Chewing gum and risk of oesophageal adenocarcinoma: a new hypothesis tested in a population-based study.

The aim of this study was to test the hypothesis that chewing gum is associated with risk of oesophageal and cardia adenocarcinoma. A Swedish nationwide, population-based, case-control study was conducted in 1995-1997. All patients were prospectively and uniformly documented and classified shortly after diagnosis. In all, 189 and 262 patients with oesophageal and cardia adenocarcinoma, respectively, and 820 population-based control subjects were interviewed. These patients together constituted 85% of eligible cases occurring in Sweden. Odds ratios (OR) with 95% confidence intervals (CI) were calculated by multivariable logistic regression with adjustment for plausible confounders. Regular users of chewing gum (P3 times/week for P6 months) were not at increased risk of oesophageal adenocarcinoma (OR 1.0, 95% CI 0.6-2.2), and no duration-response relation was observed (P = 0.38). No association between regular gum chewing and cardia adenocarcinoma was found (OR 1.0, 95% CI 0.6-1.7), irrespective of duration of use (P = 0.56). In conclusion, with regard to risk of oesophageal or cardia adenocarcinoma, gum chewing seems harmless.