Table 2.

Evidence grades

Convincing	There is enough evidence to determine that an association with cancer risk is certain and taking preventive action is recommended
Probable	There is enough evidence to determine that an association with cancer risk is almost certain and taking preventive action is generally recommended
Limited-suggestive	Although neither ‘‘convincing’’ nor ‘‘probable’’ can be determined, there is evidence suggesting an association with cancer risk
Limited-no conclusion	Data are insufficient and an association with cancer risk cannot be determined
Substantial effect on risk unlikely	There is enough evidence to determine that there is no substantial effect on cancer risk