Mohammad-Bagher Behyar - Assistant Professor, Meteorological Research Center, Meteorological Office, Tehran.
Shahram Moradi - Specialist in Infectious Diseases, Skin Diseases and Leishmaniosis Research Center, Isfahan University of Medical Sciences, Isfahan.
Mohammad-Ali Nilforoushzadeh - Assistant Professor of Dermatology, Tehran University of Medical Sciences, Tehran Skin and Leprosy Research Center, and Isfahan Skin Diseases and Leishmaniosis Research Center, Isfahan University of Medical Sciences, Isfahan.
Leila Shirani-Bidabadi - Medical Entomology, Skin Diseases and Leishmaniosis Research Center, Isfahan University of Medical Sciences, Isfahan.

Abstract    BACKGROUND: Ultraviolet radiation can contribute to various damages to body organs especially to skin. However, the effect of Ultraviolet B on the function of viruses, immunologic changes and antioxidants levels which protect human skin health are still unknown. We aimed to find the harmful level of UVB that can be helpful in taking preventive action against the increasing depletion of Ozone layer.    METHODS: In this cross-sectional study conducted in Isfahan population, two areas with high and low levels of UVB radiation were investigated based on the information obtained from Meteorological Office. Samples in each area were selected by a cluster-sampling method. ۲۵۰ persons were assigned to each group. The antioxidant capacity and glutathione peroxide level of samples were measured. Data were analyzed with Student t test by using SPSS software.    RESULTS: The mean (± standard deviation) of Malondialdehide in high and low UVB radiation areas were ۲.۸ ± ۰.۳۲ and ۱.۶۵ ± ۰.۳۸ nmoles/ml, respectively (P < ۰.۰۰۱). Mean (± standard deviation) of antioxidants capacity levels were ۸۱.۶ ± ۲.۳۶ μmol/l in patients living in low UVB radiation area and ۷۶.۵ ± ۲.۶ μmol/l in patients living in high UVB radiation area (P < ۰.۰۰۰۱). Glutathione Peroxide levels were ۳۸.۲ ± ۱.۷ and ۳۵.۳ ± ۱.۹ μmol/l in areas with low and high UVB radiation respectively (P < ۰.۰۰۰۱).     CONCLUSION: Findings of this study indicates that the amount of free radicals and antioxidant capacity in high UVB radiation areas are less than areas with low levels of UVB radiation. Therefore, it is suggested that necessary considerations should be taken into account for the residents of such areas in order to reduce its health damages.      Keywords: Ultraviolet B, antioxidant, malondialdehyde, glutathione peroxide.