Objective: Associations between body mass index (BMI) and stature and cancers at different sites have been explored in a number of studies. For esophageal cancer there seems to be different effects of BMI for different histological subtypes. We explored these relations in a Norwegian cohort.
Material and methods: Height and weight were measured in 2 million Norwegians during 1963-2001. During follow-up, 2245 histologically verified esophageal cancer cases were registered. Relative risks (RR) of esophageal cancer were estimated using proportional Cox regression.
Results: Compared with normal weighted (BMI 18.5-24.9 kg/m(2)) an increased risk of esophageal adenocarcinoma (OA) was observed in overweight men (BMI 25-29 kg/m(2)): RR=1.80 (95% CI: 1.48-2.19) and in obese men (BMI > or =30 kg/m(2)): RR=2.58 (95% CI: 1.81-3.68). The corresponding risk estimates for women were RR=1.64 (95% CI: 1.08-2.49) and RR=2.06 (95% CI: 1.25-3.39). The opposite relation was observed for esophageal squamous cell carcinoma (OSCC). For overweight men the RR of OSCC was 0.72 (95% CI: 0.63-0.82) and 0.68 (95% CI: 0.50-0.93) for obese. The corresponding RR estimates for women were 0.52 (95% CI: 0.42-0.65) and 0.43 (95% CI: 0.32-0.59). In addition, the lowest men had the highest risk of esophageal cancer in general. Adjustment for smoking did not change these relations.
Conclusion: BMI had opposite relations to the two most common histological groups of esophageal cancer. While low BMI increased the risk of OSCC, high BMI increased the risk of OA. An increased risk of esophageal cancer was found in the lowest men.