Associations of pesticides, HCV, HBV, and hepatocellular carcinoma in Egypt

Abstract

The rate of hepatocellular carcinoma (HCC) is increasing in Egypt where the major risk factors are chronic infections with hepatitis B and C viruses (HBV and HCV). A major segment of the population is employed in agriculture, raising the possibility that exposure to pesticides is an additional risk factor for HCC. The objective of this study is to investigate pesticides as environmental risk factors for HCC while taking into account viral risk factors. We conducted a case-control study of 236 subjects with confirmed HCC recruited from the National Cancer Institute, Cairo University, Egypt, and 236 controls matched on sex, age group and urban-rural status recruited from orthopedic department, Cairo University Hospital, Egypt. Patients who agreed to participate signed a consent form, answered a questionnaire and gave a blood sample for hepatitis virus testing. The manuals of the Ministry of Agriculture for approved use and type of pesticides since 1965 were linked to the questionnaire data for types of crops and pests that the subject had to combat, to attribute specific pesticides that were used by each subject. Subjects also reported duration of the exposure (years). Case-control comparisons in these data were stratified by sex, age group, and urban vs. rural residence. Data were analyzed using unconditional logistic regression models adjusting for age, HCV RNA, and current hepatitis B infection. Among rural males, the adjusted odds ratio (OR) for organophosphorus compounds was 2.7 (95% CI = 1.3-5.3) and for carbamates it was 2.9 (95% CI = 1.4-5.8). No statistically significant associations between HCC and pesticides were observed for urban males or for females. As expected, the strongest risk factors for HCC in this study were HCV RNA (OR = 16-17) and current HBV infection (OR = 27-28). This study therefore suggests that exposures to organophophorus and carbamate pesticides are additive risk factors to current HCV and HBV infection among rural males. Future investigation should address the possible hepatocarcinogenicity of pesticides using biomarkers of exposure and other techniques to better estimate dose-response relationships.