Date of Award

7-15-2009

Document Type

Dissertation

Degree Name

Master of Medicine (MMed)

First Supervisor/Advisor

A. J. Raja

Second Supervisor/Advisor

S. Hassan

Department

General Surgery (East Africa)

Abstract

Background: Esophageal squamous cell carcinoma (ESCC) is a common malignancy inKenya with a dismal outcome with a majority of patients presenting late. The factors that are operative in the etiology of this disease and its geographic distribution withinKenya have not been characterized thus far.

Objectives: The objective of this study was to determine the association of ESCC with Khat chewing, which is prevalent in parts ofKenya, and other commonly implicated risk factors (i.e. smoking, alcohol, diet, socioeconomic status, caustic ingestion and first degree family history of ESCC). We also determined the geographic (provincial) origin, age/sex and ethnicity of cases visiting the participating centers.

Methodology: A multi-center based matched case-control study was carried by means of a questionnaire and a food frequency table to collect data on proposed risk factors, demographics and dietary habits among cases of histology confirmed ESCC and controls within the same center.

Setting: The study was conducted between August 2008 and April 2009 at St. Mary’sMissionHospital (Nairobi),KenyattaNationalHospital (Nairobi),ChogoriaMissionHospital (Eastern province) andAga KhanUniversityHospital (Nairobi).

Subjects: We had 83 cases and 166 controls matched for age (±5 years) and sex.

Analysis: The degree of association between development of ESCC and proposed risk factors was calculated through logistic regression.

Results: The male:female ratio of cases was 2.1:1, the majority of cases were from Central and Eastern province and mostly of Kikuyu ethnic origin and 42% were below 55 years with 19% below 45 years of age. The cases were of a lower socio-economic status based on the type of housing, education and type of cooking fuel used.

Univariate analysis show that caustic ingestion (OR 9.292 CI 2.541 – 33.981), poor housing (OR 1.710 CI 1.002 – 2.919), family history of ESCC (OR 2.670 CI 1.012 – 7.046), a low education level (OR 1.7515 CI 1.001 – 2.936), and cigarette smoking (OR 1.059 CI 1.026 – 1.093) were each associated with a higher adjusted odds ratio for development of ESCC. Chewing of khat (OR 1.002 CI 0.987 – 1.018), alcohol (OR 1.00 CI 1.00 – 1.00), tea (OR 1.001 CI 1.00 – 1.002) and a staple diet consisting of starch (OR 1.00 CI 0.99 – 1.00) were not associated with development of ESCC.

On multivariate analysis the most significant factors were caustic ingestion (OR 11.354 CI 3.036 – 42.461), first degree family history of ESCC (OR 3.505 CI 1.294 – 9.490) and poor housing (OR 1.978 CI 1.109 – 3.527).

Conclusions: Most of the patients were from central and eastern provinces and a large proportion were younger when compared to studies in other high incident regions in the world. Low socio-economic status, family history of ESCC and a history of caustic ingestion were significant risk factors. The small sample size and nature of the study are significant limitations and a larger study targeting the identified regions may shed more light into the demographics and specific risk factors for ESCC. Close follow-up of caustic injury patients and improvement of socio-economic status within the region may serve to control disease.

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