Some etiologies are pretty obvious from the audiometric configuration (cookie-bite, reverse slope, otosclerosis) but many are not. You could have a genetic panel done, I suppose? I hear that in the states you can just pay for whatever medical procedures you want.
Congential hearing loss is hugely genetic. I believe, when not assossicated with other syndromes, it often comes down to one of two recessive genes that you can be heterozygous or homozygous for. In well-babies without a genetic component, I believe the next most common cause is congenital cytomegalovirus, which I believe is also the most common infectious cause of birth defects generally but which is weirdly unknown. [The typical route of infection is that an older toddler picks it up and passes it to the pregnant mother through saliva and then it passes through the placental barrier to the fetus. Infection can be reduced by not sharing food with your toddlers, avoiding saliva transfer generally, hand washing. So, if you know anyone who is pregnant or planning to get pregnant let them know; I don’t know why doctors don’t talk about this.] After genetics and cCMV, in well-babies I believe next up is idiopathic hypoplastic auditory nerve. Lots of possible risk factors in NICU babies (e.g. forced oxygen, chemotheraputrics, glucocorticoids).
There are some other rare genes that cause progressive loss later in life (cookie-bite confuguration being one). A child with a strong history of ear infection, tubes, eardrum perforation may also present with minor conductive hearing losses later in life. And then childhood illnesses that were once common and now less so can be associated with hearing loss (e.g. measles, rubella, scarlet fever).
Non-genetic and non-noise causes in adults include autoimmune and cardio issues. However, there is noise and then there is NOISE. Long-term exposure to, say, factory noise will cause what we generally think of when we think of “noise-related” hearing loss and tends to be sloping high frequency or notched high frequency, but artillary fire can cause actual mechanical sheering damage within the cochlea and may look quite different in terms of audiometric configuration.
PSA: Smoking also increases your risk for noise-related hearing loss and hearing loss generally. I mean, it’s 2023, who smokes anymore? But boy it was cool when I was younger and what a beast of a habit for some people to kick.