Table 2.

Risk factors for small intestinal adenocarcinoma

Factor	Disease	Risks of small intestinal adenocarcinoma	Ref.
Animal fat		Correlation coefficient of 0.61	[21]
Animal protein		Correlation coefficient of 0.75	[21]
		2–3-fold higher risk	[36]
Bile salts		Bile salts may transform into carcinogenic deoxycholic acid	[22]
Hereditary polyposis	FAP	APC mutation; 5% is small bowel adenocarcinoma and half is duodenal adenocarcinoma	[27]
		The incidence is 330 times higher than that in the general population	[28]
	HNPCC	MMR gene mutation; lifetime risk is at approximately 1% in a French registry	[29]
	PJS	STK11 mutation; incidence is 520 times higher than that in the general population	[30]
Disease	Crohn’s disease	The incidence is 17.4 times higher than that in the general population	[37]
		The incidence is almost 3 times higher than that in the average American	[38]
	Celiac disease	It is implicated in 8%-13% of small bowel adenocarcinoma cases	[39,40]

FAP: Familial adenomatous polyposis; APC: Adenoma polyposis coli; HNPCC: Hereditary nonpolyposis colorectal cancer; MMR: Mismatch repair: PJS: Peutz-Jeghers syndrome; STK 11: Serine/threonine kinase 1.