Objectives: Several lines of evidence have shown that insufficient humidity could result in health problems but no studies have been performed in ultra-low humidity (ULH) environments. The aims of this study are to investigate the health examination items alterations and skin symptoms of workers exposed to ULH environment based on a longitudinal study design.
Methods: Twelve male ULH (RH = 1.5%) workers and 12 age-sex-matched reference workers were selected. The examination items in blood and urine as well as the skin problems were compared between ULH workers and controls, and between ULH workers in 2000 and 2003. Biochemistry analysis of blood and urine were implemented from annual health examinations. Information on skin symptoms and diseases were obtained from a structured questionnaire in 2000 and 2003.
Results: The alterations in mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and total cholesterol in blood analysis and only sediment-WBC in urine analysis were found significantly different in 2000. These changes were almost fully recovered in 2003 although a consistently significant elevation in the urine specific gravity was found during the 3-year follow-up period. Skin disorders, however, showed an earlier elevated itching symptom in lower limb and pretibial that developed to physician-diagnosed contact dermatitis.
Conclusions: Long-term ULH exposure could cause progressive pathological changes in the skin and urine concentration elevation. Because low humidity condition occurs frequently in air-conditioned buildings, the findings of this study suggest the population long-term exposed to low humidity should be cautious about health manifestations living in a low humidity environment. While the indoor environment is equipped with an air-conditioner, continuous monitoring on the humidity is recommended.