Association between occupational noise and obesity: a retrospective cohort study in China.

Objectives: To determine the relationship between occupational noise, and obesity and body mass index (BMI) changes.

Methods: Baseline data were collected from participants (n = 1264) who were followed for 6 years in a retrospective study. The noise exposure level (L_Aeq,8h) was determined by equivalent continuous weighted sound pressure levels using the fixed-point surveillance method for noise monitoring. The cumulative noise exposure (CNE) level was determined using the equal energy formula, which is based on exposure history and level.

Results: The incidence of obesity at low (RR = 2.364, 95% CI 1.123-4.739]), medium (RR = 3.921, 95% CI 1.946-7.347]), high (RR = 5.242, 95% CI 2.642-9.208]), and severe noise levels (RR = 9.322, 95% CI 5.341-14.428]) was higher risk than the L_Aeq,_8h control level. The risk of obesity among participants exposed to low (RR = 2.957, 95% CI 1.441-6.068]) and high cumulative noise levels (RR = 7.226, 95% CI 3.623-14.415]) was greater than the CNE control level. For every 1 dB(A) increase in L_Aeq,8h, the BMI increased by 0.063 kg/m² (95% CI 0.055-0.071], SE = 0.004). For every 1 dB(A) increase in the CNE, the BMI increased by 0.102 kg/m² (95% CI 0.090-0.113], SE = 0.006).

Conclusions: Occupational noise is related to the incidence of obesity. The occupational noise level and occupational noise cumulative level were shown to be positively correlated with an increase in BMI.