- Email: [email protected]
LEUKAEMIA RISK IN AMATEUR RADIO OPERATORS
1516
occupational exposure to mains frequency electromagnetic fields,1-3 other studies have not found a correlation.4The question needs further careful study but we disagree with Milham’s conclusion that there is a causal link with amateur radio operations, and we also disagree with the selection of a group of radio amateurs to test his
hypothesis. The operating habits of amateurs are highly variable and often not
subpopulation of 22 nm particles. Antibodies to this receptor (antiHBV infection by pHSA-receptor) could be relevant in reducing the 7 blocking access of the virus to the hepatocyte.7 Dr Coursaget and colleagues (May 18, p 1152) indicate that vaccine containing p34 and p36 polypeptides including pHSA receptors was more immunogenic than vaccine devoid of these receptors. They suggested excluding from the hepatitis B vaccine preparation process all steps which remove or nullify the activity of these receptors. We have receptor activity for pHSA in Merck vaccine (’H-B-Vax; lot 0998J). The tests were done by an enzyme-linked immunosorbent assay on tubes sensitised with glutaraldehyde polymerised human albumin and binding was revealed by anti-HBs/peroxidase.8 Optical densities (at 492 nm) were greater than 2’ 000 in positive samples, 0-115 and 0140 in two negative samples, and 0’ 916 and 0-930 in two samples of Merck vaccine. Furthermore, polystyrene tubes were sensitised with the vaccine suspension from Merck (0 - 30 g/ml) and the binding for polymerised human albumin was revealed with pHSA conjugated with peroxidase. The results (see figure) confirm the species-specificity of this binding. Thus the Merck vaccine contains receptors for pHSA despite treatment with protease, urea, formalin during manufacture of the vaccine. D. E. SANSONNO P. DETOMASO M. A. PAPANICE M. V. PRIMAVERA O. G. MANGHISI
Laboratory of Immunohistochemistry and Medical Section, Istituto di Ricovero e Cura a Carattere Scientifico, Castellana Grotte, Bari, Italy
1 Deinhardt F Control of hepatitis A and B vaccines Ann Clin Res 1982; 14: 326-44. 2 Szmuness W, Stev ens CE, Znag EA, Harley EJ, Kellner A A controlled clinical trial on the efficacy of the hepatitis B vaccine (Heptavax B) a final report. Hepatology 1981,
very extensive. A 1980 survey of 8895 amateurs in the USA and Canada showed that typical amateurs spend 61 hours per week on amateur radio.5 Much of this time is itself highly variable, for most of it is spent listening, with any transmissions made intermittently, with highly modulated (fluctuating) wave-forms, giving low average radiated power. Milham also states that 35% of the Washington amateurs were employed in electrically related occupations. Were the additional cases of leukaemia related to this occupational exposure or to the lesser time spent on amateur radio? Furthermore, silent keys are not representative of the amateur radio community as a whole, deaths being listed in QST only when reported by a family member. Therefore silent keys tend to be those particularly prominent in amateur radio just before their deaths. Amateurs are also more well-to-do than the general population,5which may be an added selection bias. The whole question is further complicated by the possibility that toxic chemicals were commonly present in electrical/electronic equipment in days past.1 There are pitfalls associated with the use of ratios when the population exposed to a risk (and the exposure) is not adequately defined. 6, The numerators of the ratios are known but not the denominators. MacMahon and Pugh8 explain that "numbers of cases of a disease are sometimes expressed relative to the total number of cases of all diseases, rather than to the population. For example, the number of deaths ascribed to a particular disease may be expressed as a proportion of all deaths. This value is known as the proportional mortality rate (PMR). Such proportional rates do not, of course, express the risk of members of the population contracting or dying from the disease. Even Monson,9 originator of PMR and cited by Milham, offers similar caveats, which Milham seems to
ignore. For these reasons, and because of other defects ofMilham’s study in regard to sample sizes, we believe that his hypothesis that electromagnetic fields are carcinogenic remains purely speculative. On the basis of the data we have seen, it cannot be assumed that participation in amateur radio activites increases the risk of leukaemia. Milham’s study has methodological weaknesses similar to those admitted by Wertheimerlo in respect of her studies associating mains frequency fields with cancer incidence (promotion) in children and adults. i1 Milham is less modest: he goes all the way and offers a carcinogenic hypothesis. RAYMOND B. WANGLER, -
Chairman, Committee
5: 377-85
CC, Askey A Susceptibility to hepatitis B despite high titre anti-HBs Lancet 1984, i: 346-47. Swenson PD, Escobar MR, Carithers RL, Sobieski TJ Failure of preexisting antibody
antibody against
hepatitis B surface antigen
to
prevent subsequent hepatitis B infection. Clin
Microbiol
5
1983; 18: 305-09. Iwarson S, Tabor E, Thomas HC, Snoy P, Gerety RJ Protection against hepatitis B
infection by immunization with hepatitis B core antigen Gastroenterology 1985, 88: 763-67. 6 Hopt U, Moller B, Schermer M, Lobeck H. Binding activity of HBsAg particles from chronic HBsAg carriers to polystyrene beads coated with polymerized human serum albumin diagnostic relevance of the assay Liver 1984, 4: 372-78 7 Alberti A, Pontisso P, Schiavon E, Realdi G An antibody which precipitates Dane particles in acute hepatitis type B relation to receptor sites which bind polymerized human serum albumin virus particles Hepatology 1984; 4: 220-26. 8 Sansonno DE, Minoia GM, Detomaso P, Manghisi OG. Binding and receptors for virus
human albumin carriers
polymers and IgM/HBs circulating complex Hepato-Gastroenterology (in press).
in
HBsAg
American Radio Relay League, Newington, Connecticut 06111, USA 1.
2. 3. 4.
chronic
LEUKAEMIA RISK IN AMATEUR RADIO OPERATORS
5 6. 7
(p 814) Dr Milham uses the "silent key" (recent deaths) information from two US states published in the American Radio Relay League’s magazine QST to claim an
8.
increased incidence of certain leukaemias in a group of amateur radio operators as compared with a "normal" population. While some previous studies have suggested a link between leukaemia and
10.
SIR,-In his letter of April
6
on
the
Biological Effects of RF Energy
3 Linnemann 4
_m
9
11.
PETER M. BRADLEY W. D. CLIFT DAVID DAVIDSON LAWRENCE HIGGINS KERRY SANDSTROM ROGER STEPHENS
Peter JM, Mack TM. Leukaemia in workers exposed to electrical and magnetic fields Lancet 1982; ii: 1160-61. McDowall ME Leukaemia mortality in electrical workers in England and Wales. Lancet 1983, i: 246. Coleman M, Bell J, Skeet R. Leukaemia incidence in electrical workers. Lancet 1983,i: 982-83 Environmental health criteria document no 16: radiofrequency and microwaves. Geneva: World Health Organisation, 1981. Sumner D. Survey of amateur radio, 1980. QST 1981 (March); 65: 11-18. Shorr SS Fundamentals of biostatistics. New York: G P Putnam, 1968 Hill AB A short textbook of medical statistics. London: Hodder and Stoughton, 1977: 265-72. MacMahon B, Pugh TF. Epidemiology principles and methods Boston: Little Brown, 1970: 59-60. Monson RR. Analysis of relative survival and proportional mortality. Computers Biomed Res 1974; 7: 331 US Court of Appeals, 7th Circuit. Decision in County of Marquette, Michigan vs Caspar W. Weinburger. No 84-1569: p 21 (decided Aug 20, 1984). Wertheimer N, Leeper E. Adult cancer related to electrical wires near the home. Int J
Wright W,
Epidemiol 1982; 11:
345-55
occupational exposure to mains frequency electromagnetic fields,1-3 other studies have not found a correlation.4The question needs further careful study but we disagree with Milham’s conclusion that there is a causal link with amateur radio operations, and we also disagree with the selection of a group of radio amateurs to test his
hypothesis. The operating habits of amateurs are highly variable and often not
subpopulation of 22 nm particles. Antibodies to this receptor (antiHBV infection by pHSA-receptor) could be relevant in reducing the 7 blocking access of the virus to the hepatocyte.7 Dr Coursaget and colleagues (May 18, p 1152) indicate that vaccine containing p34 and p36 polypeptides including pHSA receptors was more immunogenic than vaccine devoid of these receptors. They suggested excluding from the hepatitis B vaccine preparation process all steps which remove or nullify the activity of these receptors. We have receptor activity for pHSA in Merck vaccine (’H-B-Vax; lot 0998J). The tests were done by an enzyme-linked immunosorbent assay on tubes sensitised with glutaraldehyde polymerised human albumin and binding was revealed by anti-HBs/peroxidase.8 Optical densities (at 492 nm) were greater than 2’ 000 in positive samples, 0-115 and 0140 in two negative samples, and 0’ 916 and 0-930 in two samples of Merck vaccine. Furthermore, polystyrene tubes were sensitised with the vaccine suspension from Merck (0 - 30 g/ml) and the binding for polymerised human albumin was revealed with pHSA conjugated with peroxidase. The results (see figure) confirm the species-specificity of this binding. Thus the Merck vaccine contains receptors for pHSA despite treatment with protease, urea, formalin during manufacture of the vaccine. D. E. SANSONNO P. DETOMASO M. A. PAPANICE M. V. PRIMAVERA O. G. MANGHISI
Laboratory of Immunohistochemistry and Medical Section, Istituto di Ricovero e Cura a Carattere Scientifico, Castellana Grotte, Bari, Italy
1 Deinhardt F Control of hepatitis A and B vaccines Ann Clin Res 1982; 14: 326-44. 2 Szmuness W, Stev ens CE, Znag EA, Harley EJ, Kellner A A controlled clinical trial on the efficacy of the hepatitis B vaccine (Heptavax B) a final report. Hepatology 1981,
very extensive. A 1980 survey of 8895 amateurs in the USA and Canada showed that typical amateurs spend 61 hours per week on amateur radio.5 Much of this time is itself highly variable, for most of it is spent listening, with any transmissions made intermittently, with highly modulated (fluctuating) wave-forms, giving low average radiated power. Milham also states that 35% of the Washington amateurs were employed in electrically related occupations. Were the additional cases of leukaemia related to this occupational exposure or to the lesser time spent on amateur radio? Furthermore, silent keys are not representative of the amateur radio community as a whole, deaths being listed in QST only when reported by a family member. Therefore silent keys tend to be those particularly prominent in amateur radio just before their deaths. Amateurs are also more well-to-do than the general population,5which may be an added selection bias. The whole question is further complicated by the possibility that toxic chemicals were commonly present in electrical/electronic equipment in days past.1 There are pitfalls associated with the use of ratios when the population exposed to a risk (and the exposure) is not adequately defined. 6, The numerators of the ratios are known but not the denominators. MacMahon and Pugh8 explain that "numbers of cases of a disease are sometimes expressed relative to the total number of cases of all diseases, rather than to the population. For example, the number of deaths ascribed to a particular disease may be expressed as a proportion of all deaths. This value is known as the proportional mortality rate (PMR). Such proportional rates do not, of course, express the risk of members of the population contracting or dying from the disease. Even Monson,9 originator of PMR and cited by Milham, offers similar caveats, which Milham seems to
ignore. For these reasons, and because of other defects ofMilham’s study in regard to sample sizes, we believe that his hypothesis that electromagnetic fields are carcinogenic remains purely speculative. On the basis of the data we have seen, it cannot be assumed that participation in amateur radio activites increases the risk of leukaemia. Milham’s study has methodological weaknesses similar to those admitted by Wertheimerlo in respect of her studies associating mains frequency fields with cancer incidence (promotion) in children and adults. i1 Milham is less modest: he goes all the way and offers a carcinogenic hypothesis. RAYMOND B. WANGLER, -
Chairman, Committee
5: 377-85
CC, Askey A Susceptibility to hepatitis B despite high titre anti-HBs Lancet 1984, i: 346-47. Swenson PD, Escobar MR, Carithers RL, Sobieski TJ Failure of preexisting antibody
antibody against
hepatitis B surface antigen
to
prevent subsequent hepatitis B infection. Clin
Microbiol
5
1983; 18: 305-09. Iwarson S, Tabor E, Thomas HC, Snoy P, Gerety RJ Protection against hepatitis B
infection by immunization with hepatitis B core antigen Gastroenterology 1985, 88: 763-67. 6 Hopt U, Moller B, Schermer M, Lobeck H. Binding activity of HBsAg particles from chronic HBsAg carriers to polystyrene beads coated with polymerized human serum albumin diagnostic relevance of the assay Liver 1984, 4: 372-78 7 Alberti A, Pontisso P, Schiavon E, Realdi G An antibody which precipitates Dane particles in acute hepatitis type B relation to receptor sites which bind polymerized human serum albumin virus particles Hepatology 1984; 4: 220-26. 8 Sansonno DE, Minoia GM, Detomaso P, Manghisi OG. Binding and receptors for virus
human albumin carriers
polymers and IgM/HBs circulating complex Hepato-Gastroenterology (in press).
in
HBsAg
American Radio Relay League, Newington, Connecticut 06111, USA 1.
2. 3. 4.
chronic
LEUKAEMIA RISK IN AMATEUR RADIO OPERATORS
5 6. 7
(p 814) Dr Milham uses the "silent key" (recent deaths) information from two US states published in the American Radio Relay League’s magazine QST to claim an
8.
increased incidence of certain leukaemias in a group of amateur radio operators as compared with a "normal" population. While some previous studies have suggested a link between leukaemia and
10.
SIR,-In his letter of April
6
on
the
Biological Effects of RF Energy
3 Linnemann 4
_m
9
11.
PETER M. BRADLEY W. D. CLIFT DAVID DAVIDSON LAWRENCE HIGGINS KERRY SANDSTROM ROGER STEPHENS
Peter JM, Mack TM. Leukaemia in workers exposed to electrical and magnetic fields Lancet 1982; ii: 1160-61. McDowall ME Leukaemia mortality in electrical workers in England and Wales. Lancet 1983, i: 246. Coleman M, Bell J, Skeet R. Leukaemia incidence in electrical workers. Lancet 1983,i: 982-83 Environmental health criteria document no 16: radiofrequency and microwaves. Geneva: World Health Organisation, 1981. Sumner D. Survey of amateur radio, 1980. QST 1981 (March); 65: 11-18. Shorr SS Fundamentals of biostatistics. New York: G P Putnam, 1968 Hill AB A short textbook of medical statistics. London: Hodder and Stoughton, 1977: 265-72. MacMahon B, Pugh TF. Epidemiology principles and methods Boston: Little Brown, 1970: 59-60. Monson RR. Analysis of relative survival and proportional mortality. Computers Biomed Res 1974; 7: 331 US Court of Appeals, 7th Circuit. Decision in County of Marquette, Michigan vs Caspar W. Weinburger. No 84-1569: p 21 (decided Aug 20, 1984). Wertheimer N, Leeper E. Adult cancer related to electrical wires near the home. Int J
Wright W,
Epidemiol 1982; 11:
345-55