Many cases cannot be prevented. Avoidance of smoking could prevent some cases, such as those due to COPD and lung cancer. Avoidance of obesity can prevent some cases of sleep apnea. Taking medications as prescribed can prevent noisy breathing due to congestive heart failure, gastroesophageal reflux disease, or asthma.
Long-term effects are related to the cause. For example, cases due to infection often go away and have no long-term effects. Cancer can result in death. Cases due to nervous system conditions may sometimes be permanent.
Noisy breathing itself is not contagious. If the cause is an infection, such as pneumonia, the infection may be transmitted to others.