Using National Health and Nutrition Examination Survey (NHANES)

Dietary Supplement Data

Centers for Disease Control and PreventionNational Center for Health Statistics

Jaime Wilger

Sponsor

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

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.

Office of Dietary Supplements

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

NHANES Oversamples(1999-2006):

• African Americans

• Mexican Americans

• Adolescents aged 12-19

• Older persons aged 60+

• Pregnant women

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

Dietary Supplements Flowchart

h i

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

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%

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.”

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.

TRIAL SIZE

PLUS IRON

Complete

WITH ESSENTIAL MINERALS

WITH ESSENTIAL MINERALS

Complete

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?

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.

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

Matching Supplements

1. Exact or near exact match of name;

2. Close match; name not identical to one in database, but no other reasonable option exists.

3. 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.

Matching Supplements, cont.

4. 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.

5. Default match; exact supplement could not be obtained because the name was imprecise or the exact brand supplement could not be located.

6. No match; no supplement could be found and not enough detail existed for a generic or default match to be made.

Create Generic Products

• Generic supplements: all supplement ingredients and amounts known.

• Example:– Single or dual ingredient

• calcium 600mg; calcium 600 + vitamin D 200 IU

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 >> Centrum Advance

Formula High Potency Multivitamin Multimineral with Lycopene

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

What is entered from the label?

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.

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.

Uses for Dietary Supplement Data

1. 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.

EXAMPLE 1

1. Determine prevalence of dietary supplement use.

A. Navigating the website

B. Download data

C. Merge files

D. Append different cycle years (1999-2000 AND 2001-2002 DATA)

E. Merge demographic data – which also includes weight variables, design variables

F. Use SAS callable SUDAAN to analyze data

A. Navigating the Website

A. Navigating the Website

A. Navigating the Website

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

A. Navigating the Website

B. Downloading Data

B. Downloading Data

LIBNAME DSQ_BXP XPORT "C:\NHANES\DSQ_B.XPT";

LIBNAME DSQ_B "C:\NHANES\DSQ_B";

PROC COPY IN= DSQ_BXP OUT= DSQ_B ;

RUN;

Extract Data and Save as SAS Dataset

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. 

The first line of the program assigns a library name (DSQ_BXP) to the SAS transport file you downloaded

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

Flie 2: Supplement RecordsVariable Name LabelSEQN 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

File 3: Supplement InformationVariable Name LabelDSDSUPID 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

File 4: Ingredient Information

Variable Name LabelDSDSUPID Supplement ID number

DSDSUPP Supplement name

DSDINGID Ingredient ID

DSDINGR Ingredient name

DSDOPER Ingredient operator(<,>,=)

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

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

File 1: Supplement CountsRespondent sequence number (SEQN)Any dietary supplements taken? (DSD010)Total # of dietary supplements taken? (DSDCOUNT)

File 2: Supplement RecordsSEQNSupplement 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)

File 3: Supplement informationDSDSUPIDDSDSUPPSupplement information source (DSDSRCE)Formulation type (DSDTYPE)Serving size quantity (DSDSERVQ)Serving size unit (DSDSERVU)Alternative 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)

File 4: Ingredient informationDSDSUPIDDSDSUPPIngredient ID (DSDINGID)Ingredient Name (DSDINGR)Ingredient operator <,=,> (DSDOPER)Ingredient Quantity (DSDQTY)Ingredient Unit (DSDUNIT)Ingredient category (DSDCAT)Blend Flag (DSDBLFLG)

File 5: Supplement blendDSDINGIDDSDINGRBlend component ID (DSDBCID)Blend component name (DSDBCNAM)Blend component category (DSDBCCAT)

File 4: Ingredient informationDSDSUPIDDSDSUPPIngredient ID (DSDINGID)Ingredient Name (DSDINGR)Ingredient operator <,=,> (DSDOPER)Ingredient Quantity (DSDQTY)Ingredient Unit (DSDUNIT)Ingredient category (DSDCAT)Blend Flag (DSDBLFLG)

DSDSUPID

SEQN

DSDINGID

DSDSUPID

Data File Structure and Relationships

SEQN DSD010 DSDCOUNT

101 (Steve) 1 (Yes) 2

102 (Mary) 2 (No) 0

File 1

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)

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

File 2

File 3

Indicates if any dietary supplements were taken

Indicates the number of dietary supplements taken

Supplement ID

Supplement Name

Indicates whether or not container was seen

The counts of vitamins, minerals, botanicals, amino acids, and other ingredients in each supplement

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)

DSDINGID DSDINGR DSDBCID DSDBCNAM DSDSBCCAT

10001227 Chitozyme 10000317 Psyllium Seed Husks

Botanical

10001227 Chitozyme 10000642 Chitosan Other

File 4

File 5

Ingredient ID

Ingredient Name

Ingredient Quantity and Unit

Indicates if there is a blend in the supplement

Ingredient Category

Blend ingredient ID, name, category

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

C. Program – Merging files*/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)• BY DSDSUPID;• RUN;

*/Merging F1_3 and File 4 in the 2001-2002 data by the Supplement ID number */• proc sql; • create table file1_4 as • select * • from dsq_b.dsq4_b as h, • F1_3 as m • where h.dsdsupid=m.dsdsupid;

SORT that last file in which FILE 1 and

FILE 2 were merged, by

DSDSUPID as well as File 3

MERGE FILE1 and 2 with FILE 3 by

DSDSUPID

SORT FILE 4 by DSDSUPID

MERGE FILE 1 ,2, 3 with FILE 4 by

DSDSUPID

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.dsdsupid=m.dsdsupid;

MERGE FILE 1 ,2, 3, 4 with FILE 5 by

DSDINGID

SORT FILE 1,2,3,4 by DSDSUPID

SORT FILE 5 by DSDSUPID

D. Appending 1999-2000 and 2001-2002 Data

• DATA ALLDATA;• SET DS01_02 DS99_00;

• RUN; APPEND 1999-2000 AND 2001-

2002 DATA

Variables in Demographic FileVariable LabelRIAGENDR 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

E. Adding Demographic Data• DATA DEMO;• SET DSQ.DEMO (1999-2000

Demographic data) DSQ_B.DEMO_B(2001-2002

Demographic data);• RUN;• PROC SORT DATA=DEMO;• BY SEQN;• RUN;• PROC SORT DATA=ALLDATA;• BY SEQN;• RUN;• DATA DEMO_DS;• MERGE DEMO ALLDATA;• BY SEQN;• RUN;

APPEND demographic data from 1999-2000 and 2001-2002.

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

F. SAS callable SUDAAN• PROC CROSSTAB DATA=“DEMO_DS" FILETYPE=SAS

DESIGN=WR;• NEST SDMVSTRA SDMVPSU;• WEIGHT WTINT4YR;

• SUBPOPN RIDAGEYR (age) >=18/ NAME="ADULTS";• SUBGROUP RIAGENDR (gender) DSD010(yes or no to

taking dietary supplement);• LEVELS 2 4;• TABLES DSD010*RIAGENDR;• 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.

Example 2

2. Estimate daily intake of Calcium to the diet. Combining dietary supplements to total nutrient intake from foods.

A. Calculate total calcium intake from supplements for each participant.

B. Merge Food Data files with Dietary Supplement Data file

C. limitations and issues

A. Calculating total Calcium per participant

• DATA CALCIUM;• SET DS01_02;

• IF DSD010=1 (took a supplement) AND DSDINGID=10000070 (the Ingredient ID for Calcium) THEN OUTPUT;

• RUN;

First we are out all supplement users in which calcium

is an ingredient in the supplement

(s) used.

• DATA CALCIUM1;• SET CALCIUM;• SSCALCIUM = DSD122Q / DSDSERVQ;

• if DSDINGID=10000070 then totalcal = SSCALCIUM*dsdqty;

• if (dsdunit=5)then total = totalcal * 1000;

• else if (DSDunit = 1) then total = totalcal;

• RUN;

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

Multiply the amount of the

serving size taken by the amount of

calcium in the supplement

A. Calculating total Calcium per participant

• DATA FinalCa;• SET Calcium1;• BY SEQN;• IF FIRST.SEQN THEN TOTCAL=0;• TOTCAL+TOTAL;• IF LAST.SEQN;• RUN;

This code adds up the calcium intake

for each participant

• DATA DS_Calcium;• MERGE FINALCA (KEEP=SEQN TOTCAL) DSQ_B.DSQ1_B DSQ_B.DSQ2_B DEMO;

• BY SEQN;• RUN;

Merge file with total calcium for each participant

with File 1 and File 2 by respondents

number.

B. Merge Food Data files with Dietary Supplement Data file

• DATA COMBINE;• MERGE DS_CALCIUM RECALL.DRXTOT_B;

• BY SEQN;• TOTALCALCIUM = DRXTCALC + TOTCAL

• RUN;

Dietary Interview Total Nutrient Intakes

File

Dietary supplement total

calcium file

Dietary supplement total calcium variable

Dietary Interview total calcium

variable

New Total Calcium Variable

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

Strengths of Data

• Nationally representative sample

• In-person interview

• Transcription of supplement name and manufacturer information from supplement container (88% of the time)

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.

Acknowledgements

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

• NCHS, Kathy Radimer

Stage 4SPs

Stage 1Counties Stage 2

Segments

Stage 3Households

OP96017

Formatting Variables - 2001-2002 data

• PROC FORMAT CNTLIN=DSQ_B.DSQFMT_B ;• PROC DATASETS LIB=DSQ_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. ;• FORMAT DSDUNIT DSDUNTF. ;• FORMAT DSDCAT DSDCATF. ;• FORMAT DSDBLFLG DSDBLF. ; • MODIFY DSQ5_B;• FORMAT DSDINGR $DSDINGF. ;• FORMAT DSDBCCAT DSDCATF. ;• FORMAT DSDBCNAM $BCNAMF. ;• QUIT;• OPTIONS LS=240;

Merging formats for 1999-2000 and 2001-2002 Data

Data dsqfmt_combined;

set dsq_b.dsqfmt_b dsq.dsqfmt;

run;

proc sort data=dsqfmt_combined nodupkey;

by fmtname start;

proc format cntlin=dsqfmt_combined;

run;