Risk factors for esophageal cancer in a low-incidence area of Brazil

CONTEXT AND OBJECTIVESEsophageal cancer is the eighth commonest type of cancer worldwide, occupying sixth place in terms of mortality. Smoking and alcohol use are known risk factors for this type of cancer. The aim here was to evaluate the risk factors for esophageal cancer in a low-incidence area.DESIGN AND SETTINGCase-control study in Goiânia, with 99 cases of esophageal cancer and 223 controls.METHODSThe variables were sociodemographic, dietary, occupational and lifestyle data. The sample was analyzed using the chi-square test, Mann-Whitney test and Mantel-Haenszel approach for multivariate analysis. Odds ratios (OR) were calculated with 5% significance and 95% confidence intervals.RESULTSThe risk of esophageal cancer was higher in patients ≥ 55 years (OR = 1.95; P < 0.001). Patients from rural areas were at greater risk of esophageal cancer (OR = 4.9; P < 0.001). Smoking was a risk factor among the cases (OR = 3.8; P < 0.001), as was exposure to woodstoves (OR = 4.42; P < 0.001). The practice of oral sex was not a risk factor (OR = 0.45; P = 0.04). Consumption of apples, pears, vegetables, cruciferous vegetables and fruit juices were protective against esophageal cancer.CONCLUSIONIn a region in which the incidence of esophageal cancer is low, the most significant risk factors were exposure to woodstoves, smoking and living in rural areas.

背景与目的
食管癌（esophageal cancer）是全球第八大常见癌症，死亡率位居第六。吸烟与饮酒已被证实为该癌症的公认危险因素。本研究旨在评估低发地区食管癌的危险因素。

研究设计与研究地点
本研究为在戈亚尼亚开展的病例对照研究，共纳入99例食管癌患者与223例对照个体。

研究方法
本研究收集的变量涵盖社会人口学、饮食、职业及生活方式相关数据。采用卡方检验（chi-square test）、曼-惠特尼检验（Mann-Whitney test）及用于多因素分析的曼特尔-亨塞尔方法（Mantel-Haenszel approach）对样本进行分析。本研究计算比值比（Odds ratios, OR），检验水准设定为5%，并给出95%置信区间。

研究结果
年龄≥55岁的人群罹患食管癌的风险更高（OR=1.95；P<0.001）。来自农村地区的个体食管癌发病风险显著升高（OR=4.9；P<0.001）。吸烟为该疾病的危险因素之一（OR=3.8；P<0.001），暴露于柴灶环境亦为危险因素（OR=4.42；P<0.001）。而口交行为并非该病的危险因素（OR=0.45；P=0.04）。食用苹果、梨、蔬菜、十字花科蔬菜及果汁可降低食管癌的发病风险。

研究结论
在食管癌发病率较低的地区，最显著的危险因素为柴灶暴露、吸烟及居住于农村地区。