Helicobacter pylori: the primary cause of duodenal ulceration or a secondary infection?

Table 1 Endoscopy reports of Helicobacter pylori-negative duodenal ulcer (DU) unrelated to NSAIDs

Authors	Places	Year	% H.pylori-negative DU
Oshowo[8]	UK, London	1999	30
Jones[9]	UK, Manchester	1986	41
Maher[10]	USA, Rochester	1987	43
Jyotheeswaran et al[11]	USA,Rochester	1998	39
Greenberg et al[12]	USA, Harvard	1997	40
Gislason et al[13]	USA, Baltimore	1997	30
Fenger et al[14]	Greenland (Inuit)	1997	50
Mirghani et al[15]	Sudan, Khartoum	1994	38
Kontou and Katelaris[16]	Australia, Sydney	1997	32.5
Uyub et al[17]	Malaysia, N. Peninsular	1994
	Malayans		72
	Non Malayans		14
Petersen et al[18]	USA, N. Carolina	1996	26
Lanza et al[19]	USA, Houston	1996	30
Bruno et al[20]	USA, Military Hospital	1997	75
Sprung and Apter[21]	USA, Florida
	Retrospective	1998	68
	Prospective	1998	69
Dres Pest et al[29]	Argentina	1996	33
	Early DU		59
	Chronic DU		22
Parsonnet[28]	All countries (meta-analysis)	1998	40
Sprung and Gano[22]	USA, Florida (retrospective)		52
Ciociola et al[23]	USA	1999	27
Henry and Batey[24]	Australia	1998	33
Pilotto et al[25]	Italy	2000	18.6
Lahaie et al[26]	Canada	2000	38