Decrease in Urinary Biomarkers of Di-2-Ethylhexyl Phthalate (DEHP) Metabolites and Oxidative Stress in Children after Withdrawal from Exposure to 2011 Taiwan's DEHP-Tainted Food Scandal: A 44-Month Follow-Up

摘要

Background: A major health scandal involving phthalate-tainted foodstuffs occurred in Taiwan in 2011. The presence of a clear relationship between phthalate toxicity in children and oxidative stress as the main cause is still under question. This study investigated temporal changes of oxidative stress by monitoring two urinary oxidative stress biomarkers: 8-OHdG and MDA with urinary DEHP oxidative metabolites during 44 months following withdrawal of the tainted food. Methods: Two cohorts were established. One cohort was collected from a Phthalates Clinic for Children in southern Taiwan between May 31 and June 17, 2011, in Kaohsiung Medical University Hospital (KMU cohort). That cohort of children was followed up at 2, 6, and 44 months. The other cohort was collected from a nationwide health survey conducted by Taiwan's National Health Research Institutes (NHRI) for people potentially exposed to phthalate-tainted foods post-scandal, between August 2012 and January 2013 (NHRI cohort). The current study only included children 10 years old and younger who had provided enough urine for the final analysis, including urinary DEHP oxidative metabolites, 8-OHdG and MDA concentrations. Results: In the KMU cohort, estimates of DEHP daily intake and the two biomarkers of oxidative stress levels (urinary 8-OHdG and MDA) were found to have decreased to nadir by the follow up at six months. These low points were maintained at follow-up of 44 months and were similar to those found for the NHRI cohort whose urine samples were collected post scandal at 15 tol8 months. Generalized linear mixed models by generalized estimating equation (GEE) in KMU cohort found that levels of predicted values of 8-OHdG and MDA at visit of 2, 6, and 44 months, were significantly lower than at baseline visit (p<0.001). Conclusions: We conclude that oxidative stress can be reversed in children exposed to phthalate-tainted foodstuffs after withdrawal from the sources of exposure till 44-months follow up.