title: Associations of individual characteristics and lifestyle factors with metabolism of di-2-ethylhexyl phthalate in NHANES 2001-2012.
abstract: Previous studies suggest that a higher ratio of primary to secondary metabolites of di-2-ethylhexyl phthalate (DEHP), reflective of a slower DEHP conversion rate, is associated with a greater physiologic effect. We examined associations of several individual characteristics and lifestyle factors with the ratio of mono-2-ethylhexyl phthalate to mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHP:MEHHP) and %MEHP (the ratio of MEHP to the sum of the secondary metabolites).
  
  
  
  We used the data from the National Health and Nutrition Examination Survey, 2001-2012. The study included adults with BMI<30 and no diabetes. Pregnant women were excluded. We examined associations of age, race, gender, Body Mass Index, smoking, alcohol and caffeine consumption, medication use, cancer history, and menopausal status and postmenopausal hormone use (in women) with MEHP:MEHHP and %MEHP using multivariable linear regression. The values for %MEHP were log-transformed in the analysis.
  
  
  
  In multivariable analysis, non-Caucasian individuals had higher %MEHP (non-Hispanic Blacks: β=0.114, 95% Confidence interval [CI]: 0.050, 0.177; Hispanic: β=0.089, 95% CI: 0.024, 0.154; other race: β=0.126, 95% CI: 0.033, 0.219). Age was inversely associated with MEHP:MEHHP (β=-0.001, 95% CI: -0.002, -0.001) and %MEHP (β=-0.006, 95% CI: -0.008, -0.004). Overweight individuals had lower MEHP: MEHHP and lower %MEHP (β=-0.035, 95% CI: 0.062, -0.008 and β=-0.104, 95% CI: -0.162, -0.046, respectively). Alcohol consumption was inversely associated with %MEHP among men (p-trend=0.03).
  
  
  
  Individual and lifestyle characteristics are associated with differences in DEHP metabolism. Understanding underlying biological mechanisms could help to identify individuals at a greater risk of adverse effects from DEHP exposure.
authors.affiliation: Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, 2004 Mowry Rd., Gainesville, FL, USA. Electronic address: lyaghjyan@ufl.edu.
authors.forename: Lusine
authors.initials: L
authors.lastname: Yaghjyan
authors.affiliation: Division of Public Health Sciences, Department of Surgery, School of Medicine, Washington University in St. Louis, 660 S. Euclid Ave., St. Louis, MO, USA. Electronic address: carlssonn@wudosis.wustl.edu.
authors.forename: Nils P
authors.initials: NP
authors.lastname: Carlsson
authors.affiliation: Department of Biostatistics, College of Public Health and Health Professions and College of Medicine, University of Florida, 2004 Mowry Rd., Gainesville, FL, USA. Electronic address: glghita0429@ufl.edu.
authors.forename: Gabriela L
authors.initials: GL
authors.lastname: Ghita
authors.affiliation: Division of Public Health Sciences, Department of Surgery, School of Medicine, Washington University in St. Louis, 660 S. Euclid Ave., St. Louis, MO, USA. Electronic address: changsh@wudosis.wustl.edu.
authors.forename: Su-Hsin
authors.initials: SH
authors.lastname: Chang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004051:Diethylhexyl Phthalate / Q000652:urine*; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000652:urine*; D005260:Female; D006801:Humans; D008019:Life Style; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D012959:Socioeconomic Factors; D014481:United States; D055815:Young Adult
chemical_list: D004785:Environmental Pollutants; D004051:Diethylhexyl Phthalate
keywords: Endocrine disruptors; Lifestyle; Phthalate exposure; Risk factors