Poor oral health was associated with higher risk of gastric cancer: Evidence from 1431677 participants

Table 1 Baseline characteristics of included studies

Ref.	Country	Study date	Patients	Study type	Follow-up	Diagnosis of gastric cancer	Definition of oral health	NOS
Watabe et al[32], 1998	Japan	October 1996 to September 1997	242	Retrospective cohort study	NA	Gastric cancer	Brush teeth, decayed teeth, gingivitis, bad occlusion, dentures (partial and full), and lack of teeth ≥ 10	6
Abnet et al[27], 2001	China	March 1986 to May 1991	28868	Prospective cohort study	5.25 yr	Gastric cardia tumor and non-cardia tumor	Tooth loss	8
Hujoel et al[20], 2003	United States	1971 to 1992	11328	Prospective cohort study	Until 1992	Gastric cancer (ICD-9 151.0-151.9)	Periodontitis, gingivitis, and edentulism	7
Abnet et al[28], 2005	Finland	1985 to 1999	29124	Prospective cohort study	April 1993 to April 1999	Gastric non-cardia adenocarcinoma	Tooth loss included 0-10 teeth lost, 11-31 teeth lost, and edentulous	8
Michaud et al[29], 2008	United States	1986 to January 2004	49375	Prospective cohort study	Median of 17.7 yr	Gastric cancer	Periodontal disease and tooth loss	9
Hiraki et al[19], 2008	Japan	2000 to 2005	15720	Case-control study	NA	Gastric cancer (ICD-10 C16)	Remaining teeth	7
Shakeri et al[31], 2013	Iran	January 2004 to June 2008	922	Case-control study	December 2004 to December 2011	Gastric adenocarcinoma included non-cardia, cardia, and mixed-locations	Tooth loss, decayed, missing, filled teeth score, and frequency of tooth brushing	6
Ndegwa et al[30], 2018	Sweden	1973 to 1974	19831	Prospective cohort study	569233 person-years	Gastric cancer was divided into cardia (ICD 151.1) and non-cardia gastric cancer (all ICD-7 151 codes except ICD 151.1)	Number of teeth, dental plaque status, and presence of any oral mucosal lesions	7
Yano et al[33], 2021	Iran	January 2004 to June 2008	50045	Prospective cohort study	Until December 31, 2019	Gastric cancer cases were limited to adenocarcinomas (cardia and non-cardia)	Frequency of tooth brushing, tooth loss, and the sum of decayed, missing, or filled teeth	9
Zhang et al[8], 2022	China	October 2010 to September 2013	2873	Case-control	NA	Gastric cancer was divided into esophagogastric junction cancer and total gastric cancer	Tooth loss after 20 yr, number of tooth loss after age 20 yr, age of first tooth loss after age 20 yr, denture wearing, number of filled teeth, missing and filled teeth, frequency of toothbrushing, frequency of oral discomfort while eating, avoidance of some foods because of oral problems	6
Zhang et al[34], 2022	China	2004 to 2008	510148	Prospective cohort study	Median of 9.17 yr and range of 0.1 to 11.5 yr	Gastric cancer (ICD-10 C16)	Gum bleeding and rarely or never brush teeth	9
Kim et al[21], 2022	South Korea	January 2003 to December 2015	713201	Retrospective cohort study	Up to 10 yr	Gastric cancer (ICD-10 C16)	Periodontitis (who visited a dental clinic two or more than two times within one year and were diagnosed with periodontitis under those ICD-10 codes (K05.2, K05.3, K05.4, K05.5, and K05.6)	9

ICD: International Classification of Diseases; NA: Not available; NOS: Newcastle-Ottawa Scale.