Qat Use And Oesophageal Cancer In Ethiopia: A Pilot Case-Control Study

Maria LEON, IARC, France
ASSEFA M. 2 , GAMECHU T. 3 , BANE A. 2 , KASSA E. 2 , TILAHUN Y. 2 , FERRO G. 1 , ENDALAFER N. 4 , STRAIF K. 5 , ASEFFA A. 4 , SCHUZ J. 1 , JEMAL A. 6

1 Section of Environment and Radiation, International Agency for Research on Cancer, Lyon, France
2 Department of Internal Medicine, Faculty of Medicine, Addis Ababa University, Addis Ababa, Ethiopia
3 Department of Pathology, Faculty of Medicine, Addis Ababa University, Addis Ababa, Ethiopia
4 Armauer Hansen Research Institute, Addis Ababa, Ethiopia
5 IARC Monographs, International Agency for Research on Cancer, Lyon, France
6 Surveillance and Health Services Research, American Cancer Society, Atlanta, USA

Purpose of pilot study:
To assess the feasibility for a multi-center case-control study of oesophageal cancer (OC) in Addis Ababa and to generate preliminary estimates on the association between the occurrence of OC and suspected (qat use) and established (tobacco and alcohol) risk factors.
Methods:
All consenting OC cancer patients seeking cancer treatment in Addis Ababa University Teaching Hosptal or diagnostic services in two endoscopy clinics in the city between May 2012 and 2013 were enrolled. Two controls (hospital, hospital visitor) were matched to cases on sex, age (± 5 years) and place of residence. A face-to-face structured questionnaire was administered. Odds ratios (OR) with 95% confidence intervals (95% CI) were calculated using conditional logistic regression.
Results:
Findings are reported on a total of 206 participants, including 73 OC cases and 133 controls (40 hospital and 93 healthy visitors). Only 8% of OC cases enrolled resided in Addis Ababa. Ever tobacco use (OR: 3.31, 95% CI: 0.53, 20.6; p=0.20) and ever alcohol use (OR: 2.30, 95% CI: 0.32, 16.5; p=0.41) were associated with elevated risk of OC as compared to never users, although confidence intervals were wide.  Our study showed no overall excess risk of OC in association with ever qat use (OR: 0.95, 95% CI: 0.22, 4.22), but an association in non-tobacco users. Other factors associated with increased risk of OC included low consumption of green vegetables and high salt intake, education and religion.
Conclusions:
We report for the first time tobacco, alcohol and qat-associated OC risk estimates in Ethiopia, though based on an unrepresentative pilot study. A large case-control study, with proper sample size, and enrolment of cancer cases at health facilities from the country side (where the majority of cases occur) is needed to confirm findings, particularly of qat chewing and elevated OC risk in non-tobacco users.