| Summary: | 博士 === 國立成功大學 === 環境醫學研究所 === 97 === Background: In modern industries, many products are manufactured in environments under strict control to ensure the quality. In these environments, the physical conditions controlled by engineering measures may include humidity, dust, temperature, illumination, and airflow. A higher prevalence of urinary tract infection (UTI) was observed among clean room workers. 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.
Materials & Methods: We recruited workers working in an industrial park in Tainan, Taiwan who received the annual routine health examination at the clinic in the park in Sept. 2001 and Sept. 2003. We conducted the following five studies: (1) Higher prevalence of dry symptoms in skin, eyes, nose and throat among workers in clean rooms with moderate humidity. (2) Tear Secretion Dysfunction among Woman Workers Engaged in Light-on Tests in the TFT-LCD Industry. (3) Prevalence of urinary tract infections and associated factors among pregnant workers in the electronics industry. (4) Reducing Urinary Tract Infections through intensive health education among Female Clean Room Workers. (5) Using Urine Specific Gravity to Evaluate the Hydration Status of Workers Working in Ultra-Low Humidity Environment.
Results: In study (1), among the 3,154 participants without past history of skin diseases, clean room workers had higher prevalence of dry eye symptoms , dry nose and throat symptoms , and dry skin symptoms (itching, scaling, and fissuring) in comparison with other workers. In clean room workers, dry skin symptoms affected relatively more frequently the palm but less frequently the face. Multiple logistic regressions showed that working in clean rooms (OR=1.38), 28 to 30 years of age (OR=0.73), family history of atopic diseases (OR=1.75), and skin moisturizers use (OR=1.64) were independent predictors of skin symptoms. In study (2), the 319 qualified light-on test workers showed that eye dryness was the most prevalent (prevalence = 43.3 %) within the 11 ophthalmic symptoms. In addition, the prevalence of tear secretion dysfunction in at least one eye was 40.1% (128 cases), and contact lens users had an odds ratio of 1.73 in comparison with non-contact lens users. Comparing the Schirmer’s test results of those who also participated in the screening in the previous year, we found the prevalence of tear secretion dysfunction increased with statistically significant (32% vs. 40.9%, p = 0.02 for McNemar’s test). In study (3), a total of 2,062 workers, including 118 pregnant and 1,944 non-pregnant women, participated in the study. Pregnancy was a significant risk factor for both symptomatic (OR= 6.33) and asymptomatic (OR= 2.13) UTIs. Urine voiding three or more times during a shift was a significant protective factor for asymptomatic UTI (OR= 0.40) and a protective factor for symptomatic UTI with marginal statistical significance (OR= 0.24). In study (4), for 1414 clean room workers and 252 non-clean room workers, agreed to participate, we found similar prevalence (both 0.8%) of symptomatic UTIs (patients with clinical symptoms such as voiding frequency, urgency, and burning sensation during voiding) in clean room and non-clean room workers. In the 366 participants who also participated in the previous study, we found a significant decrease in the prevalence of UTI (from 9.8% to 1.6%) and significant increases in the prevalence of water intake and urine voiding 3 times or more during a shift (p < 0.001 for all McNemar’s tests). In study (5), we found the exposure group were younger and had shorter employment durations compared to the comparison group (p < 0.05 for two-sample t test). The exposure group had a higher prevalence of abnormal concentrated urine (24.0% vs. 4.1%, p < 0.001 for χ2 test) and had an adjusted odds ratio of 12.6 using the comparison group as the reference.
Conclusions: Whereas the humidity in clean room working environments is not very low, for workers living in a high humidity environment, the relatively low humidity may still cause dry symptoms of the eye, nose, and throat. The prevalence of tear secretion dysfunction in clean room female workers engaged in light-on tests is high. The use of contact lens may further increase the risk. And UTI is common among pregnant clean room workers, and frequent voiding appears to be a protecting factor. The interventions had achieved behavior modification and decreases in the prevalence of UTI. For ultra-low humidity working environment, we found USG is a good biomarker for evaluating the hydration status of 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.
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