Urinary aflatoxin biomonitoring in the Maule cohort (MAUCO), Chile: population exposure and risk factors

Aflatoxins are carcinogenic metabolites produced by toxigenic Aspergillus species that contaminate foods. This cross-sectional study, nested within the Maule Cohort (MAUCO)—a population-based prospective cohort of 9,462 rural adults aged 38 to 74 years in Molina, Chile—measured urinary aflatoxin M1 (AFM1), a biomarker of recent aflatoxin B1 (AFB1) exposure, in 1,000 randomly selected first-morning urine samples collected at baseline (2014–2017) using a validated ELISA kit. Of these, 95 were excluded due to extreme dilution or concentration (creatinine <0.3 or >3 mg/mL), leaving 905 for analysis. Detectable AFM1 was found in 29.2% of samples, with 4% quantifiable at a mean (SD) of 0.44 (±0.09) ng/mL or 0.42 (±0.20) ng/mg creatinine. Using substitution methods in all 905 participants (modified Lower, Medium, and Upper Bound), estimated mean probable daily intakes (PDI) of AFB1 ranged from 1.06 (±1.98) to 5.24 (±3.43) ng/kg BW/day. The margin of exposure for detectable subjects ranged from 243 to 5,856, indicating a public health concern (MOE < 10,000). Adjusted (for age, sex, ethnicity, and education) modified Poisson regression revealed a significant association between urinary AFM1 and consumption of fresh and dried red chilli, with prevalence ratios [PR] of 1.52 (CI95% 1.02–2.26) and 1.93 (1.24–3.00), respectively; current smokers had a PR of 1.40 (1.10–1.78), and those with moderate fatty liver had a PR of 1.41 (1.11–1.81). AFB1 exposure warrants prioritisation in Chilean food safety risk management, along with further education and monitoring of good agricultural practices in chilli production.