Here is a study in the Journal of Clinical Sleep Medicine out of Denmark that analyzed which diseases were more common in patients later diagnosed with obstructive sleep apnea (OSA). The researchers used 1% as the cutoff off for inclusion. The results showed that in those diagnosed with OSA, their was an increased risk of the person having already been diagnosed with diabetes, hearing loss, high blood pressure, angina, atrial fibrillation, pneumonia, emphysema, asthma, deviated nasal septum, and prostate enlargement. These make sense clinically, and many of the conditions co-exist. Obesity is a common factor in OSA, and this could link some of the conditions listed.
The hearing loss is interesting, and may be related to loud snoring. Deviated nasal septum could impact airflow through the nose, increasing snoring and OSA. OSA can increase night time urination. In men, they might get diagnosed more with prostate enlargement when they report this nighttime urination. But their doctor may not think about OSA as a cause until later.