Perhaps you should try some spelling variations:
decrease iris » decrease risk (Expand search), decrease its (Expand search), decreased risk (Expand search)
iris patterns » risk patterns (Expand search), firing patterns (Expand search), drives patterns (Expand search)
decrease and » decreases and (Expand search), decrease in (Expand search), decrease of (Expand search)
and decrease » and decreases (Expand search), and decreased (Expand search), and increase (Expand search)
decrease any » decreases and (Expand search), decreased and (Expand search), decreased ant (Expand search)
any decrease » can decrease (Expand search), may decrease (Expand search), on decrease (Expand search)
decrease il » decreased il (Expand search), decrease in (Expand search), decrease hiv (Expand search)
il decrease » l decrease (Expand search), will decrease (Expand search), oil decreases (Expand search)

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (( decrease AND decrease any decrease ) OR ( decrease il decrease iris patterns ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( decrease and decrease any decrease ) OR ( decrease il decrease iris patterns ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease and decrease any decrease ) OR ( decrease il decrease iris patterns ))*.