Survey of mobile phone use and their chronic effects on the hearing of a student population

Effect of Electromagnetic Radiation from Mobile Phones on Auditory Brainstem Response

Mobile phones are being used by around 70% of the global population. A simple non-invasive procedure to detect early impairment of the acoustic nerve and auditory pathway is by auditory brainstem response (ABR). It's a response to the sound stimulus generated from the brainstem in the form of electrical impulses. To determine the effect of long-term usage of mobile phones on auditory brainstem responses (ABRs). This Epidemiological, cross-sectional study was undertaken at a tertiary care hospital and includes 865 individuals aged between 18 to 45 years using mobile phone for > 2 years. Users were categorized into various groups according to the minutes of mobile usage per day, years of mobile usage and total duration of mobile phone use in dominant (mobile using) and non-Dominant (non-mobile using) ears. The changes in ABR were studied in each ear to ascertain the effect of EMF exposure due to chronic mobile phone use. Mean age of subjects was 27.01 years. (M: F = 1.57:1.0). Range of mobile phone usage was from 4 to 900 min/day, with mean as 85.94 min/day. No significant differences were seen between dominant and non-dominant ears in regard to amplitudes of wave I, III and V, latencies of wave I and V and Inter peak latency (IPL) of wave I-III, III-V and I-V. No statistically significant difference for I-III, III-V and I-V IPL were found b/w two groups/ears except for usage of mobile phone for > 180 min/day in wave I-V, usage for 0-4 years in wave I-III and I-V and net hours usage for > 1500 h in wave I-V. The mean IPL in all the waves increases with the increase in years of mobile usage and is maximum in all waves in > 12 years mobile users. The long-term exposure to EMF does induce measurable changes in ABRs. Amplitude and IPLs of ABR were found comparable between the dominant and non-dominant ears using mobile phones, except for those using mobile usage for > 180 min/day and with increasing years of usage of mobile phone. Therefore, prudent use of mobile phone should be encouraged for a shorter period of time and for essential purpose only.

Association between mobile phone use and hearing impairment: a systematic review and meta-analysis

OBJECTIVES

To investigate whether a possible association of mobile phone use with hearing impairment was conducted a systematic review and meta-analysis.

CONTENT

This is a systematic review and meta-analysis. A comprehensive literature search was carried out based on the Meta-analysis of Observational Studies in Epidemiology (MOOSE) methodology using PubMed, Scopus, Web of Science, OVID, and Cochrane. The Robins-I tool was used for quality assessment and risk of bias. Two investigators independently reviewed all articles. Pooled effect size was calculated and meta-analysis was performed to compute an overall effect size.

SUMMARY

Overall, five relevant studies (two cross-sectional and three cohort studies) with 92,978 participants were included in the analysis. The studies were stratified by design, there was no significant association between mobile phone use and hearing impairment in cross-sectional studies (OR=0.94, 95% CI=0.57-1.31) and cohort studies (OR=1.09, 95% CI=0.93-1.25). In addition, the effect estimates did not differ significantly between cross-sectional and cohort studies (Q=0.50, p=0.48). Overall, the pooled odds ratio (OR) of hearing impairment was 1.07 (95% CI: 0.94-1.20), which indicates no significant association between mobile phone use and hearing impairment.

OUTLOOK

Our findings indicate no association between mobile phone use and hearing impairment. However, these findings must be interpreted with caution.

Effect of Mobile Phone use on Hearing in Young Adults: An Observational Study

There are concerns regarding the health effects of electromagnetic fields (EMFs) generated by mobile phones. There are apprehensions regarding the effect of these radiations on auditory system. The objective of this study was to find the effect of mobile phone on hearing in young adults. We studied 75 medical students who were mobile phone users for >1 year. Initial hearing status of subjects was assessed by Pure Tone Audiometry (PTA), Otoacoustic emissions (OAE) and Brainstem evoked response audiometry (BERA) at the time of enrollment in the study and repeat audiological assessment was conducted at 6 months and again at one year and comparison was done. The mean age of the population was 20.13 + 1.33 years. Right, left and no particular preference for any ear was seen in 74.7%, 16% and 9.3%, respectively. Mean PTA at baseline in right ear at baseline, 6 months and 1 year was 12.71 ± 3.51 dB, 13.73 ± 3.69 dB and 14.07 ± 3.25 dB (p value=0.120), respectively and the same values for left ear were 13.28±3.57, 14.32±3.10 and 14.24±3.20 (p = 0.170) at baseline, 6 months and 1 year. No statistically significant difference in hearing thresholds was seen at baseline and at subsequent follow-ups and between dominant ear and non-dominant ear on BERA and OAE. We did not find any short term effect of mobile phones on the hearing in young adults, however, long term effect on hearing with progressing age cannot be ruled out.

Auditory Brainstem Responses and EMFs Generated by Mobile Phones

There has been a manifold increase in the number of mobile phone users throughout the world with the current number of users exceeding 2 billion. However this advancement in technology like many others is accompanied by a progressive increase in the frequency and intensity of electromagnetic waves without consideration of the health consequences. The aim of our study was to advance our understanding of the potential adverse effects of GSM mobile phones on auditory brainstem responses (ABRs). 60 subjects were selected for the study and divided into three groups of 20 each based on their usage of mobile phones. Their ABRs were recorded and analysed for latency of waves I-V as well as interpeak latencies I-III, I-V and III-V (in ms). Results revealed no significant difference in the ABR parameters between group A (control group) and group B (subjects using mobile phones for maximum 30 min/day for 5 years). However the latency of waves was significantly prolonged in group C (subjects using mobile phones for 10 years for a maximum of 30 min/day) as compared to the control group. Based on our findings we concluded that long term exposure to mobile phones may affect conduction in the peripheral portion of the auditory pathway. However more research needs to be done to study the long term effects of mobile phones particularly of newer technologies like smart phones and 3G.

Cell phone exposures and hearing loss in children in the Danish National Birth Cohort

BACKGROUND

Children today are exposed to cell phones early in life, and may be the most vulnerable if exposure is harmful to health. We investigated the association between cell phone use and hearing loss in children.

METHODS

The Danish National Birth Cohort (DNBC) enrolled pregnant women between 1996 and 2002. Detailed interviews were conducted during gestation, and when the children were 6 months, 18 months and 7 years of age. We used multivariable-adjusted logistic regression, marginal structural models (MSM) with inverse-probability weighting, and doubly robust estimation (DRE) to relate hearing loss at age 18 months to cell phone use at age 7 years, and to investigate cell phone use reported at age 7 in relation to hearing loss at age 7.

RESULTS

Our analyses included data from 52 680 children. We observed weak associations between cell phone use and hearing loss at age 7, with odds ratios and 95% confidence intervals from the traditional logistic regression, MSM and DRE models being 1.21 [95% confidence interval [CI] 0.99, 1.46], 1.23 [95% CI 1.01, 1.49] and 1.22 [95% CI 1.00, 1.49], respectively.

CONCLUSIONS

Our findings could have been affected by various biases and are not sufficient to conclude that cell phone exposures have an effect on hearing. This is the first large-scale epidemiologic study to investigate this potentially important association among children, and replication of these findings is needed.

Prenatal and Postnatal Cell Phone Exposures and Headaches in Children

OBJECTIVE

Children today are exposed to cell phones early in life, and may be at the greatest risk if exposure is harmful to health. We investigated associations between cell phone exposures and headaches in children.

STUDY DESIGN

The Danish National Birth Cohort enrolled pregnant women between 1996 and 2002. When their children reached age seven years, mothers completed a questionnaire regarding the child's health, behaviors, and exposures. We used multivariable adjusted models to relate prenatal only, postnatal only, or both prenatal and postnatal cell phone exposure to whether the child had migraines and headache-related symptoms.

RESULTS

Our analyses included data from 52,680 children. Children with cell phone exposure had higher odds of migraines and headache-related symptoms than children with no exposure. The odds ratio for migraines was 1.30 (95% confidence interval: 1.01-1.68) and for headache-related symptoms was 1.32 (95% confidence interval: 1.23-1.40) for children with both prenatal and postnatal exposure.

CONCLUSIONS

In this study, cell phone exposures were associated with headaches in children, but the associations may not be causal given the potential for uncontrolled confounding and misclassification in observational studies such as this. However, given the widespread use of cell phones, if a causal effect exists it would have great public health impact.

Non-specific physical symptoms and electromagnetic field exposure in the general population: can we get more specific? A systematic review

OBJECTIVE

A systematic review of observational studies was performed to address the strength of evidence for an association between actual and perceived exposure to electromagnetic fields (EMF) and non-specific physical symptoms (NSPS) in the general population. To gain more insight into the magnitude of a possible association, meta-analyses were conducted.

METHODS

Literature databases Medline, Embase, SciSearch, PsychInfo, Psyndex and Biosis and additional bibliographic sources such as reference sections of key publications were searched for the detection of studies published between January 2000 and April 2011.

RESULTS

Twenty-two studies met our inclusion criteria. Qualitative assessment of the epidemiological evidence showed either no association between symptoms and higher EMF exposure or contradictory results. To strengthen our conclusions, random effects meta-analyses were performed, which produced the following results for the association with actual EMF; for symptom severity: Headache odds ratio (OR)=1.65; 95% confidence interval (CI)=0.88-3.08, concentration problems OR=1.28; 95% CI=0.56-2.94, fatigue-related problems OR=1.15; 95% CI=0.59-2.27, dizziness-related problems OR=1.38; 95% CI=0.92-2.07. For symptom frequency: headache OR=1.01; 95% CI=0.66-1.53, fatigue OR=1.12; 95% CI=0.60-2.07 and sleep problems OR=1.18; 95% CI=0.80-1.74. Associations between perceived exposure and NSPS were more consistently observed but a meta-analysis was not performed due to considerable heterogeneity between the studies.

CONCLUSIONS

This systematic review and meta-analysis finds no evidence for a direct association between frequency and severity of NSPS and higher levels of EMF exposure. An association with perceived exposure seems to exist, but evidence is still limited because of differences in conceptualization and assessment methods.

Cohort study on the effects of everyday life radio frequency electromagnetic field exposure on non-specific symptoms and tinnitus

BACKGROUND

There is public concern regarding potential health effects of radio frequency electromagnetic fields (RF-EMF) exposure, as produced by mobile phones or broadcast transmitters. The objective of this study was to investigate the association between RF-EMF exposure and non-specific symptoms and tinnitus in a prospective cohort study.

METHODS

In 2008, 1375 randomly selected participants from Basel, Switzerland, were enrolled in a questionnaire survey with follow-up after one year (participation rate 82%). A score for somatic complaints (von Zerssen list) and headache (HIT-6) was assessed. Far-field environmental RF-EMF exposure was predicted using a validated prediction model. Regarding near-field exposure, self-reported mobile and cordless phone use as well as mobile phone operator data were collected. In multivariate regression models, we investigated whether exposure at baseline (cohort analysis) or changes in exposure between baseline and follow-up (change analysis) were related to changes in health scores.

RESULTS

For participants in the top decile of environmental far-field RF-EMF exposure at baseline, in comparison to participants exposed below the median value, the change in the von Zerssen- and HIT-6-scores between baseline and follow-up was -0.12 (95%-CI: -1.79 to 1.56) and -0.37 (95%-CI: -1.80 to 1.07) units, respectively. Exposure to near-field sources and a change in exposure between baseline and follow-up were not related to non-specific symptoms. Similarly, no association between RF-EMF exposure and tinnitus was observed.

CONCLUSIONS

In this first cohort study using objective and well-validated RF-EMF exposure measures, we did not observe an association between RF-EMF exposure and non-specific symptoms or tinnitus.

PREVALENCE OF CUMULATIVE TRAUMA DISORDERS IN CELL PHONE USERS

Purpose: In recent years, ownership and usage of cell phones have become widespread, especially amongst young people. The increasing use of text messaging on mobile phones has focused concern on possible musculoskeletal disorders for the users. Hence the purpose of this study was to find the prevalence of cumulative trauma disorders (CTDs) of the upper limb in cell phone users. Methods: A questionnaire-based survey was undertaken to detect the prevalence of CTDs in 1500 college students. Results: The response rate of the survey was 91.9%. Overall prevalence of CTD in the upper limb was found to be 18.5%. Maximum symptoms were noted in thumb (52%). Pain (61.7%) and fatigue (44.3%) were the two most common symptoms reported by the respondents. Conclusions: Mild form of CTD is present in students using cell phones and mainly depends on the pattern of phone usage.

Auditory Changes in Mobile Users

Objective. Genuine concerns are being raised as to the potential health risks posed by electromagnetic frequency exposure secondary to mobile phone usage. This study was undertaken to assess and compare potential changes in hearing function at the level of the inner ear and central auditory pathway due to chronic exposure to electromagnetic waves from both global system for mobile communications (GSM) and code division multiple access (CDMA) mobile phone usage.

Design. Cohort study.

Setting. Tertiary referral center.

Subjects and Methods. One hundred twenty-five subjects who were long-term mobile phone users (more than 1 year; 63 GSM and 62 CDMA) and 58 controls who had never used mobile phones underwent audiological investigations including pure tone audiometry (250-12 kHz), tympanometry, distortion product otoacoustic emissions (DPOAE), auditory brain responses (ABR), and middle latency responses (MLRs). The changes in various parameters were studied in mobile-using and non-mobile-using ears of both GSM and CDMA subjects and corresponding ears of the controls to ascertain the effects of electromagnetic exposure.

Results. GSM and CDMA users were found to be at a significantly higher risk of having DPOAE absent as compared with controls ( P < .05). They were found to have higher speech frequency thresholds and lower MLR wave and Na and Pa amplitudes. More than 3 years of mobile phone usage emerged as a risk factor ( P < .05). The damage done was bilateral, with the quantum of damage being the same for both GSM and CDMA.

Conclusion. Long-term and intensive GSM and CDMA mobile phone use may cause damage to cochlea as well as the auditory cortex.

Effect of chronic exposure to cellular telephone electromagnetic fields on hearing in rats

Objective:

To study the effects of the electromagnetic field emitted by cellular telephones upon the inner ear of rats, using distortion product otoacoustic emissions.

Methods:

Forty Wistar Albino rats were used. Twenty newborn and 20 adult rats were divided into two groups of 10, one to participate in the study and one as a control. The rats were exposed to the electromagnetic field for 6 hours per day, for 30 consecutive days. Before and after the 30 day exposure period, distortion product otoacoustic emissions were measured in each group and a signal-to-noise ratio calculated, which was later used in statistical analysis.

Results:

For both the newborn and adult rat groups, there was no significant difference in distortion product otoacoustic emissions recorded before and after exposure to the cellular telephone electromagnetic field (p > 0.05).

Conclusion:

Exposure to the electromagnetic field emitted by cellular telephones, for 6 hours a day for 30 consecutive days, had no effect on the hearing of newborn or adult rats, at the outer ear, middle ear or cochlear level.

Survey of ownership and use of mobile phones among medical science students in Yazd

As the use of mobile phones is increasing every day, public concern about possible adverse health effects of exposure to radio frequency electromagnetic fields (rf-emf) is also growing. Despite the extensive use of mobile phones, little is known about the pattern of mobile phone ownership and its use by the general population and students. The aim of this study was to assess the pattern of ownership and use of mobile phones in medical science students and their views about any possible negative effects. The current cross-sectional study was conducted on 309 selected Medical Science students who were selected from Yazd Medical Sciences University using a self administrated questionnaire. The mean talking time and listening to music on the mobile phone was 28.3 +/- 50.5 and 51.9 +/- 81.5 min day(-1), respectively. They also received or sent a mean of 18.8 +/- 37 text messages. Participants reported that location wise, the use of cell phones at home was 87.2% followed by street (79.6%), classroom (37.6%), during driving (18.6%) and in the library (17.8%), respectively. Keeping at pace with changes in community and technology, including mobile phones and their effects on university environments, it seems that responsible departments or managers must predict their possible effects and establish new regulations, accordingly.

Association of tinnitus and electromagnetic hypersensitivity: hints for a shared pathophysiology?

Background

Tinnitus is a frequent condition with high morbidity and impairment in quality of life. The pathophysiology is still incompletely understood. Electromagnetic fields are discussed to be involved in the multi-factorial pathogenesis of tinnitus, but data proofing this relationship are very limited. Potential health hazards of electromagnetic fields (EMF) have been under discussion for long. Especially, individuals claiming themselves to be electromagnetic hypersensitive suffer from a variety of unspecific symptoms, which they attribute to EMF-exposure. The aim of the study was to elucidate the relationship between EMF-exposure, electromagnetic hypersensitivity and tinnitus using a case-control design.

Methodology

Tinnitus occurrence and tinnitus severity were assessed by questionnaires in 89 electromagnetic hypersensitive patients and 107 controls matched for age-, gender, living surroundings and workplace. Using a logistic regression approach, potential risk factors for the development of tinnitus were evaluated.

Findings

Tinnitus was significantly more frequent in the electromagnetic hypersensitive group (50.72% vs. 17.5%) whereas tinnitus duration and severity did not differ between groups. Electromagnetic hypersensitivity and tinnitus were independent risk factors for sleep disturbances. However, measures of individual EMF-exposure like e.g. cell phone use did not show any association with tinnitus.

Conclusions

Our data indicate that tinnitus is associated with subjective electromagnetic hypersensitivity. An individual vulnerability probably due to an over activated cortical distress network seems to be responsible for, both, electromagnetic hypersensitivity and tinnitus. Hence, therapeutic efforts should focus on treatment strategies (e.g. cognitive behavioral therapy) aiming at normalizing this dysfunctional distress network.