Participation bias, which can happen when people who are diagnosed with brain tumors are more likely than healthy people (known as controls) to enroll in a research study. Also, controls who did not or rarely used cell phones were less likely to participate in the Interphone study than controls who used cell phones regularly. For example, the Interphone study reported participation rates of 78% for meningioma patients (range among the individual studies 56–92%), 64% for glioma patients (range 36–92%), and 53% for control subjects (range 42–74%) (6).
Yes, the information transferred between the base unit (the phone’s stationary unit) and the wireless phone’s mobile unit is transferred as radiowave radiation. Therefore, the “precautionary principle” should also be adopted regarding wireless phones. In addition to the guidelines regarding mobile phones, the Ministry of Health recommends regarding wireless phones:
With our Phone Pouch, you can carry your phone at a safer distance. And with our powerful shielding material that lines the back of the Phone Pouch and deflects up to 99% of cell phone radiation (65-80 dB attenuation of frequencies from 30MHz to 1GHz), you’re exposed to even less harmful cell phone radiation. Our Phone Pouch uses well established science– inside each Pouch is a layer of fabric, interwoven with gossamer thin metallic threads that form a shield to deflect EMF radiation, working much like a Faraday cage.
The perfect way to shield your ears. Comfortable enough to sleep in, and stylish enough to wear in public. High shielding performance silver stretch fabric gives excellent radiofrequency and microwave shielding. Made of double thickness 2" wide 71% polyamide + 29% elastomer fiber. Ideal for cellphone shielding or any other activity when you need to shield your ears and forehead. Thin enough to fit under a hat or helmet. Durable and unwrinkleable, washable too (no bleach). Silver provides anti-bacterial properties and suppresses odor. Folds small for easy transport. Pretty Silver color.

Stick on anti-radiation protection shields etc are often made of metal which may block signal and prevent reliable mobile phone communications with signal towers. Mobile phones recognise the potential for a dropped signal and actually increase power to compensate. The result is a fast draining battery and an even higher radiation output as a result of using the product (an exception to this are shields that are placed in between the phone and the user as these do not impede signal to cell towers to any significant degree)
I love this case. However, I don't understand what happens to the radiation that must collect under the case; isn't there a burst of radiation when the case is opened? I posted this question but the answers were from people who hadn't thought of that issue; they didn't have the answer, except for one who theorized that the radiation is slowly leaking out the top, bottom, and sides. I assume the case keeps radiation off the hand that holds the case with the phone in it, which is great, but I do wonder about the stored radiation when, for example, I'm listening to a podcast with the case closed, then open it later.
The World Health Organization states that "A large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use."[2] In a 2018 statement, the FDA said that "the current safety limits are set to include a 50-fold safety margin from observed effects of radiofrequency energy exposure".[3]

Radiofrequency radiation is a form of electromagnetic radiation. Electromagnetic radiation can be categorized into two types: ionizing (e.g., x-rays, radon, and cosmic rays) and non-ionizing (e.g., radiofrequency and extremely low frequency, or power frequency). Electromagnetic radiation is defined according to its wavelength and frequency, which is the number of cycles of a wave that pass a reference point per second. Electromagnetic frequencies are described in units called hertz (Hz).