Abdominal obesity increases risk for esophageal cancer: a nationwide population-based cohort study of South Korea.

<bold>Background: </bold>The relationship between overall obesity, as measured by body mass index (BMI) and risk of esophageal squamous cell carcinoma (ESCC) has been reported to show a negative correlation. However, the relationship of ESCC, which accounts for around 90% of esophageal cancers in South Korea, with abdominal obesity, as measured by waist circumference (WC), may be different. Thus, we investigated the association between abdominal obesity and esophageal cancer in a nationwide population-based cohort.<bold>Methods: </bold>A retrospective cohort study of 22,809,722 individuals who had undergone regular health check-ups provided by the National Health Insurance Corporation between 2009 and 2012 (median follow-up period, 6.4 years) in South Korea was conducted. Abdominal obesity was defined as a WC > 90 cm for men and > 85 cm for women. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) using χ2 test and Cox proportional hazards model adjusted for confounding factors. The primary outcome was newly developed esophageal cancer.<bold>Results: </bold>After adjusting for BMI, abdominal obesity increased the risk of esophageal cancer (HR 1.29, 95% CI 1.23-1.36). WC increased the risk for esophageal cancer in a dose-dependent manner (p values for trend < 0.0001). Among overweight (BMI 23-24.9 kg/m2) and obese I (BMI 25-29.9 kg/m2) individuals, abdominal obesity was a risk factor for esophageal cancer (HR 1.22, 95% CI 1.11-1.34; HR 1.28, 95% CI 1.18-1.39, respectively).<bold>Conclusion: </bold>Increasing abdominal obesity may be associated with an increased risk for esophageal cancer. Further studies are warranted to confirm the relationship. [ABSTRACT FROM AUTHOR]