ARIC Visit 1
Derived Variable Dictionary
November, 2004
Dictionary for variables in the following derived files
DERIVE10, UBMD4, ECGMA03, PULM, and STROKE01
ARIC Visit 1 Derived Variable Dictionary
Table of Contents
Variables are in DERIVE10 unless otherwise noted.
November, 2004
1.Alcohol Use
1.1DRNKR01(Drinker Status)
1.2ETHANL01(Discontinued)
1.3ETHANL02(Discontinued)
1.4ETHANL03(Usual Ethanol Intake in g/wk)
1.5CURDRK02(Current Drinker)
1.6FORDRK01(Former Drinker)
1.7EVRDRK01(Ever Drinker)
2.Anthropometry
2.1BMI01(Body Mass Index in Kg/m2)
2.2SIT_HT01(Sitting Height in cm)
2.3MNTRCP01(Mean Triceps in mm)
2.4MNSSCP01(Mean Subscapular in mm)
2.5WSTHPR01(Waist-to-Hip Ratio)
3.B-Mode Variables in File UBMD4 (Descriptions of B-Mode Ultrasound Variables)
3.1Original Derived Variables
3.2Imputed Ultrasound Data for Far Wall Thickness
3.3Reader Trend Adjusted Derived Variables for Far Wall Thickness
4.Disease Prevalence
4.1RPOSMI01(Rose Possible Myocardial Infarction)
4.2RANGNA01(Rose Angina)
4.3ROSEIC03(Rose Intermittent Claudication)
4.4SYMCHD03(Symptomatic Coronary Heart Disease)
4.5QWAVE04A(Diagnostic Q-Wave present from Adjudicated ECG Data)
4.6QWAVE07A(Major Q-Wave present with no 7-1-1, 7-1-2, or 7-4 from Adjudicated ECG Data)
4.7QWAVEM07(Major Q-Wave present with no 7-1-1, 7-1-2, or 7-4 from Original Machine Coded ECG Records)
4.8QWAVE08B(Minor Q-Wave present with ST or T codes and no 7-1-1, 7-1-2 or 7-4 codes from Adjudicated ECG Records)
4.9QWVEM08B(Minor Q-Wave present with ST or T codes and no 7-1-1, 7-1-2 or 7-4 codes from Original Coded ECG Records)
4.10PRVCHD05(Prevalent Coronary Heart Disease)
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4.11PREVMI05(Prevalent MI from ECG or Medical History)
4.12MDDXMI02(MD Diagnosed Myocardial Infarction)
4.13HXOFMI02(History of Myocardial Infarction)
4.14ECGMI04(Prevalent Myocardial Infarction from Adjudicated Electrocardiograms)
4.15MACHMI02(Prevalent Myocardial Infarction from Original Machine coded Electrocardiograms)
4.16DIABTS02(Diabetes - Lower Cutpoint 140 mg/dL)
4.17DIABTS03(Diabetes - Lower Cutpoint 126 mg/dL)
5.ECG Derived Variables in File ECGMA03(Descriptions of ECG Variables)
6.Hypertension
6.1HYPERT04(Hypertension, definition 4)
6.2HYPERT05(Hypertension, definition 5)
6.3HYPERT06(Hypertension, definition 6)
7.Medication Use
7.1HYPTMD01(Blood Pressure Lowering Medications in Past 2 Weeks)
7.2HYPTMD02(Discontinued)
7.3HYPTMD03 (Discontinued)
7.4HYPTMD04(Hypertension Lowering Medications within Past 2 Weeks)
7.5CHOLMD01(Cholesterol Lowering Medications in past 2 Weeks)
7.6CHOLMD02(Medications Which Secondarily Affect Cholesterol)
8.Nutrition Derived Variables in file ANUT1 (Descriptions of Nutrition Variables)
9.Other Variables
9.1DEPTH01(Average Depth of the Six Site-Specific in Pixels) in file UBMD4
9.2DEPTH02(Average Depth in mm of the Six Specific Sites) in file UBMD4
9.3ELEVEL01(Education Level, Definition 1)
9.4ELEVEL02(Education Level, Definition 2)
9.5GLUCOS01(Blood Glucose Level in mg/dL)
9.6TGLEFH01(Triglycerides less than or equal to 400 mg/dL)
9.7TOTCAL01(Discontinued)
9.8TOTCAL02(Discontinued)
9.9TOTCAL03(Total Caloric Intake in Kcal/day from dietary and ethanol consumption, but excluding other calories from alcoholic beverages)
9.10V1AGE01(Age at Visit 1)
9.11V1DATE01(Visit 1 Date)
9.12FAST0802(8 Hours or more of Fasting Time)
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9.13FAST1202(12 Hours or more of Fasting Time)
9.14MENOPS01(Menopausal Status)
9.15LATEREAD(Later Readings of Scan) in files UBMDBF02, UBMDBM02, UBMDWF02, UBMDWM02
9.16HORMON02(Use of Hormones)
9.17BIRTHDAT(Date of Birth)
9.18GENDER(Sex)
9.19RACEGRP(Race)
9.20CENTER(FieldCenter)
9.21OCCUPN01(Derived Occupation)
9.22ECGSEN01(ECG Visual Coding Flag)
10.Physical Activity
10.1WORK_I02(Physical Activity at Work, Definition 2)
10.2WORK_I03(Physical Activity at Work, Definition 3)
10.3SPRT_I01(Discontinued)
10.4SPRT_I02(Sport During Leisure Time)
10.5LISR_I01(Physical Activity During Leisure Time Excluding Sport)
11.Plaque Derived Variables
11.1BIFSHD01 (Shadowing in either carotid bifurcation)
11.2INTSHD01 (Shadowing in either internal carotid artery)
11.3COMSHD01 (Shadowing in either common carotid artery)
11.4BIFPLQ01 (Plaque in either carotid bifurcation)
11.5INTPLQ01 (Plaque in either internal carotid artery)
11.6COMPLQ01 (Plaque in either common carotid artery)
11.7LCOMPS01 (Plaque/shadowing (both 1 w/o other, neither) in the left common carotid)
11.8RCOMPS01(Plaque/shadowing (both, 1 w/o other, neither) in the right commoncarotid)
11.9LBIFPS01(Plaque/shadowing (both, 1 w/o other, neither) in the left carotid
bifurcation)
11.10RBIFPS01(Plaque/shadowing (both, 1 w/o other, neither) in the right carotid bifurcation)
11.11LINTPS01(Plaque/shadowing (both, 1 w/o other, neither) in the left internal carotid)
11.12RINTPS01(Plaque/shadowing (both, 1 w/o other, neither) in the right internal carotid)
11.13COMPS01 (Plaque/shadowing (both, 1 w/o other, neither) in either common carotid)
11.14BIFPS01(Plaque/shadowing (both, 1 w/o other, neither) in either carotid bifurcation)
11.15INTPS01(Plaque/shadowing (both, 1 w/o other, neither) in either internal carotid)
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11.16LPLQSD01(Plaque/shadowing (both, 1 w/o other, neither) in any left carotid site)
11.17RPLQSD01(Plaque/shadowing (both, 1 w/o other, neither) in any right carotid site)
11.18PLQSHD01 (Plaque/shadowing (both, 1 w/o other, neither) in any carotid site)
11.19PLAQUE01(Plaque (with or without shadowing) in any carotid site)
11.20PLAQUE03(Plaque in any carotid site - alternative definition)
12.Pulmonary Derived Variables in file PULM (Description of Pulmonary Variables)
13.Recalibrated Lipids
13.1LDL02(Recalibrated LDL Cholesterol)
13.2HDL01(HDL Cholesterol)
13.3HDL201(HDL2 Cholesterol)
13.4HDL301(HDL3 Cholesterol)
14.SI Unit Change
14.1GLUSIU01(Recalibrated Glucose in SI Units)
14.2TCHSIU01(Total Cholesterol in SI Units)
14.3HDLSIU02(Recalibrated HDL Cholesterol in SI Units)
14.4HD3SIU02(Recalibrated HDL(3) Cholesterol in SI Units)
14.5HD2SIU02(Recalibrated HDL(2) Cholesterol in SI Units)
14.6APASIU01(Apolipoprotein AI in SI Units)
14.7APBSIU01(Apolipoprotein B in SI Units)
14.8LDLSIU02(Recalibrated LDL Cholesterol in SI Units)
14.9TRGSIU01(Triglycerides in SI Units)
14.10INSSIU01(Insulin in SI Units)
15.Smoking
15.1CIGT01(Cigarette Smoking Status)
15.2CIGTYR01(Cigarette Years of Smoking)
15.3PIPE01(Pipe Smoking Status)
15.4PIPEYR01(Ounce Years of Smoking)
15.5CIGR01(Cigar/Cigarillo Smoking Status)
15.6CIGRYR01(Cigar/Cigarillo Years of Smoking)
15.7CURSMK01(Current Cigarette Smoker)
15.8FORSMK01(Former Cigarette Smoker)
15.9EVRSMK01(Ever Smoked Cigarettes)
16.Symptom-Specific TIA/Stroke Derived Variables in file STROKE01
16.1Description of the TIA/Stroke variables
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16.2Creation of TIA intermediate variables
16.3Creation of STROKE intermediate variables
16.4Creation of TIA/STROKE intermediate variables
16.5Creation of variable TIA01
16.6Creation of variable STROKE01
16.7Creation of variable STIA01
Figures B-G: ARIC TIA Stroke Algorithm
17.Ankle Brachial Index
17.1 ABI02 (Discontinued)
17.2 ABI03(Discontinued)
17.3 ABI04(Ankle Brachial Index V1, Definition 4)
17.4 ABIV1(ABI measurement status at V1)
17.5PAD01(Peripheral Artery Disease V1, Definition 1)
17.6 PAD02(Peripheral Artery Disease V1, Definition 2-same for both genders)
17.7 LEGANK01(Leg used for ankle BP at V1)
18.Cornell Voltage LVH
18.1LVHSCR01(Cornell voltage in UV (S in V3+R in aVL))
18.2NLVHSC01(Cornell voltage in mm)
18.3CLVH01(LVH present by Cornell)
19. Family History of Stroke, CHD or Diabetes
19.1MOMHXCHD (Maternal history of CHD)
19.2DADHXCHD (Paternal history of CHD)
19.3FAMHXCHD (Family history of CHD)
19.4MOMHXDIA (Maternal history of Diabetes)
19.5DADHXDIA (Paternal history of Diabetes)
19.6FAMHXDIA (Family history of Diabetes)
19.7MOMHXSTR (Maternal history of Stroke)
19.8DADHXSTR (Paternal history of Stroke)
19.9FAMHXSTR (Family history of Stroke)
Appendix A: Medi-Span’s Therapeutic Classification System
Appendix B: AmericanHospital Formulary Service Classification Compilation Number
(AFHSCC Therapeutic Class Code)
Variables in data file DERIVE10in Alphabetic Order
with Labels and Section # in this Dictionary
Variable Name / Variable Label / Section in Dictionary where variable definedABI04 / Ankle Brachial Index V1, Definition 4 / 17.3
ABIV1 / ABI measurement status at V1 / 17.4
APASIU01 / Apolipoprotein AI in mg/L / 14.6
APBSIU01 / Apolipoprotein B in mg/L / 14.7
BIFPLQ01 / Plaque in either carotid bifurcation / 11.4
BIFPS01 / Plaque/shadowing in either carotid bifurcation / 11.14
BIFSHD01 / Shadowing in either carotid bifurcation / 11.1
BIRTHDAT / Date of birth of subject / 9.17
BMI01 / Body mass index in kg/m2 / 2.1
CENTER / Aric field center / 9.20
CHOLMD01 / Cholesterol lowering medication use / 7.5
CHOLMD02 / Meds that secondarily lower cholesterol / 7.6
CIGR01 / Cigar/Cigarillo smoking status / 15.5
CIGRYR01 / Cigar/Cigarillo years of smoking / 15.6
CIGT01 / Cigarette smoking status / 15.1
CIGTYR01 / Cigarette years of smoking / 15.2
CLVH01 / LVH present by Cornell definition / 18.3
COMPLQ01 / Plaque in either common carotid / 11.6
COMPS01 / Plaque/shadowing in either common / 11.13
COMSHD01 / Shadowing in either common carotid / 11.3
CURDRK02 / Current drinker / 1.5
CURSMK01 / Current cigarette smoker / 15.7
DADHXCHD / Paternal history of CHD / 19.2
DADHXDIA / Paternal history of diabetes / 19.5
DADHXSTR / Paternal history of stroke / 19.8
DIABTS02 / Diabetes / 4.16
DIABTS03 / Diabetes with fasting glucose cutpt. <126 / 4.17
DRNKR01 / Drinker status / 1.1
ECGMI04 / Previous MI from composite ECG / 4.14
ECGSEN01 / Derived ECG visual coding flag / 9.22
ELEVEL01 / Education level, definition 1 / 9.3
ELEVEL02 / Education level, definition 2 / 9.4
ETHANL03 / Usual ethanol intake grams/wk / 1.4
EVRDRK01 / Ever drinker / 1.7
EVRSMK01 / Ever smoked cigarettes / 15.9
FAMHXCHD / Family history of CHD / 19.3
FAMHXDIA / Family history of diabetes / 19.6
FAMHXSTR / Family history of stroke / 19.9
FASTO802 / Fasting time of 8 hours or more / 9.12
FAST1202 / Fasting time of 12 hours or more / 9.13
FORDRK01 / Former drinker / 1.6
FORSMK01 / Former cigarette smoker / 15.8
GENDER / Sex (from FTRA22) / 9.18
GLUCOS01 / Derived glucose value in mg/dl / 9.5
GLUSIU01 / Blood glucose level in mmol/L / 14.1
HD2SIU02 / Re-calibrated HDL (2) chol. in mmol/L / 14.5
HD3SIU02 / Re-calibrated HDL (3) chol. in mmol/L / 14.4
HDL01 / Re-calibrated HDL chol. in mmol/L / 13.2
HDL201 / Re-calibrated HDL (2) chol. in mmol/L / 13.3
HDL301 / Re-calibrated HDL (3) chol. in mmol/L / 13.4
HDLSIU02 / Re-calibrated H chol. in mmol/L / 14.3
HORMON02 / Hormone use / 9.16
HXOFMI02 / History of myocardial infraction / 4.13
HYPERT04 / Hypertension, definition 4 / 6.1
HYPERT05 / Hypertension, definition 5 / 6.2
HYPERT06 / Hypertension, definition 6 / 6.3
HYPTMD01 / Hypertension lowering med. Use, def. 1 / 7.1
HYPTMD04 / Hypertension lowering med. Use, def. 4 / 7.4
INSSIU01 / Insulin in pmol/L / 14.10
INTPLQ01 / Plaque in either internal carotid / 11.5
INTPS01 / Plaque/shadowing in either internal carotid / 11.15
INTSHD01 / Shadowing in either internal carotid / 11.2
LBIFPS01 / Plaque/shadowing in left bifurcation / 11.9
LCOMPS01 / Plaque/shadowing in common / 11.7
LDL02 / Re-calibrated LDL chol. in mg/dl / 13.1
LDLSIU02 / Re-calibrated LDL chol. in mmol/L / 14.8
LEGANK01 / Leg used at V1 for ankle BP / 17.7
LINTPS01 / Plaque/shadowing in any left side / 11.11
LISR_I01 / Leisure index / 10.5
LPLQSD01 / Plaque/shadowing in any left side / 11.16
LVHSCR01 / Cornell voltage in uV (S in V3+R in aVL) / 18.1
MACHMI02 / Previous MI from mach.code ECG / 4.15
MDDXMI02 / MD diagnosed myocardial infraction / 4.12
MENOPS01 / Menopausal status / 9.14
MNSSCP01 / Mean subscapular in MM / 2.4
MNTRCP01 / Mean triceps in MM / 2.3
MOMHXCHD / Maternal history of CHD / 19.1
MOMHXDIA / Maternal history of diabetes / 19.4
MOMHXSTR / Maternal history of stroke / 19.7
NLVHSC01 / Cornell voltage in mm / 18.2
OCCUPN01 / Most recent occupation / 9.21
PAD01 / Peripheral artery diseaseV1, Definition 1 / 17.5
PAD02 / PAD V1, Def 2 (same for both genders) / 17.6
PIPE01 / Pipe smoking status / 15.3
PIPEYR01 / Pipe years of smoking / 15.4
PLAQUE01 / Plaque in any site / 11.19
PLAQUE03 / Alt. plaque in any site / 11.20
PLQSHD01 / Plaque/shadowing in any site / 11.18
PREVMI05 / Prevalent MI (composite ECG or Med Hist) / 4.11
PREVCHD05 / Prevalent coronary heart disease / 4.10
QWAVE04A / Diagnostic Q-wave present / 4.5
QWAVE07A / Major Q-wave present w/o 711 or 74 / 4.6
QWAVE008B / Minor Q-wave w Sor ST & no 711/74 / 4.9
QWAVEM07 / Same as QWAVE07A but uses machine code / 4.7
QWAVEM08 / Same as QWAVE08A but uses machine code / 4.8
RACEGRP / Race (from FTRA23) / 9.19
RANGNA01 / Rose angina / 4.2
RBIFPS01 / Plaque/shadowing in right bifurcation / 11.10
RCOMPS01 / Plaque/shadowing in right common / 11.8
RINTPS01 / Plaque/shadowing in right internal / 11.12
ROSEIC03 / Rose intermittent claudication, Def. 3 / 4.3
RPLQSD01 / Plaque/shadowing in any right side / 11.17
RPOSMI01 / Rose possible myocardial infraction / 4.1
SIT_HT01 / Sitting height in CM / 2.2
SPRT_I02 / Sport index def. 2 / 10.4
SYMCHD03 / Symptomatic coronary heart disease / 4.4
TCHSIU01 / Total cholesterol in mmol/L / 14.2
TGLEFH01 / Triglycerides <= mg/dl / 9.6
TOTCAL03 / Total calorie intake in Kcal/day / 9.9
TRGSIU01 / Total triglycerides in mmol/L / 14.9
V1AGE01 / Age at visit 1 / 9.10
V1DATE01 / Visit 1 date / 9.11
WORK_I02 / Work index, definition 2 / 10.1
WPRL_I03 / Work index, definition 3 / 10.2
WSTHPR01 / Waist to hip ratio / 2.5
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1. Alcohol Use
1.1 DRNKR01 (Drinker Status)
This will be a numeric variable with values ranging from 1 to 4. These values are explained below.
1 - Current drinker
2 - Former drinker
3 - Never drinker
4 - Unknown
Table of Assignment of Values to DRNKR01
DTIA91: Have you ever consumed alcoholic beverages? / DTIA90: Do you presently drink alcoholic beverages?Y / N / Missing
Y / 1 / 2 / 4 (d)
N / Missing (a) / 3 / 3 (b)
Missing / 1 / 4 (c) / Missing
(a)Bad data (contradictory answers)
(b)Even though Q90 is not answered, Q91 clearly defines the person as a never drinker
(c)Could be either former or never drinker
(d)Could be either former or current drinker
1.2 ETHANL01 (Discontinued)
1.3 ETHANL02 (Discontinued)
1.4 ETHANL03 (Usual Ethanol Intake in g/wk)
i.Current drinker(DRNKR01 = 1)
ETHANL03 =[(DTIA96) x 10.8]
+[(DTIA97) x 13.2]
+[(DTIA98) x 15.1]
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ii.Former or never drinker
[(DRNKR01 = 2) OR (DRNKR01 = 3)]
ETHANL03 = 0
iii.Any of the following could not be determined:
a.Drinking status
b.Amount of wine
c.Amount of beer
d.Amount of hard liquor
ETHANL03 = missing
DTIA96:Number of glasses of wine per week
{4 oz. glasses; round down}
DTIA97:Number of bottles/cans of beer per week
{12 oz. bottles/cans; round down}
DTIA98:Number of drinks of hard liquor per week
{1.5 oz. shots; round down}
1.5 CURDRK02 (Current Drinker)
CURDRK02 is a categorical variable that takes values according to the definition table below:
CURDRK02 / DTIA90 / DTIA911 / Y / Y or Missing
0 / N / any
Missing / N
T / Y / N
Missing / Not N
DTIA90:Do you presently drink alcoholic beverages?Yes, No
DTIA91:Have you ever consumed alcoholic beverages: Yes, No
1.6 FORDRK01 (Former Drinker)
FORDRK01 is a categorical variable that takes values according to the definition table below:
FORDRK01 / DTIA90 / DTIA911 / N / Y
0 / Y / Y or Missing
N or Missing / N
T / N / Missing
Y / N
Missing / Y or .
DTIA90:Do you presently drink alcoholic beverages?Yes, No
DTIA91:Have you ever consumed alcoholic beverages?Yes, No
1.7 EVRDRK01 (Ever Drinker)
EVRDRK01 is a categorical variable that takes values according to the definition table below:
EVRDRK01 / DTIA90 / DTIA911 / Y / Missing
any / Y
0 / not Y / N
T / Y / N
not Y / Missing
DTIA90:Do you presently drink alcoholic beverages?Yes, No
DTIA91;Have you ever consumed alcoholic beverages?Yes, No
2. Anthropometry
2.1 BMI01 (Body Mass Index in Kg/m2)
[Weight (lbs) / 2.20 ] / [height (cm) / 100 ]2
BMI01 = ( ANTA04 / 2.20 ) / ( ANTA01 / 100)2
= missing, if either or both measure is missing
2.2 SIT_HT01 (Sitting Height) in cm
[ Unadjusted sitting height (cm) ] - [ Stool height (cm) ]
SIT_HT01 = ANTA02 - ANTA03
= missing, if either or both measure is missing
2.3 MNTRCPO1 (Mean Triceps) in mm
Mean of both Triceps measurements (mm)
MNTRCPO1 = Mean ( ANTA05A, ANTA05B )
Where the mean function is the mean for the non-missing values. It is missing if all values are missing.
2.4 MNSSCP01 (Mean Subscapular) in mm
Mean of both Subscapular measurements (mm)
MNSSCP01 = Mean ( ANTA06A, ANTA06B )
Where the mean function is the mean for the non-missing values. It is missing if all values are missing.
2.5 WSTHPR01 (Waist-to-Hip Ratio)
WSTHPR01 = ANTA07A / ANTA07B
ANTA07A : Girth of Waist in cm
ANTA07B : Girth of Hip in cm
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3. B-Mode in file UBMD4(Descriptions of B-Mode Ultrasound Variables)
3.1 Original Derived Variables (See diagram for graphic illustration)
1.mx23:maximum near wall thickness is the maximum of all available (up to eleven) distances between pairs of points on the near wall, using splined data when five or more points were actually read in an interface, or using only observed data when four or less points were read.
There is a *mx23 for every site, where * is one of the prefixes listed in Appendix A, corresponding to the specific site.
lanamx23lbiamx23linamx23lopamx23lpoamx23
ranamx23rbiamx23rinamx23ropamx23rpoamx23
lppamx23qclamx23
rppamx23qc2amx23
2.mx45:is similarly defined, for the far wall
There is a*mx45 for every site, where * is one of the prefixes listed in Appendix A, corresponding to the specific site.
lanamx45lbiamx45linamx45lopamx45lpoamx45
ranamx45rbiamx45rinamx45ropamx45rpoamx45
lppamx45qc1amx45
rppamx45qc2amx45
3.av45:mean far wall thickness, is the arithmetic mean of all available (up to eleven) distances between pairs of points on the far wall, using splined data when five or more points were actually read in an interface, or using only observed data when four or less points were read.
There is a *av45 for every site, where * is one of prefixes listed in Appendix A, corresponding to the specific site.
lanaav45lbiaav45linaav45lopaav45lpoaav45
ranaav45rbiaav45rinaav45ropaav45rpoaav45
lppaav45qc1aav45
rppaav45qc2aav45.
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4.av23:is similarly defined, for the rear wall
there is a *av23 for every site, where * is one of the prefixes listed in Appendix A, corresponding to the specific site.
lanaav23lbiaav23linaav23lopaav23lpoaav23
ranaav23rbiaav23rinaav23ropaav23rpoaav23
lppaav23qc1aav23
rppaav23qc2aav23
5.av25:arterial diameter is similarly defined, as the mean of all available 2-5 distances
There is a *av25 for every site, where * is one of the prefixes listed in Appendix A, corresponding to the specific site.
lanaav25lbiaav25linaav25lopaav25lpoaav25
ranaav25rbiaav25rinaav25ropaav25rpoaav25
lppaav25qc1aav25
rppaav25qc2aav25
6.mn34:minimum lumen diameter, is the minimum of all available (up to eleven) distances between pairs of points on the 3-4 interfaces, using splined data when five or more points were actually read in an interface, or using only observed data when four or less points were read.
There is a *mn34 for every site, where * is one of the prefixes listed in Appendix A, corresponding to the specific site.
lanamn34lbiamn34linamn34lopamn34lpoamn34
ranamn34rbiamn34rinamn34ropamn34rpoamn34
lppamn34qc1amn34
rppamn34qc2amn34
7.DEPTH01is the overall average depth in pixels
8.DEPTH02is the overall average depth in millimeters
9.QC01is the site name of the first repeat site scanned
10.QC02is the site name of the second repeat site scanned
11.QCCNTis the number of QC sites with repeated scans
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3.2 Imputed Ultrasound Data for Far Wall Thickness
This section contains details concerning the imputed ultrasound datasets provided on the ARIC Visit 1 data tapes. The topics covered are:
*description of data set contents
*data sets and variable naming conventions
*imputed versus unimputed data
Description of Data Set Contents
Included on the updated data tapes are four data sets containing imputed ultrasound values. The data set names and variables included in each data set are described below.
Data Set and Variable Naming Conventions
Data Sets Containing Imputed Values
Because gender-race specific regression models were used to perform the imputation, a separate data set exists for White Males, White Females, Black Males, and Black Females. Each data set name consists of UBMD (indicating ultrasound) + IM (indicating the data are imputed) + WM, WF, BF, or BM (indicating the specific gender-race group). For example, the data set containing imputed ultrasound data for white males is named UBMDIMWM. Similarly, the data set containing imputed ultrasound data for black females is named UBMDIMBF. A similar pattern holds for the other gender-race groups.
The variables contained within the data sets are summarized in the table below. Most variable names consist of LBIA, RBIA, LOPA, ROPA, LINA, or RINA (indicating location) + DA or WA (indicating the type of statistic) +45 (indicating that the measurement is of the far wall). There are a few other summary variables which have unique names. These are included in the following list.
VARIABLEDESCRIPTIONTYPE
IDParticipant ID numberCharacter
*DA45Imputed site-specific average far wall thicknessContinuous
*=LBIA, RBIA, LOPA, ROPA, LINA, RINA
*WA45Weight for site-specific imputed average wallContinuous
thickness
*=LBIA, RBIA, LOPA, ROPA, LINA, RINA
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SUM45_1 Simple average of *DA45Continuous
SUM45_2Weighted average of *DA45Continuous
SUM45_3Z score summary statistic for *DA45Continuous
SUMWT45Number of observed values / 6 = weight for Continuous
SUM45_1, 2, or 3
Imputed versus Unimputed Data
You may want to rerun analyses previously run on unimputed (observed) ultrasound data (using the UBMD4 data set), on imputed data (using the UBMDIMxx data sets, where xx can be BM, BF, WM, or WF). Because of the naming conventions used, this should be a relatively easy task. Note that the data set containing unimputed ultrasound data (UBMD) contains variables of average far wall width, such as LINAAV45 and LBIAAV45. These unimputed variables on the UBMD data set correspond to the imputed variables LINADA45 and LBIADA45, respectively, on the UBMDIMxx data sets. Thus, only the middle component of the variable name must be changed for AV (unimputed average) to DA (imputed average). This logic holds true for all of the site-specific averages.
Use of Weights
The weights are a measure of precision which varies by number of sites observed. Regression estimates, using *DA45 or SUM45_1 as dependent variables, will generally be more precise if weighted regression is used.
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Appendix A
B-Mode Derived Variable Site Prefixes
LANLeft Common Carotid: Anterior Angle
RANRight Common Carotid: Anterior Angle
LBI Left Bifurcation
RBIRight Bifurcation
LINLeft Internal Carotid
RINRight Internal Carotid
LOPLeft Common Carotid: Optimal Angle
ROPRight Common Carotid: Optimal Angle
LPOLeft Common Carotid: Posterior Angle
RPORight Common Carotid: Posterior Angle
LPPLeft Popliteal
RPPRight Popliteal
QC1First QC Repeat Scan (refer to QC01 for site identification)
QC2Second QC Repeat Scan (refer to QC02 for site identification)
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Schematic Overview of Carotid Artery B-Mode Ultrasound Measurements
Interfaces:1-Boundary between the periadventitia and adventitia of the near wall (not measured)
2-Boundary between the adventitia and media of the near wall
3-Boundary between the intima of the near wall and the blood
4-Boundary between blood and intima of the far wall
5-Boundary between media and adventitia of the far wall
6-Boundary between adventitia and periadventitia of the far wall (not measured)
Max 23 = B-A; Max 45 = D-C; Min 34 = H-G