Are Short People Prone to Hearing Loss?
New research says problems may be tied to prenatal development
FRIDAY, Nov. 21, 2003 (HealthDayNews) -- If you are short, you may be predisposed to hearing problems.
That's the conclusion of a new study by Swedish researchers that appears in the Nov. 22 issue of the British Medical Journal.
"The potential for adult hearing problems may develop during the prenatal period," says study author Marie-Louise Barrenas, an associate professor of otorhinolaryngology at the Goteborg Pediatric Growth Research Centre of Goteborg University.
This appears to be particularly prevalent among shorter-than-average adults, she adds.
Barrenas' findings are based on the "thrifty phenotype theory," which says that events before birth -- such as malnutrition or exposure to alcohol or nicotine -- may cause disease in adulthood.
"This may also be the case for hearing loss," she says.
Barrenas's team tested the hearing of 479 men, aged 20 to 64, who were exposed to noise in their jobs. Then they randomly selected 500 other men born in 1974. For both groups of men, the researchers collected data on height, weight, exposure to noise, heredity for hearing loss and other medical disorders, including use of medication.
The researchers report that among the randomly selected men, short men were twice as likely to have hearing loss. They also found shortness was associated with a family history of hearing loss. However, there was no association with exposure to noise and hearing loss in this group.
Among the workers, the researchers found short workers had worse hearing than expected for their age. Short workers were also three times more likely to have hearing loss compared with taller workers. In addition, short workers were 12 times more likely than taller workers to be taking medication.
During the fetal period, there are factors that can affect growth, Barrenas says. So when you are born shorter than normal, that may affect your health as you grow older, she adds.
In the fetus, a low level of the growth hormone (IGF-1) might be a marker for adverse events, leading to a reduced number of cells at birth, which may cause shortness and the risk for early onset of age-related problems, Barrenas notes.
Barrenas's group is continuing its research by looking at adults who were born short for gestational age. "We are finding similar results," she says.
"We are looking for hearing treatment to prevent sensorineural hearing loss," Barrenas notes. "If we can show an association between growth disturbances and hearing, we think that we might be able to treat sensorineural hearing loss with growth stimulating substances."
"Our goal is to have a treatment instead of hearing aids," she says.
Dr. Thomas Murry, a professor of clinical otolaryngology head and neck surgery at Columbia University, says the Swedish study is very interesting but is "open to many critical factors, none the least of which is the type of noise exposure the subjects were exposed to.
"We are only at the beginning of studies that relate problems such as hearing loss to nonauditory factors such as growth, types of medicines and early childhood activities -- especially early childhood middle ear infections. Additional studies of factors such as early childhood health are very important in ascribing hearing-loss causes," he says.
To learn more about hearing loss, visit the American Speech-Language-Hearing Association and the National Institute on Deafness and Other Communication Disorders.