Volume in the first 1.0 second, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
741 to 5378 Range of Values 457 457
. Missing 7038 7495

SPXBFEV3 - 2nd Test FEV 3 (mL)

Variable Name:
SPXBFEV3
SAS Label:
2nd Test FEV 3 (mL)
English Text:
Bronchodilator 2nd Test Spirometry, Forced Expiratory Volume in the first 3.0 seconds, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
985 to 6435 Range of Values 457 457
. Missing 7038 7495

SPXBFEV6 - 2nd Test FEV 6 (mL)

Variable Name:
SPXBFEV6
SAS Label:
2nd Test FEV 6 (mL)
English Text:
Bronchodilator 2nd Test Spirometry, Forced Expiratory Volume in the first 6.0 seconds, in mL.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1139 to 6767 Range of Values 457 457
. Missing 7038 7495

SPXBPEF - 2nd Test PEF (mL/s)

Variable Name:
SPXBPEF
SAS Label:
2nd Test PEF (mL/s)
English Text:
Bronchodilator 2nd Test Spirometry, Peak Expiratory Flow Rate, in mL/s.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1575 to 13551 Range of Values 457 457
. Missing 7038 7495

SPXBF257 - 2nd Test FEF 25-75% (mL/s)

Variable Name:
SPXBF257
SAS Label:
2nd Test FEF 25-75% (mL/s)
English Text:
Bronchodilator 2nd Test Spirometry, Forced Expiratory Flow Rate 25-75%, in mL/s.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
246 to 5164 Range of Values 457 457
. Missing 7038 7495

SPXBFET - 2nd Test Forced Expiratory Time (s)

Variable Name:
SPXBFET
SAS Label:
2nd Test Forced Expiratory Time (s)
English Text:
Bronchodilator 2nd Test Spirometry, Forced Expiratory Time, in seconds.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.1 to 23.3 Range of Values 457 457
. Missing 7038 7495

SPXBQFVC - 2nd Test FVC Quality Attribute

Variable Name:
SPXBQFVC
SAS Label:
2nd Test FVC Quality Attribute
English Text:
Bronchodilator 2nd Test Spirometry, Forced Vital Capacity Quality Attribute.
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
A Exceeds ATS data collection standards 321 321
B Meets ATS data collection standards 107 428
C Potentially usable value, but does not meet all ATS standards 28 456
D Questionable result, use with caution 1 457
F Results not valid 0 457
< blank > Missing 7038 7495

SPXBQFV1 - 2nd Test FEV1 Quality Attribute

Variable Name:
SPXBQFV1
SAS Label:
2nd Test FEV1 Quality Attribute
English Text:
Bronchodilator 2nd Test Spirometry, Forced Expiratory Volume in the first 1.0 second Quality Attribute
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
A Exceeds ATS data collection standards 334 334
B Meets ATS data collection standards 90 424
C Potentially usable value, but does not meet all ATS standards 33 457
D Questionable result, use with caution 0 457
F Results not valid 0 457
< blank > Missing 7038 7495

SPDBACC - 2nd Test Number of Acceptable Curves

Variable Name:
SPDBACC
SAS Label:
2nd Test Number of Acceptable Curves
English Text:
Bronchodilator 2nd Test Spirometry, Number of Acceptable Curves Performed (ATS Criteria)
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2 to 8 Range of Values 457 457
. Missing 7038 7495

SPXBQEFF - 2nd Test Effort Quality Attribute

Variable Name:
SPXBQEFF
SAS Label:
2nd Test Effort Quality Attribute
English Text:
Bronchodilator 2nd Test Spirometry, Effort Quality Attribute
Target:
Both males and females 6 YEARS - 79 YEARS
Code or Value Value Description Count Cumulative Skip to Item
A All 6 spirometry quality curve attributes are acceptable 444 444
B The curves had a large time to peak flow or a non-repeatable peak flow 3 447
C The curves had either < 6 seconds of exhalation or no plateau 10 457
D The curves had either a cough or large extrapolated volume 0 457
< blank > Missing 7038 7495