Higher phthalate concentrations are associated with precocious puberty in normal weight Thai girls

Background: The cause of precocious puberty may be associated with genetics and other conditions such as central nervous system (CNS) insults, or the exposure to endocrine disrupting chemicals (EDCs). Phthalates is known to be one of the EDCs and have estrogenic and antiandrogenic activities, and may be associated with advanced puberty. The objective of the study was to determine the association between urinary phthalate metabolites and advanced puberty. Methods: A cross-sectional study was conducted in patients with precocious puberty (breast onset < 8 years, n = 42) and early puberty (breast onset 8-9 years, n = 17), compared to age-matched controls (n = 77). Anthropometric measurements, estradiol, basal and gonadotropin releasing hormone (GnRH)-stimulated follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels, uterine sizes, ovarian diameters and bone ages (BA) were obtained. Urine samples were collected and mono-methyl phthalate (MMP) and mono-ethyl phthalate (MEP) were analyzed by high performance liquid chromatography (HPLC) and adjusted with urine creatinine. Results: The median adjusted-MEP concentration in girls with precocious puberty, was greater than in normal girls (6105.09 vs. 4633.98 mu g/g Cr: p < 0.05), and had the same trend among early puberty and normal puberty (5141.41 vs. 4633.98 mu g/g Cr: p = 0.4), but was not statistically significant. Conclusions: Precocious puberty girls had an association with increased MEP concentration. This is the first report of the association between urinary phthalate levels and precocious puberty in Thai girls.