Interaction between noise and cigarette smoking for the outcome of hearing loss among women: A population-based study
Background We investigated the interaction between exposure to noise and smoking in relation to prevalence of hearing loss among women.
Methods A sample of women aged 20–49 years (n = 1,723) from a population-based cross-sectional study carried out in Brazil in 2006 was examined. Hearing loss was assessed using a yes–no validated question. Biological interaction was analyzed using the additive scale and measured with interaction contrast ratio (ICR) and assessment of dose–response relationship.
Results The combined effect of exposure to noise and cigarette smoking on hearing loss (adjusted prevalence ratio (PRadj) = 3.94, 95% confidence interval (CI): 2.81, 5.52) was greater than expected based on the additive single effects of smoking (PRadj = 1.39, 95% CI: 1.07, 1.81) and noise (PRadj = 2.66, 95% CI: 1.86, 3.82). ICR estimates were not statistically significant. The prevalence of hearing loss among noise-exposed women increased with duration of smoking (P trend = 0.026), number of cigarettes smoked per day (P trend = 0.034), cumulative tobacco use (P trend = 0.030), and early age at smoking initiation (P trend = 0.047).
Conclusions Noise and smoking may have a combined effect on hearing loss but further studies are still needed. A dose–response relation of smoking for the noise effect among women is suggested.