Dose passive smoking induce sensorineural hearing loss in children?

Objectives: Smoking plays major role in development of vascular and respiratory serious diseases. It has been reported that negative smoker children are prone for conductive hearing impairment due to repeated attacks of Eustachian tube dysfunction and middle ear effusion. This study aims to identify negative smoking as potential risk factor for development of sensorineural hearing loss.

Study: This study was done between January 2010 and November 2012. 411 children aged 5-11 years (8.2 ± 1.5) participated in this study; they were children attending the Ear, Nose, and Throat clinic of a tertiary care hospital and their siblings. The inclusion criteria were: (i) normal speech and language, (ii) absence of any disease or condition that may cause sensorineural hearing loss, and (iii) normal middle ear function on the day of hearing assessment. They were divided into three groups according to the exposure to second-hand smoke at home; group of "no exposure" whereas no smoker in the family (131 children), group of 'mild exposure" whereas the father was the only smoking parent and smoking was prohibited at home (155 children), and group of "heavy exposure", whereas the mother was smoking, or the father was freely smoking at home and in the presence of his children (125 children). Audiological evaluation in the form of pure tone and speech audiometry and immitancemetry was done for the study group.

Results: Audiological evaluation revealed that the prevalence of hearing loss was 3.8%, 4.5% and 12% in the "no exposure", "mild exposure", and "heavy exposure" groups, respectively. Significant difference was only detected between the high exposure group and the other two groups. All children had minimal sensorineural hearing loss, i.e. threshold of frequencies showing hearing loss was 20 or 25 dB HL. The risk ratios (95% confidence interval) for hearing loss in the study subgroups were 1.18 (0.38, 3.64) for mild exposure group (p>0.05), 3.14 (1.18, 8.3) for heavy exposure group (p<0.05).

Conclusions: Passive smoking in childhood correlates with sensorineural hearing loss, and it is an important risk factor for development of minimal hearing loss. Strict prevention of children exposure to second-hand smoke should be encouraged by every mean.