Mann et al. · 1998
Researchers exposed healthy volunteers to 900 MHz electromagnetic fields (similar to older cell phones) while they slept and measured hormone levels throughout the night. They found a small, temporary increase in cortisol (stress hormone) right after exposure began, but no effects on growth hormone, reproductive hormones, or melatonin. The study suggests our bodies may quickly adapt to this type of EMF exposure.
Mann, K, Roschke, J, Connemann, B, Beta, H · 1998
Researchers monitored heart rate patterns during sleep in healthy adults exposed to radiofrequency fields from digital mobile phones. They found no changes in heart rate variability or the balance between the sympathetic and parasympathetic nervous systems (the body's automatic stress and rest responses) during EMF exposure compared to placebo conditions. The study suggests that weak pulsed RF fields from mobile phones don't disrupt the heart's natural rhythm control during sleep.
Malyapa RS et al. · 1998
Researchers exposed rats to 2450 MHz microwave radiation (the same frequency used in microwave ovens and some WiFi devices) for 2 hours to see if it would damage DNA in brain cells, as a previous study had suggested. They found no DNA damage in either the brain's cortex or hippocampus regions, contradicting the earlier research. This study suggests that short-term exposure to this type of radiation at moderate levels may not cause immediate genetic damage to brain cells.
Jimenez A et al. · 1998
Spanish researchers tested whether cell phones interfere with implantable cardioverter defibrillators (ICDs), which are life-saving devices that shock the heart back to normal rhythm during dangerous arrhythmias. They found that while phones caused minor interference with monitoring signals, they did not affect the defibrillators' ability to detect or treat heart rhythm problems. The study concluded that cell phone use appears safe for ICD patients, though maintaining 15 cm (6 inches) distance is still recommended as a precaution.
Imaida K et al. · 1998
Japanese researchers exposed rats to 929.2 MHz cell phone radiation for 90 minutes daily over 6 weeks to test whether the radiation could promote liver cancer development. The study used relatively high SAR levels (up to 7.2 W/kg) and found no difference in pre-cancerous liver lesions between exposed and unexposed rats. This suggests that cell phone radiation at these levels does not accelerate liver cancer progression in this animal model.
Imaida et al. · 1998
Researchers exposed rats to 1.439 GHz radiofrequency radiation (the type used in Japanese cell phones) to see if it would promote liver cancer development. Despite using exposure levels up to 1.91 W/kg and finding evidence of biological stress (increased stress hormones), the radiation did not increase cancer-promoting changes in the liver. This suggests that cell phone radiation at these levels does not accelerate liver cancer progression in this animal model.
Frei et al. · 1998
Researchers exposed 100 mice genetically prone to breast cancer to microwave radiation at 2450 MHz (the same frequency used in microwave ovens and early WiFi) for 78 weeks, 20 hours per day. They found no difference in cancer rates between exposed mice (38%) and unexposed mice (30%), and no difference in how quickly tumors developed or grew. This suggests that chronic exposure to this specific level of microwave radiation did not increase breast cancer risk in these cancer-prone animals.
Fetter JG, Ivans V, Benditt DG, Collins J, · 1998
Researchers tested whether digital cell phones interfere with implantable cardioverter-defibrillators (ICDs), life-saving devices that shock the heart back into normal rhythm when dangerous arrhythmias occur. Testing 41 patients with ICDs and various phone models, they found no interference with normal ICD function during typical phone use. However, placing a phone directly on top of an ICD (within half a centimeter) could temporarily disable the device's ability to detect dangerous heart rhythms.
Dmoch A, Moszczynski P · 1998
Polish researchers studied immune system function in workers exposed to microwave radiation from TV transmission and satellite communication equipment (6-12 GHz frequencies). They found several changes in immune cell populations and antibody levels, including increased immunoglobulins (infection-fighting proteins) and altered ratios of different white blood cell types. However, the authors concluded these changes had no clinical significance, meaning they didn't appear to cause actual health problems.
de Seze R, Fabbro-Peray P, Miro L · 1998
French researchers exposed 20 healthy men to cell phone radiation for 2 hours daily over one month and measured six key hormones produced by the pituitary gland. They found no lasting changes in hormone levels, with only a temporary 21% decrease in thyroid-stimulating hormone that returned to normal after exposure ended. This suggests that typical cell phone use doesn't cause permanent disruption to the body's hormone control center.
Malyapa RS et al. · 1998
Researchers exposed rats to microwave radiation at 2450 MHz (the same frequency used in microwave ovens) for 2 hours to test whether it causes DNA breaks in brain cells. They found no DNA damage in either the brain's cortex or hippocampus regions, contradicting an earlier study that reported such damage. This suggests that short-term exposure to this type of microwave radiation at moderate levels may not harm brain cell DNA.
Szmigielski et al. · 1998
Polish researchers studied 61 workers exposed to radiofrequency EMF at radio stations and compared their daily blood pressure and heart rate patterns to 42 unexposed workers. They found that EMF exposure disrupted the natural daily rhythms of both blood pressure and heart rate, with higher exposure levels causing more pronounced effects. This suggests that radiofrequency radiation may interfere with the body's autonomic nervous system, which controls these vital functions.
Shckorbatov YG et al. · 1998
Ukrainian researchers exposed human cheek cells to millimeter wave radiation at 42.2 GHz and found it altered the cells' nuclei in two key ways: it reduced the electrical charge of the cell nucleus and increased chromatin condensation (DNA packaging became tighter). The effects varied based on radiation dose and individual differences between cell donors, suggesting that millimeter wave exposure can directly impact cellular structures at the genetic level.
Michelozzi P, Ancona C, Fusco D, Forastiere F, Perucci CA · 1998
Researchers investigated a cluster of leukemia cases near a high-power radio transmitter in Rome, Italy. They found that men living within 3.5 kilometers of the transmitter had 3.5 times higher leukemia death rates than expected, with risk declining significantly as distance from the transmitter increased. This suggests a potential link between proximity to radio frequency radiation sources and increased leukemia risk in men.
Schlegel RE, Grant FH, Raman S, Reynolds D · 1998
Researchers tested 29 different cardiac pacemaker models with five types of wireless phones to see if the phones interfered with the pacemakers' normal operation. They found that certain combinations caused problems in 21% of tests, with some pacemaker models being particularly vulnerable to interference from specific phone technologies. The study confirmed that keeping phones at least 6 inches away from pacemakers prevents interference, and all devices returned to normal function when the interfering phone was turned off.
Pavel A, Ungureanu CE, Bara II, Gassner P, Creanga DE · 1998
Romanian researchers exposed wheat seeds to low-intensity 9.75 GHz microwaves and examined the genetic material under microscopes. They found multiple types of DNA damage including chromosome fragments, delayed chromosomes, and other cellular abnormalities that didn't appear in unexposed control seeds. This demonstrates that even low-intensity microwave radiation can cause measurable genetic damage in living organisms.
Obukhan KI · 1998
Researchers exposed rats to microwave radiation at frequencies of 2375, 2450, and 3000 MHz and examined the effects on their blood-forming organs including bone marrow, spleen, and thymus. They found structural and functional changes in various types of blood cells that were dependent on radiation intensity, with bone marrow cell development and reproduction showing the most significant disruption. Even at low radiation intensities, the study detected increased numbers of immature blast cells and abnormal cell division patterns.
Nelson BK, Conover DL, Krieg EF Jr, Snyder DL, Edwards RM · 1998
Researchers exposed pregnant rats to radiofrequency radiation at 10 MHz combined with an industrial solvent to see if environmental temperature affected birth defects. They found that while cooler environments required more RF energy to heat the animals' bodies to the same temperature, the rate of developmental abnormalities remained the same. This confirms that RF radiation's harmful effects on developing fetuses depend on how much it heats body tissue, not the specific energy absorption rate.
Kwee S, Raskmark P · 1998
Researchers exposed human cells to 960 MHz microwave radiation (similar to early cell phone frequencies) at different power levels and durations to see how it affected cell growth. They found that microwave exposure consistently reduced cell proliferation compared to unexposed control cells, with stronger fields requiring less exposure time to achieve maximum effects. This suggests that radiofrequency radiation can directly interfere with normal cellular processes in a dose-dependent manner.
Johnson Liakouris AG · 1998
Researchers re-examined health data from U.S. Embassy staff exposed to microwave radiation in Moscow during the Cold War, finding that previously dismissed symptoms matched a recognized pattern called radiofrequency sickness syndrome. The study suggests these health effects were linked to chronic exposure to low-intensity, modulated microwave radiation similar to what we encounter from modern wireless devices.
Irnich W, Tobisch R · 1998
German researchers tested how mobile phones interfere with 224 life-saving medical devices like respirators and defibrillators across 2,016 different scenarios. They found that while interference can occur, dangerous situations are extremely rare because multiple factors must align simultaneously and medical devices have built-in safety features. The study concluded that blanket hospital bans on mobile phones are based on theoretical fears rather than actual evidence, recommending instead a simple 1-meter distance rule from medical equipment.
Hocking, B · 1998
Researchers surveyed 40 mobile phone users who experienced unusual symptoms like burning sensations and dull aches in their head and ears during or after phone calls. These symptoms typically started within minutes of use and lasted up to an hour afterward, with 75% of cases linked to digital phones. The study found that most people got relief by changing how they used their phones or switching to different devices.
Hardell L, Nasman A, Ohlson CG, Fredrikson M. · 1998
Swedish researchers studied 148 men with testicular cancer and 314 healthy controls to identify occupational risk factors. They found that men working with video display units (computer screens) had an 80% higher risk of testicular cancer after extended exposure (about 480 working days). Amateur radio operators, radar workers, and electronics engineers also showed elevated risks, though based on smaller numbers of cases.
Hanson Mild et al. · 1998
Swedish and Norwegian researchers compared symptoms between users of older analog mobile phones (NMT) and newer digital phones (GSM) in a large study of over 17,000 people. Surprisingly, they found that digital phone users actually reported fewer symptoms like warmth sensations around the ear compared to analog users, contradicting their initial hypothesis. However, both phone types showed a clear pattern: the more people talked on their phones, the more they experienced symptoms like headaches, fatigue, and ear warmth.
Grisanti G et al. · 1998
Italian researchers studied how cellular phone radiation affects the inner ear by measuring otoacoustic emissions (tiny sounds the ear produces naturally). They found that the electromagnetic fields from phones altered these natural ear responses in nearly all test subjects. This suggests that phone radiation can interfere with normal inner ear function, potentially affecting hearing.
