Is ptosis more common among ethnic communities or any other group?

Not really. Is age related not race related.
Ptosis and ethnicity. Eyelid ptosis can often be an inherited condition and can be seen in any ethnicity, but may be seen in families. Eyelid ptosis, or drooping eyelid, has a number of possible causes. The most common cause of ptosis that is seen as part of the aging process is called involutional ptosis and is due to the stretching of the muscle fibers that lift the eyelid.
No. There are many causes of breast ptosis and several options for correction. If the ptosis is minimal sometimes an augmentation alone can improve the appearance, however, most often some sort of surgical mastopexy with or without an implant (depending upon the woman's desired result) is necessary. Always choose a surgeon certified by the american board of plastic surgery (www.Abplsurg.Org).