Relationship between Exposure to Household Humidifier Disinfectants and Risk of Lung Injury: A Family-Based Study

Abstract

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.

Standardization of a Protocol for Quantitative Evaluation of Anti-Aerosolized Influenza Virus Activity by Vapors of a Chemically-Characterized Essential Oil Blend

“…The aerosolized chemical disinfectants used to inactivate viral particles in hospitals, nurseries, schools, army facilities, aeroplanes, airports, cooling towers, abattoirs, and closed farm systems are rejected by many people, due to documented reports about their toxicity [21][22][23].…”

Evaluation report on the causal association between humidifier disinfectants and lung injury

“…Three epidemiological studies have shown consistent results, that the risk of incidence, as well as mortality increased with larger doses, longer durations [13,15], and closer proximity [14] of exposure to HDs.…”

“…There were four case-control studies: an epidemiologic study initially performed immediately after a report of lung injury from a university hospital to the KCDC in 2011 [12]; a case-control study matching sex, age, and date of diagnosis in three controls in children [13]; a case-control study matching sex, age, residential area, and experience of childbirth in a community control group [14]; and a study comparing patients exposed to humidifiers more closely and longer to other family members, as well as to a control group within a family [15]. In order to exclude bias due to confounding variables in this study, either matching for major confounders or statistical adjustment in analysis was conducted.…”

“…Although each epidemiological study had different populations (adults [12-14] vs. children [13]), the study design (case-control [12-15] vs. retrospective cohort [16]) or other control groups (hospital [12,13], community [14], and family [15]) showed consistency.…”

Humidifier disinfectant and use characteristics associated with lung injury in Korea

“…Details of this approach have been described elsewhere. 6,10,11 Trained environmental health scientists visited the residences of registered subjects and investigated the following information related to HD use: HD brand/s used; HD volume added to the humidifier; duration of HD use in the household in terms of average months/year, weeks/ month, days/week, and hours/day; average sleeping hours in a room with an operating humidifier containing disinfectant; number of HD brands used; and average distance of the bed from the humidifier in meters. Cumulative HD use hours were calculated by multiplying together the total years, months per year, weeks per month, days per week, and hours per day during which disinfectant was actually used.…”