Idiopathic environmental intolerance attributed to electromagnetic field (IEI-EMF) called electromagnetic hypersensitivity or electrosensitivity appeared in Polish society awareness due to a considerable change made at the end of 2019 in Polish telecommunication laws. The aims of the project were to access the prevalence of IEI-EMF in Poland and to define a reliable methodology to study this phenomenon. The first step was the internet survey performed at the end of 2018. The IEI-EMF prevalence estimated at the level of 39.7% suggested considerable bias affecting the results. The faults of the first approach were analysed and then a second study stage was performed as a telephone survey at the end of 2020. The latter survey allowed estimating the prevalence of IEI-EMF as less than 1.8%. These discrepancies in the results of both surveys were connected to the medium used in the first survey (Internet) indirectly causing that the group pooled was not representative. The second pitfall was the definition of the criteria used for an electrosensitive person classification. This is why the IEI-EMF prevalence was investigated in the second stage with the use of numerous criteria. The application of different criteria allowed for essential conclusions concerning the appropriate methodology for such kinds of studies. Corrections of the methodology before the second survey allowed reliable results consistent with the results obtained in similar studies performed in other countries. Our findings also show that the IEI-EMF frequency reports presented in the literature have to be treated carefully and with some dose of scepticism.
Keywords: EMF impact on humans; Electromagnetic hypersensitivity; IEI-EMF; IEI-EMF in Poland; IEI-EMF prevalence; survey studies.