BEHAVIOURAL, NUTRITIONAL AND ENVIRONMENTAL FACTORS ASSOCIATED WITH ESOPHAGEAL CANCER IN WESTERN KENYA

Abstract

Cancer of the esophagus is the most common cancer among men and third most common in women in Kenya. It has a unique geographic distribution with some of the highest incidence rates being in Southern and East Africa, Iran and China. Factors such as tobacco and alcohol, environmental exposures, nutritional factors and low socio economic status have been shown to increase the risk of esophageal squamous cell carcinoma (ESCC). The objective of this study was to determine the distribution and factors associated with ESCC in western Kenya. A case-control study was conducted at the Moi Teaching and Referral Hospital in Eldoret, Kenya from August 2013 to September 2014 in which patients with a history of progressive difficulty in swallowing presenting for endoscopy were enrolled into the study. Biopsies were done for histological confirmation of ESSC. Hospital based controls was selected by frequency matching. Both cases and controls were interviewed and biological samples were collected from them. A qualitative was conducted in Elgeyo Marakwet County, Kenya, an area of incidence for this cancer. Chi square and Fisher‘s exact test were used to compare categorical variables while Students‘ t-test was used to compare continuous variables. Simple logistic regression with 95% confidence intervals was used to estimate the association between ESCC and the risk factors. Data from 132 histologically confirmed cases of ESCC and 158 controls were analysed. The mean age of the cases and controls was 58.4 and 56.7 years respectively. The male to female ratio of the cases was 2:1. The odds of a male having ESCC are higher than that of a female having the cancer (OR 1.7, CI: 1.0, 2.8). Farmers had a higher risk for ESCC (OR 1.8, CI: 1.1, 3.0). The odds ratio for men where the exposure is farming was higher (OR 2.6, CI: 1.4, 5.0) than for females. Consumption of alcohol and smoking were individually associated with ESCC (OR 2.2, CI: 1.3, 3.7 and (OR 2.7, CI: 1.6, 4.3), respectively. When both habits were practiced, the odds ratio was higher (OR 2.9, CI: 1.7, 4.7). Low consumption of traditional vegetables was associated ESCC (OR 1.93 CI: 1.14). Consumption of fresh fruit and traditional vegetables was significantly inversely associated with ESCC, (OR 4.97 CI: 1.75, 9.02) for low consumption. Poor oral hygiene was also associated with ESCC (OR 2.30 CI: 1.40, 3.78). The qualitative study revealed that ESCC was common in the study area and was in agreement with the quantitative study with respect to alcohol and tobacco being risk factors for ESCC. This study supports the concept of multifactorial etiology for ESSC. The data showed significant strengths of associations for behavioural, dietary and environmental factors. The risk factors are amenable to change therefore this information will be useful to health professionals in developing strategies for changing the modifiable risk factors as a means of reducing the occurrence of this cancer.