Snoring like any other sound is always caused by vibrations. It is caused due to vibrations of nose and throat tissues that are not meant to vibrate by nature. It is due to the result of turbulent airflow causing those tissues to vibrate during sleep.
Studies show that around 45 per cent males and 30 per cent females snore regularly. There are many people who do not snore regularly, do snore when they are drunk or during illness and sometime while under medication.
No clear relation has been found to body weight and snoring. Some time a thin lady may snore more loudly than a very fat man or vice versa. Usually people tend to snore more as they grow older.