Table 1 |.

Level of evidence for obesity and physical activity as risk factors for gastrointestinal cancer

Cancer site	WCRFa		IARCb
	Level of evidence	Risk	Level of evidence	Risk
Obesity
Colorectum	Strong convincing	Increased	Sufficient	Increased
Liver	Strong convincing	Increased	Sufficient	Increased
Oesophagus	Strong convincing	Increased	Sufficient	Increased
Pancreas	Strong convincing	Increased	Sufficient	Increased
Stomach	• Strong probable (non-cardia)	• Increased (non-cardia)	Sufficientc	Increasedc
	• Limited (cardia)	• No conclusion (cardia)
Physical activity
Colorectum	Strong convincing	Decreased	NA	NA
Liver	Limited-suggestive	Decreased	NA	NA
Oesophagus	Limited-suggestive	Decreased	NA	NA
Pancreas	Limited	No conclusion	NA	NA
Stomach	Limited	No conclusion	NA	NA

IARC, International Agency for Research on Cancer; NA, not available; WCRF, World Cancer Research Fund.

^aDefinitions by the WCRF are as follows: strong convincing evidence is defined as judgement of a convincing causal relationship, which is highly unlikely to be modified in the near future as new evidence accumulates; strong probable evidence is defined as a judgement of a probable causal relationship, which would generally justify goals and recommendations designed to reduce the incidence of a disease; limited-suggestive evidence indicates that there is too limited evidence to allow a judgement of a probable or a convincing causal relationship, but there is evidence suggestive of a direction of effect; limited evidence indicates that there is insufficient evidence to allow a firm conclusion.

^bSufficient evidence (as defined by the IARC Working Group on Energy Balance and Cancer) indicates the presence of a preventive relationship in humans between the absence of body fatness and the risk of cancer that has been observed in studies where chance, bias and confounding factors could be ruled out with confidence.

^cIARC assessments do not distinguish between cardia and non-cardia stomach cancer.