AUTHOR=Felício João Soares , de Alcântara Angélica Leite , Janaú Luísa Corrêa , de Moraes Lorena Vilhena , de Oliveira Maria Clara Neres Iunes , de Lemos Manuela Nascimento , de Souza Neto Norberto Jorge Kzan , Neto João Felício Abrahão , da Silva Wanderson Maia , de Souza Ícaro José Araújo , Said Nivin Mazen , de Lemos Gabriela Nascimento , Vieira Giovana Miranda , Khayat André Salim , Santos Ândrea Kely Campos Ribeiro dos , de Queiroz Natércia Neves Marques , de Sousa Ana Carolina Contente Braga , Santos Márcia Costa dos , de Melo Franciane Trindade Cunha , Piani Pedro Paulo Freire , Felício Karem Miléo 

TITLE=Association of Soy and Exclusive Breastfeeding With Central Precocious Puberty: A Case-Control Study

JOURNAL=Frontiers in Endocrinology

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2021.667029

DOI=10.3389/fendo.2021.667029

ISSN=1664-2392

ABSTRACT=Introduction: While soy is suggested as a possible risk factor, exclusive breastfeeding (EBF) has a likely protective effect in precocious puberty. Our aim was to evaluate the association between both of these variables with central precocious puberty (CPP) 
Methods: We performed a retrospective, case-control study. A total of 161 girls were divided into two groups: 84 patients diagnosed with CPP composed the case group and 77 patients without the diagnosis of CPP (had gone through normal onset of puberty) were the control group. 
Results: Our control group had a higher presence of EBF > 6 months, which was an important protective factor for CPP (OR:0.5; IC95%: 0.3-0.9, p=0.05) and also correlated negatively with the presence of it (r = -0.2; p <0.05). Oppositely, the use of soy was significantly higher in the CPP group, (OR: 3.8; IC95%: 1.5-6, p<0.05) and positively correlating (r = 0.2; p < 0.01) with the presence of CPP. Duration of soy intake (years) correlated with bone age (r = 0.415; p <0.05). A logistic regression was performed to evaluate the effects of EBF duration and soy on CPP. The model was significant (x² (2) = 20,715, p = <0.001) and explained 12.2% (Nagelkerke R2) of the variance, correctly classifying 62.5% of cases. EBF was associated with a reduction of likelihood of having CPP (OR = 0,187 (CI = 0.055-0,635); Wald = 7,222, p = 0.007), while soy intake increased the risk (OR = 3.505 (CI) = 1,688-7,279, Wald = 11,319, p = 0.001).
Conclusion: Our data found the use of soy was associated with CPP. Additionally, EBF was pointed as a protective factor. However, future prospective studies are needed to clarify this issue.