About 20 percent of the total adult population (18 years and over) of the UK has a hearing loss of 25dB or greater in the better hearing ear (Davis, 1989). In terms of self-reported disability, 26 percent of the population said that they had great difficulty hearing what was said against a background noise, whereas only 10 percent reported some difficulty in quiet on the better ear, with 19 percent reporting some difficulty in quiet on their worse ear (Cochrane, 1971; and Hinchcliffe, 1961).
According to Greville (2001), in New Zealand, 10.3% of the population (390,600) report having a hearing loss of some degree. In the non-industrialised population, 9.8% (368,600) report having a hearing loss of some degree, and 6.6% of the population (250,300) report having a disability caused by hearing loss. In the non- industrial adult population, 0.7% (2,620) report disability attributed to deafness. One third of all types of hearing loss can be attributable to noise and music exposure. In the last three decades we have created noisier equipment without much in the way of regulation to control it.
The relationship between exposure to loud noise and hearing loss has been recognised for over a century. However, it is only in the past 30-40 years that leisure noise, particularly music, has attracted attention as a possible cause of hearing loss. Apart from the standards, there are psychological aspects such as attitudes towards noisy musical settings and the individual's behaviour regarding the use of hearing protection, which may be considered as important factors in the understanding of why the prevalence of hearing related problems has increased significantly. According to a recent study (Callahan, et al., 2011), a majority of musicians showed a casual attitude about hearing protection despite the elevated risks of hearing loss.
According to The World Health Organization (2002), hearing loss caused by noise exposure is a significant occupational health problem. Throughout the world,
exposure to excessive noise/music is the major preventable cause of permanent hearing impairment. The total population of the world is approximately 7 billion and the majority of the population (approximately 5 billion) live in developing countries. In developing countries, occupational noise and urban environmental noise are increasing risk factors for hearing impairment. Most of these nations have rapidly expanding economies with occupational noise exposure increasing in all types of industry. In a developed country, this is at least partially the cause in more than one third of those with hearing problems. (Nelson, Nelson, Concha-Barrientos & Fingerhut, 2005) estimated that the prevalence of noise induced hearing loss is about 7% of the population in developed countries and 21% in developing countries.
In many industrial nations, noise induced hearing loss remains the biggest compensational occupational hazard worldwide. Though it has been estimated that the risk from occupational noise begins to decrease in developed countries, according to Thorne et al., (2008), in New Zealand there has been a substantial increase in the number of new NIHL claims annually, rising from 2823 in July 1995–June 1996 to 5580 in July 2005–June 2006. Together with ongoing claims, the overall costs of NIHL claims increased by an average of 20% each year (a six-fold increase over the decade), resulting in a total cost to the New Zealand Government’s Accident Compensation Corporation of $193.82M over the review period. Thorne concluded that the substantial and increasing societal costs, despite decades of NIHL control legislation, suggest that current strategies addressing this problem are not effective, inadequately implemented, or both, and that the hearing loss caused by recreational noise is on the increase.
In Berglund, Lindvall & Schwela (1999), many of the workers in the developing world are neither concerned with nor aware of the need for using the ear protection, and in many countries legislation is not in effect or enforced. Hence there is a world- wide increase in occupational and non-occupational noise induced hearing loss, and today it is a global phenomenon. The risk from occupational noise is beginning to decrease in developed countries, but globally there is a significant increase in social/recreational noise.
According to WHO-PDH (1997) document, the substantial increase in longevity has stemmed from the medical profession’s improved success in controlling infectious and chronic diseases. As people are living longer and industrialisation spreads so rapidly, noise induced hearing loss started to add substantially to the global burden of health and social disability. So as mentioned before, hearing loss has taken a public health priority.
Understandably, given the serious health and social consequences of hearing impairment, its increasing prevalence is cause for concern, and it is very important that prevention of preventable hearing loss should become a national health priority In Wallhagen et al., (1997), for example, according to New Zealand's Department of Labour’s key facts on NIHL, the Accident Compensation Scheme (ACC) spends about $40 million per year (double that of five years ago), and noise induced hearing loss appears in the top five of all claims. Hearing losses from different causes are additive and interaction can occur between noise exposure and chemicals such as toluene, or antibiotics such as the amino glycosides. In the elderly, NIHL may add to the hearing loss of presbyacusis to produce a hearing handicap sooner and worse than would occur from age alone (WHO-PDH, 1997).