Evaluation of fumonisin biomarkers in a cross-sectional study with two high-risk populations in China.

Levels of serum and urinary sphinganine (Sa) and sphingosine (So), the Sa/So ratio, and urinary-free fumonisin B(1) (FB(1)) were determined in a cross-sectional study consisting of 43 adults in Huaian and 34 adults in Fusui, China. Home-produced corn had 100% contamination with FB(1). There were 93.0% (40/43) of Huaian subjects and 52.9% (18/34) of Fusui subjects with daily FB(1) intakes greater than 2 microg kg(-1) body weight, which showed a significant difference (p < 0.01). Levels of sphinganine and sphingosine and the Sa/So ratio were not correlated with levels of dietary exposure. The median level of the serum Sa/So ratio in Huaian subjects (0.41, range = 0.14-0.85) was significantly lower than that in Fusui subjects (0.78, range = 0.57-1.08) (p < 0.01). The median level of the urinary Sa/So ratio was also significantly lower in Huaian subjects (0.31, range = 0.08-1.33) than in Fusui subjects (0.57, range = 0.03-2.52) (p < 0.01). Urinary-free FB(1) was detected in 83.7% (36/43) of Huaian samples and in 82.4% (28/34) of Fusui urine samples (p > 0.05). However, the median level of urinary-free FB(1) in Huaian subjects, 3.91 (range = 0.06-253.61) ng mg(-1) creatinine, was significantly higher than 0.39 (range = 0.01-3.72) ng mg(-1) creatinine found in Fusui subjects (p < 0.01). These results suggest that urinary-free FB(1) may be a potential biomarker for human fumonisin exposure, while further validation is needed in human epidemiological and intervention studies.