Association of Aflatoxin Biomarker Levels with Health Status and HIV Disease
The goals of UAB 148 were to determine the relationship between aflatoxin biomarker levels and the socio-demographic economic, health, nutritional, and immune characteristics of people in Ghana with HIV and other infectious diseases including tuberculosis and malaria. Aflatoxins impair the immune system, which could cause more rapid progression of health debilitating diseases, and adversely affect the health pregnant women and their babies. Therefore, UAB 148 also examined the association between AF-ALB levels and health status in pregnant women, and on adverse birth outcomes (low birth weight, pre-term delivery, small for gestational age, stillbirth) in Ghana. The outcome of this project will provide understanding for improved health through reduced aflatoxin exposure.
Association was found between aflatoxin exposure and poor health status. In Ghana, the research team established the association between high aflatoxin B1 albumin(AF-ALB) levels in pregnant women, birth outcomes, and anemia. It was found that 100 percent of the women had AF-ALB in their blood. With regard to birth outcomes, pregnant women with aflatoxin levels in the highest quartile were twice as likely to have low birth weight infants when compared to women in the lowest quartile. There was a trend of increasing risk for low birth weight with increasing aflatoxin levels. This association remained after adjusting for known confounders, including malaria parasitemia, anemia and worm infections. Aflatoxin also increased the odds of pregnant women developing anemia in pregnancy, with an 85 percent increase from the lowest to very high AF-ALB category, which suggest that the prevalence of anemia among these pregnant women is associated with AF-ALB levels in their blood.
Results showed that high aflatoxin levels appeared to accentuate some HIV-associated changes in T cell phenotypes and B cells in HIV positive people. The loss of T regulatory cells (Tregs) in HIV positive people with high aflatoxin levels may facilitate HIV associated immune hyper-activation and lead to more severe disease and faster disease progression. The intensive, multifaceted studies at clinical and immunological levels along with investigation of disease progression over time are proving extremely valuable in understanding these relationships, and allowing development of appropriate and targeted strategies to decrease the rate of progression of HIV disease in infected people. A short-term biomarker of aflatoxin exposure (AFM1) and fumonisin exposure (FB1) in urine (developed in cooperation with TAM 149) was used to measure the effects on concentrations of vitamin A and E in Ghanaians. The study demonstrated that participants with high AFM1 had significantly lower vitamin A concentrations and marginally lower vitamin E. Conversely, AFB1 was positively associated with vitamin A and vitamin E. These data indicate that aflatoxin may modify plasma micronutrient status. Thus, the prevention of aflatoxin exposure may greatly reduce vitamins A and E deficiencies.
By the identification of the effect of aflatoxin on HIV immune and clinical status, appropriate and targeted strategies can be implemented widely (in Ghana and in developing country populations worldwide) to decrease aflatoxin intake and possibly decrease the rate, and progression, of diseases as noted in 2011 studies. Further, because of the immune suppressive and other health effects of aflatoxin, the effect of antiretroviral therapy (ART) in delaying AIDS may not be as great in populations of developing countries who are exposed to the toxin as it is in unexposed groups. This also raises the question of the benefit of current vaccines (and the benefit of a potential HIV vaccine) to people in aflatoxin exposed regions of the world, since aflatoxin suppresses the immune responses to vaccinations. For all of these reasons, this study of HIV disease progression associated with aflatoxin exposure is a highly significant and urgent area of research.
The investigation on the association between AF-ALB and TB infection demonstrated, for the first time, an association between aflatoxin levels and an increased hazard for developing TB in HIV positive individuals. This increased hazard result represents an important addition to the body of knowledge on the harmful effects of dietary aflatoxin exposure in individuals with HIV.
The longitudinal design of the 2011 study provides certain strengths over previous studies in the project. It will allow bias to be avoided in measuring exposure, determine time sequence between exposure and disease progression, study multiple exposures and multiple outcomes, and calculate progression of disease in relation to level of exposure.
Dr. Pauline Jolly
Kwame Nkrumah University of Science and Technology
- Dr. William Otoo Ellis
Texas A and M University
- Dr. Timothy Phillips
University of Georgia