Premature sexual development in children following the use of estrogen- or placenta-containing hair products

Personal Care Product Use during Puberty and Incident Breast Cancer among Black, Hispanic/Latina, and White Women in a Prospective US-Wide Cohort

BACKGROUND

Some personal care products (PCPs) contain endocrine-disrupting chemicals that may affect breast cancer (BC) risk. Patterns of use vary by race and ethnicity. Use often starts in adolescence, when rapidly developing breast tissue may be more susceptible to environmental carcinogens. Few studies have examined associations of BC with PCP use during this susceptible window.

OBJECTIVES

We characterized race and ethnicity-specific patterns of PCP use at 10-13 years of age and estimated associations of use with incident BC.

METHODS

At enrollment (2003-2009), Sister Study participants (n = 4,049 Black, 2,104 Latina, and 39,312 White women) 35-74 years of age reported use of 37 "everyday" PCPs during the ages of 10-13 y (did not use, sometimes, or frequently used). We conducted race and ethnicity-specific latent class analyses to separately identify groups of women with similar patterns of beauty, hair, and skincare/hygiene product use. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of identified PCP classes and single products with incident BC using Cox proportional hazards regression.

RESULTS

During a mean follow-up time of 10.8 y, 280 Black, 128 Latina, and 3,137 White women were diagnosed with BC. Classes of adolescent PCP use were not clearly associated with BC diagnosis among Black, Latina, or White women. HRs were elevated but imprecise for frequent nail product and perfume use in Black women (HR = 1.34; 95% CI: 0.85, 2.12) and greater hair product use in Black (HR = 1.28; 95% CI: 0.91, 1.80) and Latina (HR = 1.42; 95% CI: 0.81, 2.48) women compared with lighter use. In single-product models, we observed higher BC incidence associated with frequent use of lipstick, nail products, pomade, perfume, makeup remover, and acne/blemish products in at least one group.

DISCUSSION

This work provides some support for the hypothesis that PCP use during puberty is associated with BC risk. More research is needed to confirm these novel findings. https://doi.org/10.1289/EHP13882.

Hair relaxer use and risk of uterine cancer in the Black Women's Health Study

BACKGROUND

Chemical hair relaxers, use of which is highly prevalent among Black women in the US, have been inconsistently linked to risk of estrogen-dependent cancers, such as breast cancer, and other reproductive health conditions. Whether hair relaxer use increases risk of uterine cancer is unknown.

METHODS

In the Black Women's Health Study, 44,798 women with an intact uterus who self-identified as Black were followed from 1997, when chemical hair relaxer use was queried, until 2019. Over follow-up, 347 incident uterine cancers were diagnosed. We used multivariable Cox proportional hazards regression models, adjusted for age and other potential confounders, to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of hair relaxer use with risk of uterine cancer.

RESULTS

Compared to women who never used hair relaxers or used them infrequently (<4 years and ≤1-2 times/year), the HR for uterine cancer associated with heavy use (≥15 years and at least 5 times/year) was 1.18 (95% CI: 0.81, 1.71). However, among postmenopausal women, compared to never/light use, the HR for moderate use was 1.60 (95% CI: 1.01, 2.53), the HR for heavy use was 1.64 (1.01, 2.64), and the HR for ≥20 years of use regardless of frequency was 1.71 (1.08, 2.72). Results among premenopausal women were null.

CONCLUSIONS

In this large cohort of Black women, long-term use of chemical hair relaxers was associated with increased risk of uterine cancer among postmenopausal women, but not among premenopausal women. These findings suggest that hair relaxer use may be a potentially modifiable risk factor for uterine cancer.

Targeting estrogen signaling and biosynthesis for aged skin repair

Non-healing skin wounds are disproportionally prevalent in older adults. Current treatments do not account for the particularities of aged skin and result in inadequate outcomes. Overall, healing chronic wounds in the elderly remains a major unmet clinical need. Estrogens play a critical role in reproduction but also have important actions in non-reproductive organs. Estrogen biosynthesis and signaling pathways are locally activated during physiological wound healing, processes that are inhibited in elderly estrogen-deprived skin. Estrogen deprivation has been shown to be a critical mediator of impaired wound healing in both postmenopausal women and aged men, and topical estrogen application reverses age-associated delayed wound healing in both elderly men and women. These data indicate that adequate estrogen biosynthesis and properly regulated estrogen signaling pathways are essential for normal wound healing and can be targeted to optimize tissue repair in the elderly. However, due to fundamental questions regarding how to safely restore estrogen signaling locally in skin wounds, there are currently no therapeutic strategies addressing estrogen deficiency in elderly chronic wounds. This review discusses established and recent literature in this area and proposes the hypothesis that estrogen plays a pleiotropic role in skin aging and that targeting estrogen signaling and biosynthesis could promote skin repair in older adults.

Precocious Puberty: Types, Pathogenesis and Updated Management

Precocious puberty (PP) means the appearance of secondary sexual characters before the age of eight years in girls and nine years in boys. Puberty is indicated in girls by the enlargement of the breasts (thelarche) in girls and in boys by the enlargement of the testes in either volume or length (testicular volume = 4 mL, testicular length = 25 mm, or both). Two types of PP are recognized - namely central PP (CPP) and peripheral PP (PPP). This paper aims to describe the clinical findings and laboratory workup of PP and to illustrate the new trends in the management of precocious sexual maturation. Gonadotropin-releasing hormone (GnRH)-independent type (PPP) refers to the development of early pubertal maturation not related to the central activation of the hypothalamic-pituitary-gonadal (HPG) axis. It is classified into genetic or acquired disorders. The most common forms of congenital or genetic causes involve McCune-Albright syndrome (MAS), familial male-limited PP, and congenital adrenal hyperplasia. The acquired causes include exogenous exposure to androgens, functioning tumors or cysts, and the pseudo-PP of profound primary hypothyroidism. On the other hand, CPP is the most common and it is a gonadotropin-dependent form. It is due to premature maturation of the HPG axis. CPP may occur as genetic alterations, such as MKRN3, DLK1, or KISS1;as a part of mutations in the epigenetic factors that regulate the HPG axis, such as Lin28b and let-7; or as a part of syndromes, central lesions such as hypothalamic hamartoma, and others. A full, detailed history and physical examination should be taken. Furthermore, several investigations should be conducted for both types of PP, including the estimation of serum gonadotropins such as luteinizing and follicle-stimulating hormones and sex steroids, in addition to a radiographic workup and thyroid function tests. Treatment depends on the type of PP: Long-acting GnRHa, either intramuscularly or implanted, is the norm of care for CPP management, while in PPP, especially in congenital adrenal hyperplasia, the goal of management is to suppress adrenal androgen secretion by glucocorticoids. In addition, anastrozole and letrozole - third-generation aromatase inhibitors - are more potent for MAS.

Evaluating Neighborhood-Level Differences in Hair Product Safety by Environmental Working Group Ratings among Retailers in Boston, Massachusetts

BACKGROUND

Personal care products are a notable source of exposure to endocrine-disrupting chemicals (EDCs). Racial/ethnic differences in the use of hair products containing EDCs are reported, with women and children of color more commonly using hair products that are hormonally active and contain EDCs than other racial/ethnic groups. There is limited research examining the neighborhood-level social and economic factors that may contribute to these reported disparities.

OBJECTIVES

We aimed to examine the safety of hair products across sociodemographically diverse neighborhoods in Boston, Massachusetts.

METHODS

Eight neighborhoods were identified based on indicators of race/ethnicity and socioeconomic status (SES). We randomly selected 50 stores and collected data on the hair products for sale and their corresponding Environmental Working Group (EWG) Skin Deep hazard score. The association between neighborhood and EWG hazard category (low, moderate, high) was examined using a multinomial logistic regression.

RESULTS

A total of 14,019 hair products were identified in the eight neighborhoods. When considering products with EWG hazard scores, Roxbury, a lower income community of color, and Mission Hill, a lower income community, were reported to have a higher percentage of high-hazard hair products in comparison with Beacon Hill [12.2% (163/1,332), 11.4% (65/571) vs. 7.9% (30/382), respectively]. Differences between the safety of hair products were observed, with Roxbury and Mission Hill reporting more than a 2-fold higher risk ratio (RR) of finding hair products with high vs. low EWG scores in comparison with that of Beacon Hill [RR for Roxbury: 2.3, 95% confidence interval (CI): 1.1, 4.6; RR for Mission Hill: 2.3, 95% CI: 1.0, 5.4]. Other neighborhoods were also observed to have an increased RR in comparison with Beacon Hill, however, with 95% CIs that extended beyond the null.

DISCUSSION

Retail stores in neighborhoods with a higher percentage of residents of color and lower SES were found to be more likely to sell products with high hazard scores than stores in a higher SES and predominately non-Hispanic White neighborhood. https://doi.org/10.1289/EHP10653.

Uncovering Evidence: Associations between Environmental Contaminants and Disparities in Women's Health

Over the years, industrial accidents and military actions have led to unintentional, large-scale, high-dose human exposure to environmental contaminants with endocrine-disrupting action. These historical events, in addition to laboratory studies, suggest that exposure to toxicants such as dioxins and polychlorinated biphenyls negatively impact the reproductive system and likely influence the development of gynecologic diseases. Although high-level exposure to a single toxicant is rare, humans living in industrialized countries are continuously exposed to a complex mixture of manmade and naturally produced endocrine disruptors, including persistent organic pollutants and heavy metals. Since minorities are more likely to live in areas with known environmental contamination; herein, we conducted a literature review to identify potential associations between toxicant exposure and racial disparities in women's health. Evidence within the literature suggests that the body burden of environmental contaminants, especially in combination with inherent genetic variations, likely contributes to previously observed racial disparities in women's health conditions such as breast cancer, endometriosis, polycystic ovarian syndrome, uterine fibroids, and premature birth.

Perturbation of Nuclear Hormone Receptors by Endocrine Disrupting Chemicals: Mechanisms and Pathological Consequences of Exposure

Much of the early work on Nuclear Hormone Receptors (NHRs) focused on their essential roles as mediators of sex steroid hormone signaling in reproductive development and function, and thyroid hormone-dependent formation of the central nervous system. However, as NHRs display tissue-specific distributions and activities, it is not surprising that they are involved and vital in numerous aspects of human development and essential for homeostasis of all organ systems. Much attention has recently been focused on the role of NHRs in energy balance, metabolism, and lipid homeostasis. Dysregulation of NHR function has been implicated in numerous pathologies including cancers, metabolic obesity and syndrome, Type II diabetes mellitus, cardiovascular disease, hyperlipidemia, male and female infertility and other reproductive disorders. This review will discuss the dysregulation of NHR function by environmental endocrine disrupting chemicals (EDCs), and the associated pathological consequences of exposure in numerous tissues and organ systems, as revealed by experimental, clinical, and epidemiological studies.

Hair dye and chemical straightener use and breast cancer risk in a large US population of black and white women

Many hair products contain endocrine-disrupting compounds and carcinogens potentially relevant to breast cancer. Products used predominately by black women may contain more hormonally-active compounds. In a national prospective cohort study, we examined the association between hair dye and chemical relaxer/straightener use and breast cancer risk by ethnicity. Sister Study participants (n = 46,709), women ages 35-74, were enrolled between 2003 and 2009, and had a sister with breast cancer but were breast cancer-free themselves. Enrollment questionnaires included past 12-month hair product use. Cox proportional hazards models estimated adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the association between hair products and breast cancer; effect measure modification by ethnicity was evaluated. During follow-up (mean = 8.3 years), 2,794 breast cancers were identified. Fifty-five percent of participants reported using permanent dye at enrollment. Permanent dye use was associated with 45% higher breast cancer risk in black women (HR = 1.45, 95% CI: 1.10-1.90), and 7% higher risk in white women (HR = 1.07, 95% CI: 0.99-1.16; heterogeneity p = 0.04). Among all participants, personal straightener use was associated with breast cancer risk (HR = 1.18, 95% CI 0.99-1.41); with higher risk associated with increased frequency (p for trend = 0.02). Nonprofessional application of semipermanent dye (HR = 1.28, 95% CI 1.05-1.56) and straighteners (HR = 1.27, 95% CI 0.99-1.62) to others was associated with breast cancer risk. We observed a higher breast cancer risk associated with any straightener use and personal use of permanent dye, especially among black women. These results suggest that chemicals in hair products may play a role in breast carcinogenesis.

The diagnosis of androgenetic alopecia in children: Considerations of pathophysiological plausibility

Androgenetic alopecia (AGA), one of the most common causes of hair loss in men and women, is an infrequent cause of alopecia in children. In AGA, patients generally start noticing hair thinning after the onset of puberty due to progressive miniaturisation of the hair follicle which leads to vellus transformation of terminal hair. However, the occurrence of prepubertal AGA has rarely been reported in the literature. The pathophysiology of AGA is tightly linked to androgen hormones; prepubertal children do not usually produce significant amounts of adrenal or gonadal androgens. When it does occur, an underlying abnormality should be suspected. Secondary causes of AGA must be excluded when evaluating a patient before the appearance of puberty. Premature puberty, polycystic ovarian syndrome and other causes of hyperandrogenism can present with hair loss in an androgenetic pattern. This article reviews the normal physiology of androgen hormones and their role in the pathophysiology of childhood AGA.

Associations between Personal Care Product Use Patterns and Breast Cancer Risk among White and Black Women in the Sister Study

BACKGROUND

Many personal care products include chemicals that might act as endocrine disruptors and thus increase the risk of breast cancer.

OBJECTIVE

We examined the association between usage patterns of beauty, hair, and skin-related personal care products and breast cancer incidence in the Sister Study, a national prospective cohort study (enrollment 2003-2009).

METHODS

Non-Hispanic black (4,452) and white women (n=42,453) were examined separately using latent class analysis (LCA) to identify groups of individuals with similar patterns of self-reported product use in three categories (beauty, skin, hair). Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between product use and breast cancer incidence.

RESULTS

A total of 2,326 women developed breast cancer during follow-up (average follow-up=5.4y). Among black women, none of the latent class hazard ratios was elevated, but there were <100 cases in any category, limiting power. Among white women, those classified as "moderate" and "frequent" users of beauty products had increased risk of breast cancer relative to "infrequent" users [HR=1.13 (95% CI: 1.00, 1.27) and HR=1.15 (95% CI: 1.02, 1.30), respectively]. Frequent users of skincare products also had increased risk of breast cancer relative to infrequent users [HR=1.13 (95% CI: 1.00, 1.29)]. None of the hair product classes was associated with increased breast cancer risk. The associations with beauty and skin products were stronger in postmenopausal women than in premenopausal women, but not significantly so.

CONCLUSIONS

This work generates novel hypotheses about personal care product use and breast cancer risk. Whether these results are due to specific chemicals or to other correlated behaviors needs to be evaluated. https://doi.org/10.1289/EHP1480.

Hair product use, age at menarche and mammographic breast density in multiethnic urban women

BACKGROUND

Select hair products contain endocrine disrupting chemicals (EDCs) that may affect breast cancer risk. We hypothesize that, if EDCs are related to breast cancer risk, then they may also affect two important breast cancer risk factors: age at menarche and mammographic breast density.

METHODS

In two urban female cohorts (N = 248): 1) the New York site of the National Collaborative Perinatal Project and 2) the New York City Multiethnic Breast Cancer Project, we measured childhood and adult use of hair oils, lotions, leave-in conditioners, root stimulators, perms/relaxers, and hair dyes using the same validated questionnaire. We used multivariable relative risk regression models to examine the association between childhood hair product use and early age at menarche (defined as <11 years of age) and multivariable linear regression models to examine the association between childhood and adult hair product use and adult mammographic breast density.

RESULTS

Early menarche was associated with ever use of childhood hair products (RR 2.3, 95% CI 1.1, 4.8) and hair oil use (RR 2.5, 95% CI 1.2, 5.2); however, additional adjustment for race/ethnicity, attenuated associations (hair products RR 1.8, 95% CI 0.8, 4.1; hair oil use RR 2.3, 95% CI 1.0, 5.5). Breast density was not associated with adult or childhood hair product or hair oil use.

CONCLUSIONS

If confirmed in larger prospective studies, these data suggest that exposure to EDCs through hair products in early life may affect breast cancer risk by altering timing of menarche, and may operate through a mechanism distinct from breast density.

Hair product use and breast cancer risk among African American and White women

Exposures to carcinogens in hair products have been explored as breast cancer risk factors, yielding equivocal findings. We examined hair product use (hair dyes, chemical relaxers and cholesterol or placenta-containing conditioners) among African American (AA) and White women, and explored associations with breast cancer. Multivariable-adjusted models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) to describe the associations of interest among 2280 cases (1508 AA and 772 White) and 2005 controls (1290 AA and 715 White). Among controls, hair dye use was more common among Whites than AAs (58 versus 30%), while relaxer (88 versus 5%) and deep conditioner use (59 versus 6%) was more common among AAs. Among AAs, use of dark hair dye shades was associated with increased breast cancer risk (OR = 1.51, 95% CI: 1.20-1.90) and use of dark shades (OR = 1.72, 95% CI: 1.30-2.26) and higher frequency of use (OR = 1.36, 95% CI: 1.01-1.84) were associated with ER+ disease. Among Whites, relaxer use (OR = 1.74, 95% CI: 1.11-2.74) and dual use of relaxers and hair dyes (OR = 2.40, 95% CI: 1.35-4.27) was associated with breast cancer; use of dark hair dyes was associated with increased ER+ disease (OR = 1.54, 95% CI: 1.01-2.33), and relaxer use was associated with increased ER- disease (OR = 2.56, 95% CI: 1.06-6.16). These novel findings provide support a relationship between the use of some hair products and breast cancer. Further examinations of hair products as important exposures contributing to breast cancer carcinogenesis are necessary.

The environmental injustice of beauty: framing chemical exposures from beauty products as a health disparities concern

The obstetrics-gynecology community has issued a call to action to prevent toxic environmental chemical exposures and their threats to healthy human reproduction. Recent committee opinions recognize that vulnerable and underserved women may be impacted disproportionately by environmental chemical exposures and recommend that reproductive health professionals champion policies that secure environmental justice. Beauty product use is an understudied source of environmental chemical exposures. Beauty products can include reproductive and developmental toxicants such as phthalates and heavy metals; however, disclosure requirements are limited and inconsistent. Compared with white women, women of color have higher levels of beauty product-related environmental chemicals in their bodies, independent of socioeconomic status. Even small exposures to toxic chemicals during critical periods of development (such as pregnancy) can trigger adverse health consequences (such as impacts on fertility and pregnancy, neurodevelopment, and cancer). In this commentary, we seek to highlight the connections between environmental justice and beauty product-related chemical exposures. We describe racial/ethnic differences in beauty product use (such as skin lighteners, hair straighteners, and feminine hygiene products) and the potential chemical exposures and health risks that are associated with these products. We also discuss how targeted advertising can take advantage of mainstream beauty norms to influence the use of these products. Reproductive health professionals can use this information to advance environmental justice by being prepared to counsel patients who have questions about toxic environmental exposures from beauty care products and other sources. Researchers and healthcare providers can also promote health-protective policies such as improved ingredient testing and disclosure for the beauty product industry. Future clinical and public health research should consider beauty product use as a factor that may shape health inequities in women's reproductive health across the life course.

State of the evidence 2017: an update on the connection between breast cancer and the environment

BACKGROUND

In this review, we examine the continually expanding and increasingly compelling data linking radiation and various chemicals in our environment to the current high incidence of breast cancer. Singly and in combination, these toxicants may have contributed significantly to the increasing rates of breast cancer observed over the past several decades. Exposures early in development from gestation through adolescence and early adulthood are particularly of concern as they re-shape the program of genetic, epigenetic and physiological processes in the developing mammary system, leading to an increased risk for developing breast cancer. In the 8 years since we last published a comprehensive review of the relevant literature, hundreds of new papers have appeared supporting this link, and in this update, the evidence on this topic is more extensive and of better quality than that previously available.

CONCLUSION

Increasing evidence from epidemiological studies, as well as a better understanding of mechanisms linking toxicants with development of breast cancer, all reinforce the conclusion that exposures to these substances - many of which are found in common, everyday products and byproducts - may lead to increased risk of developing breast cancer. Moving forward, attention to methodological limitations, especially in relevant epidemiological and animal models, will need to be addressed to allow clearer and more direct connections to be evaluated.

Associations among personal care product use patterns and exogenous hormone use in the NIEHS Sister Study

It is hypothesized that certain chemicals in personal care products may alter the risk of adverse health outcomes. The primary aim of this study was to use a data-centered approach to classify complex patterns of exposure to personal care products and to understand how these patterns vary according to use of exogenous hormone exposures, oral contraceptives (OCs) and post-menopausal hormone therapy (HT). The NIEHS Sister Study is a prospective cohort study of 50,884 US women. Limiting the sample to non-Hispanic blacks and whites (N=47,019), latent class analysis (LCA) was used to identify groups of individuals with similar patterns of personal care product use based on responses to 48 survey questions. Personal care products were categorized into three product types (beauty, hair, and skincare products) and separate latent classes were constructed for each type. Adjusted prevalence differences (PD) were calculated to estimate the association between exogenous hormone use, as measured by ever/never OC or HT use, and patterns of personal care product use. LCA reduced data dimensionality by grouping of individuals with similar patterns of personal care product use into mutually exclusive latent classes (three latent classes for beauty product use, three for hair, and four for skin care. There were strong differences in personal care usage by race, particularly for haircare products. For both blacks and whites, exogenous hormone exposures were associated with higher levels of product use, especially beauty and skincare products. Relative to individual product use questions, latent class variables capture complex patterns of personal care product usage. These patterns differed by race and were associated with ever OC and HT use. Future studies should consider personal care product exposures with other exogenous exposures when modeling health risks.

A Literature Review on the Practice of Placentophagia

Placentophagia (consuming the placenta) has historically not been a common practice among humans. Over the past few decades the practice has gained attention as more women, particularly educated, middle-class, White American women, choose to partake in this practice. Purported benefits of placentophagia include pain relief, increased breast milk production, and decreased risk of postpartum depression; however, there is a lack of evidence to support these claims. The placenta can be consumed raw, cooked, or encapsulated; it can be used for keepsakes; or it can be used to make topical applications such as dermatologic creams and hair-growth products. Placentophagia has typically been viewed as a personal choice, resulting in little rigorous scientific research on the topic. More research is necessary to determine if the purported health benefits of placentophagia are proven.

A review of hair product use on breast cancer risk in African American women

The incidence rate of breast cancer for African American women has recently converged with that of non-Hispanic White women in the United States, although African Americans have a higher mortality rate due to this disease. Although most research exploring health disparities associated with this phenomenon has focused on differences between women based on biology and behavior, both the academic and lay communities have begun to explore the potential role of environmental exposure to estrogen and endocrine disrupting chemicals (EDCs). This study reviews the current state of the science associating one such means of exposure, hair products containing EDCs, with breast cancer risk in African American women. We found a growing body of evidence linking: (1) environmental estrogen and EDC exposures to breast cancer risk, (2) the presence of such chemicals in personal care products, including hair products, and (3) the use of certain hair products with potential breast cancer risk in African Americans. At the same time, there is also increasing concern in the lay community about this risk. These results indicate the need for additional research, and the opportunity to benefit from strategic partnerships in community-collaborative approaches in order to better understand the potential "cost of beauty."

Estrogenic and anti-estrogenic activity of off-the-shelf hair and skin care products

Use of personal care products is widespread in the United States but tends to be greater among African Americans than whites. Of special concern is the possible hazard of absorption of chemicals with estrogenic activity (EA) or anti-EA (AEA) in these products. Such exposure may have adverse health effects, especially when it occurs during developmental windows (e.g., prepubertally) when estrogen levels are low. We assessed the ethanol extracts of eight commonly used hair and skin products popular among African Americans for EA and AEA using a cell proliferation assay with the estrogen sensitive MCF-7:WS8 cell line derived from a human breast cancer. Four of the eight personal care products tested (Oil Hair Lotion, Extra-dry Skin Lotion, Intensive Skin Lotion, Petroleum Jelly) demonstrated detectable EA, whereas three (Placenta Hair Conditioner, Tea-Tree Hair Conditioner, Cocoa Butter Skin Cream) exhibited AEA. Our data indicate that hair and skin care products can have EA or AEA, and suggest that laboratory studies are warranted to investigate the in vivo activity of such products under chronic exposure conditions as well as epidemiologic studies to investigate potential adverse health effects that might be associated with use of such products.

Childhood hair product use and earlier age at menarche in a racially diverse study population: a pilot study

PURPOSE

Previous studies suggest that hair products containing endocrine disrupting chemicals could alter puberty. We evaluated the association between childhood hair product use and age at menarche in a racially diverse study population.

METHODS

We recruited 300 African-American, African-Caribbean, Hispanic, and white women from the New York City metropolitan area who were between 18-77 years of age. Data were collected retrospectively on hair oil, lotion, leave-in conditioner, perm, and other types of hair products used before age 13. Recalled age at menarche ranged from 8 to 19 years. We used multivariable binomial regression to evaluate the association between hair product use and age at menarche (<12 vs. ≥12), adjusting for potential confounders.

RESULTS

African-Americans were more likely to use hair products and reached menarche earlier than other racial/ethnic groups. Women reporting childhood hair oil use had a risk ratio of 1.4 (95% confidence interval [CI]: 1.1-1.9) for earlier menarche, adjusting for race/ethnicity and year of birth. Hair perm users had an increased risk for earlier menarche (adjusted risk ratio = 1.4, 95% CI: 1.1-1.8). Other types of hair products assessed in this study were not associated with earlier menarche.

CONCLUSIONS

Childhood hair oil and perm use were associated with earlier menarche. If replicated, these results suggest that hair product use may be important to measure in evaluating earlier age at menarche.

Peripheral precocious puberty: a retrospective study for six years in Hangzhou, China

AIM

To evaluate the clinical and aetiopathogenesis of peripheral precocious puberty (PPP) in Chinese children.

METHODS

A total of 91 PPP children were reviewed. Clinical features including age, gender, stage of pubertal development, presenting symptoms, features and aetiopathogenesis were investigated.

RESULTS

They were 65 girls (71.4%) and 26 boys (28.6%) with a median age of 3.6 years. The median age of girls and boys were 3.7 and 3.4 years, respectively, with a significant difference (P = 0.048). Congenital adrenal cortical hyperplasia (CAH) patients with a median age of 0.2 years were younger than other patients. The major complaint was the appearance of breast buds (56.6%), followed by menstruation (5.5%), vaginal discharge (5.5%) and vomiting (4.4%). Heterosexual PPP was common in CAH girls (10 cases) while exogenic sexual steroid exposure was common in boys (10 cases). Major cause of PPP was gonadal abnormalities (34.1%), including 24 girls with autonomous isolated ovarian cysts, one with Sertoli's cell ovarian tumour, five with testicular tumours and one with testotoxicosis. CAH was the most common cause of PPP in boys. Exogenous sexual steroid exposure was the third cause. MeCune-Albright syndrome was also found in three cases. It was noted that the causes of 24 cases (26.4%), including 20 girls and 4 boys, were still unknown.

CONCLUSION

The results imply that PPP is a common matter of children in the department of endocrinology. It is more frequently in girls. History, physical examination, clinical suspicion and imaging detection should be considered carefully to diagnose and investigate the aetiopathogenesis.

Fifteen years after "Wingspread"--environmental endocrine disrupters and human and wildlife health: where we are today and where we need to go

In 1991, a group of expert scientists at a Wingspread work session on endocrine-disrupting chemicals (EDCs) concluded that "Many compounds introduced into the environment by human activity are capable of disrupting the endocrine system of animals, including fish, wildlife, and humans. Endocrine disruption can be profound because of the crucial role hormones play in controlling development." Since that time, there have been numerous documented examples of adverse effects of EDCs in invertebrates, fish, wildlife, domestic animals, and humans. Hormonal systems can be disrupted by numerous different anthropogenic chemicals including antiandrogens, androgens, estrogens, AhR agonists, inhibitors of steroid hormone synthesis, antithyroid substances, and retinoid agonists. In addition, pathways and targets for endocrine disruption extend beyond the traditional estrogen/androgen/thyroid receptor-mediated reproductive and developmental systems. For example, scientists have expressed concern about the potential role of EDCs in increasing trends in early puberty in girls, obesity and type II diabetes in the United States and other populations. New concerns include complex endocrine alterations induced by mixtures of chemicals, an issue broadened due to the growing awareness that EDCs present in the environment include a variety of potent human and veterinary pharmaceutical products, personal care products, nutraceuticals and phytosterols. In this review we (1) address what have we learned about the effects of EDCs on fish, wildlife, and human health, (2) discuss representative animal studies on (anti)androgens, estrogens and 2,3,7,8-tetrachlorodibenzo-p-dioxin-like chemicals, and (3) evaluate regulatory proposals being considered for screening and testing these chemicals.

Role of environmental factors in the timing of puberty

Puberty-timing measures have historically been used as indicators of adequate nutrition and growth. More recently, these measures have been examined in relation to exposure to estrogenic or antiandrogenic agents, as well as other environmental factors. The scientific community has debated whether puberty timing is occurring earlier today than in the mid-1900s in the United States and, if so, whether environmental factors play a role; however, no one has asked a multidisciplinary panel to resolve this question. Thus, a multidisciplinary expert panel jointly sponsored by the US Environmental Protection Agency, the National Institute of Environmental Health Sciences, and Serono Symposia International was convened to examine the evidence of a secular trend, identify potential environmental factors of concern, and identify research needs regarding environmental factors and puberty timing at "The Role of Environmental Factors on the Timing and Progression of Puberty" workshop. The majority of the panelists concluded that the girls' data are sufficient to suggest a secular trend toward earlier breast development onset and menarche from 1940 to 1994 but that the boys' data are insufficient to suggest a trend during this same period. The weight-of-the-evidence evaluation of human and animal studies suggest that endocrine-disrupting chemicals, particularly the estrogen mimics and antiandrogens, and body fat are important factors associated in altered puberty timing. A change in the timing of puberty markers was considered adverse from a public health perspective. The panel recommended research areas to further our understanding of the relationships among environmental factors, puberty-timing outcomes, and other reproductive and adult disease at the individual and population levels.

Examination of US puberty-timing data from 1940 to 1994 for secular trends: panel findings

Whether children, especially girls, are entering and progressing through puberty earlier today than in the mid-1900s has been debated. Secular trend analysis, based on available data, is limited by data comparability among studies in different populations, in different periods of time, and using different methods. As a result, conclusions from data comparisons have not been consistent. An expert panel was asked to evaluate the weight of evidence for whether the data, collected from 1940 to 1994, are sufficient to suggest or establish a secular trend in the timing of puberty markers in US boys or girls. A majority of the panelists agreed that data are sufficient to suggest a trend toward an earlier breast development onset and menarche in girls but not for other female pubertal markers. A minority of panelists concluded that the current data on girls' puberty timing for any marker are insufficient. Almost all panelists concluded, on the basis of few studies and reliability issues of some male puberty markers, that current data for boys are insufficient to evaluate secular trends in male pubertal development. The panel agreed that altered puberty timing should be considered an adverse effect, although the magnitude of change considered adverse was not assessed. The panel recommended (1) additional analyses of existing puberty-timing data to examine secular trends and trends in the temporal sequence of pubertal events; (2) the development of biomarkers for pubertal timing and methods to discriminate fat versus breast tissue, and (3) establishment of cohorts to examine pubertal markers longitudinally within the same individuals.

Environmental factors and puberty timing: expert panel research needs

Serono Symposia International convened an expert panel to review the impact of environmental influences on the regulation of pubertal onset and progression while identifying critical data gaps and future research priorities. An expert panel reviewed the literature on endocrine-disrupting chemicals, body size, and puberty. The panel concluded that available experimental animal and human data support a possible role of endocrine-disrupting chemicals and body size in relation to alterations in pubertal onset and progression in boys and girls. Critical data gaps prioritized for future research initiatives include (1) etiologic research that focus on environmentally relevant levels of endocrine-disrupting chemicals and body size in relation to normal puberty as well as its variants, (2) exposure assessment of relevant endocrine-disrupting chemicals during critical windows of human development, and (3) basic research to identify the primary signal(s) for the onset of gonadotropin-releasing hormone-dependent/central puberty and gonadotropin-releasing hormone-independent/peripheral puberty. Prospective studies of couples who are planning pregnancies or pregnant women are needed to capture the continuum of exposures at critical windows while assessing a spectrum of pubertal markers as outcomes. Coupled with comparative species studies, such research may provide insight regarding the causal ordering of events that underlie pubertal onset and progression and their role in the pathway of adult-onset disease.

Breast development in the first 2 years of life: an association with soy-based infant formulas

OBJECTIVE

To evaluate the estrogenic effect of soy-based formulas in female infants. These formulas contain significant amounts of phytoestrogens, compounds with structural similarity to estradiol.

PATIENTS AND METHODS

A cross-sectional study consisting of 694 female infants ages 3 to 24 months that consecutively attended 10 general pediatric clinics, none of them having been referred for breast development. The presence of breast buds served as a marker for the endocrine effect of soy-derived phytoestrogens.

RESULTS

Of the participants, 92 had consumed soy formulas for more than 3 months. Breast tissue was more prevalent in the second year of life in infants fed soy-based formula vs those that were breast-fed and those fed dairy-based formula (22.0% vs 10.3%; P = 0.02) with an odds ratio of 2.45 (95% confidence interval 1.11-5.39). No differences in breast bud prevalence were observed during the first year of life. Unlike infants on dairy-based formulas and breast-feeding, infants fed a soy-based formula did not demonstrate a decline in the prevalence of breast during the second year of life.

CONCLUSIONS

We suggest that phytoestrogens impose a preserving effect on breast tissue that is evolved in early infancy, leading eventually to a slower waning of infantile breast tissue.

Precocious puberty: a comprehensive review of literature

CONTEXT

Precocious puberty currently affects 1 in 5,000 children and is 10 times more common in girls. Statistics indicate that girls in the United States are maturing at an earlier age than they did 30 years ago and the number of girls with diagnosed precocious puberty (the appearance of secondary sex characteristics before 8 years of age or the onset of menarche before age 9) is on the rise. A summary of the growing body of literature on this topic is necessary to inform nurses and other health care providers of the current trends and incidence of precocious puberty to better meet the physical and psychosocial needs of these girls and their families.

METHODS

EBSCOhost Research Databases that included CINAHL Plus, Health Source: Nursing Edition, MEDLINE, PsycINFO, and Women's Studies International were searched for journal articles published in the past 10 years (1997-2006) that explicitly examined precocious puberty in females and proposed theories to describe the phenomenon. Search terms included precocious puberty, sexual maturation, menarche, and secondary sex characteristics. These terms were searched individually and in combination with proximate determinants such as endocrine disruptors, environmental toxins, phthalates, stress, skin care, genetics, age, ethnicity, obesity, and assisted reproduction. The search yielded 947 articles addressing this issue.

RESULTS

Eighty-two studies or case reports met the criteria for inclusion in this literature review that captured six attributable causes of early sexual maturation in female children. These included genetic, ethnic, and pediatric obesity, as well as environmental toxins that disrupt endocrine function (chemicals, toxins, plasticizers, infant feeding methods, skin and hair products, assisted reproductive technologies), psychosocial stress, and early exposure to a sexualized society. The robustness of the reports varied and few of the studies were widely generalizable but did offer suggestions for assessment and nursing care.

CONCLUSIONS

Precocious puberty has health and social implications that are complex and influenced by multiple factors. Further research is needed to expand and elucidate theoretical relationships between the early development of secondary sex characteristics in young girls and the proposed causative factors.

Declines in sex ratio at birth and fetal deaths in Japan, and in U.S. whites but not African Americans

BACKGROUND

The expected ratio of male to female births is generally believed to be 1.05, also described as the male proportion of 0.515.

OBJECTIVES

We describe trends in sex ratio at birth and in fetal deaths in the United States, in African Americans and in whites, and in Japan, two industrial countries with well-characterized health data infrastructures, and we speculate about possible explanations.

METHODS

Public health records from national statistical agencies were assembled to create information on sex ratio at birth and in fetal deaths in the United States (1970-2002) and Japan (1970-1999), using SPSS.

RESULTS

Sex ratio at birth has declined significantly in Japan and in U.S. whites, but not for African Americans, for whom sex ratio remains significantly lower than that of whites. The male proportion of fetal death has increased overall in Japan and in the United States.

CONCLUSIONS

Sex ratio declines are equivalent to a shift from male to female births of 135,000 white males in the United States and 127,000 males in Japan. Known and hypothesized risk factors for reduced sex ratio at birth and in fetal deaths cannot account fully for recent trends or racial or national differences. Whether avoidable environmental or other factors--such as widespread exposure to metalloestrogens or other known or suspected endocrine-disrupting materials, changes in parental age, obesity, assisted reproduction, or nutrition--may account for some of these patterns is a matter that merits serious concern.

Exposição ambiental a interferentes endócrinos com atividade estrogênica e sua associação com distúrbios puberais em crianças

A substância exógena que causa efeitos adversos na saúde de um organismo ou sua descendência, como resultado de distúrbios na função hormonal, é denominada interferente endócrino. Nos últimos anos, produtos ambientais com atividades hormonais têm sido documentados como causadores de anormalidades puberais ou reprodutivas em animais. Os poucos casos comprovados em humanos foram aqueles relacionados a exposições acidentais. Apesar disso, pediatras e pais recomendam a suspensão de todos os alimentos potencialmente contaminados, em especial carne (aves, gado) e derivados da soja quando a criança apresenta alguma alteração puberal. Estas recomendações, se não embasadas cientificamente, podem ter conseqüências deletérias, não apenas pela eliminação de fontes protéicas da dieta, como também por retardar a investigação de causas tratáveis. Por outro lado, a não investigação dos efeitos adversos destes produtos é da mesma forma danosa. Esta revisão descreve os principais interferentes endócrinos responsáveis por alterações puberais em humanos e conclui que, excetuando exposições acidentais a altas quantidades destes produtos, mais estudos são necessários para responsabilizar a ação crônica e em baixas doses destas substâncias na alteração do tempo de desenvolvimento puberal em nossa espécie.

Personal care products that contain estrogens or xenoestrogens may increase breast cancer risk

Established models of breast cancer risk, such as the Gail model, do not account for patterns of the disease in women under the age of 35, especially in African Americans. With the possible exceptions of ionizing radiation or inheriting a known genetic mutation, most of the known risk factors for breast cancer are related to cumulative lifetime exposure to estrogens. Increased risk of breast cancer has been associated with earlier onset of menses or later age at menopause, nulliparity or late first parity, use of hormonal contraceptives or hormone replacement therapy, shorter lactation history, exposure to light at night, obesity, and regular ingestion of alcohol, all of which increase circulating levels of unbound estradiol. Among African Americans at all ages, use of hormone-containing personal care products (PCPs) is more common than among whites, as is premature appearance of secondary sexual characteristics among infants and toddlers. We hypothesize that the use of estrogen and other hormone-containing PCPs in young African American women accounts, in part, for their increased risk of breast cancer prior to menopause, by subjecting breast buds to elevated estrogen exposure during critical windows of vulnerability in utero and in early life. These early life and continuing exposures to estrogenic and xenoestrogenic agents may also contribute to the increased lethality of breast cancer in young women in general and in African American women of all ages. Public disclosure by manufacturers of proprietary hormonally active ingredients is required for this research to move forward.

Pubic hair of infancy: endocrinopathy or enigma?

Pubic hair of infancy is a rare condition that has not been well-characterized. A retrospective chart review of infants <12 months of age who presented to our pediatric endocrine clinics with isolated pubic hair over the last 5 years was performed. Eleven patients were identified (6 male and 5 female). The average age at diagnosis was 8.3 +/- 2.0 months. The majority of patients (73%) had pubic hair in an atypical location. Growth pattern, laboratory evaluation, and bone-age radiographs were unremarkable for all the infants. Of the infants that returned for follow-up, pubic hair resolved by the age of 11.0 +/- 1.5 months. From our experience and review of the literature, we suggest that isolated pubic hair of infancy is a benign entity. However, long-term follow-up needs to be done to determine if pubic hair of infancy is an atypical variant of premature adrenarche, which may place these patients at risk for later adult disease.

Endocrine disrupters and female reproductive health

There is growing evidence of the impact of estrogenic contaminants in the environment. Studies have shown that male fish in detergent-contaminated water express female characteristics, turtles are sex-reversed by polychlorinated biphenyls (PCBs), male frogs exposed to a common herbicide form multiple ovaries, pseudohermaphroditic offspring are produced by polar bears, and seals in contaminated water have an excess of uterine fibroids. Endocrine-disrupting chemicals (those found in the external environment that can mimic or inhibit endogenous hormones) mostly exhibit estrogenic effects, but a few are anti-estrogenic or anti-androgenic. Many of these compounds are industrial contaminants, such as pesticides and plasticizers, and others are natural phytoestrogens found in plants such as soy and in herbal supplements. Recent work shows that human development can also be feminized by exposure to estrogenic chemicals. Estrogen is the key hormone in the initiation (puberty) and the end (menopause) of reproductive life in women and thus of considerable importance in women's health. The same chemicals that affect wildlife may affect breast growth and lactation, and could have a role in uterine diseases such as fibroids and endometriosis. New studies provide a mechanism of action for estrogenic chemicals and other endocrine disrupters at the molecular level (called epigenetics) that may help explain the long-term effects of endocrine disruption.

Regulation and disorders of pubertal timing

Disorders of pubertal timing are common and challenging problems for pediatric endocrinologists. Early or late puberty can have immediate effects on a child's psychosocial well-being and may have long-term effects on adult stature. Much is known about the regulation of the hypothalamic-pituitary-gonadal axis, but the triggers of pubertal onset in the general population remain elusive. This article reviews recent data suggesting a possible shift in the age of pubertal onset; current knowledge regarding factors that regulate the onset of puberty; and the etiologies, diagnosis, and treatment of precocious and delayed puberty.

Androgenetic alopecia in children: report of 20 cases

Androgenetic alopecia (AGA) is the most common type of hair loss in adults. Although there are differences in the age at onset, the disease starts after puberty when enough testosterone is available to be transformed into dihydrotestosterone. We report 20 prepubertal children with AGA, 12 girls and eight boys, age range 6-10 years, observed over the last 4 years. All had normal physical development. Clinical examination showed hair loss with thinning and widening of the central parting of the scalp, both in boys and girls. In eight cases frontal accentuation and breach of frontal hairline were also present. The clinical diagnosis was confirmed by pull test, trichogram and dermoscopy in all cases, and by scalp biopsy performed in six cases. There was a strong family history of AGA in all patients. The onset of AGA is not expected to be seen in prepubertal patients without abnormal androgen levels. A common feature observed in our series of children with AGA was a strong genetic predisposition to the disease. Although the pathogenesis remains speculative, endocrine evaluation and a strict follow-up are strongly recommended.

Virilization of young children after topical androgen use by their parents

Children were virilized by contact with adults using cutaneous steroid preparations. Parents were unaware of the dangers of passive transfer. Laboratory data were consistent with exogenous androgen exposure. Each child had opportunity for passive exposure, and discontinuation of contact resulted in a decrease of androgen levels or regression of symptoms.

Putative effects of endocrine disrupters on pubertal development in the human

Pubertal development is regulated by gonadotrophins and sex hormones. There has been a clear secular trend in the timing of puberty during the last century, puberty becoming earlier. Although improved nutrition is assumed to be the cause, this could partly be associated with exposure to so-called endocrine disrupters. Precocious puberty has been described in several case reports of accidental exposure to oestrogenic compounds in cosmetic products, food and pharmaceuticals. Local epidemics of premature thelarche have also been suggested to be linked to endocrine disrupters. Children adopted from developing countries to industrialized countries often develop precocious puberty. Not only precocious puberty, but also delayed puberty can, theoretically, be associated with exposure to endocrine disrupters. While it is very plausible that endocrine disrupters may disturb pubertal development, there is very little research on this and, therefore, we do not yet have any clear cause-effect relationships in humans.

Endocrine disruption in sexual differentiation and puberty. What do pseudohermaphroditic polar bears have to do with the practice of pediatrics?

What do pseudohermaphroditic polar bears and girls with premature breast development have in common? Hormones. Sexual differentiation and the initiation of secondary sexual characteristics, such as breast growth, are both under the control of the sex hormones estrogen and androgen. Abnormal differentiation of the internal or external genitalia in bears and early onset of breast development in girls also may have a common element--exposure to environmental hormones.