Endocrine Abstracts

JOINT2623

Background: The relationship between central precocious puberty (CPP) and endocrine disrupting chemical (EDCs) has been rarely demonstrated in children from different parts of the world. Longitudinal studies showed that mercury, a heavy metal considered an EDC, may increase the risk of CPP in American girls (Boston region). In Brazil, there are regions with high mercury environmental exposure, such as North region (Amazonian region) and a which may increase the risk of CPP.

Aim: To compare the hair mercury levels in children with CPP and control groups from two distinct geographic regions of Brazil (North and Southeast) with distinct levels of mercury environmental exposure.

Patients and Methods: This is a cross-sectional cohort study in which 127 children were evaluated: 71 from the North region (47 cases with CPP and 24 controls) and 56 from the Southeast region (34 cases with CPP and 22 controls). Sample collection followed a pre-established protocol with a small fraction of hair strands (about 20 strands) taken from the occipital region (1 to 2 cm away from the scalp). Hair mercury levels were analyzed using cold vapor atomic absorption spectrometry (CV-AASa) at the Carlos Chagas Foundation. The quantification limit of the method was 0.006 mg/g, and the reference values were 2-6 mg/g of hair mercury. Data were presented as the median (interquartile range), group comparisons were performed using the Mann-Whitney test in Stata program, and statistical significance was set at p < 0.05.

Results: In North CPP and control groups, the median hair mercury levels were 0.39 mg/g (0.06-1.72 mg/g) and 0.42 mg/g (0.08-1.6 mg/g), respectively. There was no statistically significant difference between these two groups. In Southeast CPP and control groups, the median hair mercury levels were 0.07 mg/g (0.01-0.77 mg/g) and 0.25 mg/g (0.17-0.45 mg/g), respectively. The comparison between these two groups showed a statistically significant difference (P < 0.05). Of note, the North CPP and control groups had higher median hair mercury levels compared to the South CPP and control groups (p<0.05).

Conclusion: The higher hair mercury levels observed in both CPP and control groups from the North region confirmed an increased environmental mercury exposure in this part of Brazil. However, we could not identify an association between mercury exposure and CPP in this cohort.