SKIN BARRIER FUNCTION ALTERATIONS AMONG WORKERS IN AN ULTRA-LOW HUMIDITY ENVIRONMENT

Abstract

ISEE-19 Introduction: No studies have been performed in the evaluation of skin barrier alterations for humans exposed to ultra-low humidity (ULH) even though several lines of evidence have reported skin barrier alterations resulting from ULH exposure in animal experiments. Aim: The objectives of this study were to assess the barrier function changes for workers occupationally exposed to ULH (relative humidity = 1.5%), and to evaluate whether the exposure duration presents a dose-response fashion on trans-epidermal water loss (TEWL) and skin capacitance. Methods: Forty-nine ULH exposure male workers were classified into five subgroups based on their ULH exposure duration, in months (< 0.5, 0.5-1.0, 1.1-10.0, 10.1-20.0 and > 20.0). Twelve age-matched laboratory male workers were recruited as a control group from a normal humidity environment. TEWL and skin capacitance were measured to evaluate their skin barrier functions. Results: TEWL measurement showed a significant decline (8.3 +/−0.4 vs. 10.0+/−0.4 gm-2h-1, P<0.05) but no differences were found in skin capacitance (39.7 +/−1.3 a.u. vs. 45.0+/− 2.4 a.u., p=“0.68”) between the whole ULH exposure group and control. Maximum decreases were shown in < 0.5 m and 0.5-1.0 m ULH exposure of TEWL and skin capacitance, respectively. Almost completely natural recovery was received in skin capacitance after 20 months ULH exposure in contrast to less than 90% recovery for TEWL. Three stages were defined according to the pattern of alterations for TEWL and skin capacitance across the ULH exposure duration. A positive association between TEWL and skin capacitance occurred in the control group and stage I but a negative correlation in stage II. No correlation was found in stage III. Conclusion: Our study has demonstrated that the workers exposed to a ULH environment could exhibit skin barrier alterations. In duration-specific comparison, both TEWL and skin capacitance decreased within 2-weeks of ULH exposure. The maximum alterations in TEWL and skin capacitance occurred during 0.5-10 months and 2 weeks, respectively, given the workers were exposed to a ULH environment 12 hours a day. TEWL revealed a slower and partial recovery in contrast to earlier and almost complete recovery for skin capacitance.