Aflatoxins (AFs) are one of the major types of mycotoxins and are common contaminants of crops such as maize and groundnuts, especially in tropical and subtropical areas. The suitable climate for fungal growth, subsistence farming practices, and dietary reliance on staple crops contribute to chronic and high exposure to AFs in populations. AFs are known human carcinogens. However, the impact on other human health issues has been less investigated in humans. In this work, aflatoxin exposure of populations from Chile, Tanzania, and Pakistan was assessed using the aflatoxin albumin adducts (AF-alb) biomarker, in relation to various health outcomes.
The Epidemiological Investigation of Gastric Malignancies (ENIGMA) study in Chile previously found a significantly higher frequency of consumption of chili/chili products in participants living in Valdivia, a city with an increased risk of gastric cancer (GC). Chilli powder was reported to have the highest levels of AFs in foods in Chile. In this study, I explored the association between serum AF-alb levels and gastric atrophy (GA), a precancerous condition of GC, in adults (≥ 40 years) enrolled in the ENIGMA study. In total, 22 out of the 308 participants (7.1%) had detectable levels of AF-alb (5.2% and 9.1% of the cases and controls, respectively) with no association between GA and aflatoxin exposure levels. GA cases were associated with having fewer years of education (OR=1.16; CI 95% 1.09-1.29) and being overweight (OR=3.24; CI 95% 1.34- 8.26). In our study, we did not find a significant association between serum AF-alb exposure and GA, likely due to the fact that there were very few participants with detectable levels of AF-alb levels. For the Tanzania study, the geometric mean (95% CI) of AF-alb concentration for all samples is 5.4 (4.8 ~ 6.1) pg/mg albumin, and for positive samples is 7.9 (4.9 ~ 10.9) pg/mg albumin. 77.2% (190/146) of all samples from this study have detectable levels of AF-alb. The maximum level of all samples was 233.8 pg/mg albumin, and the level of all positive samples was 6.2 pg/mg albumin. There is no significant association between aflatoxin exposure and liver function biochemical indicators. For the Pakistan study, after the age of subjects matched in the liver disease group and the control group, the aflatoxin exposures AF-alb in hepatitis B and liver cancer groups were 1.5 (1.5 - 1.5) and 1.8 (1.1 - p2.5) pg/mg albumin, respectively, which were similar to those in the control group (1.7 (1.5 -2.0) pg/mg albumin), p >0.05. In contrast, the AF-alb levels in hepatitis C and liver cirrhosis groups were significantly higher than those in other groups, 2.4 (1.5 – 3.4) and 2.3 (1.3 – 3.4) pg/mg albumin (p <0.05), respectively. The study results support that hepatitis C and liver cirrhosis may be related to aflatoxin exposure.
