Is it all in the genes?

Then there is the news item on the front page of this foum 20th January 2010 headed
"Native Population in Canada affected by diabetes"
I'm not good at "cutting and pasting" sorry... It read that in 1937 non of the First Nations People studied in a particular group had diabetes while in the present day greater than 20% have diabetes. One of the thoughts was that it indicated environmental rather than genetic factors.
Alison