Contribution of Aflatoxin B1 Exposure to Liver Cirrhosis in Eastern Ethiopia: A Case-Control Study

Abstract

Background Liver cirrhosis is a global health problem due to a large number of disability-associated life years and mortality. However, evidence is scarce on its causes in Eastern-Ethiopia, a place where there is a high prevalence of liver cirrhosis of unknown etiology. This study attempted to identify the risk factors related to liver cirrhosis in the area. Methods A case-control study was conducted at a tertiary care hospital from January 2020 to July 2021. Following diagnoses using an ultrasound-based cirrhosis scale, a total of 127 cases were identified and compared with 253 control patients. A structured questionnaire and data abstraction form were used to collect demographic, lifestyle, and clinical information. A blood sample was also taken from each participant for clinical chemistry, hepatitis B virus (HBV), and hepatitis C virus tests as well as for an aflatoxin B 1 (AFB 1 ) albumin adduct (AF-alb) assay. Binary logistic regression analysis was used to determine predictors of liver cirrhosis. Results AF-alb levels were detected in 75% of the cases and 64% of the controls, with a median (IQR) level of 11 pg/mg (5.5–25) and 7.0 pg/mg (4.3–20.5), respectively (p<0.05). Moreover, the number of subjects with high AF-alb levels (≥8.6 pg/mg) was greater in cases (45%, p<0.05)) than controls (28%). Age ≥55 years (adjusted odds ratio (AOR)=0.4; 95% CI: 0.2, 0.8), being a farmer (AOR= 3.0; 95% CI: 1.5, 6.0), family history of liver disease (AOR= 2.9; 95% CI: 1.1, 7.9), HBV seropositivity (AOR=4.0; 95% CI: 1.9, 8.8), and exposure to high levels of AF-alb (AOR=2.0; 95% CI: 1.1, 3.7) were significantly associated with liver cirrhosis. Conclusion This study found a strong link between AFB 1 exposure and liver cirrhosis. Mitigation of aflatoxin exposure and a better understanding of additional environmental risk factors like pesticides may be necessary to reduce the disease burden in Ethiopia.

Copy Number Variation in the GSTM1 and GSTT1 Genes and the Risk of Liver Cirrhosis in Eastern Ethiopia

“… 33–35 Indeed, in our recent study, HBV infection and AFB 1 exposure were the major culprits of liver cirrhosis in Eastern Ethiopia. 9 …”

“…This is a follow-up of a case–control study conducted from January 2020 – July 2021 to assess the risk factors associated with liver cirrhosis in the Internal Medicine Unit of Hiwot Fana Comprehensive Specialized University Hospital (HFCSUH), Harar, Eastern Ethiopia. 9 In brief, the study consisted of 127 confirmed cases of liver cirrhosis and 253 controls without any history or clinical evidence of liver diseases. Written consent from the participants was obtained after explaining aims of the study and a detailed questionnaire was filled out for each case and control by a trained interviewer.…”

“… 7 , 8 In our recent study, we found a strong association between AFB 1 exposure and liver cirrhosis. 9 AFB 1 is mainly metabolized by CYP3A4 into the reactive free radical AFB 1 -exo-8, 9-epoxide. 10 This intermediate metabolite is typically detoxified by conjugation with glutathione through the action of GST enzymes, mainly GSTM1 and GSTT1 encoded by the GSTM1 and GSTT1 gene, respectively.…”