Last week's major UCD study on hearing found that Irish people are deafer than others and suggested that median hearing thresholds were "not causally related to type or employment . . . or use of guns".
But Prof Ray Kinsella, who directed the research team, told The Irish Times that the study must not be interpreted to read that noisy workplaces could not impair workers' hearing: "We would certainly not be saying that noise at work does not cause hearing loss. There is an abundance of evidence which suggests that exposure to loud noises does impact on hearing."
The point is that "this may not be the case for a particular individual". The study found that Irish people had "measurably inferior hearing" than ISO Table B, the international standard for average hearing, would suggest. "What we are saying is that there is unequivocal evidence that Irish people are harder of hearing . . . whichever way you cut it, compared with (ISO) Table B, we are worse."
The new study presents a "de facto Table B" for the Republic and "the parameters of what should be regarded as normal hearing have changed. This study changes the ball game in terms of normal hearing," he says. It provides Irish data for the courts. "What we've shown is the pathology of hearing in Ireland is not as predicted by the ISO. It is different, it is worse. Now had the courts known that, I don't know, a year, two years ago, and had they taken it into account, we would have a different kind of scenario at the moment," he says. Some 53 per cent of the sample of 1,008 were found to be in the Health and Safety Authority's warning or referral categories. "Now the implication of this is not so much that half the population is deaf. The implication of it is that the HSA standards and the guidelines do need to be more refined and do need to reflect the reality of Irish hearing levels today," says Prof Kinsella.
The study found that Irish people's hearing is three to five decibels worse than ISO Table B, which is "not that extraordinary because early studies are pretty crude".
He believes the research was rigorous. "We did everything we could to get it really right. And we went much further in terms of scale and analysis than a lot of international studies go. And if you look at the literature, you're looking, quite often, at much smaller samples."
While smoking causes cancer, it doesn't cause cancer in everyone, nor does excessive noise make everyone deaf. Up to now, it has been assumed "This guy shot a gun". He's got noise-induced hearing loss. The two of them are related. Pay the man.
"Now what we're saying is that you can't really go that fast. Individual susceptibility is very important so you can't say in advance whether a particular individual will or will not be susceptible to noise-induced hearing loss."
Mr John Cass, an industrial audiologist involved in the research, says: "There is a causal link. Don't get me wrong. I'm not saying that noise is good for you . . . noise is still a problem. We're not trying to say that noise is not a problem. I'm an audiologist and I know that noise causes problems in people." But the study might cast doubt as to whether, say, gunfire alone is the reason for a soldier's hearing loss, he says. For some people noise is "far more influential on them because of their make up, not because of the exceptional levels of exposure". If a soldier were exposed to very high levels of noise in artillery over a prolonged period of time and he had a noise-induced hearing loss, this would be "quite obvious". But if a soldier's exposure were not considerable, "there would certainly be doubt as to the causation. He could still have a noise-induced hearing loss, but in my opinion you would have to question if that was entirely as a result of gunfire and may, in addition, have been due to other factors".
This report is "definitely not" saying that noisy workplaces do not cause hearing damage. Noise remains a workplace hazard. But genetic make-up needs to be considered as well as levels of exposure. As for prevention, Mr Cass says: "An individual may be prone to a noise-induced problem. And for that reason, because you don't know on a working site, whether Joe or Mick or Tommy is the one that is prone to receiving an injury for this, you protect everybody."
