LETTERS TO THE EDITOR
Japan. Am J Epidemiol 1988; 128398-605. 2. Rome Group for the Epidemiology and Prevention of Cholelithiaau (GREPCO). The epidemiology of gallstone rl.t*... m Rome, Italy. I. Prevalence data m men. Hepatology 19883.-904-*. 3. Rome Group for the Epidemiology and Prevention of Cholelithiasis (GREPCO). The epidemiology of gallstone disease in Rome, Italy. II. Factors associated with the disease Hepatology 1988,8.907-13. 4. Rome Group for the Epidemiology and Prevention of Cholelithiasis (GREPCO). Prevalence of gallstone disease in an Italian adult female population. Am J Epidemiol 1984,119:796-805. 5. Capocaccia L, Rica G, Angebco F, et al, eds. Epidemiology and prevention of gallstone disease. Lancaster, England: MTP Press Ltd, 1984
Livio Capocaccia Division of Gastroenterology Rome University "La Sapienza' Viale deUVnwersita 37 00185 Rome, Italy
1. Nomura H, Kastuwagi S, Hayajtu J, et aL Prevalence of gallstone disease in a general population of Okinawa,
THE FIRST AUTHOR REPLIES In response to Prof. Capocaccia's letter (1), we are embarrassed that we failed to cite the GREPCO paper (2). We wish to apologize to Prof. Capocaccia and his colleagues in the GREPCO group for any ill feelings caused by our omission. The protocol and criteria used in our study (3) are those that have been used in similar studies in Japan for some time. Their similarity to the procedures of the GREPCO group is purely coincidental REFERENCES 1. Capocaccia L. Re: "Prevalence of gallstone disease in a general population of Okinawa, Japan." Am J Epidemiol
1990:131.1098-9. 2 Rome Group for the Epidemiology and Prevention of Cholelithiasis (GREPCO). Prevalence of gallstone diseaw in an Italian adult female population. Am J Epidemiol 1984,119:796-806 3. Nomura H, Kashiwagi S, Haya*hi J, et aL Prevalence of gallstone disease in a general population of Okinawa, Japan. Am J Epidemiol 1988:128.698-606.
Hideyuki Nomura First Dept. of Internal Medicine Kyushu University 71 Fukuoka 812, Japan
RE: "ONCOGENES AND THEIR APPLICATIONS IN EPIDEMIOLOGIC STUDIES" Taylor's recent report on oncogenes in epidemiology (1) was a timely review of an exciting topic, but a few additional comments are in order. I agree with Dr. Taylor that oncogenes may prove to be useful markers for the study of the carcinogenic process in human populations and may be valuable for monitoring, early detection, and prevention of cancer. With the advent of new molecular biologic techniques (e.g., polymerase chain reaction to study genetic changes such as point mutations in oncogenes from a limited amount of cellular material), large scale studies at the DNA level are becoming more feasible. However, studies at the genome level will still require access to cellular materials from the populations studied. As we have pointed out previously (2), this approach may be useful where cellular materials are readily available, e.g., in the examination of sputum and urine cytology specimens in the study of pulmonary and genitourinary carcinogenesis, respectively. However, in most other situations, cellular materials are less readily available. That is why we have chosen to focus on the protein products of oncogenes as potential markers of cancer or cancer risk (3). The advantage of this approach is that oncogene protein products do reach the extra-cellular
environment and are thus susceptible to detection by simple immunoblotting techniques in easily accessible biologic fluids such as serum or urine (4). These oncogene protein products are not only detectable in the biologic fluids of individuals with cancer, but they can also be found in individuals who do not yet have cancer but who may be at risk for the development of malignancy due to occupational or environmental exposures (5). For example, in screening a cohort of hazardous waste workers considered to be at risk for the development of cancer on the basis of their occupational exposure histories, we identified several individuals who had abnormal patterns of oncogene-related proteins in their serum (6). At the time, all of the individuals were clinically healthy. However, within 18 months, one of the individuals with highly aberrant oncogene proteins in his serum had developed rectal bleeding that was found to be due to a premalignant colonic polyp. On removal of the polyp, the individual's serum immunoblot for oncogene protein products reverted to normal (5). This case underscores the potential utility of oncogene protein products as markers for the early detection of oncogenic change. We are currently conducting further studies to confirm
Downloaded from https://academic.oup.com/aje/article-abstract/131/6/1099/109328 by Western Sydney University Library user on 13 January 2019
Prevention of Cholelithiasis (GREPCO), previously published in this Journal (4). Furthermore, a book entitled, Epidemiology and Prevention of Gallstone Disease, edited by our group, has been published (5). These oversights on the part of the authors are all the more surprising given the remarkable similarity between their paper and our 1984 paper (4), including details of the study protocol and of the criteria used to define gallstone disease. While we are happy to see that investigators in Japan have conducted an epidemiologic survey making ample use of our methodological approach and details, we believe that for the sake of scientific exactness, due mention should be made of our group's pioneering work in the field of gallstone epidemiology, which has been widely acknowledged in the editorial comments of international journals.
1099
1100
LETTERS TO THE EDITOR
the predictive value of this approach for early cancer detection and prevention. REFERENCES
Paul W. Brandt-Rauf Division of Environmental Sciences Columbia University School of Public Health 60 Haven Avenue, B-l Level New York, NY 10032
Editor's note: In accordance with Journal policy, Dr. Taylor was asked if he wished to respond to Dr BrandtRaufs letter, but chose not to do so.
RE: "AGREEMENT BETWEEN QUESTIONNAIRE DATA AND MEDICAL RECORDSTHE EVIDENCE FOR ACCURACY OF RECALL" Harlow and Linet (1) reviewed the accuracy with which anamnestic information is being recalled. We very much welcome their effort to create a database which permits an appreciation of the quality of data collected by questionnaire. Concerning the recall of spontaneous abortions, we wish to draw attention to three studies performed among working women in Scandinavian countries (24). In these studies, the occurrence of spontaneous abortions is treated as an outcome rather than as an exposure variable, as in Harlow and Linet (1). The results suggest that recall of reproductive outcome may vary according to factors that are closely linked to exposure status. Axelsson and Rylander (2) reported on a cohort of female laboratory workers within which exposure during pregnancy was determined by questionnaire. They observed that 6 percent of the spontaneous abortions reported by unexposed women could not be verified in medical records, against 18 percent of the events reported by exposed women. The authors suggest that subjective factors played a role in the reporting of these unverified abortions. It cannot be excluded, however, that some of these events did take place but remained unrecorded (5). Spontaneous abortions of short gestation enter less often into medical records (4) and are more often underreported (5), thus leaving the possibility of selective recall by more motivated respondents. In Denmark, laboratory workers and dental chairside assistants were compared with women in professions that presumably involved no exposure to chemicals at work (3). The proportion of reported spontaneous abortions that could not be verified in hospital records was high (43 percent), but lower for exposed women than for unexposed women (36 and 49 percent, respectively). Conversely, exposed women recalled 91 percent of recorded spontaneous abortions, while unexposed women recalled only 79 percent This was related to a more accurate reporting of the date at
which the event occurred, which facilitated the linkage of reported and recorded information. Exposed women also had a better recall of spontaneous abortions that occurred more than 5 years prior to the interview. It is difficult to disentangle whether the observed differences result from differences in educational level between the exposed and the unexposed or whether they reflect a greater motivation on the part of women who are aware of their exposure or who are concerned about the possibility of exposure and any health hazards that might ensue. Thus, a better recall among nurses compared with laundry workers in Finland (4) may either be due to a greater ability to understand and report the information that is being asked or to a greater concern among nurses, resulting from a greater awareness of their exposure and a better understanding of the risks involved. We should therefore suspect the possibility of differential recall of reproductive outcomes between subjects selected according to their exposure status in much the same way as we have learned to look for differential recall of exposure in case-control studies, i.e., in subjects selected according to an outcome of interest. REFERENCES
1. Harlow SD, Linet MS. Agreement between questionnaire data and medical records' the evidence for accuracy of recall. Am J Epidemiol 1989;129-233-48. 2. Axelsson G, Rylander R. Validation of questionnaire reported miscarriage, malformation and birth weight. Int J Epidemiol 1984,13:94-8. 3. Heidam LZ. Olsen J. Self-reported data on spontaneous abortions compared with data obtained by computer linkage with the hospital registry. Scand J Soc Med 1985; 13: 159-63. 4. Lindbohm M-L, Hemminki K. Nationwide data base on medically diagnosed spontaneous abortions in Finland. Int J Epidemiol 1988;17 568-73. 5. Wilcox AJ, Homey LF Accuracy of spontaneous abortion recall. Am J Epidemiol 1984,120-727-33.
Downloaded from https://academic.oup.com/aje/article-abstract/131/6/1099/109328 by Western Sydney University Library user on 13 January 2019
1. Taylor JA. Oncogenes and their applications in epidemiologic studies. Am J Epidemiol 1989^130:6-13. 2. Brandt-Rauf PW, Pincua MR. Oncogenes and oncogene proteins. Occup Med 1987;2:27-38. 3. Brandt-Rauf PW New markers for monitoring occupational cancer the example of oncogene proteins. J Occup Med 1988.30-.399-404. 4. Niman HL, Thomson AMH, Yu A, et aL Anti-peptide antibodies datect oncogene-related proteuu in unne. Proc Natl Acad Sci USA 1985j82:7924-8 5. Brandt-Rauf PW, Smith SJ. Perera FP. Molecular epidenuolofy and environmental carcinogenesis of the lung. In: Witek TJ, Schachter N, eds. Current issues in respi-
ratory public health. Philadelphia. JB Lippincott Co, 1990, in press. 6. Brandt-Rauf PW, Niman HL. Serum screening for oncogene proteins in workers exposed to PCBs. Br J Ind Med 1988.45:689-93
Japan. Am J Epidemiol 1988; 128398-605. 2. Rome Group for the Epidemiology and Prevention of Cholelithiaau (GREPCO). The epidemiology of gallstone rl.t*... m Rome, Italy. I. Prevalence data m men. Hepatology 19883.-904-*. 3. Rome Group for the Epidemiology and Prevention of Cholelithiasis (GREPCO). The epidemiology of gallstone disease in Rome, Italy. II. Factors associated with the disease Hepatology 1988,8.907-13. 4. Rome Group for the Epidemiology and Prevention of Cholelithiasis (GREPCO). Prevalence of gallstone disease in an Italian adult female population. Am J Epidemiol 1984,119:796-805. 5. Capocaccia L, Rica G, Angebco F, et al, eds. Epidemiology and prevention of gallstone disease. Lancaster, England: MTP Press Ltd, 1984
Livio Capocaccia Division of Gastroenterology Rome University "La Sapienza' Viale deUVnwersita 37 00185 Rome, Italy
1. Nomura H, Kastuwagi S, Hayajtu J, et aL Prevalence of gallstone disease in a general population of Okinawa,
THE FIRST AUTHOR REPLIES In response to Prof. Capocaccia's letter (1), we are embarrassed that we failed to cite the GREPCO paper (2). We wish to apologize to Prof. Capocaccia and his colleagues in the GREPCO group for any ill feelings caused by our omission. The protocol and criteria used in our study (3) are those that have been used in similar studies in Japan for some time. Their similarity to the procedures of the GREPCO group is purely coincidental REFERENCES 1. Capocaccia L. Re: "Prevalence of gallstone disease in a general population of Okinawa, Japan." Am J Epidemiol
1990:131.1098-9. 2 Rome Group for the Epidemiology and Prevention of Cholelithiasis (GREPCO). Prevalence of gallstone diseaw in an Italian adult female population. Am J Epidemiol 1984,119:796-806 3. Nomura H, Kashiwagi S, Haya*hi J, et aL Prevalence of gallstone disease in a general population of Okinawa, Japan. Am J Epidemiol 1988:128.698-606.
Hideyuki Nomura First Dept. of Internal Medicine Kyushu University 71 Fukuoka 812, Japan
RE: "ONCOGENES AND THEIR APPLICATIONS IN EPIDEMIOLOGIC STUDIES" Taylor's recent report on oncogenes in epidemiology (1) was a timely review of an exciting topic, but a few additional comments are in order. I agree with Dr. Taylor that oncogenes may prove to be useful markers for the study of the carcinogenic process in human populations and may be valuable for monitoring, early detection, and prevention of cancer. With the advent of new molecular biologic techniques (e.g., polymerase chain reaction to study genetic changes such as point mutations in oncogenes from a limited amount of cellular material), large scale studies at the DNA level are becoming more feasible. However, studies at the genome level will still require access to cellular materials from the populations studied. As we have pointed out previously (2), this approach may be useful where cellular materials are readily available, e.g., in the examination of sputum and urine cytology specimens in the study of pulmonary and genitourinary carcinogenesis, respectively. However, in most other situations, cellular materials are less readily available. That is why we have chosen to focus on the protein products of oncogenes as potential markers of cancer or cancer risk (3). The advantage of this approach is that oncogene protein products do reach the extra-cellular
environment and are thus susceptible to detection by simple immunoblotting techniques in easily accessible biologic fluids such as serum or urine (4). These oncogene protein products are not only detectable in the biologic fluids of individuals with cancer, but they can also be found in individuals who do not yet have cancer but who may be at risk for the development of malignancy due to occupational or environmental exposures (5). For example, in screening a cohort of hazardous waste workers considered to be at risk for the development of cancer on the basis of their occupational exposure histories, we identified several individuals who had abnormal patterns of oncogene-related proteins in their serum (6). At the time, all of the individuals were clinically healthy. However, within 18 months, one of the individuals with highly aberrant oncogene proteins in his serum had developed rectal bleeding that was found to be due to a premalignant colonic polyp. On removal of the polyp, the individual's serum immunoblot for oncogene protein products reverted to normal (5). This case underscores the potential utility of oncogene protein products as markers for the early detection of oncogenic change. We are currently conducting further studies to confirm
Downloaded from https://academic.oup.com/aje/article-abstract/131/6/1099/109328 by Western Sydney University Library user on 13 January 2019
Prevention of Cholelithiasis (GREPCO), previously published in this Journal (4). Furthermore, a book entitled, Epidemiology and Prevention of Gallstone Disease, edited by our group, has been published (5). These oversights on the part of the authors are all the more surprising given the remarkable similarity between their paper and our 1984 paper (4), including details of the study protocol and of the criteria used to define gallstone disease. While we are happy to see that investigators in Japan have conducted an epidemiologic survey making ample use of our methodological approach and details, we believe that for the sake of scientific exactness, due mention should be made of our group's pioneering work in the field of gallstone epidemiology, which has been widely acknowledged in the editorial comments of international journals.
1099
1100
LETTERS TO THE EDITOR
the predictive value of this approach for early cancer detection and prevention. REFERENCES
Paul W. Brandt-Rauf Division of Environmental Sciences Columbia University School of Public Health 60 Haven Avenue, B-l Level New York, NY 10032
Editor's note: In accordance with Journal policy, Dr. Taylor was asked if he wished to respond to Dr BrandtRaufs letter, but chose not to do so.
RE: "AGREEMENT BETWEEN QUESTIONNAIRE DATA AND MEDICAL RECORDSTHE EVIDENCE FOR ACCURACY OF RECALL" Harlow and Linet (1) reviewed the accuracy with which anamnestic information is being recalled. We very much welcome their effort to create a database which permits an appreciation of the quality of data collected by questionnaire. Concerning the recall of spontaneous abortions, we wish to draw attention to three studies performed among working women in Scandinavian countries (24). In these studies, the occurrence of spontaneous abortions is treated as an outcome rather than as an exposure variable, as in Harlow and Linet (1). The results suggest that recall of reproductive outcome may vary according to factors that are closely linked to exposure status. Axelsson and Rylander (2) reported on a cohort of female laboratory workers within which exposure during pregnancy was determined by questionnaire. They observed that 6 percent of the spontaneous abortions reported by unexposed women could not be verified in medical records, against 18 percent of the events reported by exposed women. The authors suggest that subjective factors played a role in the reporting of these unverified abortions. It cannot be excluded, however, that some of these events did take place but remained unrecorded (5). Spontaneous abortions of short gestation enter less often into medical records (4) and are more often underreported (5), thus leaving the possibility of selective recall by more motivated respondents. In Denmark, laboratory workers and dental chairside assistants were compared with women in professions that presumably involved no exposure to chemicals at work (3). The proportion of reported spontaneous abortions that could not be verified in hospital records was high (43 percent), but lower for exposed women than for unexposed women (36 and 49 percent, respectively). Conversely, exposed women recalled 91 percent of recorded spontaneous abortions, while unexposed women recalled only 79 percent This was related to a more accurate reporting of the date at
which the event occurred, which facilitated the linkage of reported and recorded information. Exposed women also had a better recall of spontaneous abortions that occurred more than 5 years prior to the interview. It is difficult to disentangle whether the observed differences result from differences in educational level between the exposed and the unexposed or whether they reflect a greater motivation on the part of women who are aware of their exposure or who are concerned about the possibility of exposure and any health hazards that might ensue. Thus, a better recall among nurses compared with laundry workers in Finland (4) may either be due to a greater ability to understand and report the information that is being asked or to a greater concern among nurses, resulting from a greater awareness of their exposure and a better understanding of the risks involved. We should therefore suspect the possibility of differential recall of reproductive outcomes between subjects selected according to their exposure status in much the same way as we have learned to look for differential recall of exposure in case-control studies, i.e., in subjects selected according to an outcome of interest. REFERENCES
1. Harlow SD, Linet MS. Agreement between questionnaire data and medical records' the evidence for accuracy of recall. Am J Epidemiol 1989;129-233-48. 2. Axelsson G, Rylander R. Validation of questionnaire reported miscarriage, malformation and birth weight. Int J Epidemiol 1984,13:94-8. 3. Heidam LZ. Olsen J. Self-reported data on spontaneous abortions compared with data obtained by computer linkage with the hospital registry. Scand J Soc Med 1985; 13: 159-63. 4. Lindbohm M-L, Hemminki K. Nationwide data base on medically diagnosed spontaneous abortions in Finland. Int J Epidemiol 1988;17 568-73. 5. Wilcox AJ, Homey LF Accuracy of spontaneous abortion recall. Am J Epidemiol 1984,120-727-33.
Downloaded from https://academic.oup.com/aje/article-abstract/131/6/1099/109328 by Western Sydney University Library user on 13 January 2019
1. Taylor JA. Oncogenes and their applications in epidemiologic studies. Am J Epidemiol 1989^130:6-13. 2. Brandt-Rauf PW, Pincua MR. Oncogenes and oncogene proteins. Occup Med 1987;2:27-38. 3. Brandt-Rauf PW New markers for monitoring occupational cancer the example of oncogene proteins. J Occup Med 1988.30-.399-404. 4. Niman HL, Thomson AMH, Yu A, et aL Anti-peptide antibodies datect oncogene-related proteuu in unne. Proc Natl Acad Sci USA 1985j82:7924-8 5. Brandt-Rauf PW, Smith SJ. Perera FP. Molecular epidenuolofy and environmental carcinogenesis of the lung. In: Witek TJ, Schachter N, eds. Current issues in respi-
ratory public health. Philadelphia. JB Lippincott Co, 1990, in press. 6. Brandt-Rauf PW, Niman HL. Serum screening for oncogene proteins in workers exposed to PCBs. Br J Ind Med 1988.45:689-93
