Alcohol consumption results in greater muscle relaxation, including the soft tissues of the upper airways, when sleeping.
Drugs including relaxants such as sleeping pills may have a similar effect to alcohol, and in addition to the snoring noises, limit the arousal response (waking up to breathe). This can leave the brain without oxygen for micro-seconds lengths of time, resulting in cumulative decrease of Oxygen Saturation in blood.
Allergies to pollens, food or animals (e.g. cats) can all contribute to snoring problems. These may be seasonal and/or temporary.
Obesity and weight gain, particularly in the upper body and neck region, can increase the bulkiness of the soft tissues and restrict the upper airways. This may also be noticeable when awake e.g. breathing difficulties.
Nasal problems and deformities can restrict the upper airways resulting in breathing difficulties. This may be due to enlarged tonsils, septum deviation, swellings of the thyroid, nasal polyps, etc.
Males seem to snore more and at a younger age than females. However, women often catch up to their male counterparts following menopause.