Hi alewis, For me it was quite complicated as my condition was immediately dismissed by physicians who then proceeded to ignore the issues for seven years. I was eventually able to find a GP who assisted me in identifying an autoimmune myopathy which I now suffer from; myositis. Thanks to testing positive for PL-7 antiibodies, which are indirectly linked to respiratory issues, I was finally able to convince the hospitals physicians to perform pulmonary function testing. It was these which demonstrated the low pulmonary function. My test results were extremely difficult to measure, with many of the tests failing as they couldn't measure function so low. In order to confirm the results of the tests the physicians decided to perform a sleep test, where breathing and so on are measured as you sleep. Although my AHI isn't too bad they were deeply concerned about the large drops in my blood oxygen levels overnight, confirming the results. One of the physicians remarked that it was lucky that I have never smoked before, obviously implying that further impairment of my respiratory system would have guaranteed my death by now. I am now aware that medical research has begun to determine that silica nanoparticles, such as those which I was exposed to (sourced from polyethylene resin), inhibit the transfer of phosphate from ATP for energy production within the mitochondria of cells. Since this affects both aerobic and anaerobic energy production it's little wonder that people with silica exposures experience such horrendous collapse of health. Due to the legal issues involved, with their hospital involved in deriding me for claiming that work exposures had resulted in a massively fast collapse of my health, they have declined to provide me with a diagnosis which will contradict prior diagnoses and have advised that my GP refer me to a physician specialising in legal cases in order to obtain that diagnosis. They don't deny my claims anymore, advising me that my failing health is likely to result in organ failures in coming years.