It has been around a year since I have been writing on “Cancer” for your favored monthly magazine “Samvad”, and I expect you would have known by now that about 50% cancers’ are avoidable by simply avoiding high risk behavior such as smoking and adopting certain preventive measures, I have detailed earlier. Notably, our body may also get exposed to certain environmental hazards for which we have limited choices such as air pollution. And among this, use of cell phones, is a newly added hazard. Needless to mention, that cell phones have revolutionized tele-communication and do help save lives such as, dialing for an emergency, police, fire etc and has helped create a safety net for citizens.
However, they have lately gained disrepute as a causal factor for brain tumors. Cell-phone use cause greater exposure to radiofrequency electromagnetic fields (RF-EMF) esp. on the same side of the brain the phone is repeatedly placed. It has been noted that 3G (3rd generation) mobile phones may pose greater threat in this regard; as they emit wide band microwave signals, which may result in higher biological effects.
But before, we draw conclusions let us have a look at the published evidence.
INTERPHONE STUDY 2010
It was the first case-control study conducted on the recommendations of the International Agency for Research on Cancer (IARC). Cases were those who were diagnosed to have brain tumor and controls were normal subjects selected form the same population and matched for known variables. The study was conducted in 13 countries with over 5000 participants. Although the study showed no increase in the risk of brain tumors, an intriguing finding was revealed on dose-response relationship. At the highest level of exposure based on number of phone calls and cumulative call time, an increased risk was suggested, warranting further investigations. Also, tumors of temporal lobe of the brain which happens to be closest to the ear had highest association with the exposure.
MILLION WOMEN STUDY 2013
It was a large prospective study conducted on women only in the UK. The relationship between mobile use and brain tumors was studied, but failed to find a strong link between the two. However, the incidence of a specific subtype of brain tumor known as acoustic neuroma (a slow growing brain tumor) was found to be increased significantly among long term cell-phone users (>10 yrs).
SWEDISH STUDY 2014
It is the latest case –control study with over 5000 participants and pooled data from 2 previous studies conducted between 1997-2003 and 2007-09. The analysis of the Swedish data showed increased risk even with use of > 1 year of cell/cordless phones and highest (3 times higher) risk with use >25 years. The risk was higher for those who started cell-phone use before the age of 20 years; as the brain is still developing at that age, has higher conductivity and also the skull bones are thinner. The dose-response relationship was again highlighted in this study.
COSMOS STUDY (YET TO BE PUBLISHED)
It must be noted that the abovementioned studies do suffer from recall bias, as the affected individual tries to solve the question of why me? However, the ongoing studies such as cosmos study are trying to improve exposure assessment by using records of mobile phone use, to better understand dose-relationship and establish safety cut-offs.
While the scientists are working hard to prove or refute “casual” relationship, there are certain precautions that one can easily exercise.
- Use of hands-free (decrease exposure to less than 10%, than use at the ear)
- Use of phones with loud-speaker
- Texting instead of phoning, whenever possible
- Frequently changing side of the ear while listening
- Selective use of 3G connection
IARC’s working Group in 2011 classified RF-EMF as “possibly carcinogenic to humans” and their 2013 report, labels a “causal” relationship between use of mobile phones and brain tumors as “possible” though not “definitive”.
While the jury is still out, the “bell” of their (cell phones) causal effect for brain tumors has already “rung”, and following the said precautions will only be a matter of discretion.