Prevalence of headache among handheld cellular telephone users in Singapore: a community study.

We carried out a cross-sectional community study in Singapore to determine the prevalence of specific central nervous system (CNS) symptoms among hand-held cellular telephone (HP) users compared to nonusers and to study the association of risk factors and CNS symptoms among HP users. A total of 808 men and women between 12 and 70 years of age, who lived in one community, were selected using one-stage cluster random sampling and responses to a structured questionnaire. The prevalence of HP users was 44.8%. Headache was the most prevalent symptom among HP users compared to non-HP users, with an adjusted prevalence rate ratio of 1.31 [95% confidence interval, 1.00-1.70]. There is a significant increase in the prevalence of headache with increasing duration of usage (in minutes per day). Prevalence of headache was reduced by more than 20% among those who used hand-free equipment for their cellular telephones as compared to those who never use the equipment. The use of HPs is not associated with a significant increase of CNS symptoms other than headache

Do radiofrequency radiation affect the auditory system of people with occupational exposure?

The present study intended to investigate whether radiofrequency (RF) affects auditory system of people who are occupationally exposed to RF in terms of noise-induced hearing loss (NIHL) or not. The study was carried out on 31 men from 26 to 53 years of age. All of them have been working in the Diyarbakir Radio Broadcasting Station. On the other hand, the control group was based on 30 unexposed voluntary and healthy men. The range of age for control group was the same as in the exposed group (experimental group). The results of the present study showed that the incidence of NIHL in the exposed group is more and more than that of the unexposed (control) group. The incidence of NIHL was approximately found 70 % for exposed group and 6% for unexposed group. The difference of the incidence of NIHL between exposed and unexposed groups were statistically found significant for right and left ears at “4 kHz notch” (p < 0.001). Hearing loss was not observed below 1 kHz. The percentage difference in the incidence of hearing loss (decibel) between control and experimental group was found insignificant for frequency below 1 kHz (p > 0.05). The experimental group was also divided to three subgroups of technicians, officers and men staying in the quarters of radio broadcasting station. Three subgroups were compared with one another statistically. The incidence of NIHL for the right ears of technicians was found higher than the officer (p < 0.05). The incidence of NIHL for the left ears of men staying in quarters was found higher than officers (p < 0.05). The other results of comparison were found insignificant (p > 0.05). In conclusion, the incidence of NIHL at “4 kHz Notch” in the experimental group was found more common than the control group