Humidifier disinfectant exposure and lung cancer development: A propensity score matching analysis

Abstract

Background: Although previous animal studies suggest an association between humidifier disinfectant (HD) exposure and lung cancer, epidemiological evidence remains limited. Methodology: Nationwide data from the National Health Insurance Service and survey data on the HD claimant group were used. A 1:30 propensity score matching was conducted between the HD claimant (n = 4567) and non-exposed groups (n = 153,071). Hazard ratios (HRs) and 95 % confidence intervals (CIs) were estimated using Cox proportional hazards models, incorporating a 4-year latency period. Results: After matching, the incidence of lung cancer was 2.58 % in the HD claimant group and 0.55 % in the non-exposed group. In the Cox models, the HR for lung cancer in the HD claimant group was 5.71 (95 % CI: 4.70, 6.92) compared with the non-exposed group. Stratified analyses showed an HR of 12.61 (95 % CI: 8.94, 17.79) among women and 4.31 (95 % CI: 3.40, 5.47) among men. The associations also persisted in never-smokers, with an HR of 4.33 (95 % CI: 2.26, 8.30). Conclusions: Exposure to HDs was associated with an increased risk of lung cancer development. Combined with in vivo and in vitro studies reporting similar associations and plausible mechanisms, the present study supports the potential carcinogenic effects of HDs on lung cancer.