The association between objective tongue color and endoscopic findings: Results from the Kyushu and Okinawa population study (KOPS)

Background: The relation between tongue color and gastroesophageal disease is unclear. This study was done to investigate the associations between tongue color (TC), endoscopic findings, Helicobacter.pylori infection status, and serological atrophic gastritis (SAG). Methods: The participants were 896 residents of Ishigaki Island, Okinawa, aged 28-86 years. The tongue was photographed, esophagogastroduodenoscopy was done, and serum antibody to H.pylori was measured. SAG was defined as a serum Pepsinogen (PG)Ilevel ≥70ng/ml and a PGI/IIratio ≥3.0. TC was measured by the device-independent international commission on Illumination 1976L*a*b* color space standards at four points: (1) edge, (2) posterior, (3) middle, and (4) apex. We also calculated the ratio of the tongue edge to the three other measured points to examine the association between the coating of the tongue and the endoscopic and laboratory findings. Results: Participants were excluded who had two or more endoscopic findings (n = 315) or who had SAG without seropositivity to H.pylori (n = 33). The remaining 548 participants were divided into three groups: SAG and seropositive to H.pylori (n = 67), seropositive to H.pylori alone (n = 56), and without SAG and seronegative for H.pylori (n = 425). We divided 425 residents into a single endoscopic finding positive group (n = 207) and a negative group, which served as a control (n = 218). The most frequent single endoscopic finding was esophageal hernia (n = 110), followed by erosive esophagitis (n = 35) and erosive gastritis (EG) (n = 45). EH was significantly associated with TC (2b*/1b*) (P < 0.05). EG was significantly associated with TC (3a*, 3b*) (P < 0.05). Seropositivity to H.pylori was significantly associated with TC (3L*, 3L*/1L*) (P < 0.05, <0.01), and seropositivity to both H.pylori and SAG was significantly associated with TC (3L*/1L*) (P < 0.05). Multivariate analysis extracted TC (3a*, 3b*) as an independent factor associated with a differential diagnosis of EG (Odds ratio (OR) 2.66 P = 0.008, OR 2.17 P = 0.045). Conclusions: The tongue body color of the middle area reflects acute change of gastric mucosa, such as erosive gastritis. Tongue diagnosis would be a useful, non-invasive screening tool for EG.