Objective Barrett's oesophagus is a precursor lesion of oesophageal adenocarcinoma, a cancer that, in the USA, has increased in incidence over 600% during the past 40 years. Barrett's oesophagus and oesophageal adenocarcinoma are much more common among men than among women; this finding is unexplained and most earlier studies lacked sufficient numbers of women to evaluate sex-specific risk factors. We leveraged the power of an international consortium to assess sex-specific relationships between body mass index (BMI), abdominal circumference and Barrett's oesophagus.

Design Four case–control studies provided a total of 1102 cases (316 women, 786 men) and 1400 population controls (436 women, 964 men) for analysis. Study-specific estimates, generated using individual participant data, were combined using random effects meta-analysis.

Results Waist circumference was significantly associated with Barrett's oesophagus, even after adjustment for BMI; persons in the highest versus the lowest quartiles of waist circumference had approximately 125% and 275% increases in the odds of Barrett's oesophagus among men and women, respectively (OR 2.24, 95% CI 1.08 to 4.65, I²=57; OR 3.75, 95% CI 1.47 to 9.56, I²=0). In contrast, there was no evidence of a significant association between BMI and the risk of Barrett's oesophagus, with or without adjustment for waist circumference.

Conclusions Waist circumference, independent of BMI, was found to be a risk factor for Barrett's oesophagus among both men and women. Future studies examining the biological mechanisms of this association will extend our knowledge regarding the pathogenesis of Barrett's oesophagus.