GALLBLADDER ULTRASONOGRAPHY Gallbladder examinations were conducted on all examinees aged 20 to 74 years by a certified ultrasound technician in the mobile examination center (MEC). The protocol for this component did not detail any medical, safety or other exclusions. When analyzing these data, the MEC examination sample weight should be used (WTPFEX6). For more information on the use of sample weights in NHANES III data analysis, refer to the NHANES III Analytic and Reporting Guidelines (U.S. DHHS, 1996b). Gallbladder examinations were conducted to estimate the prevalence of gallstone disease in the United States. Testing was done on examinees in both supine and left decubitus positions. The main element of the exam was real-time ultrasonography, a non-invasive technique for detecting gallstones. Although sample persons were asked to fast for at least six hours before the examination, non-fasting persons were not excluded from the examination. The rate of acceptable exams did not differ by fasting status. Details of the data collection procedures and data collection forms for the Gallbladder Ultrasonography component are included in the Gallbladder Ultrasonography Procedures Manual (U.S. DHHS, 1996b) and the Plan and Operation of the Third National Health and Nutrition Examination Survey, 1988-94 (U.S. DHHS, 1996b). All certified ultrasound technicians received training in the physics of ultrasound, calibration of equipment, and technique of administering the abdominal ultrasound examination. This training was conducted at the time of hire and at least annually thereafter by a radiologist and a physicist who were experts in ultrasonography. All examinations were recorded on videotapes and mailed to consulting radiologists who specialized in abdominal ultrasonography. No written comments or technician findings were disclosed to the radiologists to ensure an independent review of cases except for the "rapid review" cases (in which immediate evaluations were needed due to abnormal findings potentially requiring medical attention). A diagnosis of gallstones was made using the common criteria of echoes within the gallbladder with shadowing on two views. Diagnoses first were obtained by the ultrasound technician in the MEC and later were confirmed by a radiologist. If a right upper quadrant or epigastric scar was observed and the gallbladder was not seen, it was concluded that a cholecystectomy had been performed previously. Data for other abnormal pathologies observed in the surrounding areas, such as the liver or the right kidney, also were collected and recorded. Persons in wheelchairs received the ultrasound examination while sitting. The radiologists' diagnoses in GUPR1DX1 and GUPR1DX2 were compared with the technicians' diagnoses in GUPTDX1R and GUPTDX2R. If they agreed with each other, then these were used as the final diagnoses (GUPFDX1R and GUPFDX2R). If the radiologist and the technician disagreed and the radiologist was not confident of the finding because of the poor quality of the video, then the technician's diagnosis was used as the final diagnosis. Also if the radiologist's diagnosis was missing, then the technician's diagnosis was used as the final diagnosis. However, if the radiologist and the technician disagreed and the radiologist had reasonable confidence in his/her findings, then the video taped scan was given to a senior radiologist for adjudication, and that senior radiologist's diagnosis was used as the final diagnosis. The level of agreement between the technician's diagnosis and the radiologist's diagnosis was measured by the Kappa statistic and was found to be excellent (Fleiss, 1981). Analysts should use both final primary and secondary diagnosis variables in analyses. If gallstones were present (codes 3-5), it was indicated in the final, primary diagnosis (GUPFDX1R). Data processing and editing were performed to ensure internal data consistency. Notes have been provided for variables requiring additional explanation. Supplemental information was collected during the household interview. Section J of the Household Adult Questionnaire included questions on self-reported history of abdominal pain, previous diagnosis of gallstones, gallbladder surgery, and medical treatment to dissolve or remove gallstones. A question on newer methods to dissolve gallstones or remove the gallbladder was added in Phase 2 of the survey. This information can be found in the Household Adult Data File. NHANES III Examination Data File ------------------------------------------------------------------------ GALLBLADDER ULTRASONOGRAPHY ------------------------------------------------------------------------ Positions Item description SAS name Counts and code Notes ------------------------------------------------------------------------ 5453 Are there any abdominal surgical scars? GUPQ7 1239 1 Yes 12908 2 No (GUPQ9) 498 8 Blank but applicable 16666 Blank 5454 Surgical scar - area 1 See note GUPQ8A1 869 1 Yes 370 2 No 498 8 Blank but applicable 29574 Blank 5455 Surgical scar - area 2 See note GUPQ8A2 879 1 Yes 360 2 No 498 8 Blank but applicable 29574 Blank 5456 Surgical scar - area 3 See note GUPQ8A3 39 1 Yes 1200 2 No 498 8 Blank but applicable 29574 Blank 5457 Surgical scar - area 4 See note GUPQ8A4 384 1 Yes 855 2 No 498 8 Blank but applicable 29574 Blank 5458 Surgical scar - area 5 See note GUPQ8A5 170 1 Yes 1069 2 No 498 8 Blank but applicable 29574 Blank 5459 Surgical scar - area 6 See note GUPQ8A6 15 1 Yes 1224 2 No 498 8 Blank but applicable 29574 Blank NHANES III Examination Data File ------------------------------------------------------------------------ GALLBLADDER ULTRASONOGRAPHY ------------------------------------------------------------------------ Positions Item description SAS name Counts and code Notes ------------------------------------------------------------------------ 5460-5461 Thickness of gallbladder wall (mm) See note GUPQ18 13125 01-14 2 77 Less than 1 mm 504 88 Blank but applicable 17680 Blank 5462-5463 Gallbladder irregularities finding -- See note GUPQ24R Measurement of largest clump (mm) 744 01-57 319 88 Blank but applicable 30248 Blank 5464 Other non-gallbladder findings - renal - See note GUPQ37R recode after radiologist note review 234 1 Yes 759 8 Blank but applicable 30318 Blank 5465 Other non-gallbladder findings - hepatic See note GUPQ38R or liver - recode after radiologist note review 274 1 Yes 729 8 Blank but applicable 30308 Blank 5466 Radiologist notes indicate liver cyst See note GUPLCSTR 137 1 Yes 137 2 No 729 8 Blank but applicable 30308 Blank 5467-5469 Other non-gallbladder findings - liver See note GUPLCSZE cysts, size (cm) (derived from radiologist's comments) 101 0.5-009 765 888 Blank but applicable 30445 Blank NHANES III Examination Data File ------------------------------------------------------------------------ GALLBLADDER ULTRASONOGRAPHY ------------------------------------------------------------------------ Positions Item description SAS name Counts and code Notes ------------------------------------------------------------------------ 5470 Radiologist notes indicate renal cyst See note GUPRCSTR 161 1 Yes 73 2 No 759 8 Blank but applicable 30318 Blank 5471-5474 Other non-gallbladder findings - renal See note GUPRCSZE cysts, size (cm) (derived from radiologist's comments) 122 0001-09.5 798 8888 Blank but applicable 30391 Blank 5475 Radiologist notes indicate hemangioma See note GUPLHMGR 51 1 Yes 223 2 No 729 8 Blank but applicable 30308 Blank 5476-5478 Other non-gallbladder findings - See note GUPCHSZE cavernous hemangioma of liver, size (cm) (derived from radiologist's comments) 42 001-005 739 888 Blank but applicable 30530 Blank 5479-5480 Technician primary finding See note GUPTDX1R 11618 01 Normal gallbladder 36 02 Gallstones or calcified gallbladder 296 03 Gallstones, one 760 04 Gallstones, multiple 70 05 Gallstones, gallbladder filled 9 06 No conclusion - echo clumps, wall irregular, diffuse echoes within fluid only 1 shadowing view 857 07 Cholecystectomy - right upper quadrant or epigastrum scar, 2 landmarks observed 23 08 Cholecystectomy - right upper quadrant scar, less than 2 landmarks observed 12 09 No conclusion - no scar, no shadow, 2 landmarks observed, SP NHANES III Examination Data File ------------------------------------------------------------------------ GALLBLADDER ULTRASONOGRAPHY ------------------------------------------------------------------------ Positions Item description SAS name Counts and code Notes ------------------------------------------------------------------------ fast 11 10 No conclusion - no scar, no shadow, 2 landmarks observed, SP nonfast 13 11 No conclusion - no scar, less than 2 landmarks observed 1 12 No conclusion - epigastrum scar, less than 2 landmarks observed 432 13 Abnormal gallbladder - focal wall thickness, no shadowing, clumps with no calcification 50 14 Abnormal gallbladder - diffuse wall thickness with no calcification 3 15 Abnormal gallbladder - diffuse wall thickness with calcification 36 16 Abnormal bile - no shadowing internal echoes, with movement 418 88 Blank but applicable 16666 Blank 5481-5482 Technician secondary finding See note GUPTDX2R 25 13 Abnormal gallbladder - focal wall thickness, no shadowing, clumps with no calcification 22 14 Abnormal gallbladder - diffuse wall thickness with no calcification 44 16 Abnormal bile - no shadowing internal echoes, with movement 418 88 Blank but applicable 30802 Blank NHANES III Examination Data File ------------------------------------------------------------------------ GALLBLADDER ULTRASONOGRAPHY ------------------------------------------------------------------------ Positions Item description SAS name Counts and code Notes ------------------------------------------------------------------------ 5483 Radiologist identification number - See note GUPR1ID first reading 1462 1 5090 2 181 3 7174 4 738 8 Blank but applicable 16666 Blank 5484-5485 Radiologist first reading - primary See note GUPR1DX1 finding 11389 01 Normal gallbladder 8 02 Calcified gallbladder 286 03 Gallstones, one 710 04 Gallstones, multiple 80 05 Gallstones, gallbladder filled 2 06 No conclusion - echo clumps, wall irregular, diffuse echoes within fluid only 1 shadowing view 821 07 Cholecystectomy - right upper quadrant or epigastrum scar, 2 landmarks observed 10 08 Cholecystectomy - right upper quadrant scar, less than 2 landmarks observed 18 09 No conclusion - no scar, no shadow, 2 landmarks observed, SP fast 21 10 No conclusion - no scar, no shadow, 2 landmarks observed, SP nonfast 11 11 No conclusion - no scar, less than 2 landmarks observed 3 12 No conclusion - epigastrum scar, less than 2 landmarks observed 444 13 Abnormal gallbladder - focal wall thickness, no shadowing, clumps with no calcification 37 14 Abnormal gallbladder - diffuse wall thickness with no calcification 6 15 Abnormal gallbladder - diffuse wall thickness with calcification NHANES III Examination Data File ------------------------------------------------------------------------ GALLBLADDER ULTRASONOGRAPHY ------------------------------------------------------------------------ Positions Item description SAS name Counts and code Notes ------------------------------------------------------------------------ 41 16 Abnormal bile - no shadowing internal echoes, with movement 758 88 Blank but applicable 16666 Blank 5486-5487 Radiologist first reading - secondary See note GUPR1DX2 finding 1 05 Gallstones, gallbladder filled 1 11 No conclusion - no scar, less than 2 landmarks observed 1 12 No conclusion - epigastrum scar, less than 2 landmarks observed 22 13 Abnormal gallbladder - focal wall thickness, no shadowing, clumps with no calcification 16 14 Abnormal gallbladder - diffuse wall thickness with no calcification 1 15 Abnormal gallbladder - diffuse wall thickness with calcification 19 16 Abnormal bile - no shadowing internal echoes, with movement 758 88 Blank but applicable 30492 Blank 5488 Radiologist first reading - confidence See note GUPR1CNF 12754 1 Certain 960 2 Likely 185 3 Uncertain 746 8 Blank but applicable 16666 Blank 5489 Radiologist first reading - quality See note GUPR1QLT 13141 1 Adequate interpretation 637 2 Below standard 122 3 Uninterpretable 745 8 Blank but applicable 16666 Blank NHANES III Examination Data File ------------------------------------------------------------------------ GALLBLADDER ULTRASONOGRAPHY ------------------------------------------------------------------------ Positions Item description SAS name Counts and code Notes ------------------------------------------------------------------------ 5490 Radiologist identification number - See note GUPR2ID second reading 360 4 758 8 Blank but applicable 30193 Blank 5491-5492 Final primary finding See note GUPFDX1R 11666 01 Normal gallbladder 9 02 Calcified gallbladder 305 03 Gallstones, one 758 04 Gallstones, multiple 86 05 Gallstones, gallbladder filled 1 06 No conclusion - echo clumps, wall irregular, diffuse echoes within fluid only 1 shadowing view 860 07 Cholecystectomy - right upper quadrant or epigastrum scar, 2 landmarks observed 10 08 Cholecystectomy - right upper quadrant scar, less than 2 landmarks observed 16 09 No conclusion - no scar, no shadow, 2 landmarks observed, SP fast 20 10 No conclusion - no scar, no shadow, 2 landmarks observed, SP nonfast 7 11 No conclusion - no scar, less than 2 landmarks observed 3 12 No conclusion - epigastrum scar, less than 2 landmarks observed 466 13 Abnormal gallbladder - focal wall thickness, no shadowing, clumps with no calcification 39 14 Abnormal gallbladder - diffuse wall thickness with no calcification 2 15 Abnormal gallbladder - diffuse wall thickness with calcification 46 16 Abnormal bile - no shadowing internal echoes, with movement 351 88 Blank but applicable 16666 Blank NHANES III Examination Data File ------------------------------------------------------------------------ GALLBLADDER ULTRASONOGRAPHY ------------------------------------------------------------------------ Positions Item description SAS name Counts and code Notes ------------------------------------------------------------------------ 5493-5494 Final secondary finding See note GUPFDX2R 22 13 Abnormal gallbladder - focal wall thickness, no shadowing, clumps with no calcification 17 14 Abnormal gallbladder - diffuse wall thickness with no calcification 3 15 Abnormal gallbladder - diffuse wall thickness with calcification 20 16 Abnormal bile - no shadowing internal echoes, with movement 351 88 Blank but applicable 30898 Blank 5495-5496 Other gallbladder findings - See note GUPGBPSZ gallbladder polyp, size (mm) (derived from radiologist's comments) (years 4, 5, and 6) 271 02-12 568 88 Blank but applicable 30472 Blank 5497-5501 Technician number GUPTECH 6559 01501 7235 01502 535 01503 316 88888 Blank but applicable 16666 Blank NOTES GUPFDX1R, GUPFDX2R: Final primary and secondary diagnoses The radiologist's diagnoses were compared with the technician's diagnoses to determine agreement and to select cases for adjudication. The final primary and secondary diagnoses were a result of this adjudication. Most examined persons had only a single diagnosis, and the code for that diagnosis was placed in GUPFDX1R. For those persons with two diagnoses, the lowest numbered code was placed in GUPFDX1R, and the other code was placed in GUPFDX2R. However, analysts should check both variables for specific codes of interest. GUPGBPSZ: Size of the largest polyp GUPGBPSZ indicates the size of the largest polyp if a polyp was found during the technician's examination or after the radiologist's review (code 13 in either GUPFDX1R or GUPFDX2R). GUPLCSTR, GUPLCSZE: Flag for liver cyst and the size of the largest cyst During the examination, the technician scanned the area surrounding the gallbladder for other abnormal pathologies. Liver abnormality is identified in the variable GUPQ38R. GUPLCSTR indicates the presence of one or more cysts in the liver. GUPLCSZE indicates the size of the largest cyst. GUPLHMGR, GUPCHSZE: Flag for cavernous hemangioma of liver and size of the largest lesion During the examination, the technician scanned the area surrounding the gallbladder for other abnormal pathologies. Liver abnormality is identified in the variable GUPQ38R. The presence of one or more hemangiomas of the liver is recorded in the variable GUPLHMGR. The size of the largest lesion is recorded in the variable GUPCHSZE. GUPQ18: Thickness of gallbladder wall The gallbladder for a person in a non-fasting state may be contracted and appear to have a thickened wall. In such cases, the gallbladder wall thickness may be greater than 3 mm and, according to the computerized recording of results, would have been recorded as code 14, "Abnormal GB -- Diffuse W.T., With NO Calcification" although the gallbladder appeared to be normal to technicians and radiologists. For those persons in a non-fasting status with a contracted gallbladder, the final adjudicated diagnosis was edited and appropriately coded to indicate a normal gallbladder. GUPQ24R: Measurement of largest echo -- clump (mm) This variable provides measurement of the largest gallstone (codes 3 and 4 in GUPFDX1R or GUPFDX2R). GUPQ37R: Other non-gallbladder findings -- renal This variable is a recode of the response to question Q37. GUPQ38R: Other non-gallbladder findings -- hepatic or liver This variable is a recode of the response to question Q38. GUPQ8A1-GUPQ8A6: Flag for abdominal scar and its location To identify the location of a scar in GUPQ8A1-GUPQ8A6, refer to the upper body illustration (p. 394) of the Plan and Operation of the Third National Health and Nutrition Examination Survey, 1988-94 (NCHS, 1994; U.S. DHHS, 1996b). GUPR1CNF, GUPR1QLT: Radiologist's confidence in diagnoses and assessment of quality of the videotape (first reading) Three levels were used on the quality control form to record the radiologist's confidence in the diagnoses and assessment of the videotape quality. If for either variable, level 3 was marked, diagnoses from the corresponding readings were not used in computing the final, adjudicated primary and secondary diagnoses. GUPR1DX1, GUPR1DX2: Radiologists' first reading All videotaped scans were mailed to a radiologist for evaluation, which was recorded on a quality control form. After reviewing the scanned cases, the radiologist marked a maximum of two diagnoses on the quality control form and then evaluated the quality of the tapes, confidence in the diagnosis, and sometimes provided an optional, written comment explaining the diagnosis. Most examined persons had only a single diagnosis, and their code was placed in GUPR1DX1. For those persons with two diagnoses, the lowest numbered code was placed in GUPR1DX1, and the other code was placed in GUPPR1DX2. However, analysts should check both variables for specific codes of interest. GUPR1ID, GUPR2ID: Radiologists' identification numbers These are identification numbers for the radiologists reviewing the videotapes. A total of four radiologists reviewed the videotapes under professional services contracts. After the first reading, all cases with significant disagreements between the technician's diagnosis and the radiologist's diagnosis were reevaluated by the senior radiologist (radiologist number 4). GUPRCSTR, GUPRCSZE: Flag for renal cyst and the size of the largest cyst During the examination, the technician scanned the area surrounding the gallbladder for other abnormal pathologies. Right kidney abnormality is identified in the variable GUPQ37R. The presence of one or more cysts in the kidney is identified in the variable GUPRCSTR. GUPRCSZE indicates the size of the largest cyst. GUPTDX1R, GUPTDX2R: Technician's primary and secondary diagnoses Most examined persons had only a single diagnosis, and the code was placed in GUPTDX1R. For those persons with two diagnoses, the lowest numbered code was placed in GUPTDX1R, and the other code was placed in GUPTDX2R. However, analysts should check both variables for specific codes of interest.