Using National Health and Nutrition Examination Survey (NHANES) Dietary Supplement Data

1
Using National Health and Nutrition Examination
Survey (NHANES) Dietary Supplement Data
Jaime Wilger
Centers for Disease Control and
Prevention National Center for Health Statistics
2
Sponsor

• Office of Dietary SupplementsNational Institutes
  of HealthBethesda, Maryland 20892 US

3
Office of Dietary Supplements

• The collection of data on dietary supplement
  use is financially supported by the NIH's Office
  of Dietary Supplements. This includes supporting
  the huge amount of labor necessary to get all the
  label information from manufacturers of the
  dietary supplements reported in NHANES and
  converting that information into public use files
  that can be used to analyze dietary supplement
  use in the United States. Additionally, the
  Office of Dietary Supplements supports the
  collection and analysis of numerous nutritional
  biochemistries in the Laboratory component of
  NHANES.

4
NHANES 1999

• Civilian, non-institutionalized household
  population
• Residents of the 50 States and District of
  Columbia
• All ages
• A nationally representative sample of about 5,000
  individuals each year

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NHANES Oversamples(1999-2006)

• African Americans
• Mexican Americans
• Adolescents aged 12-19
• Older persons aged 60
• Pregnant women

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What Dietary Supplements are Americans Taking?

• NHANES is working on answering this question by
• Collecting dietary supplements data from
  participants
• Compiling a Dietary Supplement LABEL database

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Dietary Supplements Flowchart
Household interviews
Field Office/WESTAT
NCHS
Reported supplement labels are found in our
internal database, requested from
manufacturers/distributors, or found on internet.
Dietary Supplement data released to public NHANES
website
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Supplement Use
Survey Total Men Women
NHANES I 71-73 (no ref time) 33 28 38
NHANES II 76-80 (no ref time) 35 32 43
NHANES III 88-94 (30 days) 36 48
NHIS 1986 (2 weeks) 36
NHIS 1987 (past year) 51
NHIS 1992 (past year) 46
CSFII 94-96 (no ref time) 42 56
NHANES 99-00 (30 days) 52 47 57
NHANES 99-02 combined (30 days) adults 18 51 45 57
51
9
Household Interview

• Interviewers ask participants about their use of
  dietary supplements and also about their use of
  antacids.

Have you used or taken any vitamins, minerals,
herbals or other dietary supplements in the past
30 days? Include prescription and
non-prescription supplements.
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Supplement Containers

• If participant says that they have taken a
  dietary supplement then interviewer asks to see
  all supplement containers.
• Containers are seen 88 of the time
• It is very important that containers are seen so
  that supplement names can be recorded accurately
  and completely.

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TRIAL SIZE
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Product Usage Questions

• For how long have you been taking the product or
  a similar type of product?
• In the past 30 days, how many days did you take
  the product?
• On the days that you took the product, how much
  did you usually take on a single day?

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How do we find the actual supplement label that
was reported by participants?

• NCHS nutritionists review supplement names
  recorded by interviewers
• Match reported supplement with supplement in our
  dietary supplement database.
• If supplement is not in our database we obtain
  the product label.
• Matches are made with varying degrees of
  precision.

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Obtaining Supplement Label Data

• If we do not have the supplement label already in
  our database, or the label information is
  outdated we obtain the label by
• Contacting manufacturers and distributors
• Company websites
• Other internet sources
• Physicians Desk Reference

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Matching Supplements

• Exact or near exact match of name
• Close match name not identical to one in
  database, but no other reasonable option exists.
• Generic match supplement has known strength for
  all ingredients, either as part of name (e.g.
  vitamin C 500mg) or because the manufacturer is
  known and we have an identical supplement made by
  this manufacturer for a different distributor or
  retailer.

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Matching Supplements, cont.

1. Entered name could identify two or more
   supplements the supplement name may be
   incomplete or could be complete but other
   supplements of this brand also start with these
   same words.
2. Default match exact supplement could not be
   obtained because the name was imprecise or the
   exact brand supplement could not be located.
3. No match no supplement could be found and not
   enough detail existed for a generic or default
   match to be made.

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Create Generic Products

• Generic supplements all supplement ingredients
  and amounts known.
• Example
• Single or dual ingredient
• calcium 600mg calcium 600 vitamin D 200 IU

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Create default products

• When or if an exact supplement could not be
  obtained because the name was imprecise or the
  exact brand supplement could not be located.
• Based upon
• the most commonly reported strengths for single
  ingredients and most commonly reported brands for
  major multiple ingredient supplements such as
  multivitamins and multivitamins/minerals
• Example
• Multivitamin/Multimineral gtgt Centrum Advance
  Formula High Potency Multivitamin Multimineral
  with Lycopene

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What Information do we enter into our Dietary
Supplement Database?

• Supplement name
• Source of information (manufacturer, distributor,
  and other references such as the Internet and
  PDR.
• Product type (infant/pediatric, prenatal,
  geriatric, standard)
• Ingredient and dosage information
• Manufacturer and Distributor information
• Contact information

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What is entered from the label?
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Update Supplement Information

• We periodically obtain new labels for products
  and compare it to the label in our internal
  dietary supplement database to look for any
  changes in
• Ingredients
• ingredient amounts
• Name of supplement.
• If a product has changed, the date it was changed
  is requested from the manufacturer.

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Data Release

• We release supplement information from our
  dietary supplement database as well as
  participant information collected during the
  interview.
• Data is released in 2 year cycles.

23
Uses for Dietary Supplement Data

• How to determine the prevalence of dietary
  supplement user.
• 2. How to estimate total calcium intake from
  both the dietary supplements and Dietary
  Interview (total Nutrient Intake) data.

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EXAMPLE 1

• Determine prevalence of dietary supplement use.
• Navigating the website
• Download data
• Merge files
• Append different cycle years (1999-2000 AND
  2001-2002 DATA)
• Merge demographic data which also includes
  weight variables, design variables
• Use SAS callable SUDAAN to analyze data

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A. Navigating the Website
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A. Navigating the Website
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A. Navigating the Website
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NHANES Data Files

• Questionnaire files data collected through
  household interview and mobile examination center
  (MEC) interview
• Examination files information collected through
  physical exams, dental exams, and dietary
  interview components  (Note not every survey
  participant agreed to a physical examination)
• Laboratory files results from analyses of blood,
  urine, hair, air, tuberculosis skin test, and
  household dust and water specimens
• Demographics files survey design (e.g. weights,
  design strata) and demographic variables

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A. Navigating the Website
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B. Downloading Data
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B. Downloading Data
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Extract Data and Save as SAS Dataset
The first line of the program assigns a library
name (DSQ_BXP) to the SAS transport file you
downloaded
LIBNAME DSQ_BXP XPORT "C\NHANES\DSQ_B.XPT" LIBN
AME DSQ_B "C\NHANES\DSQ_B" PROC COPY IN
DSQ_BXP OUT DSQ_B RUN
The second line of the program assigns a library
name (DSQ_B) to the permanent data file.

• proc copy to copy your data from the transport
  file to the permanent data file. The in statement
  refers to the directory containing the SAS
  transport file to be copied. The out statement
  refers to the SAS library (directory) into which
  the permanent SAS file will be stored. 

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File 1 Supplement Counts
Variable Name Label
SEQN Respondent sequence number?
DSD010 Any dietary supplements taken?
DSDCOUNT Total of dietary supplements taken
Named DSQ1_B in the 2001-2002 Data and DSQfile1
in the 1999-2000 data
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Flie 2 Supplement Records
Variable Name Label
SEQN Respondent sequence number
DSDSUPID Supplement ID number
DSDSUPP Supplement name
DSD070 Was container seen?
DSDMTCH Matching code
DSD090 How long supplement taken (day)?
DSD103 Days supplement taken, past 30 days
DSD122Q Quantity of supplement taken per day
DSD122U Dosage form
DSDANTA Antacid reported as a dietary supplement
Named DSQ2_B in the 2001-2002 dataand DSQfile2 in
the 1999-2000 data
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File 3 Supplement Information
Variable Name Label
DSDSUPID Supplement ID number
DSDSUPP Supplement name
DSDSRCE Supplement information source
DSDTYPE Formulation type
DSDSERVQ Serving size quantity
DSDSERVU Serving size unit
DSDSERVA Alternative serving size
DSDCNTV Count of vitamins in the supplement
DSDCNTM Count of minerals in the supplement
DSDCNTA Count of amino acids in the supplement
DSDCNTB Count of botanicals in the supplement
DSDCNTO Count of other ingredients in the supplement
Named DSQ3_B in the 2001-2002 dataand DSQfile3 in
the 1999-2000 data
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File 4 Ingredient Information
Variable Name Label
DSDSUPID Supplement ID number
DSDSUPP Supplement name
DSDINGID Ingredient ID
DSDINGR Ingredient name
DSDOPER Ingredient operator(lt,gt,)
DSDQTY Ingredient quantity
DSDUNIT Ingredient unit
DSDCAT Ingredient category
DSDBLFLG Blend flag
Named DSQ4_B in the 2001-2002 data and DSQfile4
in the 1999-2000 data
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File 5 Supplement Blend
Variable Name Label
DSDINGID Ingredient ID number
DSDINGR Ingredient name
DSDBCID Blend component ID
DSDBCNAM Blend component name
DSDBCCAT Blend component category
Named DSQ5_B in the 2001-2002 data and DSQfile5
in the 1999-2000 data
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File 1 Supplement Counts Respondent sequence
number (SEQN) Any dietary supplements taken?
(DSD010) Total of dietary supplements taken?
(DSDCOUNT)
File 2 Supplement Records SEQN Supplement ID
(DSDSUPID) Supplement name (DSDSUPP) Was
Container Seen? (DSD070) Matching code
(DSDMTCH) How long supplement taken (days)?
(DSD090) Day supplement taken, past 30 days
(DSD103) Quantity of supplement taken per day
(DSD122Q) Dosage form (DSD122U) Antacid reported
as dietary supplement (DSDANTA)
SEQN
File 3 Supplement information DSDSUPID DSDSUPP Su
pplement information source (DSDSRCE) Formulation
type (DSDTYPE) Serving size quantity
(DSDSERVQ) Serving size unit (DSDSERVU) Alternativ
e serving size (DSDSERVA) Count of vitamins in
the supplement (DSDCNTV) Count of minerals in the
supplement (DSDCNTM) Count of amino acids in the
supplement (DSDCNTA) Count of botanicals in the
supplement (DSDCNTB) Count of other ingredients
in the supplement (DSDCNTO)
DSDSUPID
File 4 Ingredient information DSDSUPID DSDSUPP In
gredient ID (DSDINGID) Ingredient Name
(DSDINGR) Ingredient operator lt,,gt
(DSDOPER) Ingredient Quantity (DSDQTY) Ingredient
Unit (DSDUNIT) Ingredient category (DSDCAT) Blend
Flag (DSDBLFLG)
File 4 Ingredient information DSDSUPID DSDSUPP In
gredient ID (DSDINGID) Ingredient Name
(DSDINGR) Ingredient operator lt,,gt
(DSDOPER) Ingredient Quantity (DSDQTY) Ingredient
Unit (DSDUNIT) Ingredient category (DSDCAT) Blend
Flag (DSDBLFLG)
DSDSUPID
File 5 Supplement blend DSDINGID DSDINGR Blend
component ID (DSDBCID) Blend component name
(DSDBCNAM) Blend component category (DSDBCCAT)
Data File Structure and Relationships
DSDINGID
39
Indicates if any dietary supplements were taken
File 1
SEQN DSD010 DSDCOUNT
101 (Steve) 1 (Yes) 2
102 (Mary) 2 (No) 0
Indicates the number of dietary supplements taken
Supplement ID
File 2
Supplement Name
SEQN DSDSUPID DSDSUPP DSD070
101 (Steve) 1888340200 Calcium 600 mg Vitamin D 200 IU 1 (Yes)
101 (Steve) 1000228800 Brand X Fat Reducer 1 (Yes)
Indicates whether or not container was seen
The counts of vitamins, minerals, botanicals,
amino acids, and other ingredients in each
supplement
File 3
DSDSUPID DSDSUPP DSDCNTV DSDCNTM DSDCNTB DSDCNTA DSDCNTO
1888340200 Calcium 600 mg Vitamin D 200 IU 1 1 0 0 0
1000228800 Brand X Fat Reducer 0 0 0 0 2
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Indicates if there is a blend in the supplement
Ingredient Category
Ingredient ID
Ingredient Name
Ingredient Quantity and Unit
File 4
DSDSUPID DSDSUPP DSDINGID DSDINGR DSDQTY DSDUNIT DSDCAT DSDBLFLG
1888340200 Calcium 600 mg Vitamin D 200 IU 10000070 Calcium 600.00 1 (MG) Mineral 2 (Not a Blend)
1888340200 Calcium 600 mg Vitamin D 200 IU 10000385 Vitamin D 200.00 2 (IU) Vitamin 2 (Not a Blend)
1000228800 Brand X Fat Reducer 10001227 Chitozyme 1200.00 1 (MG) Other 1 (BLEND)
Blend ingredient ID, name, category
File 5
DSDINGID DSDINGR DSDBCID DSDBCNAM DSDSBCCAT
10001227 Chitozyme 10000317 Psyllium Seed Husks Botanical
10001227 Chitozyme 10000642 Chitosan Other
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C. Program Merging files
/Sorting File 1 and File 2 in the 2001-2002 data
by the respondent number/ PROC SORT DATA
DSQ_B.DSQ1_b BY SEQN RUN PROC SORT DATA
DSQ_B.DSQ2_B BY SEQN RUN /Merging File 1 and
File 2 in the 2001-2002 data by the respondent
number/ DATA F1_2 MERGE DSQ_B.DSQ1_b
DSQ_B.DSQ2_B BY SEQN RUN
SORT File 1 and File 2 by SEQN
MERGE File 1 and File 2 by SEQN
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C. Program Merging files
SORT that last file in which FILE 1 and FILE 2
were merged, by DSDSUPID as well as File 3

• /Sorting F1_2 and File 3 in the 2001-2002 data
  by the Supplement ID number/
• PROC SORT DATA F1_2
• BY DSDSUPID
• RUN
• PROC SORT DATA DSQ_B.DSQ3_B
• (File 3 in the 2001-2002 data)
• BY DSDSUPID
• RUN
• /Merging F1_2 and File 3 in the 2001-2002 data
  by the Supplement ID number /
• DATA F1_3
• MERGE F1_2 DSQ_B.DSQ3_B
• BY DSDSUPID
• RUN
• /Sorting F1_3 and File 4 in the 2001-2002 data
  by the Supplement ID number/
• PROC SORT DATA DSQ_B.DSQ4_B
• (File 4 in the 2001-2002 data)

MERGE FILE1 and 2 with FILE 3 by DSDSUPID
SORT FILE 4 by DSDSUPID
MERGE FILE 1 ,2, 3 with FILE 4 by DSDSUPID
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C. Program Merging files

• /Sorting F1_4 and File 5 in the 2001-2002 data
  by the Ingredient ID number/
• PROC SORT DATA F1_4
• BY DSDINGID
• RUN
• PROC SORT DATA DSQ_B.DSQ5_B
• BY DSDINGID
• RUN
• /Merging F1_4 and File 5 in the 2001-2002 data
  by the Ingredient ID number /
• proc sql
• create table DS01_02 as
• select
• from dsq_b.dsq5_b as h,
• F1_4 as m
• where h.dsdsupidm.dsdsupid

SORT FILE 1,2,3,4 by DSDSUPID
SORT FILE 5 by DSDSUPID
MERGE FILE 1 ,2, 3, 4 with FILE 5 by DSDINGID
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D. Appending 1999-2000 and 2001-2002 Data

• DATA ALLDATA
• SET DS01_02 DS99_00
• RUN

APPEND 1999-2000 AND 2001-2002 DATA
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Variables in Demographic File
Variable Label
RIAGENDR Gender
RIDAGEYR Age in years
RIDRETH1 Race/ethnicity
SDMVPSU Masked Variance Pseudo-PSU
SDMVSTRA Masked Variance Pseudo-Stratum
WTINT4YR 4 year Interview Weight
WTINT2YR 2 year Interview Weight
46
E. Adding Demographic Data
APPEND demographic data from 1999-2000 and
2001-2002.

• DATA DEMO
• SET DSQ.DEMO (1999-2000 Demographic data)
• DSQ_B.DEMO_B(2001-2002 Demographic data)
• RUN
• PROC SORT DATADEMO
• BY SEQN
• RUN
• PROC SORT DATAALLDATA
• BY SEQN
• RUN
• DATA DEMO_DS
• MERGE DEMO ALLDATA
• BY SEQN
• RUN

SORT demographic data file and the Dietary
Supplements Data from 1999-2000 and 2001-2002.
MERGE demographic data file and the Dietary
Supplements Data from 1999-2000 and 2001-2002,
by SEQN
47
F. SAS callable SUDAAN

• PROC CROSSTAB DATADEMO_DS" FILETYPESAS
  DESIGNWR
• NEST SDMVSTRA SDMVPSU
• WEIGHT WTINT4YR
• SUBPOPN RIDAGEYR (age) gt18/ NAME"ADULTS"
• SUBGROUP RIAGENDR (gender) DSD010(yes or no to
  taking dietary supplement)
• LEVELS 2 4
• TABLES DSD010RIAGENDR
• RUN

Use the nest statement with strata and PSU to
account for the design effect.
Use the weight statement to account for the
survey design, oversampling, non-response and
post stratification.
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Example 2

• 2. Estimate daily intake of Calcium to the diet.
  Combining dietary supplements to total nutrient
  intake from foods.
• Calculate total calcium intake from supplements
  for each participant.
• Merge Food Data files with Dietary Supplement
  Data file
• limitations and issues

49
A. Calculating total Calcium per participant
First we are out all supplement users in which
calcium is an ingredient in the supplement (s)
used.

• DATA CALCIUM
• SET DS01_02
• IF DSD0101 (took a supplement) AND
  DSDINGID10000070 (the Ingredient ID for Calcium)
  THEN OUTPUT
• RUN

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Calculate the amount that was actually taken by
the participant.
Multiply the amount of the serving size taken by
the amount of calcium in the supplement

• DATA CALCIUM1
• SET CALCIUM
• SSCALCIUM DSD122Q / DSDSERVQ
• if DSDINGID10000070 then totalcal
  SSCALCIUMdsdqty
• if (dsdunit5)then total totalcal 1000
• else if (DSDunit 1) then total totalcal
• RUN

Multiply the amount of the serving size taken by
the amount of calcium in the supplement
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A. Calculating total Calcium per participant

• DATA FinalCa
• SET Calcium1
• BY SEQN
• IF FIRST.SEQN THEN TOTCAL0
• TOTCALTOTAL
• IF LAST.SEQN
• RUN

This code adds up the calcium intake for each
participant
52
Merge file with total calcium for each
participant with File 1 and File 2 by respondents
number.

• DATA DS_Calcium
• MERGE FINALCA (KEEPSEQN TOTCAL) DSQ_B.DSQ1_B
  DSQ_B.DSQ2_B DEMO
• BY SEQN
• RUN

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B. Merge Food Data files with Dietary Supplement
Data file
Dietary supplement total calcium file

• DATA COMBINE
• MERGE DS_CALCIUM RECALL.DRXTOT_B
• BY SEQN
• TOTALCALCIUM DRXTCALC TOTCAL
• RUN

Dietary Interview Total Nutrient Intakes File
New Total Calcium Variable
Dietary Interview total calcium variable
Dietary supplement total calcium variable
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C. Limitations and Issues

• Different reference periods for the Dietary
  Supplement Data collection (past 30 days) and the
  Dietary Interview (past 24-hours)
• Assume Dietary Supplements were taken daily
• Analysts must be aware of differences in
  1999-2000 and 2001-2002 dietary supplements data

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Strengths of Data

• Nationally representative sample
• In-person interview
• Transcription of supplement name and manufacturer
  information from supplement container (88 of the
  time)

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Limitations of Data

• Short reference time frame of the past month/ 30
  days
• Recording supplement names from labels is still
  subject to error.
• Analytic verification of supplements actual
  ingredient content would be required to
  accurately depict nutrient content.

57
Acknowledgements

• Office of Dietary SupplementsNational Institutes
  of HealthBethesda, Maryland 20892 US
• NCHS, Kathy Radimer

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Stage 1 Counties
Stage 2 Segments
Stage 3 Households
Stage 4 SPs
OP96017
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Formatting Variables - 2001-2002 data

• PROC FORMAT CNTLINDSQ_B.DSQFMT_B
• PROC DATASETS LIBDSQ_B
• MODIFY DSQ1_B
• FORMAT DSD010 DSD010F.
• FORMAT DSDCOUNT DSDCNTF.
• MODIFY DSQ2_B
• FORMAT DSDSUPP DSDSUPF.
• FORMAT DSD070 DSD070F.
• FORMAT DSDMTCH DSDMTCHF.
• FORMAT DSD122U DSD122UF.
• FORMAT DSDANTA DSDANTAF.
• MODIFY DSQ3_B
• FORMAT DSDSUPP DSDSUPF.
• FORMAT DSDSRCE DSDSRCEF.
• FORMAT DSDTYPE DSDTYPEF.
• FORMAT DSDSERVU DSDSRVF.
• MODIFY DSQ4_B
• FORMAT DSDSUPP DSDSUPF.
• FORMAT DSDINGR DSDINGF.

60
Merging formats for 1999-2000 and 2001-2002 Data
Data dsqfmt_combined set dsq_b.dsqfmt_b
dsq.dsqfmt run proc sort datadsqfmt_combined
nodupkey by fmtname start proc format
cntlindsqfmt_combined run