携帯電話が脳腫瘍を起こすかどうかは議論が進行中であるが、新たな研究で影響しないという。30年に及ぶスカンジナビアでの脳腫瘍発生率は大きな変化がないという。しかし、コペンハーゲンのガン疫学研究所Isabelle Deltour は、脳腫瘍増加を見るほど使用していなかったという可能性はあるとしている。|
No Increase in Brain Tumors Seen From Cell Phones
Despite new findings, doubts linger about whether they cause brain cancer
By Steven ReinbergHealthDay Reporter
Despite new findings, doubts linger about whether they cause brain cancer.
THURSDAY, Dec. 3 (HealthDay News) -- Whether cell phones cause brain cancer has been a subject of ongoing debate, but a new study confirms previous evidence suggesting that they don't.
A 30-year examination of the incidents of brain tumors in Scandinavia found no substantial change in prevalence even after cell phone use became widespread, according to the report in the Dec. 3 online edition of the Journal of the National Cancer Institute.
"If mobile phones were to cause brain tumors we would expect to see a sudden rise in the number of brain tumors at some point in time, and we don't see it," said lead researcher Isabelle Deltour, from the Institute of Cancer Epidemiology at the Danish Cancer Society in Copenhagen.
However, Deltour leaves the door open to the possibility that widespread cell phone use hasn't been around long enough to see an increase in brain tumors.
"Either it means that mobile phones don't cause brain tumors or it means that we don't see it yet or we don't see it because the increase is too small to be observed in this population, or it is a risk that is limited to a small subgroup of the population," she said.
Deltour's team will continue to look at the rates of brain tumors in the study group, she added.
For the study, Deltour's team collected data on 60,000 people diagnosed with glioma and meningioma in Denmark, Finland, Norway and Sweden between 1974 and 2003.
The researchers found that the incidence of brain tumors over this 30-year period were stable, decreased or gradually increased, starting before cell phones became popular.
In addition, there was no change in the incidence of brain tumors between 1998 and 2003, during a period of rapid increase in cell phone usage, the researchers noted.
Dr. Paul Graham Fisher, an associate professor of neurology, pediatrics, and neurosurgery and human biology and the Beirne Family Director of Neuro-Oncology at Stanford University, said that "this topic won't go away."
Fisher thinks that like so many irrational fears, such as harm from radiation from electric wires, the connection between cell phones and brain tumors will persist even though there is no scientific evidence for such a connection.
"This is sort of the high-tension wires of our time," Fisher said. "This is an issue that is probably not going to go away, because people have this suspicion and it's fueled by some public paranoia and by people who make very provocative statements, and that is enough to make it not go away, despite very good science."
However, a review of existing research on the topic, published online Oct. 13 in the Journal of Clinical Oncology, did find a slight, potentially harmful association between cell phone use and brain tumors.
Commenting on that study, Dr. Deepa Subramaniam, director of the Brain Tumor Center at Georgetown Lombardi Comprehensive Cancer Center in Washington, D.C., said at the time that "we cannot make any definitive conclusions about this. But this study, in addition to all the previous studies, continues to leave lingering doubt as to the potential for increased risk. So, one more time, after all these years, we don't have a clear-cut answer."
For more information on cancer and cell phones, visit the U.S. National Cancer Institute.
SOURCES: Isabelle Deltour, Ph.D., Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen; Paul Graham Fisher, M.D., associate professor, neurology, pediatrics, and neurosurgery and human biology, and the Beirne Family Director of Neuro-Oncology, Stanford University, Palo Alto, Calif.; Dec. 3, 2009, Journal of the National Cancer Institute, online
Copyright (c) 2009 ScoutNews, LLC. All rights reserved.
Journal of Clinical Oncology, Vol 27, No 33 (November 20), 2009: pp. 5565-5572
(c) 2009 American Society of Clinical Oncology.
Mobile Phone Use and Risk of Tumors: A Meta-Analysis
Seung-Kwon Myung, Woong Ju, Diana D. McDonnell, Yeon Ji Lee, Gene Kazinets, Chih-Tao Cheng, Joel M. Moskowitz
From the Smoking Cessation Clinic, Center for Cancer Prevention and Detection; Division of Cancer Prevention, National Cancer Control Research Institute, National Cancer Center, Goyang; Department of Obstetrics and Gynecology, School of Medicine, Ewha Womans University; Department of Family Medicine, Seoul National University Hospital, Seoul, Republic of Korea; and Center for Family and Community Health, School of Public Health, University of California, Berkeley, Berkeley, CA.
Corresponding author: Seung-Kwon Myung, MD, MS, 111 Jungbalsan-ro, Ilsandong-gu, Goyang, Gyeonggi-do, 410-769, Republic of Korea; e-mail: firstname.lastname@example.org.
Purpose Case-control studies have reported inconsistent findings regarding the association between mobile phone use and tumor risk. We investigated these associations using a meta-analysis.
Methods We searched MEDLINE (PubMed), EMBASE, and the Cochrane Library in August 2008. Two evaluators independently reviewed and selected articles based on predetermined selection criteria.
Results Of 465 articles meeting our initial criteria, 23 case-control studies, which involved 37,916 participants (12,344 patient cases and 25,572 controls), were included in the final analyses. Compared with never or rarely having used a mobile phone, the odds ratio for overall use was 0.98 for malignant and benign tumors (95% CI, 0.89 to 1.07) in a random-effects meta-analysis of all 23 studies. However, a significant positive association (harmful effect) was observed in a random-effects meta-analysis of eight studies using blinding, whereas a significant negative association (protective effect) was observed in a fixed-effects meta-analysis of 15 studies not using blinding. Mobile phone use of 10 years or longer was associated with a risk of tumors in 13 studies reporting this association (odds ratio = 1.18; 95% CI, 1.04 to 1.34). Further, these findings were also observed in the subgroup analyses by methodologic quality of study. Blinding and methodologic quality of study were strongly associated with the research group.
Conclusion The current study found that there is possible evidence linking mobile phone use to an increased risk of tumors from a meta-analysis of low-biased case-control studies. Prospective cohort studies providing a higher level of evidence are needed.
Written on behalf of the Korean Meta-Analysis (KORMA) Study Group.
Supported in part by the Centers for Disease Control and Prevention through Cooperative Agreement No. U48/DP000033 (D.D.M., G.K., J.M.M.).
The contents of the article are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention.
Authors' disclosures of potential conflicts of interest and author contributions are found at the end of this article.
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