BackgroundPrevious studies have shown the association between Campylobacter species infection and that environmental factors, poor oral hygiene in particular, are linked to an increased risk of esophageal cancer (EC). However, no study has reported on these factors in Thailand. Thus, this study’s objective was to evaluate the impact of the relationship between Campylobacter infection and environmental factors on EC incidence in the population of Thailand.MethodsData from a case–control study were collected from 105 newly diagnosed EC cases and 105 controls recruited from 2007 to 2017. Infection with Campylobacter spp. was detected in the formalin-fixed paraffin-embedded (FFPE) tissue of EC taken from gastroesophageal biopsy specimens obtained from the participants, and evaluated using TaqMan® real-time PCR. Multivariable logistic regression was performed to calculate the odds ratios (ORs) and perform data analysis.ResultsSmoking, alcohol use, a family history of cancer, history of gastroesophageal reflux disease, poor oral hygiene and Campylobacter spp. infection were shown to be significant risk factors for EC (p < 0.05). The combination of poor oral hygiene and infection with Campylobacter spp. constituted significant risk for EC (p < 0.001). In addition, the risk of EC in subjects co-infected with C. rectus and C. concisus that practiced poor oral hygiene was even higher and was significant (ORadj = 4.7; 95% CI 2.41–9.98; p = 0.003).ConclusionsIn Thailand, the major risk factors for EC are smoking status, alcohol drinking, family history of cancer, GERD, poor oral hygiene and Campylobacter spp. infection. This study found Campylobacter spp. prevalence to be associated with EC and appears to be enhanced by poor oral hygiene, suggesting that a combination of poor oral hygiene and Campylobacter species infection may together act as an important etiological risk factor for EC.