Recently, the domestic media, including Xinhua Viewpoint including a heat transfer is said to be quoted in the British "Guardian" and other "foreign media" reported: called "Recent studies confirm that cell phones and brain cancer."
"The Guardian" and the "Daily Telegraph" and other media indeed released the report related content, May 13, "The Guardian" entitled: "Intensive mobile phone users at higher risk ofbrain cancers" (frequent use of mobile phone users suffer higher risk of brain cancer), spread to domestic mobile phones and brain cancer has become the correlation obtained "confirmed."
"Foreign media" report is based on the May 9 published in the "Journal of Occupational and Environmental Medicine" is a retrospective case-control study from France, then let's look at how this is a study of it ?
[Research report from France]
The researchers from the University of Bordeaux in France, including France, four different Regional Medical Center 447 cases of adult brain cancer patients in 2004 and 2006 confirmed (253 glioma, meningioma 194), and match the age, occupation, region and similar environments 892 residents as a control group of non-brain tumor, by retrospective questionnaire acquisition of these people using a cell phone case. As a result, researchers observed frequently using a mobile phone (use the phone at least once a week, and for six months or more) between brain tumor and is not associated (relative risk of glioma OR = 1.24, OR = 0.90 meningioma ). However, when the time to use the phone as a lifelong cumulative metrics that found frequent use of mobile phones and brain tumors exist between having a statistically significant positive correlation (896 hours glioma OR = 2. meningioma OR = 2.57) while glioma related indicators and converted into the number of calls (18360 phone, OR = 2.10). The researchers concluded that: glioma, temporal tumor, vocational and urban mobile phone users have a relatively high risk.
[Analysis of the research report]
Regardless of this "conclusion" somewhat nondescript, we take a look at how many people reach the study "frequently" (896 lifetime cumulative hours) using your phone's standard? With only 37 cases and 31 controls, and the conclusion of the study refers to gliomas and "frequent" use of mobile phones related, then it becomes a mere sample of 29 cases and 22 controls.
We know that the fewer the number of samples statistically, the greater the chance of statistical bias in the results. For the present study this retrospective epidemiological questionnaire-type survey, 29 cases is not enough to draw any conclusions.
In this study, the bigger problem lies in the choice of the sample, the patient group have been identified in patients with the diagnosis, while the control group was randomly matched population, causes cancer is multifactorial nature of this retrospective study is difficult except for confounding factors Impact. Sample selection bias in the history of this has caused a lot of "Own" of the study, such as the 1981 "New England Journal of Medicine," published correlation between coffee and pancreatic cancer study, it was caused by coffee lovers and manufacturing Suppliers of panic and protests and the overthrow of the subsequent more extensive studies.
Although, like the relationship between mobile phone radiation and cancer such studies impossible to double-blind study, but a prospective cohort study of large sample sets strict design can except more of the confounding factors and avoid like the present study sample selection bias. Fortunately, the British ongoing large prospective studies have recruited more than 29,000 volunteers participate on the exact correlation between the final results and tumor cell phone electromagnetic radiation that we can continue to look forward to, but do not believe according to no rigorous design, a small number of samples of such studies in the "conclusions."
[Theories and viewpoints authority]
In addition to the cause of research epidemiology methods, principles of basic research in order to reveal the nature of things. In theory, mobile phone RF radiation belonging to the low-frequency low-energy non-ionizing electromagnetic radiation, is not enough to cause the material they contain energy electrons in the atom or molecule from its natural orbit to form an ion pair, their biological effects at best, is a thermal effect, and the phone standby even enough to produce thermal effects.
In the past 20 years, scientists around the world on the biological effects of mobile phone electromagnetic radiation extensive research, although there are a few studies suggest that there may be some correlation, including the possibility of leading to the possibility of tumor, brain tumor and wherein the correlation between the most contentious. However, more research is evidence that the mobile phone radio frequency radiation on human health does not pose any hazard.
[Ionizing radiation and non-ionizing radiation]
In reality, the reason why a lot of people "talk about radiation pale", simply because the "nuclear fear" and "fear of ionizing radiation," referring to the radiation seems to simply mean "nuclear radiation" and "ionizing radiation." The following figure shows the different types of electromagnetic radiation wavelength, frequency and energy, high frequency X-rays and -rays belong to ionizing radiation, biological effects can cause DNA damage has teratogenic and carcinogenic effects, it is also well known. Ultraviolet rays can also cause DNA damage, carcinogenic effect, because of sunlight Ultraviolet rays can cause skin cancer, the international authority to warn the public attention to the sun.
Visible light, infrared and radio frequency radio communications, including mobile phones used belong to the low-frequency, low-energy electromagnetic radiation, there is evidence to support the study of the biological effects of thermal effects only, microwave focusing effect can cause tissue necrosis and even carbonized, but in the long radio phone By the time the call state to produce thermal effects people can feel (that is, heat) in the body, under a short talk and standby state, the human body does not produce any effect.
Similarly, household appliances including computers, refrigerators, etc., may also produce electromagnetic radiation, these same radiation on the body does not produce any harmful effects.
Unless the currently accepted scientific theory of the biological effects of electromagnetic radiation to be rewritten, low energy, low frequency electromagnetic radiation cause harmful effects is just one type of alarmist panic, like the mobile phone RF radiation-induced cancer research in fact only be a waste of resources in vain.
The entire contents of a user on Baidu know daily newspaper published a third party is strictly prohibited reproduced. Any third party to use the content, you must contact Baidu know daily zhidaoribao@baidu.com, obtain written authorization to use the content and in the manner prescribed.
Article Source: Baidu know daily (http://zhidao.baidu.com/daily)
Original link: http: //zhidao.baidu.com/daily/view id = 257?