Low and high oesophageal cancer incidence areas of the former Transkei region of South Africa have been associated with corresponding low and high levels of fumonisin contaminated home-grown maize. This is the first study in South Africa assessing fumonisin B (FB) mycotoxin exposure by quantifying individual maize consumption with weighed food records and FB levels from maize in each participant's household and concurrently evaluating sphinganine (Sa), sphingosine (So) and Sa/So ratios in plasma and urine of these participants as possible biomarkers of FB exposure. The high consumption of maize in Bizana (n=36) and Centane (n=30) of 0.41+/-0.21 and 0.39+/-0.19 kg/day, respectively, confirms the reliance on maize as the dietary staple. Mean total FB (FB(1)+FB(2)+FB(3)) levels in home-grown maize were 0.495+0.880 and 0.665+0.660 mg/kg in Bizana and Centane, respectively. Mean fumonisin exposure based on individual consumption was 3.9+/-7.3 and 4.1+/-7.6 microg/kg body weight/day, respectively, for Bizana and Centane. The mean combined sphinganine/sphingosine ratios in Bizana and Centane were similar and ranged from 0.10-0.55 in plasma (n=41) and urine (n=62). There was no association between sphingoid base levels and/or Sa/So ratios in the plasma and urine and individual fumonisin exposure, negating the sphingoid bases as potential biomarkers of fumonisin exposure in humans.
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