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Pediatric and Adolescent Endocrinology

MON-245 - Hair Mercury Concentrations in Brazilian Children with Idiopathic Central Precocious Puberty

Monday, June 15, 2026
9:00 AM - 2:00 PM CT
Location: ENDOExpo; Poster Floor


Background: Central precocious puberty (CPP) is a neuroendocrine disease characterized by premature reactivation of pulsatile hypothalamic GnRH secretion, leading to gonadotropins and sex steroid stimulation. Several acquired causes has been associated with CPP, including endocrine-disrupting chemicals (EDCs). The role of mercury exposure in the occurrence of CPP remains unknown.

Aims: To establish the mean hair mercury concentrations in a large cohort of Brazilian children with CPP. To compare the mean hair mercury levels in children with CPP and control groups from two different geographic regions of Brazil with distinct mercury exposure.
Patients and Methods This is a cross-sectional cohort study in which 100 Brazilian children with CPP were evaluated, all of them were female and with median age of 8 years (ranging from 7 to 9 years). A control group composed by 46 children who had normal pubertal development onset was also studied. The cohort of children with CPP and controls were originated from two different Brazilian regions: 94 from Pará-Amazonian region (69 cases with CPP and 25 controls), a region with high mercury exposure rates and 52 from Sao Paulo urban region (31 cases with CPP and 21 controls). Brain MRI was performed in majority of the children with CPP from Sao Paulo and Pará. A small fraction of hair strands was taken from the occipital region of all studied children. The hair mercury levels were analyzed using cold vapor atomic absorption spectrometry (CV-AAS).
Results Hair mercury concentrations in children with CPP were normal ( mean: 0.2 µg/g, ranging from 0.06-0.63). In Pará, the median hair mercury levels were 0.38 µg/g (0.1-0.9) and 0.42 µg/g (0.24-1 mcg/g), in children with CPP and control groups respectively (p>0.05). In São Paulo, the median hair mercury concentration was 0.001 µg/g (0.001-0.07mcg/g) and 0.25 µg/g (0.21-0.27), in children with CPP and control groups respectively, (p < 0.05).The comparison of two CPP and control groups showed a hair mercury median higher in Pará region (p < 0.05). Logistic regression did not demonstrate an increased risk of CPP associated with higher hair mercury levels.
Conclusion We confirmed higher hair mercury levels in both CPP and control groups from the Brazil North region. However, there was no direct evidence of an association between mercury exposure and CPP in this cohort.

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