title: Age and sex-specific relationships between phthalate exposures and obesity in Chinese children at puberty.
abstract: OBJECTIVE
  To examine the age and sex-specific associations of urine levels of six mono-phthalates with body size and fat distribution in Chinese children at puberty.
  
  
  METHODS
  Four hundred and ninety-three school-aged children (247 boys, 246 girls) were recruited. Obesity related anthropometric indices were measured and body fat proportion (BF%) was calculated. Spot urine samples were collected and phthalate monoesters were detected by an API 2000 electrospray triple quadrupole mass spectrometer (ESI-MS/MS). Associations between phthalate exposure and overweight/obesity measures and their trends were examined by multiple linear regression and Logistic regression analyses, respectively.
  
  
  RESULTS
  Di-2-ethylhexyl phthalate (DEHP) metabolites and monobutyl phthalate (MBP) were found to be the most detectable chemicals. In 8-10 years (yrs) group, concentrations of MEHP and MBP were significantly higher in girls than those in boys. However, concentrations of all phthalate monoesters, except for MEP and MEHP, in 11-13 yrs boys were significantly higher than those in girls. After adjusting for confounders including puberty onset, urinary concentrations of MBP and sum of low molecular-weight phthalate metabolites (∑LMP) were positively associated with boys' obesity in a concentration-effect manner, while concentrations of MEHP, MEHHP and sum of DEHP metabolites (∑MEHP) were negatively associated with girls' obesity. Associations between phthalate exposure levels and BMI z-score changes were age- and sex-specific in school-age children.
  
  
  CONCLUSIONS
  There are age and sex-specific concentration-effect associations between phthalate exposure and fat distribution in Chinese children. Urinary phthalate levels in 11-13 yrs boys were about 30 percent higher than those in girls, and ∑MEHP levels in younger boys (<10 yrs) were significantly higher than those in elder boys (>10 yrs). Associations were positive for MBP and ∑LMP with both BMI z-score and fat distribution in boys >10 years of age, and negative for ∑MEHP with fat distribution in girls <10 years of age.
authors.affiliation: Department of Environment Health, School of Public Health/Key Laboratory of Public Health Safety of Chinese Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Yunhui
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, China.
authors.forename: Xiangzhou
authors.initials: X
authors.lastname: Meng
authors.affiliation: Department of Environment Health, School of Public Health/Key Laboratory of Public Health Safety of Chinese Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Maternal, Child and Adolescent Health, School of Public Health/Key Laboratory of Public Health Safety of Chinese Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, China.
authors.forename: Lifang
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Environment Health, School of Public Health/Key Laboratory of Public Health Safety of Chinese Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Environment Health, School of Public Health/Key Laboratory of Public Health Safety of Chinese Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Luxi
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Maternal, Child and Adolescent Health, School of Public Health/Key Laboratory of Public Health Safety of Chinese Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Huijing
authors.initials: H
authors.lastname: Shi
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D002681:China; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000139:chemically induced*; D010795:Phthalic Acids / Q000633:toxicity*; D011627:Puberty
chemical_list: D010795:Phthalic Acids