The global burden of noise-induced hearing loss

Editor: We all know that noisy workplaces contribute to hearing loss. But we're pretty fortunate in the US, because we have laws that mandate maximum volumes and exposures. This report from Hear-it discusses the impact of workplace noise around the world. As you might expect, the problem is worse in developing countries.

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Noisy workplaces have a heavy impact on health around the world. Millions of years of healthy life are lost due to occupational noise-induced hearing loss. Worldwide, 16 percent of disabling hearing loss in adults is caused by occupational noise.

Men are generally more exposed than women to excessive noise in the workplace. According to an international study funded by the World Health Organization, 22 percent of all instances of hearing impairment in men are due to noisy work environments, as compared to 11 percent of women's instances.

Noise induced hearing loss represents a much heavier burden in developing countries than in developed regions of the world. The difference is mainly due to lack of noise prevention programs and awareness of the consequences of excessive noise exposure.

In developing countries occupational noise accounted for about 3.8 million years of healthy life lost on an annual basis in 2000 compared to 0.3 million years in developed countries.

The health burden of hearing loss is measured in 'disability-adjusted life years' (DALY), a calculation of the years lost from ideal lifespan due to morbidity and premature mortality.

Noisy workplaces very common

Compared with other occupational hazards, noise is one of the main causes of years of healthy life lost.

Hearing loss caused by noise represents 18 percent of all the healthy years lost due to occupational risks closely followed by lung disease causing agents (16 percent) and asthmagens (7 percent). However, unintentional occupational injuries constitute the number one leading category of loss of healthy years at 44 percent of the total burden.

Noise weighs heavily on younger workers

The study showed that hearing loss attributed to occupational noise in 2000 was most common among younger categories of workers. In men aged between 15 and 44, 29 percent of instances of hearing loss were caused by noise in the workplace.

In older age groups, noise is less of a factor in new hearing loss cases as age-related hearing loss and other factors kick in as a main cause. 21 percent of men aged between 45 and 59 were found to have hearing loss due to work noise, whereas noise in the workplace was the cause of 13 percent of hearing loss in men in the 60-69 year age group. Similar patterns were found among women.

Preventable