健康英语新闻:Exposure to secondhand smoke associated with hearing loss in adolescents: report

WASHINGTON, July 18 (Xinhua) -- Exposure to secondhand smoke ( SHS) is associated with increased risk of hearing loss among adolescents, according to a report in the July issue of Archives of Otolaryngology -- Head and Neck Surgery.

Among U.S. children, approximately 60 percent are exposed to SHS, according to background information in the article. Studies have associated exposure to secondhand smoke prenatally or during childhood with various health conditions, from low birth weight and respiratory infections to behavioral problems and otitis media. Children exposed to SHS are more likely to develop recurrent otitis media, the authors note. "Secondhand smoke may also have the potential to have an impact on auditory development, leading to sensorineural hearing loss (SNHL)," they add.

Anil Lalwani and colleagues from New York University Langone Medical Center examined the risk factors for SNHL, including SHS, among adolescents, stratified by demographic groups. They included 1,533 individuals from 12 years to 19 years of age who participated in the National Health and Nutrition Examination Survey from 2005 to 2006.

Participants were interviewed about their health status and family medical history, exposure to SHS, and self-recognition of hearing impairment. In addition, they underwent a physical examination, including blood testing for cotinine (a by-product of nicotine exposure), and hearing tests.

Compared with teens who had no SHS exposure, those who were exposed to secondhand smoke exhibited higher rates of low- and high-frequency hearing loss. The rate of hearing loss appeared to be cumulative, increasing with the level of cotinine detected by blood tests. The results also demonstrated that more than 80 percent of participants with hearing loss did not realize they had impairment.

As hearing loss early in life can cause problems with development and functioning, the authors suggest that these results have "significant implications for public health in the United States."

They note that most adolescents do not receive screening for hearing loss in the absence of risk factors.If further studies replicate these results, they state, SHS could be considered one such risk factor.