Introduction Recent evidence suggests a role for magnesium, and the ratio of calcium-to-magnesium, intake in the prevention of colonic carcinogenesis. However, the association between these nutrients and oesophageal adenocarcinoma has yet to be explored. The aim of this investigation was to explore the association between the intake of magnesium and related nutrients and the risk of oesophageal adenocarcinoma and its pre-cursor conditions, Barrett’s oesophagus and reflux oesophagitis.

Method This analysis included cases of oesophageal adenocarcinoma (n = 2 n = 218), Barrett’s oesophagus (n = 2 n = 212), reflux oesophagitis (n = 2 n = 208) and population-based controls (n = 2 n = 252) recruited between 2002 and 2005 throughout the island of Ireland. All subjects completed a 101-item food frequency questionnaire. Unconditional logistic regression analysis was applied to determine odds of disease according to the dietary intakes of magnesium, calcium, and the resulting calcium:magnesium ratio.

Results After adjustment for potential confounders, individuals consuming the highest magnesium intakes from foods had significant reductions in the odds of reflux oesophagitis (OR 0.31, 95% CI: 0.11–0.87) and Barrett’s oesophagus (OR 0.29, 95% CI: 0.12–0.71) compared with individuals consuming the lowest magnesium intakes. The protective effect of magnesium was more apparent in the context of a low calcium:magnesium intake ratio. No significant associations were observed for magnesium intake and oesophageal adenocarcinoma risk (OR 0.77, 95% CI: 0.30–1.99 comparing the highest and lowest tertiles of consumption).

Conclusion Dietary magnesium intakes were inversely associated with reflux oesophagitis and Barrett’s oesophagus risk in this Irish population, suggesting a chemopreventive role for magnesium in the earlier stages of the inflammation-metaplasia-adenocarcinoma pathway. Further observational studies are needed to determine if dietary interventions are warranted.

Disclosure of interest None Declared.