Age is a factor. Cats generally become type 2 diabetic in middle age, so we can assume that diet and life circumstances have a major influence. It is believed that diabetes is becoming more common in recent years. According to this source, it was estimated twenty years ago that 0,5% of the general population was diagnosable. Recent studies suggest that this figure has increased in recent years to somewhere between 1 and 2 percent of the general population. This is also comfirmed by Dr. Elizabeth Hodgkins, who is widely recognized as an authority on the subject.