title: Mono-2-ethylhexyl phthalate associated with insulin resistance and lower testosterone levels in a young population.
abstract: Phthalates are commonly used as plasticizers and are reported to associate with testicular dysfunction or insulin resistance in different studies, but the concurrent relationship between phthalate exposure, testosterone levels, and insulin resistance in the young population is not well understood. We recruited 786 subjects aged 12-30 years from a population-based sample of Taiwanese adolescents and young adults from 2006 to 2008. Generalized additive models were used to evaluate glucose homeostasis and testicular function in relation to seven urinary phthalate metabolites among adolescents (aged 12-20) and young adults (aged 20-30) in Taiwan. We observed a trend toward a decrease in male testosterone and an increase in urinary mono-2-ethylhexyl phthalate (MEHP) levels across four quartiles of homeostasis model assessment of insulin resistance (HOMA-IR). After adjusting for potential covariates, generalized additive models further showed that log-transformed insulin and HOMA-IR were raised by 0.055 [95% confidence interval (CI), 0.027-0.082] and 0.056 (95% CI, 0.027-0.084), respectively, with a one-unit increase in log-transformed MEHP in young adults. In male adults (aged 22-30), the log-testosterone levels were reduced by 0.018 (95% CI, 0.001-0.036), with a one-unit of increase in log-transformed MEHP. Such relationships were not observed in adolescents. In conclusion, this study demonstrated age-related associations of urinary MEHP metabolites with impaired metabolic homeostasis of glucose that were only observed in young adults. In addition, MEHP exposure was concurrently associated with lower testosterone levels in young, male adults.
authors.affiliation: Division of Surgical Intensive Care, Department of Critical Care Medicine, E-Da Hospital, I-Shou University, Kaohsiung 824, Taiwan; Department of Nursing, Fooyin University, Kaohsiung 831, Taiwan.
authors.forename: Szu-Ying
authors.initials: SY
authors.lastname: Chen
authors.affiliation: Institute of Statistical Science, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Jing-Shiang
authors.initials: JS
authors.lastname: Hwang
authors.affiliation: Institute of Environmental Health, College of Public Health, China Medical University, Taichung 404, Taiwan.
authors.forename: Fung-Chang
authors.initials: FC
authors.lastname: Sung
authors.affiliation: Department of Internal Medicine, En Chu Kong Hospital, New Taipei City 237, Taiwan; School of Medicine, Fu Jen Catholic University, New Taipei City 242, Taiwan.
authors.forename: Chien-Yu
authors.initials: CY
authors.lastname: Lin
authors.affiliation: Department of Public Health, Tzu Chi University, Hualian County 970, Taiwan; Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei 10002, Taiwan.
authors.forename: Chia-Jung
authors.initials: CJ
authors.lastname: Hsieh
authors.affiliation: Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei 10002, Taiwan; Department of Public Health, College of Public Health, National Taiwan University, Taipei 10002, Taiwan; Department of Environmental and Occupational Medicine, National Taiwan University Hospital, Taipei 10002, Taiwan.
authors.forename: Pau-Chung
authors.initials: PC
authors.lastname: Chen
authors.affiliation: Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei 10002, Taiwan; Department of Internal Medicine and Cardiovascular Center, National Taiwan University Hospital, Taipei 10002, Taiwan. Electronic address: tachensu@gmail.com.
authors.forename: Ta-Chen
authors.initials: TC
authors.lastname: Su
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004051:Diethylhexyl Phthalate / Q000031:analogs & derivatives* / Q000633:toxicity / Q000652:urine; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D004785:Environmental Pollutants / Q000378:metabolism* / Q000652:urine; D005260:Female; D006801:Humans; D007328:Insulin; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D010795:Phthalic Acids; D010968:Plasticizers; D013624:Taiwan / Q000453:epidemiology; D013739:Testosterone / Q000378:metabolism*; D055815:Young Adult
chemical_list: D004785:Environmental Pollutants; D007328:Insulin; D010795:Phthalic Acids; D010968:Plasticizers; D013739:Testosterone; C032279:phthalic acid; D004051:Diethylhexyl Phthalate; C016599:mono-(2-ethylhexyl)phthalate
keywords: Diabetes; Insulin resistance; Mono-2-ethylhexyl phthalate; Testosterone