[High intake of phytoestrogens and precocious thelarche: case report with a possible correlation]

Association between a soy-based infant diet and the onset of puberty: A systematic review and meta-analysis

The objective of this systematic review was to evaluate the association between a soy-based infant diet and the onset of puberty. We included studies in which children were fed a soy-based diet, and we compared them with those who were not. The primary outcomes were the onset of puberty in girls (thelarche, pubarche, and menarche age), boys (pubarche, voice change, testicular and penis enlargement age), and both (risk of delayed and precocious puberty [PP]). Search strategies were performed in PubMed, Embase, LILACS, and CENTRAL databases. Two reviewers selected eligible studies, assessed the risk of bias, and extracted data from the included studies. The odds ratio (OR) and mean difference (MD) were calculated with a 95% confidence interval (CI) as a measure of the association between soy consumption and outcomes. We used a random-effects model to pool results across studies and the Grading of Recommendations Assessment, Development, and Evaluation to evaluate the certainty of evidence. We included eight studies in which 598 children consumed a soy-based diet but 2957 did not. The primary outcomes that could be plotted in the meta-analysis were the risk of PP and age at menarche. There was no statistical difference between groups for PP (OR: 0.51, 95% CI: 0.09 to 2.94, 3 studies, 206 participants, low certainty of evidence). No between-group difference was observed in menarche age (MD 0.14 years, 95% CI -0.16 to 0.45, 3 studies, 605 children, low certainty of evidence). One study presented this outcome in terms of median and interquartile range, and although the onset of menarche was marginally increased in girls who received a soy-based diet, the reported age was within the normal age range for menarche. We did not find any association between a soy-based infant diet and the onset of puberty in boys or girls.

Trial Registration: PROSPERO registration: CRD42018088902.

Neither soyfoods nor isoflavones warrant classification as endocrine disruptors: a technical review of the observational and clinical data

Soybeans are a rich source of isoflavones, which are classified as phytoestrogens. Despite numerous proposed benefits, isoflavones are often classified as endocrine disruptors, based primarily on animal studies. However, there are ample human data regarding the health effects of isoflavones. We conducted a technical review, systematically searching Medline, EMBASE, and the Cochrane Library (from inception through January 2021). We included clinical studies, observational studies, and systematic reviews and meta-analyses (SRMA) that examined the relationship between soy and/or isoflavone intake and endocrine-related endpoints. 417 reports (229 observational studies, 157 clinical studies and 32 SRMAs) met our eligibility criteria. The available evidence indicates that isoflavone intake does not adversely affect thyroid function. Adverse effects are also not seen on breast or endometrial tissue or estrogen levels in women, or testosterone or estrogen levels, or sperm or semen parameters in men. Although menstrual cycle length may be slightly increased, ovulation is not prevented. Limited insight could be gained about possible impacts of in utero isoflavone exposure, but the existing data are reassuring. Adverse effects of isoflavone intake were not identified in children, but limited research has been conducted. After extensive review, the evidence does not support classifying isoflavones as endocrine disruptors.

Evaluation of Bone Age in Children: A Mini-Review

Bone age represents a common index utilized in pediatric radiology and endocrinology departments worldwide for the definition of skeletal maturity for medical and non-medical purpose. It is defined by the age expressed in years that corresponds to the level of maturation of bones. Although several bones have been studied to better define bone age, the hand and wrist X-rays are the most used images. In fact, the images obtained by hand and wrist X-ray reflect the maturity of different types of bones of the skeletal segment evaluated. This information, associated to the characterization of the shape and changes of bone components configuration, represent an important factor of the biological maturation process of a subject. Bone age may be affected by several factors, including gender, nutrition, as well as metabolic, genetic, and social factors and either acute and chronic pathologies especially hormone alteration. As well several differences can be characterized according to the numerous standardized methods developed over the past decades. Therefore, the complete characterization of the main methods and procedure available and particularly of all their advantages and disadvantages need to be known in order to properly utilized this information for all its medical and non-medical main fields of application.

Bone Age: A Handy Tool for Pediatric Providers

Pediatricians have relied on methods for determining skeletal maturation for >75 years. Bone age continues to be a valuable tool in assessing children's health. New technology for bone age determination includes computer-automated readings and assessments obtained from alternative imaging modalities. In addition, new nonclinical bone age applications are evolving, particularly pertaining to immigration and children's rights to asylum. Given the significant implications when bone ages are used in high-stake decisions, it is necessary to recognize recently described limitations in predicting accurate age in various ethnicities and diseases. Current methods of assessing skeletal maturation are derived from primarily white populations. In modern studies, researchers have explored the accuracy of bone age across various ethnicities in the United States. Researchers suggest there is evidence that indicates the bone ages obtained from current methods are less generalizable to children of other ethnicities, particularly children with African and certain Asian backgrounds. Many of the contemporary methods of bone age determination may be calibrated to individual populations and hold promise to perform better in a wider range of ethnicities, but more data are needed.

The relation of urinary bisphenol A with kisspeptin in girls diagnosed with central precocious puberty and premature thelarche

BACKGROUND

Bisphenol A (BPA) is known as an endocrine disruptor and it is supposed to have a role on the development of central precocious puberty (CPP). Kisspeptin, a hypothalamic peptide, is a neuromodulator of gonadotropin releasing hormone and it has an important role on regulation of the onset of puberty. The BPA levels in girls with CPP and premature thelarche (PT) and its relation with kisspeptin levels were investigated.

METHODS

Twenty-eight girls with CPP, 28 girls with PT and 22 prepubertal girls as a control group were enrolled to the study. Urinary BPA and serum kisspeptin levels were compared in the groups. Bivariate correlations were performed to evaluate the relations of BPA with kisspeptin and estradiol.

RESULTS

There was no statistical difference between groups regarding BPA levels. Serum kisspeptin levels were higher in CPP group than controls [306.56 (interquartile range (IQR), 175.63-504.66) vs. 157.62 (IQR, 55.61-285.00) p: 0.008]. There were no correlations between BPA and kisspeptin levels (r: 0.088, p: 0.391) and between BPA and estradiol (r: -0.171, p: 0.144).

CONCLUSIONS

The BPA levels did not differentiate between groups and it seems that the exposed amount of BPA in daily life did not affect kisspeptin levels in girls with CPP and PT.

Safety of soya-based infant formulas in children

Soya-based infant formulas (SIF) containing soya flour were introduced almost 100 years ago. Modern soya formulas are used in allergy/intolerance to cows' milk-based formulas (CMF), post-infectious diarrhoea, lactose intolerance and galactosaemia, as a vegan human milk (HM) substitute, etc. The safety of SIF is still debated. In the present study, we reviewed the safety of SIF in relation to anthropometric growth, bone health (bone mineral content), immunity, cognition, and reproductive and endocrine functions. The present review includes cross-sectional, case-control, cohort studies or clinical trials that were carried out in children fed SIF compared with those fed other types of infant formulas and that measured safety. The databases that were searched included PubMed (1909 to July 2013), Embase (1988 to May 2013), LILACS (1990 to May 2011), ARTEMISA (13th edition, December 2012), Cochrane controlled trials register, Bandolier and DARE using the Cochrane methodology. Wherever possible, a meta-analysis was carried out. We found that the anthropometric patterns of children fed SIF were similar to those of children fed CMF or HM. Despite the high levels of phytates and aluminium in SIF, Hb, serum protein, Zn and Ca concentrations and bone mineral content were found to be similar to those of children fed CMF or HM. We also found the levels of genistein and daidzein to be higher in children fed SIF; however, we did not find strong evidence of a negative effect on reproductive and endocrine functions. Immune measurements and neurocognitive parameters were similar in all the feeding groups. In conclusion, modern SIF are evidence-based safety options to feed children requiring them. The patterns of growth, bone health and metabolic, reproductive, endocrine, immune and neurological functions are similar to those observed in children fed CMF or HM.

The prevalence and risk factors of premature thelarche and pubarche in 4- to 8-year-old girls

AIM

To assess the prevalence of premature thelarche (PT) and pubarche in healthy 4- to 8-year-old girls and to investigate factors associated with early pubertal development.

METHOD

Eight hundred and twenty girls were examined by two paediatric endocrinologists to determine Tanner staging. The effects of body mass index, gestational age, intrauterine growth status, age at the first tooth eruption, socio-economical status, maternal age of menarche and consumption of certain food items on early pubertal development were analysed through parametric and nonparametric tests.

RESULTS

The prevalence of PT and of premature pubarche was 8.9% and 4.3%, respectively. We found a strong association between the prevalence of PT and the body mass index standard deviation scores (BMI SDS). There were more girls with BMI SDS values above 1 in the PT group (56.1%) than among the remaining subjects (22.9%). Premature thelarche was not significantly associated with intrauterine growth, premature birth, socioeconomic status, age of first tooth eruption or maternal age of menarche. Similarly, the amount of milk, eggs, chicken or fish consumed was not associated with PT. None of the investigated factors were associated with premature pubarche.

CONCLUSION

Occurrence of PT is strongly associated with BMI SDS. Studies investigating secular trends in pubertal development must consider a secular change in body mass index.

Relationships between urinary biomarkers of phytoestrogens, phthalates, phenols, and pubertal stages in girls

Phytoestrogens, phthalates, and phenols are estrogen-disrupting chemicals that have a pronounced effect at puberty. They are exogenous chemicals that are either plant-derived or man-made, and can alter the functions of the endocrine system and cause various health defects by interfering with the synthesis, metabolism, binding, or cellular responses of natural estrogens. Phytoestrogens, phthalates, and phenols are some of the potent estrogens detectable in urine. Phytoestrogens are plant-derived xenestrogens found in a wide variety of food products, like soy-based food, beverages, several fruits, and vegetables. Exposure to phytoestrogens can delay breast development and further lead to precocious puberty. The effect of phytoestrogens is mediated through estrogen receptors α and β or by binding with early immediate genes, such as jun and fos. Phthalates are multifunctional synthetic chemicals used in plastics, polyvinyl chloride products, cosmetics, hair spray, and children’s toys. Phthalates have been shown to cause defeminization, thelarche, precocious puberty, and an increase in breast and pubic hair in pubertal girls. However, reports are also available that show no association of phthalates with precocious puberty in girls. Phthalates can act through a receptor-mediated signaling pathway or affect the production of luteinizing hormone and follicle-stimulating hormone that has a direct effect on estrogen formation. Phenols like bisphenol A are industrial chemicals used mainly in the manufacture of polycarbonates and plastic materials. Bisphenol A has been shown to cause precocious puberty and earlier menarche in pubertal girls. Reports suggest that the neurotoxic effect of bisphenol A can be mediated either by competing with estradiol for binding with estrogen receptors or via the ERK/NK-kappa or ERRγ pathway. This review demonstrates the effects of phytoestrogens, phthalates, and phenols on the development of girls during puberty.