URINE SPECIFIC GRAVITY AS A MARKER OF HYDRATION IN WORKERS WORKING IN LOW-HUMIDITY ENVIRONMENT

Abstract

ISEE-418 Introduction: Under ultra-low humidity working environment, a worker may have concentrated urine or dehydrated status due to excessive body water loss (epidermal evaporation). We use urine specific gravity (USG) as a biomarker to evaluate the hydration status of workers in such a controlled environment. Methods: We collected the urine routine data of workers of a high-tech plant during annual health examination in 2001. The relative humidity of some working areas was 1.5%±1%. We recruited workers in ultra-low humidity areas as the exposure group (N=50), and the remaining workers, including administration office workers, were defined as the comparison group (N=122). The participants were excluded if they had renal diseases, diabetes, or proteinuria. We compared the prevalence of abnormal concentrated urine (USG>1.030) and related factors between these two groups. Results: We found the exposure group were younger and had shorter employment durations than the comparison group (p<0.05 for two-sample t test,). The exposure group had a higher prevalence of abnormal concentrated urine (p<0.001 for chi-square test) and had an adjusted odds ratio of 13.23 (95% confidence interval: 2.78 to 62.9) using the comparison group as the reference. Discussion: We found USG is a good biomarker for evaluating the hydration status of ultra-low humidity environment workers. If a worker does not have proper occupational protection and adequate fluid supply, he or she may have concentrated urine or even dehydration state and other adverse health effects.