Introduction. The broad spread of cell phones (CP) among schoolchildren and the absence of age standards for their safe use determined the purpose of the study: to reveal the regimens of CP use, critical for the health of children and adolescents. Material and methods. In a cross-sectional study in 2008-2010, by the questionnaire data of 2,137 schoolchildren aged 6-15 years there was assessed the impact of CP usage indices (daily number of calls - CN, call duration - CD, and total daily duration of calls - TCDD) on health (the incidence of headaches and sleep disorders, number of colds). Student and Mann-Whitney criteria and assessment of relative risks were used. Results. The study revealed age-dependent critical values of usage indices (in 6-10 years: CN=2, TCDD=6 minutes.; in 11-13 years: CN=6; in 14-15 years CN=6, CD=3 minutes., TCDD=4 -10 min.), the exceeding of which due to risks: in 6-10 years - to have more than 4 colds a year (OR 2.25, 95% CI 1.09-4.62); in 11-13 years to have several headaches per week (OR 1.61, 95% CI 1.12-2.30); in 14-15 years - to have several headaches (OR 1.79, 95% CI 1.27-2.54) and several sleep disorders (OR 1.66, 95% CI 1.17-2.37) per week. Discussion. Age differences in critical modes of CP use and in health violations, as well as the importance of radiation intensity are discussed. Conclusions. Age-related CP use regimens, critical for health, were established. It was shown the need to develop more precise age criteria for safe CP use with taking into account a wider range of health indicators and radiation intensity.

To test the effect of mobile phones (MP) of various radiation intensities on the functional state of the brain in children and adolescents, a sham-controlled EEG-study was conducted in a group of thirteen 6-13 years old children, including eight 6-10 years old children. The study showed that a 3-minute exposure to the MP causes the significant decline in alpha-band absolute power, which depends on the radiation intensity and the user’s age. Different from sham, an EEG-effect of MP with the energy flux density (EFD) about 100 mW/cm2 was registered both in total, and in a younger (6-10 yr) group. Its bilateral character, more prominent in the hemisphere that is ipsilateral to MP, indicates that this intensity of the radiation influences not only the superficial cortical areas of the ipsilateral hemisphere, but also the deep structures of the brain. MP with the EFD less than 1 mW/cm2 differed from sham by EEG-effect only in the group of children who are 6-10 years old. Its local, ipsilateral character indicates to the superficial influence of such intensity of the radiation on the cortex of the ipsilateral hemisphere. The results show that for the regulation of MP-radiation it’s necessary to consider age features of the brain’s response. The high significance of the EFD, as an index in the assessment of the impact of MP on the EEG of children, is shown. Since almost all schoolchildren are the users of mobile phones, the situation with the valuation of MP-effects on children of various ages, requires hygienic solution.

Introduction. The wide coverage of modern schoolchildren with cell phones (CP), the increased vulnerability of children to radiofrequency radiation, the lack of age standards for safe CP use determined the aim of the study: to identify CP radiation levels and use modes, associated with the health risks in modern schoolchildren. Material and methods. In a cross-sectional study of 80 modern schoolchildren (8.57 ± 0.75 y.o; 2017-2018 education years) without neurological complications in history by measuring CP power flux density (PFD), questioning and risks calculating, there were determined the radiation levels and daily modes of СT use (calls number - CN, duration of call - CD, and calls total duration - CTD), which are associated with the risks of clinically significant health deviations (dizziness, 4 or more colds per year, and frequent (several times a week) headaches, sleep disturbances, fatigue, anxiety, low mood, poor attention, and memory). Results. The risk of dizziness increases when children use CP with a maximal PFD ≥100 µW/cm² (OR = 4.44; 95% CI: 1.15-9.27), or if CTD increases from 6.25 to ≥12 minutes (OR= 8.55; 95% CI 1.74-7.11). Increasing CN from 1-2 to 3-5 causes the risk of frequent anxiety (OR 7.86; 95% CI 1.26-31.8). Using the «push-button» CPs in comparison with smartphones is associated with the frequent low mood (OR= 5.42; 95% CI: 1.47-6.10). Conclusion. The use of «push-button» CР, CР with PFD ≥ 100 µW/cm², CTD ≥ 6.25 minutes, CN > 1-2 cause risks for children’s health

In a one-stage study of 135 Moscow schoolchildren of 1st -3rd grade (2017–2018) the meanings of ener-gy flux density (EFD) of individual mobile phones (MP) was measured, and modes of MP use and health indicators were determined by questionnaires. The EFD maximal values exceeded the norm for adults (100 μW/cm²) in 43.5 % of children. In most children, the total daily duration of calls (TDC) reached 6 minutes, their number (NC) 1–4 and the duration of each (DC) 1–4 minutes. The positive cor-relations (p ≤ 0.04) were found between the time mode of MP use and health violations. They were more numerous in the group of children with normal anamnesis (80 people), in which the influence of MP was not masked by an abnormalities of early development. These correlations were found for the inci-dence of headache (NC r = 0.24, TDC r = 0.26) and of anxiety (DC r = 0.22). The incidence of giddiness positively correlated with the PFD (r = 0.24). Negative correlations (p ≤ 0.04) were found of the fre-quency of inattention, forgetfulness, sleep disorders with the years of MP use (r from –0.24 to –0.36), and also positive correlations were found for the frequency of headache and of anxiety with the age of children (r= 0.27). The results attest to the predominantly negative impact of MP radiation on the chil-dren central nervous system and require the regulation of the MP use in childhood.