TABLE 7: RFR AND GENERAL HEALTH
| Authors | Effects Sought or Examined | Exposure Modality | Effects Reported | Notes & Comments | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Pazderová (1971) | Clinically significant differences between exposed and control groups of both genders in Czechoslovakia. | Occupational exposure to TV transmitters that emitted 48.5-230 MHz RFR at up to 9.2 V/m (0.022 mW/cm²). | Neurotic complaints were less frequent in the exposed than the control group. The only significant difference was a higher mean plasma protein level in the exposed group. | Medical histories of subjects were recorded and each was given a complete medical examination, including blood tests and eye, neurologic and psychiatric examinations.
| Pazderová et al. (1974)
| Mostly changes in the levels of blood-plasma proteins, such as those reported by Pazderová (1971).
| Exposure to RFR from transmitters emitting 60-300 MHz at 0.5-9 V/m, 3-30 MHz at 66 V/m, and 640-1500 kHz at 55 V/m.
| All mean and individual blood-protein levels and their fractions were within normal physiologic limits, but there were significant frequency-band-dependent differences in mean values for the exposed and control groups. However, the changes differed from those of the previous study, e.g., no elevation of gamma-globulin was seen.
| Separate groups were exposed to the three frequency bands, designated as TV, SW, and MW, with a control group for each. The differences in findings of the two studies vitiate the validity of either study.
| Klimkova-Deutschova (1974)
| Computer analysis of 119 health parameters in Czechoslovak workers.
| Occupational exposure of metal and plastic welders, steel temperers, TV and radio technicians, and others to RFR and various other agents.
| Various effects were reported, including EEG disorders and biochemical changes, described as nonthermal RFR effects, but the author indicated that most of the subjects suffered less serious injury than some groups that used noxious chemicals.
| The RFR levels and exposure durations for most groups were not given. The author noted when the differences among groups for specific endpoints were significant, but did not give any data or statistical treatment. Little credence is given to the findings.
| Kalyada et al. (1974)
| Clinical changes due to exposure from RFR generators in the USSR.
| Occupational exposure to RFR in the range 40-200 MHz at not stated nonthermal levels or durations.
| No organic lesions were found, but functional changes in the central nervous system were reported, principally as "vegetative dysfunction accompanied by neurasthenic symptoms".
| The findings were presented in narrative form, with no data given. Changes in a few endpoints relative to controls were shown as bar graphs, but no statistical treatment was given. Findings questionable.
| Sadchikova (1974)
| Clinical changes in health status of two groups of USSR workers.
| RFR-exposure from tuning, testing, and regulating microwave emitters, one group at levels up to a few mW/cm² and another up to a few hundredths of a mW/cm², at unstated frequencies.
| The results were shown in bar-graph form with error bars for percentage changes in 5 neurologic, 6 autonomic-vascular, and 5 cardiac symptoms. The changes in the higher-RFR group were larger than for the control group for all symptoms except arterial hypertension. Similar results were found for the lower-RFR group relative to controls, but for 11 of the 16 symptoms, the differences were larger for the lower-RFR than the higher-RFR group. Lens opacities in both groups did not exceed control values.
| The mixed findings, notably the larger differences for the lower-RFR group, render doubtful that RFR was the causative agent.
| The author described the "asthenic syndrome" and "microwave sickness," neither of which is found in Western RFR-bioeffects studies. Siekierzynski (1974)
| Health status and work fitness of two groups pulsed-radar workers in Poland.
| Group I at average power densities that exceeded 0.2 mW/cm², and Group II at 0.2 mW/cm² or less, both at unspecified radar frequencies. Highest level for Group I was 6 mW/cm² for short times (Siekierzynski et al., 1974a).
| The subjects were given slit-lamp eye examinations and neurologic checkups plus psychological tests and EEGs. Other details were described in Czerski et al. (1974a), and Siekierzynski et al. (1974a, 1974b). The data and their statistical treatment were presented in a set of tables. No significant effects of the RFR were found regarding the health status of either group.
| An unexposed comparison group for Group I was difficult to obtain, so Group II served as the controls, an expedient that weakens the validity of the negative finding.
| Robinette and Silverman (1977)
| RFR-related higher mortality.
| Occupational exposure to RFR of personnel who served in the U.S. Navy during the Korean war (levels and durations not estimated).
| No significant differences were found between the high-exposure and low-exposure groups in deaths from all causes. The death rates from trauma were significantly higher in the high-exposure group, but were not RFR-related.
| The high-exposure group was picked by occupational titles Electronics Technician, Fire Control Technician, Aircraft Electronics Technician. The titles of the low-exposure group were Radioman, Radarman, Aircraft Electrician's Mate.
| Silverman (1979) [Review paper]
| See Robinette and Silverman (1977).
| See Robinette and Silverman (1977). Some in the high-exposure group were exposed at levels exceeding 10 mW/cm² at some times on some ships, but those in the low-exposure group were exposed at well below 1 mW/cm².
| There were no significant RFR-related differences between the high-exposure and low-exposure groups in long-term-mortality or hospitalization patterns. No morbidity data were presented in Robinette and Silverman (1977) or in this review paper.
| Other Naval personnel were added to those included in Robinette and Silverman (1977).
| Robinette et al. (1980)
| Same as Robinette and Silverman (1977). In addition, the numbers of admissions to Naval hospitals in various periods and admission rates for both groups were compared by ICD diagnoses.
| See Robinette and Silverman (1977).
| Only 2 of the 18 comparisons between the high-exposure and low-exposure groups were significant: The low-exposure group had higher admission rates for mental disease, and for accidents, poisonings, and violence. The admission rates did not differ between groups for any disease class.
| ICD = International Classification of Disease.
| The use of occupational titles is open to question, but the large numbers of persons and the estimated exposure levels lend considerable weight to the negative findings. Forman et al. (1982)
| Health effects of an accidental exposure of two military men to high-level RFR, one for 80 seconds and the other for 75 seconds.
| Operation of X-band CW radar tracking system; probable electric field strength about 580 V/m; 90 mW/cm² free-space equivalent.
| Hypertension was diagnosed in both men, but no secondary cause was found. No lenticular opacities were evident. Neurologic results were normal, and various psychological tests showed no evidence of organicity. The overall diagnosis for both men was acute post-traumatic stress disorder.
| Each man exhibited various postexposure physiological and psychological symptoms, and were given extensive medical, ophthalmologic, endocrine, and psychiatric examinations.
| Djordjevich et al. (1979)
| Effects on 322 radar workers in Yugoslavia of occupational exposure to pulsed microwaves for 5-10 years. The controls were 220 persons matched in age, and in working, social, and living conditions.
| Frequencies or other characteristics were not given, but power-density measurements indicated that the workers generally were exposed to less than 5 mW/cm².
| The numbers and percentages of exposed and control subjects diagnosed for various ailments were tabulated. Most prevalent was "Neurocirculatory Asthenia," in 49 (15.2%) of the exposed subjects and 29 (13.2%) of the control subjects; the difference was said to be nonsignificant. The differences between groups for the other ailments were also nonsignificant. The authors concluded that prolonged occupational exposure to microwaves did not affect the health status of the radar workers.
| Clinical examinations included detailed internal, neurologic, ophthalmologic, otologic, hematologic, and biochemical investigations.
| Although health status was not affected by RFR-exposure, the lack of statistical treatment of the data diminishes the credibility of that finding. "Neurocirculatory Asthenia" is a disorder not recognized in Western medicine. Djordjevich et al. (1983)
| A 15-year clinical study for the years 1970, 1975, and 1980 of 500 occupationally RFR-exposed workers; 350 controls were used for comparison.
| Unstated frequencies in the centimeter-wave band, for about 2 hours daily at levels usually less than 5 mW/cm².
| "Neurovegetative Dystonia" was the most prevalent diagnosis, seen in 17% of the exposed group versus 20% in the control group for 1970; in 12% versus 8.8% for 1975; and in 15% versus 10% for 1980. The authors noted that the differences for each year were not significant, but gave no statistical treatment.
| Unclear is whether some or all of the data from Djordjevich et al. (1979) were included. The comment above about the lack of statistical treatment applies here as well.
| "Neurovegetative Dystonia" is also not recognized in Western medicine. Lilienfeld et al. (1978)
| Health effects of RFR-irradiation of the US Embassy in Moscow on the personnel assigned there and their dependents.
| Details are given in Pollack (1979) and in NTIA (1981). Signals were in the range 0.5 to 10 GHz. Highest level was 24 µW/cm² for a 2-hour period.
| Medical records of (US) Moscow employees and their dependents were compared with those of employees and dependents in the embassies and consulates in various Eastern European cities during the same period. No discernible differences were seen between Moscow and control groups in total mortality or mortality from specific causes, or in mortality between groups of dependent children or adults.
| The authors recognized the limitations of this study due to their inability to acquire full sets of medical records, death certificates, and health questionnaire returns, and to the imprecision in classifying the probable extent of RFR-exposure of each employee.
| Hamburger et al. (1983)
| Health effects on male physical therapists from use of various diathermy modalities on patients, based on therapist responses to a questionnaire.
| Surveys by Ruggera (1980) of diathermy units yielded mean equivalent power densities for 2.45-GHz units well below 1 mW/cm². For 27-MHz units, the magnetic-component levels were 1-2.5 mW/cm² and the electric-component levels were 1.2-4.1 mW/cm².
| The modalities were: "microwave (M), shortwave (S), infrared (I), ultrasound (U)". Subgroups were formed for each modality and combined modalities, but some small-size groups were merged. No significant differences were found for the U or I subgroups, but the all-four-modalities (IMSU) subgroup showed significantly higher rates for heart disease than for the other subgroups. A similar finding was reported in the new subgroups formed: "microwave, shortwave, joint microwave/shortwave exposure".
| The small numbers in various subgroups and their merging into larger groups, the absence of supporting results in animal experiments, and the use of self-reported responses to a questionnaire raise strong doubts regarding the validity of the heart-disease finding.
| Burr and Hoiberg (1988)
| Hospitalization rates for Naval pilots of "electronically modified aircraft" (test group) versus the rates for pilots of other types of aircraft (controls).
| Test group presumed exposed to higher ionizing-radiation levels (at higher altitudes) and higher nonionizing-radiation levels (from onboard antennas & electronic equipments) than control group.
| The controls in age group 21-26 years had a significantly higher mortality rate for aviation-related injuries, and higher hospitalization rates for accidents, poisonings, and violence than the test group. The controls in age group 27-32 years had a significantly higher hospitalization rate for mental disorders than the test group. However, neither group had any hospitalizations related to presumed ionizing-radiation or nonionizing-radiation exposure.
| Although the results for both ionizing and nonionizing radiation were negative, the validity of the findings could be questioned because neither the exposure levels nor the exposure durations were measured or estimated.
| Kolmodin-Hedman et al. (1988)
| Health problems from occupational exposure of men & women to RFR from plastic welding machines of various types in Sweden. The findings were based on interviews regarding general health and history, and on tests of eye coordination and neurologic state.
| Electric and magnetic fields in the range 25-30 MHz were probed at each welding machine. No numerical values were given, but the numbers of machines for which either the electric field or the magnetic field exceeded the then Swedish exposure standard were shown.
| Operators of sewing machines comprised the control group for female welders; an adequate control group for male welders could not be found. The fertility outcome of the female welders did not differ significantly from the averages of Swedish birth and malformation registers. About 83% of the control women reported being healthy, compared with about 75% of the welders of both genders.
| Assessment of the results of this this study is difficult because the data presented were insufficient in kind or number to analyze.
| Nilsson et al. (1989)
| RFR effects in radar mechanics & engineers, based on neurologic tests including assays of cerebrospinal fluid (CSF); psychological and psychiatric tests.
| Pulsed 1.3-, 3-, and 10-GHz RFR at a few watts average power from navigational radars, and several kilowatts from air-surveillance radars.
| CSF assays also done on 2 monkeys exposed at 10 mW/cm²(SAR 2.6-4.8 W/kg) to 2.45-GHz pulsed RFR, 1 monkey to CW RFR, and on 1 unexposed monkey. No significant differences were seen between the exposed and control groups of humans in the neurologic and psychological tests or in the CSF assays. However, the monkey CSF assays showed some differences between CW and pulsed exposure.
| Measurements made near some transmitters showed very low RFR leakage levels, but with the magnetron covers removed, some of the levels exceeded Swedish exposure guidelines.
| Little credence can be given to either the positive or negative findings of this study because of the paucity of details on both the human and animal aspects. Goldoni (1990)
| Hematologic effects in 14 radar technicians (male) in air traffic control. The controls consisted of 10 male electronic technicians who worked at the airport but far from any microwave sources.
| Pulsed 1.25-1.35 GHz RFR for 7-14 years at power densities of 10 µW/cm² to 20 mW/cm², generally but less than 5 mW/cm². They periodically entered the near field where the levels ranged up to 20 mW/cm².
| Two counts were done of the peripheral leukocytes, lymphocytes, erythrocytes, reticulocytes, and thrombocytes for each person two years apart. Bar graphs of thrombocyte and leukocyte counts of the exposed men indicated decreases in the 2-year interval between the two tests, results stated to be significant, but similar graphs were not shown for the controls. In addition, the lower final values were within normal limits. No significant differences in lymphocyte and reticulocyte counts were reported.
| Both the positive and negative findings are open to question, mostly because of the small numbers of persons examined.
| Hocking et al. (1991)
| The authors described the Telecom-Australia basic protocol on occupational exposure to RFR for employees who have medical implants such as orthopedic devices, cardiac pacemakers, and cochlear implants.
| An example was given of a radio technician who had had cardiac surgery, and had 1-mm stainless-steel wire sutures securing his sternum. He was exposed to low levels (<2 mW/cm²) of 6-22 MHz RFR, but could be exposed for up to 8 hours at 25-mW/cm² or for 6 minutes at up to 100 mW/cm² [the allowable Australian limits]. He may also have to work at above 30 MHz, but within the limits for those frequencies.
| The electric-field enhancement factors of the structures were determined, the incident fields on the implant from exposure of the person at the Australian RFR limits were calculated, and both were used to calculate the in-situ fields that could cause tissue heating. From heat-transfer calculations, the tissue-temperature rises at the RFR frequencies of interest were tabulated for the indicated exposure limits. The largest temperature rise tabulated was 2.4°C, in the frequency range 1.65-3.0 GHz, for which the short-term (6-minute) exposure limit is 5 mW/cm². The next highest rise was 1.3°C at 80 MHz (near whole-body resonance), for which the short-term exposure limit is also 5 mW/cm². The other temperature rises were all well below 1°C.
| The advice given the subject and management was to permit work at exposure levels up to the occupational limits for frequencies below 30 MHz, but not to permit the subject to work at the maximum short-term limits in the range 50-150 MHz or in the gigahertz range.
| Isa and Noor (1991)
| Discussion of three cases of occupational exposure to RFR treated in a Malaysian outpatient clinic.
| The first case had maintained 1-kW TV transmitters during 2-hour sessions in the transmitter room for 11 years, with the transmitter off; during the 12th year, another transmitter was on while he was doing maintenance. The other two cases worked as aerial riggers, installing and maintaining antennas on 400-foot towers for about 10 years with the transmitters off, but did the work during the 11th year with the transmitters on.
| The three patients displayed symptoms of neck strain accompanied by throbbing headache, irritability, appetite loss, fatigue, memory difficulties, and numbness of extremities. In addition, all three exhibited alopecia areata (a patchy loss of hair) at specific areas of the head. Blood and other laboratory tests on the three patients yielded results within normal ranges, but scalp biopsies confirmed alopecia areata. Steroid injections into the bald areas produced complete hair regrowth. The authors noted that the subjective symptoms above were reversible.
| In the absence of data on the RFR levels in the transmitter rooms in which the first case worked, it is difficult to ascribe any credence to the authors' opinion about a link between alopecia areata and chronic exposure to RFR. Regarding the two aerial riggers, it is conceivable that the RFR levels were within the range that can cause deleterious thermal effects (whole-body SARs well above 4 W/kg), a point noted by Jauchem (1993).
| Papandreou et al. (1992)
| The case of an army officer with a severe illness suggested to be associated with his exposure to RFR while serving at a Greek radar base for 18 years.
| Frequent unauthorized RFR-exposure in the antenna main beam of an "improved high-powered illuminator radar" at levels exceeding 1 mW/cm². The frequencies or other characteristics of the radar were not described.
| The presence of a dense fibrous mass between the lungs (mediastinal fibrosis) that caused a significant occlusion of the left pulmonary artery, with poor perfusion of the left lung.
| The patient was a smoker ("24 pack years"), and previously had been cured of double vision. Without other data on the patient's lifestyle and the fact that this is the only such case in medical records, it seems unlikely that the patient's illness was due to RFR-exposure, a conclusion also reached by Jauchem (1993) and Hocking and Joyner (1993). The latter authors suggested that such radars operate at about 6 GHz, a frequency that does not penetrate very far into wet human tissues, and that the power density at the affected region would only be a few nanowatts per cm².
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