@karthasmi: Thank you for this. Good knowledge for everyone.
Sometimes it can be as innocuous as a slightly misaligned air passageway. My girlfriend got a nighttime mouth guard to prevent nighttime grinding and suddenly her snoring and middle-of-the-night coughing fits decreased by a huge percentage. And she's healthy and lean. Now she's on invisalign and the snoring has returned. So even though a lot of people point to weight issues and even if you're in shape, get checked out.