Cambridge, MA 

Lexington, MA 

Hadley, MA 

Bethesda, MD 

Chicago, IL 

Abt Associates Inc. 

Suite 800 North 

4550 Montgomery Avenue 

Bethesda, MD 20814-3343 

The Study of 

Thimerosal and 

Autism 

Documentation and 

Codebook for the 

Main Analysis File: 

September 3, 2010 

Prepared for 

Frank DeStefano 

National Immunization 

Program 

Centers for Disease Control 

and Prevention 

Atlanta, GA 30329 

Prepared by 

Cristofer Price 

Yeqin He 
This documentation was prepared by Cristofer Price and Yeqin He of Abt Associates Inc. 

for the Immunization Safety Office (ISO) of the Centers for Disease Control and 

Prevention (CDC) Atlanta, GA 30333. Questions about the documentation, substantive 

questions, or technical issues regarding the data file should be directed to the CDC ISO, 

MS D26, 1600 Clifton Road, Atlanta, Georgia 30333 (404-639-8256). 

Suggested Citation for Study of Thimerosal and Autism Public Use Data Set: 

Price, C.S., He, Y. (2010) The Study of Thimerosal and Autism: Data Set 

Documentation. Bethesda MD: Abt Associates, Inc; Prepared for the National 

Immunization Program Centers for Disease Control and Prevention Atlanta, GA 

Abt Associates Inc. 1 
Documentation and Codebook
 

for the
 

Main Analysis File
 

1. Introduction to the Main Analysis File..................................................................... 2
 

2. List of the Variables Included on the Data Set......................................................... 4
 

3. Variable Descriptions............................................................................................... 10
 

4. Reproducing Results from the Technical Report.................................................... 27
 

1. Introduction to the Main Analysis File 

The Thimerosal and Autism Main Analysis File (hereafter called the Main Analysis File) 

is analytical file that was used for the primary analyses1 of the Study of Thimerosal and 

Autism. The study design, data sources, analyses and results are explained in detail in the 

Thimerosal and Autism Technical Reports, Volumes I and II (hereafter called the 

Technical Report), which is also included on the public use CD. 

The Main Analysis File is one of four data files included in the data set. The Main 

Analysis File contains n=1,095 records, corresponding to one record per participant child. 

The remaining three data files contained within the set are provided to give researchers a 

rich source of data on the timing, sources, and amount of prenatal and postnatal exposure 

to ethylmercury from thimerosal-containing vaccines and immune globulin preparations. 

1 All results reported in “Price, C.S., Thompson, W.W., Goodson, Ph.D., B., Weintraub, E.S., Croen, L.A., 

Hinrichsen, V.L., Marcy, M., Robertson, A., Eriksen, E., Lewis, E., Bernal, P., Shay, D., Davis, R.L., 

DeStefano, F. Prenatal and Infant Exposure to Thimerosal from Vaccines and Immunoglobulins and Risk 

of Autism Pediatrics published online: September 13, 2010 (doi: 10.1542/peds.year.2010-0309) can be 

reproduced using the Main Analysis File. Additionally, analyses reported in the Technical Report Chapters 

9, 11, 12, 15, 19, 20, and Sections 21.2 and 21.3 also used this data set. Due to the sensitive nature of the 

information, the indicator variable for use of cocaine or narcotics during pregnancy (the variable 

“PreNatIllDrug”) has been omitted from the Main Analysis File. That variable was used a covariate for 

models of outcomes “ASD-not-AD” and “AD with screened controls”. Therefore results from models fit to 

the data from the Main Analysis file will differ slightly from those reported in the Technical Report for 

these two outcomes. Analyses based both study participants and non-participants, e.g. Chapters 13, 14, 22 

and part of Chapter 5, used sampling frame data which are not included in the public use data set. 

Replication of results in Chapter 16 will require the use of both the Main Analysis File, and the Child 

Vaccination Histories File. Some of the analyses reported in Chapter 17 used data from medical charts or 

parent interviews that are not needed for replication of any of the main analyses, and are not included in the 

public use data set. Analyses results shown Technical Report Chapter 18 were based on the Child Body 

Weights File. 

Abt Associates Inc. 2 
Those data sets are explained in the documents titled “Documentation and Codebook for 

the Prenatal Ethlymercury Exposures File”, “Documentation and Codebook for the Child 

Vaccination Histories File”, and “Documentation and Codebook for the Child Body 

Weights File” 

The remainder of the current document is organized as follows. Section 2 is a listing 

showing the names, labels, minimum, maximum, and number of missing values for each 

of the numeric variables included in the Analysis File. The listing of variables in Section 

2 is intended to give the user a quick overview of the variables included in the file. 

Section 3 provides detail on the data sources, valid values, and construction of the 

variables included in the file. Section 4 provides information that will help data users to 

reproduce results presented in the Technical Report. This section includes example SAS 

code that can be used to reproduce the results shown Section 19, “Detail of Model 

Results” of Volume II of the Technical Report 

Abt Associates Inc. 3 
2. List of the Variables Included on the Data Set
 

Exhibit 2.1. List of Variables Included in the Analysis File 

Variable Label n 

n 

Miss Min Max 

Data Management Variables 

ChildID ID for merging files 1095 0 1 1095 

DS_ASD_Main =1 if ASD Main Data Set 1095 0 1 99 

DS_AD_Main =1 if AD Main Data Set 1095 0 1 99 

DS_ASD_Only =1 if ASD Only Data Set 1095 0 1 99 

DS_ASD_Regr =1 if ASD w/Regression data set 1095 0 1 99 

DS_AD_ExLoIQ =1 if AD w/Lo IQ Excluded data set 1095 0 1 99 

DS_ASD_TCln =1 if ASD T Clean Data Set 1095 0 1 99 

DS_AD_TCln =1 if AD T Clean Data Set 1095 0 1 99 

StatusCode 1=full participant control, 2=full participant ASD case, 

3=Full participant below criteria case 1095 0 1 3 

InElig_Cntrl =1 if control ineligible 1095 0 0 1 

MatchStrat Matching Stratum 1095 0 2 48 

weight1 weight1 DS_ASD_main=1 1008 87 0.333 1.8 

weight2 weight2 DS_AD_main=1 911 184 0.273 1.5 

weight3 weight3 DS_ASD_only=1 773 322 0.136 1.5 

weight4 weight4 DS_ASD_Regr=1 701 394 0.115 1 

weight5 weight5 DS_AD_ExLoIQ=1 884 211 0.273 1.5 

weight6 weight6 DS_ASD_TCln=1 821 274 0.5 3 

weight7 weight7 DS_AD_TCln=1 728 367 0.3 3 

Outcome Indicators 

ASD_Outc =1 if ASD/AD, =0 Cntr, .=exclude 1018 77 0 1 

ASD_time =1 if ASD/AD, =2 Cntr, .=exclude 1018 77 1 2 

AD_Outc =1 if AD, =0 Cntr, .=exclude 949 146 0 1 

AD_time =1 if AD, =2 Cntr, .=exclude 949 146 1 2 

ASD_Only =1 if ASD only, =0 Cntr, .=exclude 831 264 0 1 

ASD_Only_time =1 if ASD only, =2 Cntr, .=exclude 831 264 1 2 

ASD_Regr =1 if ASD w/Regress,=0 Cntr 701 394 0 1 

ASD_Regr_Time =1 if ASD w/Reg, =2 if Cntr,=. exclude 701 394 1 2 

AD_ExLoIQ =1 if AD w/Lo IQ Excluded,=0 Cntr 884 211 0 1 

Abt Associates Inc. 4 
Exhibit 2.1. List of Variables Included in the Analysis File 

n 

Variable Label n Miss Min Max 

AD_ExLoIQ_Time =1 if AD w/IQ excluded, =2 if Cntr,=. exclude 884 211 1 2 

ASD_TCln =1 if ASD/AD, =0 Tot Cln Cntr, .=exclude 828 267 0 1 

ASD_TCln_time =1 if ASD/AD, =2 Tot Cln Cntr, .=exclude 828 267 1 2 

AD_TCln =1 if AD/AD, =0 Tot Cln Cntr, .=exclude 759 336 0 1 

AD_TCln_time =1 if AD/AD, =2 Tot Cln Cntr, .=exclude 759 336 1 2 

Exposure Variables 

PreNatThimer PreNat Exp Amt 1095 0 0 100 

PreNatThimer_Alt PreNat Exp Amt (Alt) 1095 0 0 111 

Exp01mos Amt/Wt(KGs) birth-28 days 1095 0 0 21 

Exp17mos Amt/Wt(KGs) 29-214 days 1095 0 0 66.9 

Exp07mos Amt/Wt(KGs) birth-214 days 1095 0 0 66.9 

Exp020mos Amt/Wt(KGs) birth-609 days 1095 0 0 76.7 

Amt01mos Amt Merc birth-28 days 1095 0 0 50 

Amt17mos Amt Merc 29-214 days 1095 0 0 188 

Amt07mos Amt Merc birth-214 days 1095 0 0 191 

Amt020mos Amt Merc birth-609 days 1095 0 0 300 

AbExp01mos Concur Amt/Wt(KGs) birth-28 days 1095 0 0 6.77 

AbExp07mos Concur Amt/Wt(KGs) birth-214 days 1095 0 0 54.9 

AbExp17mos Concur Amt/Wt(KGs) 29-214 days 1095 0 0 54.9 

AbExp020mos Concur Amt/Wt(KGs) birth-609 days 1095 0 0 54.9 

AbAmt01mos Concur Amt Merc birth-28 days 1095 0 0 12.5 

AbAmt07mos Concur Amt Merc birth-214 days 1095 0 0 188 

AbAmt17mos Concur Amt Merc 29-214 days 1095 0 0 188 

AbAmt020mos Concur Amt Merc birth-609 days 1095 0 0 188 

ncAbExp01mos NonConcur Amt/Wt(KGs) birth-28 days 1095 0 0 21 

ncAbExp07mos NonConcur Amt/Wt(KGs) birth-214 days 1095 0 0 65.2 

ncAbExp17mos NonConcur Amt/Wt(KGs) 29-214 days 1095 0 0 65.2 

ncAbExp020mos NonConcur Amt/Wt(KGs) birth-609 days 1095 0 0 70.3 

ncAbAmt01mos NonConcur Amt Merc birth-28 days 1095 0 0 50 

ncAbAmt07mos NonConcur Amt Merc birth-214 days 1095 0 0 191 

ncAbAmt17mos NonConcur Amt Merc 29-214 days 1095 0 0 188 

ncAbAmt020mos NonConcur Amt Merc birth-609 days 1095 0 0 300 

AbDays01mos # days on Abiots birth-28 days 1095 0 0 28 

Abt Associates Inc. 5 
Exhibit 2.1. List of Variables Included in the Analysis File 

n 

Variable Label n Miss Min Max 

AbDays07mos # days on Abiots 1-214 days 1095 0 0 69 

AbDays17mos # days on Abiots 29-214 days 1095 0 0 69 

AbDays020mos # days on Abiots birth-609 days 1095 0 0 216 

AnyAb01mos =1 if any Abiots 01 mos 1095 0 0 1 

AnyAb07mos =1 if any Abiots 07 mos 1095 0 0 1 

AnyAb17mos =1 if any Abiots 17 mos 1095 0 0 1 

AnyAb020mos =1 if any Abiots 020 mos 1095 0 0 1 

PreNatAllMerc Prenatal exposure from multiple sources 1095 0 0 5 

General Information about Child 

SexMale =1 if Sex=Male 1095 0 0 1 

AgeAtPIYrs Age in Years at Par Interview, from IQ_Status.sas 1095 0 5.903 13.2 

Ravens_Score_n Cases only-Score if given Raven, from IQ_Status.sas 298 797 6 140 

Mullen_Age Cases only-IQ Age equiv if given Mullen, from IQ_Status.sas 21 1074 0.917 5.5 

RatioIQ (Mullen_age/AgeAtPIYrs)*100, from IQ_Status.sas 21 1074 8.806 69.6 

LowIQ =1 if Ravens_Score<35 or Mullen RatioIQ<35, from IQ_Status.sas 321 774 0 1 

ScreenOut =1 if should be excluded from screened control group analyses 1095 0 0 1 

Q11 ADIR Loss of Lang Skills, see Regression_Status.sas 321 774 0 8 

Q12b_SkillsLost # skills lost in ADIR Q12b, see Regression_Status.sas 317 778 0 7 

Q12b_skillsprior # skills before 24 mos in ADIR Q12b 13 1082 3 7 

Q12b_PctLost % skills lost in ADIR Q12b 13 1082 14 100 

Regression =1 if Regression (loss of lang/skills), created in Regression_Status.sas 321 774 0 1 

Older_aut_sib =1 if child has older autistic sibling 1095 0 0 1 

MC_epilepsy_230 230: Epilepsy/seizures/convulsions (specify) 1095 0 0 1 

MC_CerePal_212 212: Cerebral Palsy 1095 0 0 1 

MC_HearingDis_233 233: Hearing disorder (specify) 1095 0 0 1 

MC_VisImp_261 261: Visual Impairment 1095 0 0 1 

DownsSyndrome 1 if down syndrome dx in med chart 1095 0 0 1 

MC_Neuro_243 243: Neurofibromatosis 1095 0 0 1 

MC_PKU_250 250: PKU 1095 0 0 0 

MC_CMV_225 225: CMV 1095 0 0 0 

MC_DevDelay_227 227: Developmental delay, other (specify) 1095 0 0 1 

PI_DevDelay Any other developmental delay, such as mental retardation 1095 0 0 1 

MC_AbPain_214 214: Chronic abdominal pain/cramps before age 3 1095 0 0 0 

Abt Associates Inc. 6 
Exhibit 2.1. List of Variables Included in the Analysis File 

n 

Variable Label n Miss Min Max 

MC_bloating_215 215: Chronic bloating before age 3 1095 0 0 0 

MC_celiac_216 216: Chronic celiac disease before age 3 1095 0 0 0 

MC_const_217 217: Chronic constipation before age 3 1095 0 0 1 

MC_FoodInt_218 218: Chronic food intolerance before age 3 (specify) 1095 0 0 1 

MC_gastroenteritis_219 219: Chronic gastroenteritis before age 3 1095 0 0 1 

MC_MalAbs_220 220: Chronic malabsorption before age 3 1095 0 0 0 

MC_diarrhea_221 221: Chronic/recurrent diarrhea before age 3 1095 0 0 1 

MC_enteritis_222 222: Chronic regional enteritis before age 3 1095 0 0 0 

MC_VomitColic_224 224: Chronic vomiting/colic before age 3 1095 0 0 1 

Covariates: Child and Family Characteristics 

BWLt1k =1 if Birth wgt < 1 Kg 1095 0 0 1 

BW1_1p5k =1 if Birth wgt 1.0 Kg to 1.499 Kg 1095 0 0 1 

BW1p5_2p5k =1 if Birth wgt 1.5 Kg to 2.499 Kg 1095 0 0 1 

BW2p5_4k =1 if Birth wgt 2.5 Kg to 3.999 Kg 1095 0 0 1 

BW4kup =1 if Birth wgt 4.0 Kg and up 1095 0 0 1 

BwgtCat 1=<1kg;2=1-1.4999;3=1.5-2.4999;4=2.5-3.999;5=ge4kg 1095 0 1 5 

PovertyRatio_imp =1 if missing value imputed 1095 0 0 1 

PovertyRatio1 Ratio of household income to poverty line. 1095 0 0.185 20 

MomEduc 0=NoHSDip;1=HS_GED;2=SomeCollege;3= CollDegree(BA, Associate's or above) 1095 0 0 3 

momeduc_imp =1 if momeduc imputed 1 1094 1 1 

MomEduc_NoHS =1 if Mom has no HS diploma 1095 0 0 1 

MomEduc_HS =1 if Mom HS Grad 1095 0 0 1 

MomEduc_Some =1 if Mom Some Coll 1095 0 0 1 

MomEduc_Coll =1 if Mom Coll Grad 1095 0 0 1 

SingleParent Child lives in a single parent household(0/1) 1095 0 0 1 

MomAgeCat 1=lt20;2=20-24;3=25-29;4=30-34;5=ge35 1095 0 1 5 

MomLt20 Mom Age at child birth lt 20 1095 0 0 1 

Mom20_24 Mom Age at child birth 20 - 24 1095 0 0 1 

Mom25_29 Mom Age at child birth 25 - 29 1095 0 0 1 

Mom30_34 Mom Age at child birth 30 - 34 1095 0 0 1 

MomGE35 Mom Age at child birth ge 35 1095 0 0 1 

BioDadAge_Imp =1 if missing value imputed 1095 0 0 1 

BioDadAgeCat_1 1=0-19, 2=20-29, 3=30-39, 4=40-49, 5=49+ 1095 0 1 5 

Abt Associates Inc. 7 
Exhibit 2.1. List of Variables Included in the Analysis File 

n 

Variable Label n Miss Min Max 

Dadlt20_i1 Dad <20 years old 1095 0 0 1 

Dad20_29_i1 Dad 20-29 years old 1095 0 0 1 

Dad30_39_i1 Dad 30-39 years old 1095 0 0 1 

Dad40_49_i1 Dad 40-49 years old 1095 0 0 1 

DadGE49_i1 Dad >49 years old 1095 0 0 1 

BirthOrder_Imp Imputation indicator for birth order 1095 0 0 1 

BirthOrderCat_1 1=1st,2=2nd,3=3rd or higher 1095 0 1 3 

BirthOrder1_1 =1 if 1st born 1095 0 0 1 

BirthOrder2_1 =1 if 2nd born 1095 0 0 1 

BirthOrderGE3_1 =1 if 3rd born or higher 1095 0 0 1 

Multiple =1 if twin or triplet (this variable omitted from file) 1095 0 0 1 

BFNone =1 if Breastfed 0 months 1095 0 0 1 

BF1_6mos =1 if Breastfed 1-5.99 months 1095 0 0 1 

BFgt6mos =1 if Breastfed 6+ months 1095 0 0 1 

BFMthsCat Breastfed: 1=lt 1mo;2=1-5.99;3=6+mos 1095 0 0 2 

Covariates: Child Birth Conditions 

C5APGAR 5-minute APGAR score 1095 0 5 10 

BirthAsphyxia =1 if Birth asphyxia 1095 0 0 1 

RespDistress =1 if Resp Distress Syndrome (hyaline) 1095 0 0 1 

Bilirubin =1 if hyperbilirubinemia 1095 0 0 1 

Covariates: Prenatal non-vaccine exposures 

PreNatNicotine_Imp =1 if missing value imputed 1095 0 0 1 

PreNatNicotine_1 =1 if any tobacco use: pregnancy 1095 0 0 1 

PreNatAlcohol_Imp =1 if missing value imputed 3 1092 1 1 

PreNatAlcohol_1 0=Never,1=Occasional,2=light,3=moderate 1095 0 0 3 

PreNatTuna Prenatal Tuna (0=none, 1=moderate, 2=high) 1095 0 0 2 

PreNatTuna_Imp =1 if missing value imputed 1095 0 0 1 

PreNatOceanFresh Hi Prenatal OceanFresh (1= ate other OceanFresh often or very often) 1095 0 0 1 

PreNatOceanFresh_Imp =1 if missing value imputed 1095 0 0 1 

PreNatFish =1 if PreNatTuna=Hi or PreNatOceanFresh in(Often,VeryOften) 1095 0 0 1 

PreNatFish_Imp =1 if missing value imputed 1095 0 0 1 

PreNatOthMerc_Any =1 if any prenat non-vac merc exposures 1095 0 0 1 

PreNatFillings_Imp =1 if missing value imputed 1095 0 0 1 

Abt Associates Inc. 8 
Exhibit 2.1. List of Variables Included in the Analysis File 

n 

Variable Label n Miss Min Max 

PreNatFillings_1 0=None,1=Have(noWrk,Grnd,gum)2=Have(YesWrk,Grnd or Gum) 1095 0 0 2 

PreNatLead_Imp =1 if PreNatResiLead_imp or PreNatOccupLead_imp = 1 1095 0 0 1 

PreNatLead_1 =1 if PreNatResiLead or PreNatOccupLead=1 1095 0 0 1 

PreNatIllDrug =1 if Cocaine or Narcotic use during pregnancy (This variable omitted from file) 1095 0 0 1 

PreNatValproic Used Prenatal Valproic acid 1095 0 0 1 

Folic_PNVit_Multi =1 if Folic,PreNatVit or Multivit prenatally 1095 0 0 1 

PreNatViralInf =1 if any viral infections during pregnancy 1095 0 0 1 

Covariates: Child Medical Condition 

Anemia =1 if anemia 6-30 mos 1095 0 0 1 

Enceph =1 if Encephalitis or any CNS infection <36mos 1095 0 0 1 

ChildLead =1 if child exposure to lead 1095 0 0 1 

ChildPica =1 if child had pica 1095 0 0 1 

Covariates: Health care seeking 

HC_Cholest Cholesteral Test 0=never,1=>3yrs,2=w/in3yrs 1095 0 0 2 

HC_Cholest_0 0=never 1095 0 0 1 

HC_Cholest_1 1=>3yrs 1095 0 0 1 

HC_Cholest_2 2=w/in3yrs 1095 0 0 1 

HC_pap Pap Smear 0=never,1=>3yrs,2=w/in3yrs 1095 0 0 2 

HC_PAP_0 0=never 1095 0 0 1 

HC_PAP_1 1=>3yrs 1095 0 0 1 

HC_PAP_2 2=w/in3yrs 1095 0 0 1 

HC_InitInad_1 =1 if Kotel = Inadeq PreNat Care 1095 0 0 1 

HC_InitInad_Imp =1 if imputed 7 1088 1 1 

Abt Associates Inc. 9 
3. Variable Descriptions
 

Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

Data Management Variables 

ChildID ChildID for merging data sets Numeric variable, ranging from 1 to1093. 

DS_ASD_Main =1 if ASD Main Data Set 

=98 if control omitted because no cases 

within matching stratum. 

=99 ineligible control or below criteria case X X X 

Use this variable to create the ASD with 

matched controls data set (n=256 ASD, n=752 

Controls) 

See Vol Ia

, Section 5.5, Exhibit 5.5.1 for 

details. 

See this variable used in “Example Analysis”, 

below. 

DS_AD_Main =1 if AD Main Data Set 

=98 if control omitted because no cases 

within matching stratum. 

=99 ineligible control or below criteria case 

X X X 

Use this variable to create the AD with 

matched controls data set (n=187 AD, n=724 

Controls) 

See Vol I, Section 5.5, Exhibit 5.5.1 for details. 

DS_ASD_Only =1 if ASD only Data Set 

=98 if control omitted because no cases 

within matching stratum. 

=99 ineligible control or below criteria case 

X X X 

Use this variable to create the ASD-no-AD 

with matched controls data set (n=69 Cases, 

n=704 Controls) 

See Vol I, Section 5.5, Exhibit 5.5.1 for details. 

DS_ASD_Regr =1 if ASD with regression Data Set 

=98 if control omitted because no cases 

within matching stratum. 

=99 ineligible control or below criteria case 

X X X 

Use this variable to create the ASD 

w/regression with matched controls data set 

(n=49 Cases, n=652 Controls) 

See Vol I, Section 5.5, Exhibit 5.5.1 for details. 

DS_AD_ExLoIQ =1 if AD with low cognitive function 

excluded data set 

=98 if control omitted because no cases 

within matching stratum. 

=99 ineligible control or below criteria case 

X X X 

Use this variable to create the AD with low 

cognitive function excluded with matched 

controls data set (n=165 Cases, n=719 

Controls) 

See Vol I, Section 5.5, Exhibit 5.5.1 for details. 

DS_ASD_TCln =1 if ASD and screened controls data set 

=98 if control omitted because no cases 

within matching stratum. 

=99 ineligible control or below criteria case 

X X X 

Use this variable to create the ASD with 

matched screened controls data set (n=255 

Cases, n=566 Controls) 

See Vol I, Section 5.5, Exhibit 5.5.1 for details. 

Abt Associates Inc. 10 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

DS_AD_TCln =1 if AD and screened controls data set 

=98 if control omitted because no cases 

within matching stratum. 

=99 ineligible control or below criteria case 

X X X 

Use this variable to create the AD with 

matched screened controls data set (n=186 

Cases, n=542 Controls) 

See Vol I, Section 5.5, Exhibit 5.5.1 for details. 

StatusCode Status code of each subject X X X =1 if control; =2 if case confirmed; =3 if case 

below criteria. 

InElig_Cntrl =1 if control ineligible 

X X 

=1 if control ineligible because of diagnosis of 

Asperger’s syndrome, tuberous sclerosis, or 

pervasive developmental disorder. 

See Vol I, Section 5.5. 

MatchStrat Matching Stratum 

HMO, Birth year, Sex 

X X X Matching strata are numbered 1-48. 

See this variable used in “Example Analysis”, 

below. 

weight1 Weight for DS_ASD_main=1 Used in Vol II , Section 16. See Section 16.3. 

Weights were created for DS_ASD_main=1 

so that for each matching stratum, the sum of 

weights of controls is 3 times of the number of 

cases. 

weight2 Weight for DS_AD_main=1 Used in Vol II , Section 16. See Section 16.3. 

Weights were created for DS_AD_main=1 so 

that for each matching stratum, the sum of 

weights of controls is 3 times of the number of 

cases. 

weight3 Weight for DS_ASD_only=1 Used in Vol II , Section 16. See Section 16.3. 

Weights were created for DS_ASD_only=1

so that for each matching stratum, the sum of 

weights of controls is 3 times of the number of 

cases. 

weight4 Weight for DS_ASD_regr=1 Used in Vol II , Section 16. See Section 16.3. 

Weights were created for DS_ASD_regr=1

so that for each matching stratum, the sum of 

weights of controls is 3 times of the number of 

cases. 

Abt Associates Inc. 11 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

weight5 Weight for DS_AD_ExLoIQ=1 Used in Vol II , Section 16. See Section 16.3. 

Weights were created for DS_AD_ExLoIQ=1

so that for each matching stratum, the sum of 

weights of controls is 3 times of the number of 

cases. 

weight6 Weight for DS_ASD_TCln=1 Used in Vol II , Section 16. See Section 16.3. 

Weights were created for DS_ASD_TCln=1 

so that for each matching stratum, the sum of 

weights of controls is 3 times of the number of 

cases. 

weight7 Weight for DS_AD_TCln=1 Used in Vol II , Section 16. See Section 16.3. 

Weights were created for DS_AD_TCln=1 so 

that for each matching stratum, the sum of 

weights of controls is 3 times of the number of 

cases 

Outcome Indicators 

ASD_Outc =1 if ASD/AD, =0 Cntr, .=exclude X See this variable used in “Example Analysis”, 

below. 

ASD_time =1 if ASD/AD, =2 Cntr, .=exclude X See this variable used in “Example Analysis”, 

below. 

AD_Outc =1 if AD, =0 Cntr, .=exclude X 

AD_time =1 if AD, =2 Cntr, .=exclude X 

ASD_Only =1 if ASD only, =0 Cntr, .=exclude X 

ASD_Only_time =1 if ASD only, =2 Cntr, .=exclude X 

ASD_Regr =1 if ASD w/Regress,=0 Cntr X 

ASD_Regr_Time =1 if ASD w/Reg, =2 if Cntr,=. exclude X 

AD_ExLoIQ =1 if AD w/Lo IQ Excluded,=0 Cntr X 

AD_ExLoIQ_Time =1 if AD w/IQ excluded, =2 if Cntr,=. 

exclude X 

ASD_TCln =1 if ASD/AD, =0 Tot Cln Cntr, .=exclude X 

ASD_TCln_time =1 if ASD/AD, =2 Tot Cln Cntr, .=exclude X 

AD_TCln =1 if AD/AD, =0 Tot Cln Cntr, .=exclude X 

AD_TCln_time =1 if AD/AD, =2 Tot Cln Cntr, .=exclude X 

Exposure Variables 

PreNatThimer PreNat Exp Amt X X PreNatThimer measures the sum total amount 

Abt Associates Inc. 12 
 

 

 

Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

of mother’s ethyl mercury exposure to 

Thimerosal in influenza vaccine or Rhogam or 

any other immune globulin products, during 

pregnancy, expressed in g units 

See Vol I, Section 7.4 for variable creation. 

See Vol I, Section 9.4.1 for use in analysis 

models 

See this variable used in “Example Analysis”, 

below. 

PreNatThimer_Alt PreNat Exp Amt (Alt) X X PreNatThimer_Alt is an alternate amount of 

prenatal ethyl mercury exposure from 

thimerosal in vaccines and immune globulins 

received by the mother during her pregnancy 

with focus child. Calculated using alternative 

prenatal immune globulin amount variables 

(PN_IG1_Amt_Alt, PN_IG2_Amt_Alt). 

See Vol I, Section 7.4 for variable creation. 

See Vol II, Section 11.1 for use in analysis 

models 

Exp01mos Amt/Wt(KGs) birth-28 days X X Exp01mos measures the g of ethyl mercury 

received from Thimerosal in vaccines in the 

first 28 days of life divided by child’s weight in 

grams at the time of receipt of the vaccine. 

See Vol I, Section 7.3 for variable creation. 

See Vol I, Section 9.4.1 for use in analysis 

models 

See this variable used in “Example Analysis”, 

below. 

Exp17mos Amt/Wt(KGs) 29-214 days X X Exp17mos is a cumulative measure of ethyl 

mercury exposure to Thimerosal during the 

age range of one to seven months (29 to 214 

days), expressed in g units per kg of body 

weight. Prenatal exposures and exposure to 

Thimerosal from a hepatitis B vaccination 

received at birth (i.e., in the first month of life) 

are not included in this measure. 

Abt Associates Inc. 13 
 

 

 

 

Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

See Vol I, Section 7.3 for variable creation. 

See Vol I, Section 9.4.1 for use in analysis 

models 

See this variable used in “Example Analysis”, 

below. 

Exp07mos Amt/Wt(KGs) birth-214 days X X Exp07mos is a cumulative measure of ethyl 

mercury exposure to Thimerosal during the 

age range of birth through seven months (1 to 

214 days), expressed in g units per kg of 

body weight. Prenatal exposures are not 

included in this measure. 

Exp020mos Amt/Wt(KGs) birth-609 days X X Exp07mos is a cumulative measure of ethyl 

mercury exposure to Thimerosal during the 

age range of birth through twenty months (1 to 

609 days), expressed in g units per kg of 

body weight. Prenatal exposures are not 

included in this measure. 

See Vol I, Section 7.3 for variable creation. 

See Vol I, Section 9.4.1 for use in analysis 

models 

See this variable used in “Example Analysis”, 

below. 

Amt01mos Amt Merc birth-28 days X X Amt01mos measures the g of ethyl mercury 

received from Thimerosal in vaccines in the 

first 28 days of life 

See Vol I, Section 7.3 for variable creation. 

See Vol II, Section 11.1 for use in analysis 

models 

Amt17mos Amt Merc 29-214 days X X Amt17mos measures the g of ethyl mercury 

received from Thimerosal in vaccines in days 

29 to 214 of life. Prenatal exposures and 

exposure to Thimerosal from a hepatitis B 

vaccination received at birth (i.e., in the first 

month of life) are not included in this measure. 

See Vol I, Section 7.3 for variable creation. 

See Vol II, Section 11.1 for use in analysis 

Abt Associates Inc. 14 
 

 

Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

models 

Amt07mos Amt Merc birth-214 days X X Amt07mos measures the g of ethyl mercury 

received from Thimerosal in vaccines in the 

first 214 days of life. Prenatal exposures are 

not included in this measure. 

See Vol I, Section 7.3 for variable creation. 

See Vol I, Exhibit 8.3 for use. 

Amt020mos Amt Merc birth-609 days X X Amt020mos measures the g of ethyl 

mercury received from Thimerosal in vaccines 

in the first 609 days of life. Prenatal exposures 

are not included in this measure. 

See Vol I, Section 7.3 for variable creation. 

See Vol I, Exhibit 8.3 for use. 

AbExp01mos Concur Amt/Wt(KGs) birth-28 days X X AbExp01mos is a cumulative measure of 

ethylmercury exposure from thimerosal in 

vaccines received concurrent with 

antibiotics during the age ranges from birth 

through one month1 (1 – 28 days), expressed 

in microgram units per kilograms of body 

weight at the time of vaccine receipt. 

See Vol I, Section 9.4.5 for details and use. 

AbExp07mos Concur Amt/Wt(KGs) birth-214 days X X AbExp07mos is a cumulative measure of 

ethylmercury exposure from thimerosal in 

vaccines received concurrent with 

antibiotics during the age range from birth 

through seven months (1 – 214 days), 

expressed in microgram units per kilograms of 

body weight at the time of vaccine receipt. 

See Vol I, Section 9.4.5 for details and use. 

AbExp17mos Concur Amt/Wt(KGs) 29-214 days X X AbExp17mos is a cumulative measure of 

ethylmercury exposure from thimerosal in 

vaccines received concurrent with 

antibiotics during the age ranges from one 

through seven months (29 – 214 days), 

expressed in microgram units per kilograms of 

Abt Associates Inc. 15 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

body weight at the time of vaccine receipt. 

See Vol I, Section 9.4.5 for details and use. 

AbExp020mos Concur Amt/Wt(KGs) birth-609 days X X AbExp020mos is a cumulative measure of 

ethylmercury exposure from thimerosal in 

vaccines received concurrent with 

antibiotics during the age range from birth 

through twenty months (1 – 609 days), 

expressed in microgram units per kilograms of 

body weight at the time of vaccine receipt. 

See Vol I, Section 9.4.5 for details and use. 

ncAbExp01mos NonConcur Amt/Wt(KGs) birth-28 days X X ncAbExp01mos is a cumulative measure of 

ethylmercury exposure from thimerosal in 

vaccines received without concurrent 

antibiotics use during the age ranges from 

birth through one month1 (1 – 28 days), 

expressed in microgram units per kilograms of 

body weight at the time of vaccine receipt. 

See Vol I, Section 9.4.5 for details and use. 

ncAbExp07mos NonConcur Amt/Wt(KGs) birth-214 days X X ncAbExp07mos is a cumulative measure of 

ethylmercury exposure from thimerosal in 

vaccines received without concurrent 

antibiotics use during the age range from 

birth through seven months (1 – 214 days), 

expressed in microgram units per kilograms of 

body weight at the time of vaccine receipt. 

See Vol I, Section 9.4.5 for details and use. 

ncAbExp17mos NonConcur Amt/Wt(KGs) 29-214 days X X ncAbExp17mos is a cumulative measure of 

ethylmercury exposure from thimerosal in 

vaccines received without concurrent 

antibiotics use during the age ranges from 

one through seven months (29 – 214 days), 

expressed in microgram units per kilograms of 

body weight at the time of vaccine receipt. 

See Vol I, Section 9.4.5 for details and use. 

ncAbExp020mos NonConcur Amt/Wt(KGs) birth-609 days X X ncAbExp020mos is a cumulative measure of 

Abt Associates Inc. 16 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

ethylmercury exposure from thimerosal in 

vaccines received without concurrent 

antibiotics use during the age range from 

birth through twenty months (1 – 609 days), 

expressed in microgram units per kilograms of 

body weight at the time of vaccine receipt. 

See Vol I, Section 9.4.5 for details and use. 

AbDays01mos # days on Abiots birth-28 days X X AbDays01mos is the number of days a child 

was on antibiotics in the period 1- 28 days old. 

See Vol I, Section 9.4.5 for details and use. 

AbDays07mos # days on Abiots 1-214 days X X AbDays07mos is the number of days a child 

was on antibiotics in the period 1- 214 days 

old. 

See Vol I, Section 9.4.5 for details and use. 

AbDays17mos # days on Abiots 29-214 days X X AbDays17mos is the number of days a child 

was on antibiotics in the period 29-214 days 

old. 

See Vol I, Section 9.4.5 for details and use. 

AbDays020mos # days on Abiots birth-609 days X X AbDays020mos is the number of days a child 

was on antibiotics in the period 1- 609 days 

old. 

See Vol I, Section 9.4.5 for details and use. 

AnyAb01mos =1 if any Abiots 01 mos X X =1 if a child was on antibiotics in the period 1­

28 days old. =0 if not. 

See Vol I, Section 9.4.6 for details and use. 

AnyAb07mos =1 if any Abiots 07 mos X X =1 if a child was on antibiotics in the period 1­

214 days old. =0 if not. 

See Vol I, Section 9.4.6 for details and use. 

AnyAb17mos =1 if any Abiots 17 mos X X =1 if a child was on antibiotics in the period 

28-214 days old. =0 if not. 

See Vol I, Section 9.4.6 for details and use. 

AnyAb020mos 

=1 if any Abiots 020 mos 

X X =1 if a child was on antibiotics in the period 1­

609 days old. =0 if not. 

See Vol I, Section 9.4.6 for details and use. 

PreNatAllMerc X X X A broader measures of prenatal exposure 

Abt Associates Inc. 17 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

including mercury exposures from thimerosal 

in vaccines and immune globulins, maternal 

fish consumption, maternal use of mercury 

containing health care produces (contact lens, 

nasal, ear, eye drops), maternal exposure 

from home products, and from amalgam 

fillings. 

See Vol I, Section 9.4.4 for details and use. 

General Information about Child 

SexMale =1 if Sex=Male X X X Used in Vol I, Section 9.1 “Descriptive 

Statistics” 

AgeAtPIYrs Age in Years at Par Interview, from 

IQ_Status.sas 

X X X Used in Vol I, Section 9.1 “Descriptive 

Statistics” 

Ravens_Score_n Cases only-Score if given Raven, from 

IQ_Status.sas 

X See Vol I, Section 7.1.3 for details and 

use. 

Mullen_Age Cases only-IQ Age equiv if given Mullen, 

from IQ_Status.sas 

X See Vol I, Section 7.1.3 for details and 

use. 

RatioIQ (Mullen_age/AgeAtPIYrs)*100, from 

IQ_Status.sas 

X See Vol I, Section 7.1.3 for details and 

use. 

LowIQ =1 if Ravens_Score<35 or 

Mullen RatioIQ<35, from IQ_Status.sas 

X See Vol I, Section 7.1.3 for details and 

use. 

SCQ_Administered =1 if SCQ was administered X See Vol I, Section 7.2 for details and use. 

ScreenOut =1 if should be excluded from 

screened control group analyses X X X See Vol I, Section 7.2 for details and use. 

Q11 ADIR Loss of Lang Skills, see 

Regression_Status.sas 

X See Vol I, Section 7.1.2 for details and 

use. 

Q12b_SkillsLost # skills lost in ADIR Q12b, see 

Regression_Status.sas 

X See Vol I, Section 7.1.2 for details and 

use. 

Q12b_skillsprior # skills before 24 mos in ADIR Q12b X See Vol I, Section 7.1.2 for details and 

use. 

Q12b_PctLost % skills lost in ADIR Q12b X See Vol I, Section 7.1.2 for details and 

use. 

Abt Associates Inc. 18 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

Regression =1 if Regression (loss of lang/skills), 

created in Regression_Status.sas 

X See Vol I, Section 7.1.2 for details and 

use. 

Older_aut_sib =1 if child has older autistic sibling X See Vol II, Section15 for details and use. 

MC_epilepsy_230 230: Epilepsy/seizures/convulsions (specify) X See Vol II, Section21.3 for details and use. 

MC_CerePal_212 212: Cerebral Palsy X See Vol II, Section21.3 for details and use. 

MC_HearingDis_233 233: Hearing disorder (specify) X See Vol II, Section21.3 for details and use. 

MC_VisImp_261 261: Visual Impairment X See Vol II, Section21.3 for details and use. 

DownsSyndrome 1 if down syndrome dx in med chart X See Vol II, Section21.3 for details and use. 

MC_Neuro_243 243: Neurofibromatosis X See Vol II, Section21.3 for details and use. 

MC_PKU_250 250: PKU X See Vol II, Section21.3 for details and use. 

MC_CMV_225 225: CMV X See Vol II, Section21.3 for details and use. 

MC_DevDelay_227 227: Developmental delay, other (specify) X See Vol II, Section21.3 for details and use. 

PI_DevDelay Any other developmental delay, such as 

mental retardation 

X See Vol II, Section21.3 for details and use. 

MC_AbPain_214 214: Chronic abdominal pain/cramps before 

age 3 

X See Vol II, Section21.3 for details and use. 

MC_bloating_215 215: Chronic bloating before age 3 X See Vol II, Section21.3 for details and use. 

MC_celiac_216 216: Chronic celiac disease before age 3 X See Vol II, Section21.3 for details and use. 

MC_const_217 217: Chronic constipation before age 3 X See Vol II, Section21.3 for details and use. 

MC_FoodInt_218 218: Chronic food intolerance before age 3 X See Vol II, Section21.3 for details and use. 

MC_gastroenteritis_219 219: Chronic gastroenteritis before age 3 X See Vol II, Section21.3 for details and use. 

MC_MalAbs_220 220: Chronic malabsorption before age 3 X See Vol II, Section21.3 for details and use. 

MC_diarrhea_221 221: Chronic/recurrent diarrhea before age 

3 

X See Vol II, Section21.3 for details and use. 

MC_enteritis_222 222: Chronic regional enteritis before age 3 X See Vol II, Section21.3 for details and use. 

MC_VomitColic_224 224: Chronic vomiting/colic before age 3 X See Vol II, Section21.3 for details and use. 

Covariates 

Child and Family Characteristics 

BwgtCat 1 = <1.0 kilograms (KG) 

2 = 1.0 to 1.4999 KGs 

3 = 1.5 to 2.4999 KGs 

X X The five category variable was made into four 

dummy variables for use in analytical models. 

Category 1 (<1.0 KGs) is omitted category in 

Abt Associates Inc. 19 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

4 = 2.5 to 3.4999 KGs 

5 = 4.0 + KGs 

models. 

BWLt1k =1 if Birth wgt < 1 Kg X X See Vol I, Sec. 8.2, Exhibit 8.2 

BW1_1p5k =1 if Birth wgt 1.0 Kg to 1.499 Kg X X See Vol I, Sec. 8.2, Exhibit 8.2 

BW1p5_2p5k =1 if Birth wgt 1.5 Kg to 2.499 Kg X X See Vol I, Sec. 8.2, Exhibit 8.2 

BW2p5_4k =1 if Birth wgt 2.5 Kg to 3.999 Kg X X See Vol I, Sec. 8.2, Exhibit 8.2 

BW4kup =1 if Birth wgt 4.0 Kg and up X X See Vol I, Sec. 8.2, Exhibit 8.2 

PovertyRatio1 Ratio of household income to poverty line. 

Values below 1 corresond to families living 

below the poverty line. Values above 1 

correspond to families living 

above the poverty line. 

X Percent of poverty line calculated from 

household (HH) size, household income, and 

the 2004 poverty guidelines for the 48 

contiguous states and the District of Columbia 

shown in Department of Health and Human 

Services Annual Update of the HHS Poverty 

Guidelines; Federal Register, Vol. 69, No. 30, 

February 13, 2004 / Notices according to the 

following algorithm: 

if HH size=2 then PovertyRatio=HH Income/12490; 

if HH size=3 then PovertyRatio =HH Income/15670; 

if HH size=4 then PovertyRatio=HH Income/18850; 

if HH size=5 then PovertyRatio=HH Income/22030; 

if HH size=6 then PovertyRatio=HH Income/25210; 

if HH size=7 then PovertyRatio=HH Income/28390; 

if HH size=8 then PovertyRatio=HH Income/31570; 

if HH size=9 then PovertyRatio=HH 

Inc./(31570+3180); 

if HH size=10 then PovertyRatio=HH 

nc./(31570+6360) 

See Vol I, Sec. 8.2, Exhibit 8.2 

PovertyRatio_imp =1 if missing value imputed X See Vol I, Section 7.5.2. 

MomEduc 0= No high school degree 

1=High school diploma or GED 

2=attended some college, but no degree 

3=Associate’s degree or higher 

X Maternal education level 

The four category variable was made into 

three dummy variables for use in analytical 

models. Category 1 (No high school degree ) 

is omitted category in models. 

momeduc_imp =1 if momeduc imputed X See Vol I, Section 7.5.2. 

MomEduc_NoHS =1 if Mom has no HS diploma X See Vol I, Sec. 8.2, Exhibit 8.2 

Abt Associates Inc. 20 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

MomEduc_HS =1 if Mom HS Grad X See Vol I, Sec. 8.2, Exhibit 8.2 

MomEduc_Some =1 if Mom Some Coll X See Vol I, Sec. 8.2, Exhibit 8.2 

MomEduc_Coll =1 if Mom Coll Grad X See Vol I, Sec. 8.2, Exhibit 8.2 

SingleParent Child lives in a single parent household 

(0=no, 1=yes) 

X See Vol I, Sec. 8.2, Exhibit 8.2 

Child and Family Characteristics 

MomAgeCat Age at birth of child 

1 = <20 years old 

2 = 20 – 24 years 

3 = 25 – 29 years 

4 = 30 – 34 years 

5 = 35 years or older 

X X X The five category variable was made into four 

dummy variables for use in analytical models. 

Category 1 (<20 years old) is omitted category 

in models. 

MomLt20 Mom Age at child birth lt 20 X X X See Vol I, Sec. 8.2, Exhibit 8.2 

Mom20_24 Mom Age at child birth 20 - 24 X X X See Vol I, Sec. 8.2, Exhibit 8.2 

Mom25_29 Mom Age at child birth 25 - 29 X X X See Vol I, Sec. 8.2, Exhibit 8.2 

Mom30_34 Mom Age at child birth 30 - 34 X X X See Vol I, Sec. 8.2, Exhibit 8.2 

MomGE35 Mom Age at child birth ge 35 X X X See Vol I, Sec. 8.2, Exhibit 8.2 

BioDadAgeCat_1 Paternal Age at birth of child 

1 = <20 years old 

2 = 20 – 29 years 

3 = 30 – 39 years 

4 = 40 – 49 years 

5 = 50 years or older 

X X The five category variable was made into four 

dummy variables for use in analytical models. 

Category 1 (<20 years old) is omitted category 

in models. 

BioDadAge_Imp =1 if missing value imputed X X See Vol I, Section 7.5.2. 

Dadlt20_i1 =1 if Dad <20 years old X X See Vol I, Sec. 8.2, Exhibit 8.2 

Dad20_29_i1 =1 if Dad 20-29 years old X X See Vol I, Sec. 8.2, Exhibit 8.2 

Dad30_39_i1 =1 if Dad 30-39 years old X X See Vol I, Sec. 8.2, Exhibit 8.2 

Dad40_49_i1 =1 if Dad 40-49 years old X X See Vol I, Sec. 8.2, Exhibit 8.2 

DadGE49_i1 =1 if Dad >49 years old X X See Vol I, Sec. 8.2, Exhibit 8.2 

BirthOrderCat_1 1=Child is first born 

2=Child is Second born 

3=Child is third born or later 

X The three category variable was made into 

two dummy variables for use in analytical 

models. Category 1 (first born) is omitted 

category in models. 

BirthOrder1_1 =1 if 1st born X See Vol I, Sec. 8.2, Exhibit 8.2 

BirthOrder2_1 =1 if 2nd born X See Vol I, Sec. 8.2, Exhibit 8.2 

Abt Associates Inc. 21 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

BirthOrderGE3_1 =1 if 3rd born or higher X See Vol I, Sec. 8.2, Exhibit 8.2 

birthOrder_imp =1 if missing value imputed X See Vol I, Section 7.5.2. 

Multiple Plurality 

=1 if child was a multiple (twin, triplet) 

=0 if child was a singleton 

(This variable omitted from file) 

X X See Vol I, Sec. 8.2, Exhibit 8.2 

BFMthsCat Breast Feeding (Duration) 

0 = Breast Fed: <1 month 

1 =Breast Fed: 1-6 months 

2 = Breast Fed: 6+ months 

X X The three category variable was made into 

two dummy variables for use in analytical 

models. Category 0 (<1 month) is omitted 

category in models. 

BFNone =1 if Breastfed 0 months X X See Vol I, Sec. 8.2, Exhibit 8.2 

BF1_6mos =1 if Breastfed 1-5.99 months X X See Vol I, Sec. 8.2, Exhibit 8.2 

BFgt6mos =1 if Breastfed 6+ months X X See Vol I, Sec. 8.2, Exhibit 8.2 

Child Birth Conditions 

C5APGAR 5-minute APGAR score X Child’s score on the 5 minute APGAR, which 

is a test given to newborns five minutes after 

birth to measure activity, pulse, grimace, 

appearance, and respiration. 

See Vol I, Sec. 8.2, Exhibit 8.2 

BirthAsphyxia =1 if medical record indicates birth asphyxia 

=0 else 

X See Vol I, Sec. 8.2, Exhibit 8.2 

RespDistress =1 if medical record indicates respiratory 

distress 

=0 else 

X See Vol I, Sec. 8.2, Exhibit 8.2 

Bilirubin =1 if neonatal hyperbilirubinemia 

=0 else 

X =1 if total bilirubin >10 on day 1; or 

If total bilirubin > 12 on day 2; or 

If total bilirubin >15 on day 3; or 

If any of the following treatments: 

phototherapy, bililites, bilirubin lights, 

exchange transfusion, or type and cross 

match blood. 

See Vol I, Sec. 8.2, Exhibit 8.2 

Prenatal Exposures (non-vaccine related) 

PreNatNicotine_1 Used tobacco during pregnancy X X = 1 if mother used any tobacco products 

during pregnancy. 

Abt Associates Inc. 22 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

See Vol I, Sec. 8.2, Exhibit 8.2 

PreNatNicotine_Imp =1 if missing value imputed X X See Vol I, Section 7.5.2. 

PreNatAlcohol_1 Alcohol use during pregnancy: X X 0= none 

1= occasional (1-4 drinks per month) 

2= light (20-24 drinks/month or 5-6 per week) 

3=moderate(10-15 drinks per week) 

4=heavy (more than 15 drinks per week) 

Entered in models as linear term. 

See Vol I, Sec. 8.2, Exhibit 8.2 

PreNatAlcohol_Imp =1 if missing value imputed X X See Vol I, Section 7.5.2. 

PreNatTuna Maternal tuna consumption 

during pregnancy 

X 0= no consumption of tuna during pregnancy. 

1 = moderate consumption (less than one 

serving per week) 

2 = high consumption (more than one serving 

per week) 

Entered in models as linear term. 

See Vol I, Sec. 8.2, Exhibit 8.2 

PreNatTuna_Imp =1 if missing value imputed X See Vol I, Section 7.5.2. 

PreNatFish_1 High consumption of fish during pregnancy. X 1= if mother reported eating tuna, and ocean 

fish, and home-caught fish during pregnancy. 

0 = else. 

PreNatFish_Imp =1 if missing value imputed 

X See Vol I, Section 7.5.2. 

PreNatFish_Imp = 1 if PreNatTuna_Imp = 1 or 

if PreNatOceanFresh =1. 

PreNatOthMerc_Any =1 if any prenat non-vac merc exposures X 

PreNat non-vac mercury exposures: 

PreNatChin= 1=used chinese herbal ball prep 

PreNatMex= 1=used native Am or Mex folk meds 

PreNatFolk= 1= used folk to treat empacho 

PreNatRelig= 1=materials Santeria,espiritismo,oth relig 

PreNatContacts= 1=used thim-containing contact soln 

PreNatNasal= 1=used thim-containing nasal soln 

PreNatEyeDrops= 1=used thim-containing eye drops 

PreNatEar = 1=used thim-containing ear wax soln 

PreNatSkin= 1=used skin lightening cream 

PreNatTherm= 1=exposed to broken merc-contain 

thermometer 

PreNatBulb= 1=exposed to broken florescent bulb 

PreNatShoes= 1=exposed to broken pre-97 shoe lights 

Abt Associates Inc. 23 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

PreNatGauge= 1=exposed to broken electronic 

switches,relays,gauges 

See Vol I, Sec. 8.2, Exhibit 8.2 

PreNatFillings_1 Mercury-containing dental amalgams X Amalgam fillings during pregnancy: 

0 = mother had no amalgam fillings 

1 = had amalgam filling, but no dental work 

and did not chew gum during pregnancy 

2= had amalgam fillings and had dental work 

or chewed gum during pregnancy. 

PreNatFillings_Imp =1 if missing value imputed X See Vol I, Section 7.5.2. 

PreNatlead_1 Prenatal exposure to lead from 

occupational or residential sources 

X =1 if during pregnancy 

mother worked in: 

Worked in smelting, soldering, construction, or 

demolition 

or if during pregnancy mother lived in : 

a pre-1950 home, or 

a pre-1978 home that underwent painting or 

renovation during her pregnancy. 

See Vol I, Sec. 8.2, Exhibit 8.2 

PreNatLead_Imp =1 if PreNatResiLead_imp or 

PreNatOccupLead_imp = 1 

X See Vol I, Section 7.5.2. 

PreNatIllDrug 1=Cocaine or Narcotic 

(this variable omitted from file) 

X X 1= if mother reported any use of cocaine, 

crack, heroin, methamphetamines, or speed 

during pregnancy, or maternal medical chart 

indicated suspected use or suspected use of 

cocaine or narcotics during pregnancy. 

0 = else. 

See Vol I, Sec. 8.2, Exhibit 8.2 

PreNatValproic = 1 if mother took valproic acid during 

pregnancy 

=0 else. 

X X If chart or parent interview indicated that 

mother took valproic acid during pregnancy, or 

phenobarbitol, depakote, monistat, 

macrodantin during pregnancy. 

See Vol I, Sec. 8.2, Exhibit 8.2 

Folic_PNVit_Multi = 1 if mother took folic acid or 

prenatal vitamins or multivitamins 

during pregnancy 

X X See Vol I, Sec. 8.2, Exhibit 8.2 

Abt Associates Inc. 24 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

=0 else. 

PreNatViralInf = 1 if medical chart indicated that mother 

had any viral infection (e.g., herpes simplex 

virus outbreak, chlamydia,strep infection, 

upper respiratory viral infection, viral 

enteritis) at anytime during pregnancy 

= 0 otherwise. 

X See Vol I, Sec. 8.2, Exhibit 8.2 

Child Medical Conditions 

Anemia Anemia or iron deficiency X =1 if any records of anemia and iron 

deficiency in child’s chart. =0 else. 

See Vol I, Sec. 8.2, Exhibit 8.2 

Enceph =1 if child had encephalitis or any CNS 

infection prior to 36 months of age 

=0 else 

X See Vol I, Sec. 8.2, Exhibit 8.2 

ChildLead =1 if child had lead test levels over 10 

or child was exposed to lead from 

home before age 3 

=0 else 

X X =1 if lead poisoning before age three indicated 

in chart; or 

Parent said child had an elevated lead test 

level before age 3; or before age 3, 

Child lived in home where water was tested 

and found to have high lead content; or 

Child had pica and child lived in a pre-1950 

home; or 

Child had pica and child lived in a 

a pre-1978 home that underwent painting or 

renovation; or 

Child had pica and parent said paint or floor 

varnish was tested and had high lead content. 

See Vol I, Sec. 8.2, Exhibit 8.2 

ChildPica =1 if child exhibited pica before his/her third 

birthday. 

X X Pica is characterized by persistent and 

compulsive cravings (lasting one month or 

longer) to eat nonfood items. 

See Vol I, Sec. 8.2, Exhibit 8.2 

Maternal Health Care Seeking Behavior 

HC_InitInad =1 if Kotelchuck initiation of prenatal care 

index in “inadequate” range 

X X If date of initiation of prenatal care is missing 

from chart, then used information from parent 

Abt Associates Inc. 25 
Exhibit 3.1 Data Sources and Construction of Variables Used in Analytical Models 

Data Sources 

Variable Description Par 

Int 

Med 

Abstr 

Comp 

Aut 

Case 

Asmt Additional Detailsa 

=0 else interview 

See Vol I, Sec. 8.2, Exhibit 8.2 

HC_InitInad_Imp =1 if missing value imputed See Vol I, Section 7.5.2. 

HC_Pap = 0 if mother has never had a pap smear. 

= 1 if mother has ever had a pap smear, 

but not within the three years 

prior to interview 

= 2 if mother had a pap smear within three 

years. 

X The three category variable was made into 

two dummy variables for use in analytical 

models. 

Category 0 (Never) is omitted category in 

models. 

This variable was considered to be a proxy 

measure for health care seeking behavior. 

HC_PAP_0 0=never X See Vol I, Sec. 8.2, Exhibit 8.2 

HC_PAP_1 1=>3yrs X See Vol I, Sec. 8.2, Exhibit 8.2 

HC_PAP_2 2=w/in3yrs X See Vol I, Sec. 8.2, Exhibit 8.2 

HC_Cholest = 0 if mother has never had 

a cholesterol test. 

= 1 if mother has ever had 

a cholesterol test, but not within the three 

years prior to interview 

= 2 if mother had a cholesterol test within 

the three years. 

X The three category variable was made into 

two dummy variables for use in analytical 

models. 

Category 0 (Never) is omitted category in 

models. 

This variable was considered to be a proxy 

measure for health care seeking behavior. 

HC_Cholest_0 0=never X See Vol I, Sec. 8.2, Exhibit 8.2 

HC_Cholest_1 1=>3yrs X See Vol I, Sec. 8.2, Exhibit 8.2 

HC_Cholest_2 2=w/in3yrs X See Vol I, Sec. 8.2, Exhibit 8.2 a Vol I and Vol II are references to Thimerosal and Autism, Technical Report, Volumes I and II. 

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4. Reproducing Results from the Technical Report 

In order to reproduce a model result presented in the Technical Report, the data user will need to 

find the corresponding model specification presented in Section 9 of the Technical Report, and 

fit the model using the covariates specified in Exhibit 8.2.of the Technical Report. Exhibit 4.1 

shows example SAS code that can be used to reproduce results. 

Exhibt 4.1 Example Analysis 

/* ***************************************************************************

Get data set 

* *************************************************************************** */

data main; set pub.pubuse_mainanalysisfile; 

/* ***************************************************************************

Subset data to the ASD & Control data set (ASD n=256, Control n=762)

* ************************************************************************** */ 

data ASD; set main;

if DS_ASD_Main=1; 

run; 

Proc freq; tables ASD_Outc;

run; 

/* ***************************************************************************

Fit model shown in Tech Report Volume II, Section 19 (Detail of Model Results)

Exhibit 19.1 

* ************************************************************************** */ 

proc phreg data=ASD;

model ASD_Time * ASD_Outc(0) =
 

PreNatThimer
 

Exp01mos

Exp17mos

/* BWLt1k omitted group */ 

BW1_1p5k

BW1p5_2p5k

BW2p5_4k

BW4kup

/* MomLt20 omitted group */

Mom20_24 

Mom25_29 

Mom30_34 

MomGE35 

/* BirthOrder1_1 omitted group */ 

BirthOrder2_1 

BirthOrderGE3_1 

/* BFNone omitted group */ 

BF1_6mos 

BFgt6mos 

PovertyRatio1 

PreNatAlcohol_1 

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Folic_PNVit_Multi 

Anemia 

ChildPica 

HC_InitInad_1 

/* HC_Cholest_0 is omitted group */

HC_Cholest_1 

HC_Cholest_2 

/* HC_PAP_0 is omitted group */

HC_PAP_1 

HC_PAP_2 

PreNatLead_1 

PreNatViralInf 

/ ties = discrete;

strata MatchStrat; 

run; 

Abt Associates Inc. 28