Reducing the risks of aflatoxin through public health interventions
Khlangwiset Pornsri, Wu Felicia and Barchowsky Aaron
Thesis, Doctor of Philosophy, University of Pittsburgh. 194 pages. 2011
2011
บทคัดย่อ
Aflatoxin, produced by the fungi Aspergillus flavus and A. parasiticus, is the most potent naturally occurring human hepatocarcinogen. Food crops colonized by these fungi, especially maize and groundnut, are the major sources of dietary aflatoxin exposure. Aflatoxin and chronic hepatitis B virus (HBV) infection, two liver cancer risk factors that synergize with each other, are prominent in sub-Saharan Africa and certain parts of Asia. Furthermore, increasing evidence from epidemiological studies suggests that aflatoxin may cause child growth impairment, which can increase risks of premature deaths. A broad range of aflatoxin control strategies, developed to reduce aflatoxin exposure or its toxicity, include preharvest, postharvest, and dietary interventions; as well as the HBV vaccine, which does not reduce aflatoxin exposure but reduces the risk of aflatoxin-induced liver cancer.
We compared the efficacy and the cost-effectiveness of four aflatoxin risk-reduction strategies: HBV vaccine, biocontrol (preharvest), a postharvest intervention package, and NovaSil clay (dietary) in preventing liver cancer and stunting in Nigeria. Aflatoxin and chronic HBV infection are attributable for 8-27%, and 59-62%, respectively, of total liver cancers in Nigeria. We found that the HBV vaccine provides the greatest health-based efficacy and the lowest cost to avert one disability-adjusted life year (DALY) in Nigeria, compared with the selected aflatoxin control interventions. The prospective burden of aflatoxin-related stunting in Nigeria varies depending on aflatoxin exposure levels, which can vary substantially by year and location. At higher levels of aflatoxin exposure, the burden of aflatoxin-associated stunting is significant. Preventing stunting by any of these interventions would greatly reduce the cost per DALY and turn these interventions from non-cost-effective to very cost-effective. Our technical feasibility assessments of these four interventions suggest some advantages and disadvantages of each intervention over the others. These data are crucial components in a decision making process to effectively allocate public health resources, and to position interventions for further development of public health interventions to prevent some aflatoxin-related public health problems, especially in high risk populations.