We conducted a comprehensive humidifier disinfectant exposure characterization for 374 subjects with lung disease who presumed their disease was related to humidifier disinfectant use (patient group) and for 303 of their family members (family group) for an ongoing epidemiological study. We visited the homes of the registered patients to investigate disinfectant use characteristics. Probability of exposure to disinfectants was determined from the questionnaire and supporting evidence from photographs demonstrating the use of humidifier disinfectant, disinfectant purchase receipts, any residual disinfectant and the consistency of their statements. Exposure duration was estimated as cumulative disinfectant use hours from the questionnaire. Airborne disinfectant exposure intensity (μg/m3) was estimated based on the disinfectant volume (mL) and frequency added to the humidifier per day, disinfectant bulk level (μg/mL), the volume of the room (m3) with humidifier disinfectant, and the degree of ventilation. Overall, the distribution patterns of the intensity, duration and cumulative exposure to humidifier disinfectants for the patient group were higher than those of the family group, especially for pregnant women and patients ≤ 6 years old. Further study is underway to evaluate the association between the disinfectant exposure estimated here with clinically diagnosed lung disease.

BackgroundIn South Korea, a cluster of acute lung disease patients included lung injury disease suspected of being caused by the use of humidifier disinfectants. We examined the relationship between humidifier disinfectant exposure and clinically diagnosed humidifier disinfectant-associated lung injury (HDLI) in a family-based study.MethodsThis case-control study included 169 clinically confirmed HDLI cases and 303 family controls who lived with the HDLI patients. A range of information on exposure to humidifier disinfectants was obtained using a structured questionnaire and field investigations. Odds ratios (ORs) and confidence intervals (CIs) were estimated using unconditional logistic regression models that were adjusted for age, sex, presence of a factory within 1 km of residence, and the number of household chemical products used.ResultsHDLI risk increased approximately two-fold or more among the highest quartile compared with the lowest quartile in terms of the hours sleeping in a room with an operating humidifier treated with disinfectant (adjusted OR = 2.0, 95 % CI = 1.1-3.7), average hours of disinfectant-treated humidifier use per day (adjusted OR = 2.1, 95 % CI = 1.0-4.5), airborne disinfectant intensity (adjusted OR = 2.6, 95% CI = 1.2-5.3), and cumulative disinfectant inhalation level (adjusted OR = 2.0, 95% CI = 1.0-4.1). HDLI risk increased as the distance of the bed from humidifier gets shorter; compared with longer distance (> 1 m), the odds ratio was 2.7 for 0.5 to 1 m (95 % CI = 1.5-5.1) and 13.2 for <0.5 m (95 % CI = 2.4-73.0).ConclusionsThe use of household humidifier disinfectants was associated with HDLI risk in a dose-response manner.

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In South Korea, many cases of humidifier disinfectant-associated lung injury (HDLI) have been reported among people who used humidifier products containing humidifier disinfectant (HD). The objectives of this study are to estimate both airborne HD concentration in the room where HD was used and the amount of humidifier disinfectant absorbed into the respiratory system. Information and data on the HDs were collected using a structured questionnaire and home environmental investigations include the volume of HD (ml) and hours used per day, concentration of disinfectants contained in the HD brand (µg/ml), volume of the room (m 3 ), assumed ventilation rate (m 3 /hr) and breathing rate assumed (m 3 /hr). We used children aged under five years old as a sample and estimated both airborne HD concentrations and amount of HD absorbed into the respiratory system. The estimated airborne concentration of HD in the room ranged from 68 to 369 µg/m 3 for PHMG (polyhexamethylene guanidine phosphate) and from 16 to 239 µg/m 3 for PGH (oligo (2-(2-ethoxy) ethoxyethyl guanidine). The amount of HD absorbed in the respiratory system per day was estimated to range from 227 to 1,225 µg for PHMG and from 53 to 794 µg for PGH. In conclusion, a great amount of HD was likely absorbed into respiratory system, likely beyond the level of the capacity of the immune system to remove the HD absorbed.

In South Korea, many cases of humidifier disinfectant-associated lung injury (HDLI) have been reported among people who used humidifier products containing humidifier disinfectant (HD). The objective of this study is to characterize exposure to HD among a total of 221 HDLI patients who used HD. Information and data on the HDs used were collected through a structured questionnaire and home environmental investigations. The conditions of these 221 HDLI patients were clinically confirmed to be caused by the use of HD. Children aged under 5 years old made up the highest proportion of HDLI cases (n=125, 56.6 %), followed by pregnant women (n=35, 15.8%). Forty-three percent (n=95) of the victims died. There were three cases of fetuses and 35 pregnant women among the victims. The number of HDLI patients who used only the Oxy Saksak brand of HD was found to be 85 (38.5%), followed by the HD brands Cefu (n=24, 10.9%), Lottemart Wiselect (n=9, 4.1%) and Aekyung (n=3). Patients who exclusively used HD brands containing polyhexamethylene guanidine phosphate (PHMG) (n=13, 55.7%) as an active ingredient made up the largest share, followed by those who exclusively †

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