Investigating the causal associations between occupational noise exposure and chronic obstructive pulmonary disease:...

Occupational noise exposure (ONE) occurs frequently, but the health risk of this exposure to chronic obstructive pulmonary disease (COPD) has not been evaluated. We aimed to explore the causal role of ONE in the risk of COPD. Instrumental variables of 3 levels of ONE were included: workplace very noisy: rarely/never (cases: 51,689; control: 39,088); workplace very noisy: sometimes (cases: 69,515; control: 21,382); workplace very noisy: often (cases: 17,469; control: 73,184). A univariate Mendelian randomization (MR) analysis was performed to determine the genetic effect of ONE on the risk of COPD and lung function based on an "Inverse variance weighted (IVW)" approach. A multivariate MR was used to adjust the interfering factors. The heterogeneity, horizontal pleiotropy and Steiger directionality test were conducted to assess the robustness and reliability of MR. 12, 14, and 18 single nucleotide polymorphisms were identified as instrumental variables for 3 conditions: workplace very noisy: rarely/never, workplace very noisy: sometimes, and workplace very noisy: often, respectively. The IVW results showed frequent ONE and a higher liability of COPD in both the training set (odds ratio [OR] = 1.020, 95% confidence interval [CI] [1.008-1.032], P = .001) and the validation set (OR = 3.259, 95% CI [1.821-5.832], P = .012). Moreover, frequent ONE decreased the forced lung capacity (training set: OR = 0.879, 95% CI [0.782-0.987], P = .029; validation set: OR = 0.882, 95% CI [0.785-0.991], P = .035) and forced expiratory volume in 1-second (training set: OR = 0.828, 95% CI [0.728-0.943], P = .004; validation set: OR = 0.870, 95% CI [0.791-0.957], P = .004). The multivariate MR found the estimated role of frequent ONE on COPD was comparable to the univariate IVW estimate (OR = 1.021, 95% CI [1.008-1.032], P = .021). The study illustrated the causal association between ONE and the risk of COPD.