Gunnhild Oftedal - Academia.edu (original) (raw)
Papers by Gunnhild Oftedal
Wireless Phones And Health II, 2002
International Archives of Occupational and Environmental Health, 2014
after adjusting for age, gender and otitis as an adult. Among the work exposure variables, years ... more after adjusting for age, gender and otitis as an adult. Among the work exposure variables, years of sailing in the Navy was the strongest predictor of reduced hearing, and significantly reduced hearing was found at the frequencies 1,000, 3,000 and 4,000 Hz. Conclusions Our results indicate that time spent on board vessels in the RNoN is a predictor of reduced hearing.
SPE Health, Safety and Environment in Oil and Gas Exploration and Production Conference, 1991
Scandinavian Journal of Work, Environment & Health, 1999
The purpose of the study was to see whether the results of an earlier study [ie, that skin sympto... more The purpose of the study was to see whether the results of an earlier study [ie, that skin symptoms were reduced by reducing electric fields from visual display units (VDU)] could be reproduced or not. In addition, an attempt was made to determine whether eye symptoms and symptoms from the nervous system could be reduced by reducing VDU electric fields. The study was designed as a controlled double-blind intervention. The electric fields were reduced by using electric-conducting screen filters. Forty-two persons completed the study while working at their ordinary job, first 1 week with no filter, then 3 months with an inactive filter and then 3 months with an active filter (or in reverse order). The inactive filters were identical to the active ones, except that their ground cables were replaced by empty plastic insulation. The inactive filters did not reduce the fields from the VDU. The fields were significantly lower with active filters than with inactive filters. Most of the symptoms were statistically significantly less pronounced in the periods with the filters when compared with the period with no filter. This finding can be explained by visual effects and psychological effects. No statistically significant difference in symptom severeness was observed between the period with an inactive filter and the one with an active filter. The study does not support the hypothesis that skin, eye, or nervous system symptoms can be reduced by reducing VDU electric fields.
Occupational Medicine, 2000
Many people in Norway and Sweden reported headaches, fatigue, and other symptoms experienced in c... more Many people in Norway and Sweden reported headaches, fatigue, and other symptoms experienced in connection with the use of a mobile phone (MP). Therefore, we initiated a cross-sectional epidemiological study among 17,000 people, all using an MP in their job. Thirty-one percent of the respondents in Norway and 13% of those in Sweden had experienced at least one symptom in connection with MP use. Next to the sensations of warmth on the ear and behind/around the ear, burning sensations in the facial skin and headaches were most commonly reported. Most symptoms usually began during or within half an hour after the call and lasted for up to 2 h. Relatively few had consulted a physician or been on sick leave because of the symptoms, but about 45% among those with an MP attributed symptom had taken steps to reduce the symptom. These results suggest an awareness of the symptoms, but not necessarily a serious health problem.
Occupational Medicine, 2001
In 1995 many people reported symptoms such as headaches, feelings of discomfort, warmth behind/ar... more In 1995 many people reported symptoms such as headaches, feelings of discomfort, warmth behind/around or on the ear and difficulties concentrating while using mobile phones. The number of complaints was higher for people using the digital (GSM) system, i.e. with pulse modulated fields, than for those using the analogue (NMT) system. Our main hypothesis was that GSM users experience more symptoms than NMT users. An epidemiological investigation was initiated including 6379 GSM users and 5613 NMT 900 users in Sweden, and 2500 from each category in Norway. The adjusted odds ratio did not indicate any increased risk for symptoms for GSM users compared with NMT 900 users. Our hypothesis was therefore disproved. However, we observed a statistically significant lower risk for sensations of warmth on the ear for GSM users compared with NMT 900 users. The same trend was seen in Norway for sensations of warmth behind/around the ear and in Sweden for headaches and fatigue. Factors distinguishing the two systems (radio frequency emission, phone temperatures and various ergonomic factors) may be responsible for these results, as well as for a secondary finding: a statistically significant association between calling time/number of calls per day and the prevalence of warmth behind/around or on the ear, headaches and fatigue.
Journal of Sound and Vibration, 1980
A modification of Leq is suggested. The modification is based on the simple fact that noise below... more A modification of Leq is suggested. The modification is based on the simple fact that noise below a certain threshold may not be heard, and consequently cannot contribute to the annoyance. Results from laboratory experiments show a reasonably good correlation with subjective evaluation. The proposed index may give a new basis for the understanding of the effects of noise control measures.
Occupational and Environmental Medicine, 2016
Acta Chemica Scandinavica, 1979
Acta Chemica Scandinavica, 1979
Epidemiology (Cambridge, Mass.), Jan 22, 2015
Research about prenatal exposure to electromagnetic fields from cell phones among expectant paren... more Research about prenatal exposure to electromagnetic fields from cell phones among expectant parents and reproductive outcome is limited. The aim of this article is to investigate the association between pregnancy outcome and parental cell phone exposure in a large prospective study. The study was based on the Norwegian Mother and Child Cohort Study conducted during the decade 1999-2009. In that study, pregnant women were recruited before a routine ultrasound examination during gestational week 15; they answered a questionnaire at that time and again around gestational week 30. The expectant father was invited to answer a questionnaire during gestational week 15 (2001-2009). The forms contained questions regarding cell phone use. The response rate was 38.7% and the cohort comprised 100,730 singleton births. Pregnancy outcomes were obtained by linkage to the Medical Birth Registry of Norway. The risk of preeclampsia was slightly lower among women with medium and high cell phone exposu...
Health physics, 2007
The frequency spectra of electromagnetic fields have to be determined to evaluate human exposure ... more The frequency spectra of electromagnetic fields have to be determined to evaluate human exposure in accordance to ICNIRP guidelines. In the literature, comparisons with magnetic field guidelines have been performed by using the frequency distribution of the current drawn from the battery. In the present study we compared the frequency spectrum in the range 217 Hz to 2.4 kHz of the magnetic flux density measured near the surface of a mobile phone with the frequency spectrum of the supply current. By using the multiple frequency rule, recommended in the ICNIRP guidelines, we estimated the magnetic field exposure in the two cases. Similar measurements and estimations were done for an electric drill, a hair dryer, and a fluorescent desk lamp. All the devices have a basic frequency of 50 Hz, and the frequency spectra were evaluated up to 550 Hz. We also mapped the magnetic field in 3D around three mobile phones. The frequency distributions obtained from the two measurement methods are no...
Scandinavian journal of work, environment & health, 1995
The objective of this work was to determine whether facial skin symptoms are reduced by decreasin... more The objective of this work was to determine whether facial skin symptoms are reduced by decreasing static and low-frequency electric fields produced by visual display units. The electric fields were reduced by electric-conducting screen filters. Twenty subjects took part in the study while working at their ordinary jobs, first two weeks without any filter, then two weeks with an inactive filter and two weeks with an active filter (or in reversed order). The inasctive filters were identical to the active ones except that the ground cable was cut. Measurements showed that the inactive filters reduced the static electric fields nonsignificantly less than the active filters. For extremely low-frequency fields the difference was greater, and the active filters reduced the very low-frequency fields significantly more than the inactive ones. Most symptoms were less pronounced with active filters than with inactive filters. The differences were small, and for one symptom only, tingling, pri...
International Archives of Occupational and Environmental Health, 2014
after adjusting for age, gender and otitis as an adult. Among the work exposure variables, years ... more after adjusting for age, gender and otitis as an adult. Among the work exposure variables, years of sailing in the Navy was the strongest predictor of reduced hearing, and significantly reduced hearing was found at the frequencies 1,000, 3,000 and 4,000 Hz. Conclusions Our results indicate that time spent on board vessels in the RNoN is a predictor of reduced hearing.
Acta Chemica Scandinavica, 1979
International Maritime Health, 2013
Part of a crew on a Norwegian naval ship was exposed to the radar waves for approximately 7 min f... more Part of a crew on a Norwegian naval ship was exposed to the radar waves for approximately 7 min from an American destroyer during an incident at sea in August 2012. Information about the exposure was not given by the navy. This is a description of what happened with the crew on board after this event. 14 persons had been on the ship bridge or outside on the deck during the exposure and the rest of the crew had been inside the ship. 27 persons were examined at a hospital 6-8 months after the event, as they had developed a large number of symptoms from different organ systems. They were very worried about all types of possible adverse health effects due to the incident. All were examined by an occupational physician and an ophthalmologist, by an interview, clinical examinations and blood tests at the hospital. The interview of the personnel revealed that they had not experienced any major heating during the episode. Their symptoms developed days or weeks after the radar exposure. They had no objective signs of adverse health effects at the examination related to the incident. Long-term health effect from the exposure is highly unlikely. The development of different symptoms after the incident was probably due to the fear of possible health consequences. Better routines for such incidents at sea should be developed to avoid this type of anxiety.
Reproductive Toxicology, 2012
This is an accepted version of a paper published in Reproductive Toxicology. This paper has been ... more This is an accepted version of a paper published in Reproductive Toxicology. This paper has been peer-reviewed but does not include the final publisher proof-corrections or journal pagination.
Journal of Occupational and Environmental Medicine, 2012
Objectives: To investigate adverse reproductive outcomes among male employees in the Royal Norweg... more Objectives: To investigate adverse reproductive outcomes among male employees in the Royal Norwegian Navy exposed to radiofrequency electromagnetic fields aboard fast patrol boats. Methods: Cohort study of Royal Norwegian Navy servicemen linked to the Medical Birth Registry of Norway, including singleton offspring born between 1967 and 2008 (n = 37,920). Exposure during the last 3 months before conception (acute) and exposure more than 3 months before conception (nonacute) were analyzed. Results: Perinatal mortality and preeclampsia increased after service aboard fast patrol boats during an acute period and also after increased estimated radiofrequency exposure during an acute period, compared with service aboard other vessels. No associations were found between nonacute exposure and any of the reproductive outcomes. Conclusions: Paternal work aboard fast patrol boats during an acute period was associated with perinatal mortality and preeclampsia, but the cause is not clear. exposure during the last 3 months prior to conception and exposure more than 3 months before conception were analyzed separately because of possible differences in biological mechanisms.
Wireless Phones And Health II, 2002
International Archives of Occupational and Environmental Health, 2014
after adjusting for age, gender and otitis as an adult. Among the work exposure variables, years ... more after adjusting for age, gender and otitis as an adult. Among the work exposure variables, years of sailing in the Navy was the strongest predictor of reduced hearing, and significantly reduced hearing was found at the frequencies 1,000, 3,000 and 4,000 Hz. Conclusions Our results indicate that time spent on board vessels in the RNoN is a predictor of reduced hearing.
SPE Health, Safety and Environment in Oil and Gas Exploration and Production Conference, 1991
Scandinavian Journal of Work, Environment & Health, 1999
The purpose of the study was to see whether the results of an earlier study [ie, that skin sympto... more The purpose of the study was to see whether the results of an earlier study [ie, that skin symptoms were reduced by reducing electric fields from visual display units (VDU)] could be reproduced or not. In addition, an attempt was made to determine whether eye symptoms and symptoms from the nervous system could be reduced by reducing VDU electric fields. The study was designed as a controlled double-blind intervention. The electric fields were reduced by using electric-conducting screen filters. Forty-two persons completed the study while working at their ordinary job, first 1 week with no filter, then 3 months with an inactive filter and then 3 months with an active filter (or in reverse order). The inactive filters were identical to the active ones, except that their ground cables were replaced by empty plastic insulation. The inactive filters did not reduce the fields from the VDU. The fields were significantly lower with active filters than with inactive filters. Most of the symptoms were statistically significantly less pronounced in the periods with the filters when compared with the period with no filter. This finding can be explained by visual effects and psychological effects. No statistically significant difference in symptom severeness was observed between the period with an inactive filter and the one with an active filter. The study does not support the hypothesis that skin, eye, or nervous system symptoms can be reduced by reducing VDU electric fields.
Occupational Medicine, 2000
Many people in Norway and Sweden reported headaches, fatigue, and other symptoms experienced in c... more Many people in Norway and Sweden reported headaches, fatigue, and other symptoms experienced in connection with the use of a mobile phone (MP). Therefore, we initiated a cross-sectional epidemiological study among 17,000 people, all using an MP in their job. Thirty-one percent of the respondents in Norway and 13% of those in Sweden had experienced at least one symptom in connection with MP use. Next to the sensations of warmth on the ear and behind/around the ear, burning sensations in the facial skin and headaches were most commonly reported. Most symptoms usually began during or within half an hour after the call and lasted for up to 2 h. Relatively few had consulted a physician or been on sick leave because of the symptoms, but about 45% among those with an MP attributed symptom had taken steps to reduce the symptom. These results suggest an awareness of the symptoms, but not necessarily a serious health problem.
Occupational Medicine, 2001
In 1995 many people reported symptoms such as headaches, feelings of discomfort, warmth behind/ar... more In 1995 many people reported symptoms such as headaches, feelings of discomfort, warmth behind/around or on the ear and difficulties concentrating while using mobile phones. The number of complaints was higher for people using the digital (GSM) system, i.e. with pulse modulated fields, than for those using the analogue (NMT) system. Our main hypothesis was that GSM users experience more symptoms than NMT users. An epidemiological investigation was initiated including 6379 GSM users and 5613 NMT 900 users in Sweden, and 2500 from each category in Norway. The adjusted odds ratio did not indicate any increased risk for symptoms for GSM users compared with NMT 900 users. Our hypothesis was therefore disproved. However, we observed a statistically significant lower risk for sensations of warmth on the ear for GSM users compared with NMT 900 users. The same trend was seen in Norway for sensations of warmth behind/around the ear and in Sweden for headaches and fatigue. Factors distinguishing the two systems (radio frequency emission, phone temperatures and various ergonomic factors) may be responsible for these results, as well as for a secondary finding: a statistically significant association between calling time/number of calls per day and the prevalence of warmth behind/around or on the ear, headaches and fatigue.
Journal of Sound and Vibration, 1980
A modification of Leq is suggested. The modification is based on the simple fact that noise below... more A modification of Leq is suggested. The modification is based on the simple fact that noise below a certain threshold may not be heard, and consequently cannot contribute to the annoyance. Results from laboratory experiments show a reasonably good correlation with subjective evaluation. The proposed index may give a new basis for the understanding of the effects of noise control measures.
Occupational and Environmental Medicine, 2016
Acta Chemica Scandinavica, 1979
Acta Chemica Scandinavica, 1979
Epidemiology (Cambridge, Mass.), Jan 22, 2015
Research about prenatal exposure to electromagnetic fields from cell phones among expectant paren... more Research about prenatal exposure to electromagnetic fields from cell phones among expectant parents and reproductive outcome is limited. The aim of this article is to investigate the association between pregnancy outcome and parental cell phone exposure in a large prospective study. The study was based on the Norwegian Mother and Child Cohort Study conducted during the decade 1999-2009. In that study, pregnant women were recruited before a routine ultrasound examination during gestational week 15; they answered a questionnaire at that time and again around gestational week 30. The expectant father was invited to answer a questionnaire during gestational week 15 (2001-2009). The forms contained questions regarding cell phone use. The response rate was 38.7% and the cohort comprised 100,730 singleton births. Pregnancy outcomes were obtained by linkage to the Medical Birth Registry of Norway. The risk of preeclampsia was slightly lower among women with medium and high cell phone exposu...
Health physics, 2007
The frequency spectra of electromagnetic fields have to be determined to evaluate human exposure ... more The frequency spectra of electromagnetic fields have to be determined to evaluate human exposure in accordance to ICNIRP guidelines. In the literature, comparisons with magnetic field guidelines have been performed by using the frequency distribution of the current drawn from the battery. In the present study we compared the frequency spectrum in the range 217 Hz to 2.4 kHz of the magnetic flux density measured near the surface of a mobile phone with the frequency spectrum of the supply current. By using the multiple frequency rule, recommended in the ICNIRP guidelines, we estimated the magnetic field exposure in the two cases. Similar measurements and estimations were done for an electric drill, a hair dryer, and a fluorescent desk lamp. All the devices have a basic frequency of 50 Hz, and the frequency spectra were evaluated up to 550 Hz. We also mapped the magnetic field in 3D around three mobile phones. The frequency distributions obtained from the two measurement methods are no...
Scandinavian journal of work, environment & health, 1995
The objective of this work was to determine whether facial skin symptoms are reduced by decreasin... more The objective of this work was to determine whether facial skin symptoms are reduced by decreasing static and low-frequency electric fields produced by visual display units. The electric fields were reduced by electric-conducting screen filters. Twenty subjects took part in the study while working at their ordinary jobs, first two weeks without any filter, then two weeks with an inactive filter and two weeks with an active filter (or in reversed order). The inasctive filters were identical to the active ones except that the ground cable was cut. Measurements showed that the inactive filters reduced the static electric fields nonsignificantly less than the active filters. For extremely low-frequency fields the difference was greater, and the active filters reduced the very low-frequency fields significantly more than the inactive ones. Most symptoms were less pronounced with active filters than with inactive filters. The differences were small, and for one symptom only, tingling, pri...
International Archives of Occupational and Environmental Health, 2014
after adjusting for age, gender and otitis as an adult. Among the work exposure variables, years ... more after adjusting for age, gender and otitis as an adult. Among the work exposure variables, years of sailing in the Navy was the strongest predictor of reduced hearing, and significantly reduced hearing was found at the frequencies 1,000, 3,000 and 4,000 Hz. Conclusions Our results indicate that time spent on board vessels in the RNoN is a predictor of reduced hearing.
Acta Chemica Scandinavica, 1979
International Maritime Health, 2013
Part of a crew on a Norwegian naval ship was exposed to the radar waves for approximately 7 min f... more Part of a crew on a Norwegian naval ship was exposed to the radar waves for approximately 7 min from an American destroyer during an incident at sea in August 2012. Information about the exposure was not given by the navy. This is a description of what happened with the crew on board after this event. 14 persons had been on the ship bridge or outside on the deck during the exposure and the rest of the crew had been inside the ship. 27 persons were examined at a hospital 6-8 months after the event, as they had developed a large number of symptoms from different organ systems. They were very worried about all types of possible adverse health effects due to the incident. All were examined by an occupational physician and an ophthalmologist, by an interview, clinical examinations and blood tests at the hospital. The interview of the personnel revealed that they had not experienced any major heating during the episode. Their symptoms developed days or weeks after the radar exposure. They had no objective signs of adverse health effects at the examination related to the incident. Long-term health effect from the exposure is highly unlikely. The development of different symptoms after the incident was probably due to the fear of possible health consequences. Better routines for such incidents at sea should be developed to avoid this type of anxiety.
Reproductive Toxicology, 2012
This is an accepted version of a paper published in Reproductive Toxicology. This paper has been ... more This is an accepted version of a paper published in Reproductive Toxicology. This paper has been peer-reviewed but does not include the final publisher proof-corrections or journal pagination.
Journal of Occupational and Environmental Medicine, 2012
Objectives: To investigate adverse reproductive outcomes among male employees in the Royal Norweg... more Objectives: To investigate adverse reproductive outcomes among male employees in the Royal Norwegian Navy exposed to radiofrequency electromagnetic fields aboard fast patrol boats. Methods: Cohort study of Royal Norwegian Navy servicemen linked to the Medical Birth Registry of Norway, including singleton offspring born between 1967 and 2008 (n = 37,920). Exposure during the last 3 months before conception (acute) and exposure more than 3 months before conception (nonacute) were analyzed. Results: Perinatal mortality and preeclampsia increased after service aboard fast patrol boats during an acute period and also after increased estimated radiofrequency exposure during an acute period, compared with service aboard other vessels. No associations were found between nonacute exposure and any of the reproductive outcomes. Conclusions: Paternal work aboard fast patrol boats during an acute period was associated with perinatal mortality and preeclampsia, but the cause is not clear. exposure during the last 3 months prior to conception and exposure more than 3 months before conception were analyzed separately because of possible differences in biological mechanisms.