PhD Thesis
Aflatoxins and fumonisins are toxic food contaminants. Knowledge about status of human exposure to, and health effects of these toxins in Tanzania is inadequate. This study was conducted to assess the magnitude of dietary exposure to aflatoxin and fumonisin in young children by using biomarkers of exposure and assess the impact of the exposure on child growth. A total of 166 children were recruited at age of 6 to 14 months in three villages; Nyabula (Iringa region), Kigwa (Tabora region) and Kikelelwa (Kilimanjaro region) and studied at recruitment, at 6 and 12 months after recruitment. Blood and urine samples were collected and analysed for plasma aflatoxin albumin adducts (AF-alb) using ELISA and urinary fumonisin B1 (UFB1) using LC-MS, respectively. Anthropometric measurements were taken and growth indices, Z-scores computed. AF-lab geometric mean concentrations with 95% CI were 4.7 (3.9 - 5.6), 12.9 (9.9 - 16.7) and 23.5 (19.9 - 27.7) pg/mg albumin at recruitment, at 6 and 12 months after recruitment, respectively. At these respective sampling periods, the geometric mean UFB1 concentrations were 313.9 (257.4 - 382.9), 167.3 (135.4 - 206.7) and 569.5 (464.5 - 698.2) pg/ml urine and the prevalence of stunted children was 44%, 55% and 56%, respectively. Poor child growth tracked over time, with 81% and 62% of children who were stunted and underweight, respectively at recruitment remaining at same status after one year. The UFB1 concentrations at recruitment were negatively associated with length for age Z-scores (LAZ) at 6 months (p = 0.016) and at 12 months after recruitment (p = 0.014). The mean UFB1 of the three surveys in each child was negatively associated with LAZ (p < 0.001) at 12 months after recruitment and length gained over the 12 months period (p = 0.004). There was a negative but non-significant association between AF-alb and child growth. The AF-alb and UFB1 levels varied between survey periods and between villages. The observations suggest that the studied children were chronically exposed to aflatoxin and fumonisin and poor child growth was prevalent and persisted over time, suggesting that exposure to aflatoxin and fumonisin may contribute to impairment of child growth
Tanzania Food and Drugs Authority (TFDA)