More than five percent of the population in La Nora, Murcia, Spain, participated in a survey trying to relate severity of symptoms to power density in the vicinity of a cell phone base station working in DCS-1800 MHz:
This survey contained health items related to ”microwave sickness” or ”RF syndrome.” The microwave power density was measured at the respondents’ homes. Statistical analysis showed significant correlation between the declared severity of the symptoms and the measured power density. The separation of respondents into two different exposure groups also showed an increase of the declared severity in the group with the higher exposure. (E. A. Navarro, J. Segura, M. Portolés, C. Gómez-Perretta de Mateo, ”The Microwave Syndrome: A Preliminary Study in Spain”, Electromag. Biol. and Med. vol 22, issue 2, 2003, DOI: 10.1081/JBC-120024625)
From a population of around 1,900 in La Nora, a little more than a hundred were selected and after individuals with a history of deep psychological or neurological disease were excluded, 101 surveys were considered valid. 47 percent of the respondents were male and 53 percent female, within a wide age range. Navarro et al. write in their article:
The first group ( 250 m from BS). Asthenic syndrome was 42% higher in the first group, diencephalic syndrome was 55% higher in the first group, sensorial alterations were 25% higher in the first group, and cardiovascular alterations 55% higher as well.
Navarro and his co-authors claim that the most interesting aspect of their results is the significance of the dependence between the declared severity of the symptom and the logarithm of the measured electric field:
[…] our work shows a similarity in procedure and results with previous surveys on noise annoyance. […]
Although noise is perceived by the senses, the same is not true for the electromagnetic field. Therefore biasing is less likely in the present study, and the results are probably more objective than in the surveys on noise annoyance.