Public Release: 

Hearing problems may be programmed at birth

The thrifty phenotype hypothesis and hearing problems BMJ Volume 327, pp 1199-1200


Hearing loss in adulthood may be programmed at birth, and short people may be particularly susceptible, say researchers from Sweden in this week's BMJ.

Their conclusions are based on the theory (known as the thrifty phenotype hypothesis) that events before birth, such as malnutrition or exposure to alcohol or nicotine, may cause disease in adulthood.

They assessed the hearing of 479 men aged 20 to 64, who were exposed to noise in their jobs, and 500 randomly selected male conscripts born in 1974. Factors such as height, weight, exposure to noise, heredity for hearing loss, and other medical disorders including use of drugs were taken into account.

Among the conscripts, shortness was found twice as often in those with hearing loss as in men with normal hearing. Shortness was also associated with a positive heredity for hearing loss but not with noise exposure.

Short workers had worse hearing than expected by age, three times more often than taller workers and were 12 times more often taking drugs.

The thrifty phenotype hypothesis is applicable to hearing loss, say the authors. They suggest that a low level of growth hormone (IGF-1) before birth leads to a reduced number of cells at birth, which results in short stature and earlier onset of age related disorders.


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