Traditional and commercial alcohols and esophageal cancerrisk in Kenya

Abstract

Squamous cell esophageal cancer is common throughout East Africa, but its etiology is poorly understood. We investigated the contribution of alcohol consumption to esophageal cancer in Kenya, based on a hospital-based case–control study conducted from08/2013to03/2018in Eldoret, western Kenya. Cases had an endoscopy-confirmed esophageal tumor whose histology did not rule out squamous cell carcinoma. Age and gender frequency-matched controls were recruited from hospital visitors/patients without digestive diseases. Logistic regression was used to calculate oddsratios (ORs) and their95%confidence intervals (CI) adjusting for tobacco (type, intensity) and6other potential confounders.A total of422cases (65% male, mean at diagnosis60(SD14)years)and414controls were included. ORs for ever-drinking were stronger in ever-tobacco users (9.0,95%CI:3.4,23.8, with few tobacco users who were never drinkers) than in never-tobacco users (2.6,95%CI:1.6,4.1). Risk increased linearly with number of drinks: OR for >6compared to >0to≤2drinks/day were5.2(2.4,11.4) in ever-tobacco users and2.1(0.7,4.4) in never-tobacco users. Although most ethanol came from low ethanol alcohols (busaa or beer), for the same ethanol intake, if a greater proportion came from the moonshine chang’aa,it was associated with a specific additional risk. The population attributable fraction for >2drinks per day was48% overall and highest in male tobacco users. Alcohol consumption, particularly of busaa and chang’aa,contributes to half of the esophageal cancer burden in western Kenya