Passive smoking may cause hearing loss
MedWire News: Exposure to secondhand cigarette smoke increases the risk for sensorineural hearing loss (SNHL) in teenagers, show US study findings.
"More than half of all children in the US are exposed to secondhand smoke, so our finding that it can lead to hearing loss in teenagers has huge public health implications," said study author Anil Lalwani from New York University Langone Medical Center.
"We need to evaluate how we deal with smoking in public places and at home, as well as how often and when we screen children for hearing loss," he said.
Lalwani and colleagues analyzed cross-sectional data from the National Health and Nutrition Examination Survey (2005-2006) from 1533 participants aged 12-19 years, who were not active smokers.
The participants underwent audiometric testing and had serum cotinine measures taken to assess exposure to cigarette smoke. In total, 799 of the adolescents had been exposed to secondhand cigarette smoke (cotinine level of 0.05-14.99 µg/l despite no smoking in past 5 days) and 754 had no exposure (undetectable cotinine level).
SNHL was defined as having a mean pure-tone level greater than 15 decibels for low- (0.5, 1, and 2 kHz) and high-frequency (3, 4, 6, and 8 kHz) sound.
Lalwani and team found that a greater percentage of teenagers exposed to secondhand cigarette smoke had high- or low-frequency SNHL in one or both ears than unexposed teenagers.
More specifically, 4.97% and 2.80% of adolescents exposed to secondhand smoke had high- or low-frequency SNHL in both ears, respectively, compared with a corresponding 2.54% and 1.65% of adolescents with no smoke exposure.
Similarly, a respective 17.09% and 11.82% of the participants with secondhand cigarette smoke exposure had high- or low-frequency SNHL in one ear, compared with a corresponding 13.86% and 7.53% of those with no smoke exposure.
The effect of smoke exposure compared with no exposure on unilateral low-frequency SNHL was statistically significant, whereas the other between-group differences were not. Multivariate analysis adjusting for gender, age, ethnicity, and poverty, demonstrated that exposure to secondhand cigarette smoke independently increased the risk for unilateral low-frequency SNHL by a significant 83%.
A concerning factor, note the researchers, is that most of the adolescents were unaware of their hearing loss, with only 18.43% and 11.43% of those with low- and high-frequency hearing loss, respectively, being aware of having some trouble with hearing.
"Milder hearing loss is not necessarily noticeable," said Lalwani. "Thus, simply asking someone whether they think they have hearing loss is insufficient."
The team concludes in the Archives of Otolaryngology - Head and Neck Surgery that teenagers exposed to secondhand cigarette smoke should be closely monitored for early hearing loss using periodic audiologic testing.
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By Helen Albert