Table 2.

The basic information of clinic-based study

Publish year Authors	Continent	Country	Total	OLK	Definition	Examination	Biopsy	Age
A Jainkittivong 2002 [60]	Asia	Thai	500	24	WHO 1980	yes	no	≥ 60
TR Saraswathi 2006 [61]	Asia	India	2017	12	un	yes	un	13–84
Ali-Rıza-İlker Cebeci 2009 [62]	Asia	Turkey	5000	20	WHO 1980	yes	yes	17–85
Raghavendra Byakodi 2011 [63]	Asia	India	24,422	75	un	yes	yes	un
Jairo Robledo-Sierra 2013 [64]	Europe	Sweden	6448	24	WHO 1978	yes	no	21–93
Mithra N. Hegde 2014 [65]	Asia	India	2000	42	WHO 1997	yes	no	all
Queiroz 2014 [66]	South America	Brazil	6560	43	un	yes	yes	aver = 57
Y Hassona 2014 [67]	Asia	Jordan	1041	5	WHO 2005	yes	yes	16–86
Sameer Rastogi 2015 [68]	Asia	India	400	48	WHO, un	yes	no	60–100
Al-Maweri SA 2018 [69]	Asia	Yemen	1052	13	OPMD 2007	yes	yes	15–87
Christiana Madjova 2018 [70]	Europe	Bulgaria	603	6	un	yes	no	18–82
Denny E. Ceena 2022 [71]	Asia	India	450	9	un	yes	un	60–90

Abbreviations: un unclear, aver average