Author's Response to Reviews the Relationship between Video Display Terminals(vdts) Usage and Dermatological Manifestations:a Cross Sectional Study

Recently,it has been observed that Video Display Terminals(VDTs)usage for long periods can cause some dermatological manifestations on the face.To determine this relationship,this analytical cross-sectional study has been designed. For this purpose,600 office workers were chosen randomly from an organization in Tehran (Iran) and then on the basis of their exposures to VDTs,they are divided into two groups.The first group (306 workers) with less than 7 hours exposure is considered as exposure negative (nonVDT worker) and the second group (294 workers) with 7 hours exposure or more is considered as exposure positive (VDT workers) and then the frequency of skin manifestations were compared in these two groups. In exposure positive and exposure negative groups,the frequency of these dermatological abnormalities were 27 and 5 respectively. With considering P.value less than 0.05 and after discarding the confounding factors,there was a statistically significant difference between these two groups for dermatological manifestation. Background There is growing evidence that long term exposure to the types of unfavorable working conditions that have been observed among some VDTs users might have serious health consequences(1).Dermatological manifestations,specially on the face are one the these health outcomes(2).The most common manifestations among these patients are nonspecific erythema, acne rosacea, seborrheic dermatitis, pruritus, burning sensation,and dry skin(3).The prevalence of these symptoms among VDTs users are different from 8-10% in a series of descriptive studies to 13.5% in other reports(4). Radiation emissions from VDTs such as x-ray,ultraviolet,infrared are in acceptable level and there are no connection between these radiations and health consequences, nor with any dermatological manifestation(4,5).As a whole,the exact cause of these symptoms on the face of VDTs users is not clear, but physical conditions of the workplace such as dryness,occupational stress(6),electrostatic fields(7),and to a lesser extent,electromagnetic fields of VDTs can play a role(8,9). There was no prior study considering the role of the working with VDTs in causing dermatological symptoms in Iran.Accordingly,this study has been designed for this purpose. Material and methods This survey conducted on the office workers of an organization in Tehran with a cross-sectional method. Age,gender and weekly hours of work with VDTs were considered as independent variables and skin symptoms on the face including erythema, acne rosacea, scaling, pruritus and burning sensation as dependent variables.600 office workes were collected randomly out of the workers with approximately the same environmental conditions (temperature,humidity,light,ect.).and divided into two groups according to their exposure to the VDTs in the past year.One group with seven hours or more weekly exposure to VDTs in the workplace or home and the other with less than seven hours.The workers filled in a questionnaire and physical examination conducted on them.Non specific erythema ,acne rosacea,scaling and seborrheic dermatitis which were detected during examination and also pruritus and burning sensation that getting worse or produced by working with VDTs and alleviated away from work,considered as acceptable positive dermatological findings. Results 251 out of 600 workers were female and the remainder 394 were male.Age and sex distribution of the workers is demonstrated in table 1.The average age was 44.5 years. 294 workers had seven hours weekly exposure or more in the past year and 306 ones had less than seven hours weekly exposure. In the exposure positive group and exposure negative groups 128 and 123 workers were female and 165 and 183 workers were male respectively. The average weekly exposure rate in exposure positive group was 14 hours. In exposure positive and exposure negative groups 27 workers (16 female and 11 male) and 5 workers (3 female and 2 male) had dermatological manifestation respectively,as depicted in table 2. Frequency of the workers with more than 7 hours exposure per week and their weekly hours of exposure accompanied with skin manifestations frequency are shown in table 3. Discussion: After discarding confounding variables (age and gender ),we performed chi square test and with considering P.value less than 0.05, we found statistically difference between exposure positive and exposure negative groups for the dermatological manifestation. On the other hand,it is obvious in the table 3 that frequency of the dermatological symptoms of the face trend to increase with increasing the weekly hours of work with VDTs(p-value <0.005). In a study conducted by Stenberg.B. et al.,Psychosocial conditions and exposure to electromagnetic fields or conditions associated with such factors were related to an increased occurrence of skin symptoms. The results also indicated that personal factors such as atopic dermatitis and physical exposure factors influencing indoor air quality, such as paper exposure and cleaning frequency were related to an increased prevalence of symptoms. The results suggest that skin symptoms reported by VDT users have a multifactorial background(10). According to some reports, mainly from Norway and Sweden, visual display terminal work is suspected of causing skin rashes. In three different studies, we have tried to elucidate the question, and the results indicate that there might be a relation between VDT work and aggravation of some common skin diseases such as rosacea, seborrheic and atopic dermatitis, and acne. Whether this depends on physical, chemical, or psychological factors is still unknown(11). According to other studies, we can propose a relationship between dermatological symptoms on the face and exposure to the VDTs. Recommendations: According to our study and similar studies,we recommend that in workers with long time exposures to VDTs and dermatological symptoms of the face , occupational history of working with VDTs,weekly hours of exposure and effects of exposure on their symptoms should be considered. Authors’ contribuitons: AO participated in the design of the study and performed the data collection. MP conceived of the study, and participated in its design and coordination. SA drafted the manuscript and coordination. RE performed the statistical analysis. IM drafted the manuscript. All authors read and approved the final manuscript REFRENCES: 1) Rom william. Environmental and occupational medicine, 3nd ed. New york Lippincott. 1998:543-568. 2)Berndet S. facial skin symptoms in VDT worker. Ijo E. 1995;24 : 769-804. 3)Erikson N,Hoog J,Sanstrom M. Facial skin symptoms in office workers. J occupational Enviromental Med. 1997 ; 39 : 108-112. 4)WHO. Visual Display Terminals and workers Health. Offset publication, 1987; 99:11-30. 5)LaDou J. occupational & environmental Medicine , 2nd ed. Appleton & Lange. 1997. 6)Mats B. Techno – Stress and VDT skin symptoms. JOM. 1994; 34: 698-701. 7)Niels F. Particle deposition on to a Human Head Influence of electatics field. Bioelectro magnetics. 1998; 19: 246-253. 8)Nilson J. Facial skin symptoms Acta Derma Vanol. JAN 1998;36: 44-47. 9)Bergovisit E. skin symptoms and disease during work with VDT contact Dermatitis. 1994; 30:197-204. 10) Stenberg B, Eriksson N, Mild KH, Hoog J, Sandstrom M,Sundell J, Wall S. Facial skin symptoms in visual display terminal (VDT) workers. A case-referent study of personal, psychosocial, building and VDT-related risk indicators. Int J Epidemiol. 1995; 24(4): 796-803 11) Wahlberg J E, Liden C. Is the skin affected by work at visual display terminals? Dermatol-Clin. 1988; 6(1): 81-85 Table 1Frequency distribution of office workers in relation to age and