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The vast majority of diabetes is lifestyle induced. Type I isn't as its an autoimmune disorder. But type II is lifestyle sensitive. Its also a giagantic hole into which we all pour money as people refuse to accept responsibility for themselves.

Fail.

Type 1: Results from the body's failure to produce insulin.
Type 2: Results from Insulin resistance, a condition in which cells fail to use insulin properly, sometimes combined with relative insulin deficiency.

Both of them can be caused by lifestyle and both of them can be genetic. The causes that you list above are typical but not absolute.