Smoking, Alcohol, and Abdominal Obesity Increase Gastric Cancer Risk after Helicobacter pylori Eradication.

[PURPOSE] Helicobacter pylori is the single most important risk factor for gastric cancer (GC). However, H. pylori eradication (HPE) does not eliminate risk of GC. To clarify the association of lifestyle factors with GC risk after HPE.

[MATERIALS AND METHODS] Using the Korean National Health Insurance Services (NHIS) database, adult individuals who claimed HPE between 2010 and 2016 were analyzed. The adjusted hazard ratios (aHR) for GC were analyzed according to the lifestyle status including smoking (never; light [<10PY]; moderate [10-20PY]; heavy [≥20PY]), alcohol (none; mild [<30g/day]; heavy [30g/day]), and abdominal obesity by using Cox proportional hazard model.

[RESULTS] During a median follow-up period of 6.7 years, 9,754 individuals were newly diagnosed with GC among the total of 1,282,702 subjects. Compared with never smokers, moderate (aHR 1.12 [95%CI 1.04-1.20]) and heavy smokers (1.34 [1.27-1.42]) had greater risks of post-HPE GC with dose-response manner. Heavy drinkers had increased risk of GC (1.23 [1.15-1.32]) compared with non-drinkers, and those with abdominal obesity had slightly elevated GC risk compared with those without that (1.11 [1.06-1.15]). In subgroup analyses, those who had HPE at age ≥ 55 were shown to be more affected by the unhealthy lifestyles (smoking [p-for-interaction <0.01], alcohol [0.03], and abdominal obesity [0.03]). Also, male showed greater risk increase by smoking habit [p-for-interaction 0.02] than female.

[CONCLUSION] Unhealthy lifestyles like smoking, alcohol, and abdominal obesity were shown as risk factors for post-HPE GC. Those with late HPE were more likely to be affected by unhealthy lifestyles.