Leon Maria E, Assefa Mathewos, Kassa Endale, Bane Abate, Gemechu Tufa, Tilahun Yared, Endalafer Nigatu, Ferro Gilles, Straif Kurt, Ward Elizabeth, Aseffa Abraham, Schüz Joachim, Jemal Ahmedin
Section of Environment and Radiation, International Agency for Research on Cancer (IARC), Lyon, France.
Department of Internal Medicine, Faculty of Medicine, Addis Ababa University, Addis Ababa, Ethiopia.
PLoS One. 2017 Jun 8;12(6):e0178911. doi: 10.1371/journal.pone.0178911. eCollection 2017.
Qat (Catha edulis) chewing is reported to induce lesions in the buccal mucosa, irritation of the esophagus, and esophageal reflux. Case series suggest a possible etiological role in oral and esophageal cancers. This pilot study aimed to generate preliminary estimates of the magnitude and direction of the association between qat use and esophageal cancer (EC) risk and to inform the logistics required to conduct a multi-center case-control study.
Between May 2012 and May 2013, 73 EC cases (including 12 gastro-esophageal junction cases) and 133 controls matched individually on sex, age, and residence were enrolled at two endoscopy clinics and a cancer treatment hospital in Addis Ababa. A face-to-face structured questionnaire was administered. Qat use was defined as ever having chewed qat once a week or more frequently for at least one year. Odds ratios were calculated using conditional logistic regression.
Only 8% of cases resided in Addis Ababa. Qat use was more frequent in cases (36%) than in controls (26%). A 2-fold elevation in EC risk was observed in ever qat chewers compared with never users in unadjusted conditional logistic regression (OR = 2.12; 95% CI = 0.94, 4.74), an association that disappeared after adjusting for differences in tobacco use, consumption of alcohol and green vegetables, education level, and religion (OR = 0.95; 0.22, 4.22). Among never tobacco users, however, a non-significant increase in EC risk was suggested in ever qat users also after adjustment. Increases in EC risk were observed with ever tobacco use, alcohol consumption, low consumption of green vegetables, a salty diet, illiteracy, and among Muslims; the four latter associations were significant.
This pilot study generated EC risk estimates in association with a habit practiced by millions of people and never before studied in a case-control design. Results must be interpreted cautiously in light of possible selection bias, with some demographics such as education level and religion differing between cases and controls. A large case-control study with enrolment of EC cases and carefully matched controls at health facilities from high-risk areas in the countryside, where the majority of cases occur, is needed to further investigate the association between qat use and EC.
据报道,咀嚼巧茶(Catha edulis)会导致颊黏膜损伤、食管刺激和食管反流。病例系列研究表明,其可能在口腔癌和食管癌的病因中起作用。这项初步研究旨在初步估计巧茶使用与食管癌(EC)风险之间关联的程度和方向,并为开展多中心病例对照研究所需的后勤工作提供信息。
2012年5月至2013年5月期间,在亚的斯亚贝巴的两家内镜诊所和一家癌症治疗医院招募了73例食管癌患者(包括12例胃食管交界部癌患者)和133名对照,对照按性别、年龄和居住地进行个体匹配。采用面对面的结构化问卷进行调查。巧茶使用定义为曾经每周咀嚼巧茶一次或更频繁,且持续至少一年。使用条件逻辑回归计算比值比。
只有8%的病例居住在亚的斯亚贝巴。病例中巧茶使用频率(36%)高于对照(26%)。在未调整的条件逻辑回归中,曾经咀嚼巧茶者与从未使用者相比,食管癌风险升高了2倍(OR = 2.12;95%CI = 0.94,4.74),在调整了烟草使用、酒精和绿色蔬菜消费、教育水平及宗教差异后,这种关联消失了(OR = 0.95;0.22,4.22)。然而,在从不吸烟的人群中,调整后曾经咀嚼巧茶者的食管癌风险也有非显著增加。在曾经吸烟、饮酒、绿色蔬菜消费量低、高盐饮食、文盲人群以及穆斯林中观察到食管癌风险增加;后四种关联具有统计学意义。
这项初步研究得出了与数百万人的一种习惯相关的食管癌风险估计值,此前从未在病例对照设计中进行过研究。鉴于可能存在的选择偏倚,结果必须谨慎解释,因为病例和对照在教育水平和宗教等一些人口统计学特征上存在差异。需要在农村高风险地区的医疗机构开展一项大型病例对照研究,纳入食管癌病例并精心匹配对照,以进一步研究巧茶使用与食管癌之间的关联。