Aging: Degeneration of inner ear structures occurs over time; it comes on gradually as a person gets older.
Loud noise: Exposure to loud noises can damage your ear-cells into inner ear. Long-time loud noise exposure or short blast of noise can damage your ear.
Heredity: Hearing loss can be passed on from parents to their children but it is not always the same case, heredity hearing loss can skip a generation or one of the members only have it where other has normal hearing. Genetic hearing loss may also occur after a spontaneous gene mutation.
Recreational noise: sounds level exceeding 132 dB can cause an acoustic trauma. It can make immediate hearing loss after a single exposure. Example: firearms.
Occupational noise: Occupational noises can be defined as a partial or permanent hearing loss. Continuous exposure of loud noise or sound over a long period of time into work field can be one of the reasons of your hearing loss.
Medication effect: Ototoxic medicines can damage your ability of hearing. Older adults who take medicines in regular basis or took some steroids can also have a chance to damage cochlea in the inner ear.
Severe illness: Some serious disease or exposure to certain chemicals can be a cause of hearing loss and prevent your quality of hearing.