The Factors Associated with Prevalence of Liver Disease among Sero Positive HBV and AFB1 Individuals in Selected Health Facilities in Kitui and Makueni Counties, Kenya

Abstract

There are various causes of liver disease including viruses, trauma and chemical poisoning. The viruses causing liver disease includes hepatitis A, B, C and D while ingestion of aflatoxinB1 contaminated food stuff may cause aflatoxicosis which manifests as hepatoxicity and in severe cases, sudden liver failure. An outbreak of aflatoxin poisoning and aflatoxicosis associated with aflatoxin B1 contaminated maize grain and flour had been reported over the years in parts of Kitui, Makueni and Machakos counties of lower easten Kenya. This could have compounded a suspected existing problem of a viral disease burden including hepatitis B virus induced hepatitis among individuals within the population. A study was therefore conducted to determine the prevalence of liver disease due to sero prevalence of HBV and AFB1 among the subjects, the relative risks of aquiring the disease in the study area and the association existing between liver disease and other suspected non causal contributory factors. The investigation was carried out in two steps, where the first was a case-control study where blood was analyzed for exposure and non exposure to AFB1 and HBV while the second was an observational cross-sectional study where subject household grain and flour samples were collected and analyzed for AFB1 in parts per billion (ppb). A non probability purposive sampling method was used to choose and divide the study area into strata with 19 health centers. The sample size (n) for the human case-control study was determined as 283 while Fisher et al, (1998) formula was used to calculate the minimum sample size for grain samples as 130, but was purposively adjusted to 283 to match the study participants. Individual serum samples were analysed for liver disease biomarkers, hepatitis B surface antigens, AFB1 lysine albumen adducts and critical liver function enzyme indicators Aspertate amino transferase and Alanine amino transferase in the study. Study participant household grain and flour samples of 0.25kg each were collected and analyzed by Elisa method for AFB1 in parts per billion (ppb). Structured questionnaire was used for data on suspected liver disease associated factors, including blood transfusion, unprotected sex, untreated water, unsterile body piercing instruments, and AFB1 contaminated maize grain. A computer software SPSS® version 18.0 was used to statistically analyze the data. The case AST level range was 55.6 IU/mL to 344.50 IU/mL with a mean of 154.86 IU/mL (95%, CI; 147.52 to 162.20) p= 0.05, while the control AST level range of 9.85 to 332.50 IU/mL had a mean of 35.30 IU/mL (95%, CI; 27.86 to 42.76), p= 0.05. The case ALT level range was 58 to 444.51 IU/mL with a mean of 173.32 IU/mL (95%, CI; 159.13 to 187.5) p= 0.05, while the control ALT range was 8.20 to73.50 IU/mL with a mean of 28.41 IU/mL (95%, CI; 25.96 to 30.86) p=0.05). The case subjects in this study had a highly elevated AST levels with 100% (n=283), of samples having values greater than 40 IU/mL and 99.64% (n=282) of serum samples with ALT levels above 30 IU/ml. Case AFB1 lysine albumin adducts level had a range of 15.5 to 135 pg/mg with a mean of 42.19 pg/mg (95%, CI; 38.45 to 45.93) p=0.05, while controls had a lower range of 3.5 to 60.5 pg/mg and a mean of 13.15 pg/mg (95%, CI; 12.3 to 15.0). In case cohort, 49.5% (n=140) of sample had HBsAg mean of 3481 IU/mL (95%, CI; 3037 to 3925) p= 0.05, while in controls 24% (n=68) of participants serum sample had a lower mean of 347.57 IU/mL (95%, CI; 278.5 to 416.80) p=0.05. The prevalence of liver disease associated with HBV was 24.73%, due to dietary AFB1 was 25.97%, while that due to combined AFB1 and HBV infection was 1.24%. The relative risk (RR) due to HBV infection and dietary AFB1 was 1.022 (95%, CI; 0.81 to 1.205) and 1.073 (95%, CI; 0.91 to 1.264), p=0.05 respectively. In conclusion, the etiologic agents HBV and dietary AFB1 were both found endemic but the dietary AFB1 induced hepatoxicity was more prevalent than HBV infections in the region. A vaccination campaign against HBV and training on better grain storage methods should be initiated to further lower AFB1 toxicity incidence and hence the disease prevalence in lower eastern Kenya.