interesitng thing, my parents never had acne as teens and i did...not an aggravating amount...and i still get it now and then depending on what i eat. The diff is they use to live in China, while i moved before my teenage years. Therefore, it is most likely something to do with the western diet? So any prevention measures would be to not eat all the foods you love
or be prepared to spend a small fourtune on acne products