Prenatal Exposure to Phthalates and Infant Development at 6 Months: Prospective Mothers and Children’s Environmental Health (MOCEH) Study

Abstract

Background: There are increasing concerns over adverse effects of prenatal phthalate exposure on the neurodevelopment of infants.Objectives: Our goal was to explore the association between prenatal di(2-ethylhexyl) phthalate and dibutyl phthalate exposure and the Mental and Psychomotor Developmental Indices (MDI and PDI, respectively) of the Bayley Scales of Infant Development at 6 months, as part of the Mothers and Children’s Environmental Health Study.Methods: Between 2006 and 2009, 460 mother–infant pairs from Seoul, Cheonan, and Ulsan, Korea, participated. Prenatal mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-n-butyl phthalate (MBP) were measured in one urine sample acquired from each mother during the third trimester of pregnancy. Associations with log-transformed creatinine-corrected phthalate concentrations were estimated using linear regression models adjusted for potential confounders.Results: MDI was inversely associated with the natural log concentrations (micrograms per gram creatinine) of MEHHP [β = –0.97; confidence interval (CI), –1.85 to –0.08] and MEOHP (β = –0.95; CI, –1.87 to –0.03), and PDI was inversely associated with MEHHP (β = –1.20; CI, –2.33 to –0.08). In males, MDI was inversely associated with MEHHP (β = –1.46; CI, –2.70 to –0.22), MEOHP (β = –1.57; CI, –2.87 to –0.28), and MBP (β = –0.93; CI, –1.82 to –0.05); PDI was inversely associated with MEHHP (β = –2.36; CI, –3.94 to –0.79), MEOHP (β = –2.05; CI, –3.71 to –0.39), and MBP (β = –1.25; CI, –2.40 to –0.11). No significant linear associations were observed for females.Conclusions: The results suggest that prenatal exposure to phthalates may be inversely associated with the MDI and PDI of infants, particularly males, at 6 months.

Exposure to widespread environmental toxicants and children’s cognitive development and behavioral problems

“…An inverse association between prenatal exposure to phthalates and the mental development (MDI) and psychomotor development (PDI) scores of infants at 6 months was observed among 460 children in South Korea [8]. In this study a strong inverse association for male infants between all measured phthalate metabolites (MEHHP, MEOHP, and MBP) were observed [8].…”

“…In all the studies, exposure to phthalates was associated with neurodevelopmental disorders: conduct problems [9], quality of alertness among girls [5], decreased (less masculine) composite score in boys [10] and lower concentration and vocabulary score among boys [7]. In the study performed in South Korea an inverse association between prenatal exposure to phthalates and the MDI and PDI scores was observed for boys [8]. The phthalate exposure was associated also with children's social impairment [11].…”

“…In males, higher total di-2-ethylhexyl phthalate (DEHP) metabolites were associated with more nonoptimal reflexes (any nonoptimal response to reflex elicitation) (p = 0.02) [6]. An inverse association between prenatal exposure to phthalates and the mental development (MDI) and psychomotor development (PDI) scores of infants at 6 months was observed among 460 children in South Korea [8]. In this study a strong inverse association for male infants between all measured phthalate metabolites (MEHHP, MEOHP, and MBP) were observed [8].…”

“…As experimental studies suggest that higher levels of di-(2-ethylhexyl) phthalate (DEHP) exposure may adversely affect neurobehavioral parameters in mice [4], there is growing concern about the adverse effects of phthalates on children's neurodevelopment. Exposure to phthalates have been examined in relation to neurodevelopment among neonates 5 days of birth [5], and 5 weeks [6] in the United States, in Korea in children at 6 months and children from elementary schools [7,8], in the United States among children 4-9 years [9] and 3.6-6.4 years of age [10]. One study (also conducted in the United States) has assessed social impairment in children 7 and 9 years old exposed to phthalates [11] ( Table 1).…”

“…Measurements of contaminants in urine, blood, semen, amniotic fluid, and breast milk usually provide the best assessment of exposure [53]. Exposure to phthalates in almost all presented studies was based on specific biomarkers of exposure mainly in urine [5][6][7][8][9][10][11]. As phthalates are metabolized to their monoesters within a few hours or days [54,55], urinary phthalate monoesters are considered good biomarkers for assessing phthalate exposure in humans [55][56][57][58].…”