[Anechoic]

I've tried searching the literature to find out whether this is either 1)wrong, or 2)generally known within the fields of audiology and occupational hygiene, but so far I've come up empty.

FWIW, I've also heard the same, but don't remember where off the top of my head. It's at least potentially true, but the conventional wisdom among acousticians/noise control engineering is that age-related hearing loss is mostly to increasing age rather than external factors.

[schiffern]

Oh, I meant about the wrong order-of-operations problem with decibels, which I have never seen anyone talk about. If you've heard of it please let me know.

The links discuss the evidence that hearing loss isn't inevitable with age, including examples of pre-industrial societies with quiet environments that when tested showed no hearing degradation with age.

The controversy seems to be mostly about how much of that effect was caused by good diet vs lack of exposure to loud sounds. I tend to think both are needed to be fully protective, eg to take an extreme example alcohol is known to cause damage to hearing cells even without exposure to loud sounds.

I expect, with apologies to Tolstoy, "All dysfunctional hearing is different, whereas all healthy hearing is the same."