Additional Risk Factors for Hearing Loss Studied

By CP Staff

Potential causes of age-related hearing loss, known as presbycusis, were recently studied in the Blue Mountains Hearing Study. In this study, the researchers investigated the role of low levels of folic acid and vitamin B12 and high levels of homocysteine in the development of presbycusis. The National Institute on Deafness and Other Communication Disorders (NIDCD) reports that an estimated 17 percent of American adults, or 36 million, have some degree of hearing loss. In addition, as increasing age is strongly correlated to hearing loss, they also report that 30 percent of adults between 65 and 74 years of age are hearing impaired.

In this new study, hearing was evaluated in 2,956 subjects. The subjects were also evaluated for serum concentrations of folic acid, vitamin B12 and the amino acid homocysteine, which is associated with increased risk of cardiovascular disease, osteoporosis and neurodegenerative disorders. Elevated homocysteine has been linked to low levels of folic acid, vitamin B6 and vitamin B12.

The results of the study showed that subjects with elevated homocysteine levels (greater than 20 µmol/L) had a 64 percent increased risk of prevalent hearing loss. Low levels of folic acid (less than 11 nmol/L) increased the risk of mild hearing loss by 37 percent. There was no significant association found between vitamin B12 and hearing loss.

Thus, the researchers demonstrated that decreased serum folic acid and increased homocysteine levels were significantly associated with increased risk of developing age-related hearing loss.

Reference:

Gopinath B, Flood VM, Rochtchina E, McMahon CM, Mitchell P. Serum Homocysteine and Folate Concentrations Are Associated with Prevalent Age-Related Hearing Loss. J Nutr. 2010 Jun 23. Published Online Ahead of Print.