Body mass index and long‐term risk of death from esophageal squamous cell carcinoma in a Chinese population

BACKGROUND Studies based on Western populations have found that body mass index (BMI) is positively related to the risk of esophageal adenocarcinoma but inversely associated with esophageal squamous cell carcinoma (ESCC). Little reliable evidence exists of an association between BMI and ESCCin China, where ESCC incidence is high but BMI is low. METHODS We evaluated the BMI-ESCC association in a population-based prospective study of 29 446 Chinese aged 40-69 with 27 years of follow-up. China-specific BMI cut-offs (underweight < 18.5, healthy ≥ 18.5 to <24, overweight ≥ 24 to <28, and obese ≥ 28) and quartile categories were used to define BMI subgroups. Adjusted hazard ratios (HRs) and confidence intervals (CIs) for death from ESCC by BMI subgroups were calculated using Cox proportional hazards models. RESULTS During a median follow-up duration of 21.2 years (555 439 person-years), 2436 ESCC deaths were identified. BMI was protective for death from ESCC with an HR of 0.97 (95% CI 0.95-0.99) for each unit increase in BMI. Relative to healthy weight, HRs for BMI were 1.21 (95% CI 1.02-1.43) for the underweight group and 0.87 (95% CI 0.78-0.98) for the overweight. Categorical quartile analyses found people with BMIs in the Q3 and Q4 groups had 16% and 13% reductions in the risk of ESCC, respectively. Gender-specific analyses found that clear effects were evident in women only. CONCLUSIONS Higher BMI was associated with a reduced risk of ESCC in aChinese population.