A few studies have reported a positive association between
phthalate exposure and pubertal timing, but several conflicting reports exist. The main objective of the study was to determine whether
phthalate exposure was associated with
central precocious puberty in girls.
METHODS: This was a multicenter case-control study wherein 47 girls with
central precocious puberty (
CPP) and 47 controls (26 pre-pubertal girls and 21 pubertal girls) were enrolled. No obese girls were included. Five
phthalate metabolites (
creatinine adjusted) and
bisphenol A (BPA) were measured in the first spot urine samples of these 94 girls in the early morning.
RESULTS: The median values of monobenzyl
phthalate (MBzP), mono-2-ethyl-5-carboxypentyl
phthalate (
MECPP), mono-2-ethyl-5-hydroxyhexyl
phthalate (MEHHP), mono-2-ethyl-5-oxohexyl
phthalate (MEOHP), and
mono-n-butyl phthalate (MnBP) were 3.1, 29.3, 18.0, 15.4, and 25.2 μg/g
creatinine in the
CPP group, 4.3, 53.7, 35.7, 29.1, and 66.0 μg/g
creatinine in the pre-pubertal control group, and 1.7, 28.7, 21.4, 12.1, and 33.3 μg/g
creatinine in the pubertal control group, respectively. The urinary concentration of the five phthalates was significantly lower in the
CPP group than in the pre-pubertal control group (P < 0.001). Conversely, there was no significant difference in the urinary concentration of the five phthalates between the
CPP and pubertal control groups (P values: 0.077 for MBzP, 0.733 for
MECPP, 0.762 for MEHHP, 0.405 for MEOHP, and 0.981 for MnBP). In addition, the BPA level was not significantly different between the
CPP and pubertal control groups (BPA median values: 0.63 μg/g
creatinine, the
CPP group; 1.7 μg/g
creatinine, the pubertal control group; P value = 0.092).
CONCLUSIONS: Our study showed that there was no significant difference in the urinary
phthalate levels between the
CPP and pubertal control groups. Moreover,
phthalate metabolites were significantly lower in the
CPP group than in the pre-pubertal control group. Further investigation about
endocrine disruptors and pubertal progression is needed.