Use of Straighteners and Other Hair Products and Incident Uterine Cancer

Fast unmasking toxicity of safe personal care products

Personal care products are used several times a day and come into contact with the skin for many hours. As hazard-related data on products are rare, an imaging safety screening was developed. For the first time, it detected known and unknown hazardous compounds in 140 personal care products from 20 different product segments, including beauty and lifestyle products. The evidence-based chromatographic-hazard-related profiling detected genotoxic, cytotoxic, and estrogenic compounds, which were assigned to structural groups, and revealed that personal care products are not as safe as stated. Wound-healing and nipple creams in contact with babies as well as lipsticks used by adolescents were shown to contain highly toxic compounds able to enter the bloodstream via wounds, micro-injuries or bleeding gums and contaminate nature when washed off. Dose-response curves pointed to half-maximal genotoxic effect doses (EC50) of around 60 µg of such products which can easily be exceeded by a factor of 100,000 for only 6 g product applied or for an aggregated use of various products increasing genotoxic exposure, as observed in consumer profiles. Simulated metabolization via S9 liver enzymes did not lead to detoxification. The new safety screening not only unmasked quickly the toxicity of personal care products but also provided an understanding of how to produce hazard-free products. It empowers industries to produce future products in compliance with their standards and claims in terms of consumer health, ethics, environmental compatibility, and sustainability, and authorities to control the safety of products on the market and tackle the current underregulation.

The utility of silicone wristbands in characterizing exposure to parabens found in commercial lotions

Silicone wristbands are increasingly used as a wearable exposure tool to assess inhalation and dermal exposure to semi-volatile organic chemicals present in indoor environments. However, little research has investigated their utility in detecting exposures specifically related to personal care product (PCP) use. Here, we assessed exposure to methyl-, ethyl-, and propylparabens after applying a lotion containing a known amount of each chemical. A convenience sample of 20 adults wore a wristband and collected all urine excreted for three days over two consecutive weeks, keeping their PCP use consistent. During one of these periods, participants were provided with a lotion containing a known amount of parabens and asked to apply it daily (4.57 g applied over three days, with one pump of lotion each day). Urine and wristband samples were extracted and analyzed for parabens via LC-MS/MS. Parabens present in the lotion were detected in 100 % of wristbands across both study periods, while urinary detection of these paraben ranged from 87 to 100 % across periods. Parabens were measured at higher levels in urine and wristbands collected during the lotion application phase. For every 10 % increase in wristband paraben concentrations, the total paraben mass excreted in urine increased an average of 4 % for methylparaben (95 % CI = 3-5 %, p < 0.0001), 4 % for ethylparaben (95 % CI = 3-5 %, p < 0.0001), and 6 % for propylparaben (95 % CI = 4-7 %, p < 0.0001). This study shows that wristband concentrations reflect differences in use of a PCP containing parabens. Differences in wristband concentrations between study periods were greater than differences in urinary biomarkers of exposure, possibly because wristbands represent total potential exposure from dermal and inhalation routes. As this investigation only required a difference of one pump of lotion applied daily, the sensitivity of wristbands to capture differences in PCP use is promising.

Associations of personal care product use during pregnancy and the postpartum period with markers of postpartum glycemic control - Results from the ERGO Study

BACKGROUND

Personal care products frequently contain endocrine disrupting chemicals (EDCs) including parabens and phthalates, which can alter glucose metabolism. The postpartum period is a time of rapid metabolic change, but whether EDC-associated product use impacts postpartum glucose metabolism is unknown.

METHODS

We included 270 participants from the Boston, MA-based Environmental Reproductive and Glucose Outcomes (ERGO) pregnancy cohort with data on self-reported personal care product use at ≤4 pregnancy visits (median: 11, 19, 26, 36 weeks of gestation) and 1 postpartum visit (median: 9 weeks). We quantified postpartum hemoglobin A1c (HbA1c), fasting insulin, fasting- and 2-h glucose post-75-g oral glucose tolerance test, and calculated homeostatic model assessment for insulin sensitivity (HOMA2-S) and beta-cell function (HOMA2-B). Using covariate-adjusted linear regression, we estimated visit-specific associations of product use with postpartum glycemic outcomes.

RESULTS

Associations of product use with postpartum glycemic measures were mixed. Users of certain hair products had lower postpartum insulin sensitivity compared to non-users (e.g., Visit1 hair gel/spray: 22.8% difference [95% CI: 39.2, -1.9] in mean HOMA2-S). Conversely, users of products like deodorant, liquid- and bar soap, had higher insulin sensitivity and lower glucose levels (e.g., postpartum deodorant: 32.1% difference [95% CI: 7.0, 63.1] in mean HOMA2-S; -3.1 mg/dL [95% CI: 6.3, -0.04] mean fasting glucose). Associations with other products were inconsistent across timepoints or null.

CONCLUSION

Use of certain personal care products during the perinatal period was associated with altered postpartum glucose metabolism. Larger studies are needed to understand the impacts of product use patterns on glycemic outcomes.

Annual Report to the Nation on the Status of Cancer, featuring state-level statistics after the onset of the COVID-19 pandemic

BACKGROUND

This report represents a collaborative effort by the major cancer surveillance organizations to present the definitive US statistics for cancer incidence and mortality.

METHODS

Cancer incidence data were obtained from population-based cancer registries funded by the Centers for Disease Control and Prevention and the National Cancer Institute and compiled by the North American Association of Central Cancer Registries. Cancer death data were obtained from the National Center for Health Statistics' National Vital Statistics System. Statistics are reported by cancer type, sex, race and ethnicity, and age. The potential impact of the coronavirus disease 2019 (COVID-19) pandemic on incidence was assessed by using state-level changes compared with previous years, the stringency of COVID-19 policy restrictions, the magnitude of COVID-19 death rates, and changes in the use of mammography.

RESULTS

Overall cancer incidence rates per 100,000 were 500 among males and 437 among females. Excluding 2020, cancer incidence rates remained stable (2013-2021) among males and increased 0.3% per year on average (2003-2021) among females. The overall cancer death rate per 100,000 was 173 among males and 126 among females. Cancer death rates decreased by 1.5% per year (2018-2022), slowing from a previous 2.1% decline. Cancer incidence in 2020 declined from prepandemic levels for all demographic groups examined. However, the magnitude of decline was not strongly associated with the study's proxies for health care capacity, health care access, or COVID-19 policies.

CONCLUSIONS

Overall cancer mortality declined over 20 years, even during the COVID-19 pandemic. Disruptions in health care use early in the pandemic resulted in incidence declines in 2020, but 2021 incidence returned to prepandemic levels.

Chemicals of concern in select packaged hair relaxers available on the Kenyan market: an examination of ingredient labels and measurement of pH

Background

There is an emerging interest in the investigation of hair relaxers as important sources of exposure to chemicals of concern (CoCs) and their associated adverse health effects. We focused on documentation of CoCs by examining labels of selected relaxers currently available on the market in Nakuru and Embu Counties, Kenya and measured the pH profiles to ensure compliance with Kenya Bureau of Standards.

Methods

We enrolled 746 women aged 15-50 years in a cross-sectional study, which ascertained participants' sociodemographic characteristics, personal care products use in the last 7-14 days and ever use of hair dyes and chemical relaxers including the brand names of products used. Based on participants' questionnaire responses and product availability at beauty shops and supermarkets, we purchased 22 different relaxer products. The label of each product was reviewed and we recorded relaxer strength, manufacturer and location, listed ingredients, and other claims. To identify CoCs, we cross-checked the list of ingredients against the Campaign for Safe Cosmetics' (CSC) Red List and European Union's prohibited and restricted substances (Annex II and III respectively), Regulation 1223/2009 on cosmetics. The pH profiles of each product were determined using a benchtop pH meter.

Results

Twenty-seven CoCs were documented upon examination with each relaxer listing more than one CoC. Thirteen out of 27 (48.2%) were fragrance chemicals with d-limonene/limonene and linalool, each being listed as an ingredient in 9 products. Fourteen (63.6%) relaxers had undisclosed ingredients listed as 'fragrance' and/or 'parfum'. Six of the identified CoCs are classified as Tier 1 (Do not use for everyone) per CSC Red List while 14.8% (4) are prohibited and 55.6% (15) are restricted substances per EU regulations. The pH values of the relaxers were within Kenya Bureau of Standards required range of 11-13.

Conclusion

These findings create awareness of CoCs listed on labels of selected hair relaxers. This justifies the need for consumer education on potentially harmful chemicals and their associated risks. Further, our findings justify the need for laboratory study to evaluate and quantify CoCs that are listed as well as those that are not listed on the label.

Personal care products exposure patterns and prostate cancer: evidence from a case-control study in Mexico City

BACKGROUND

Personal care products (PCPs) use has been associated with a high risk of hormone-sensitive cancers in women. However, this association is poorly understood in hormone-sensitive cancers in men.

OBJECTIVE

To investigate the association between PCPs use and prostate cancer (PC) and PC histological differentiation in men from Mexico City.

METHODS

We analyzed the information from 400 histologically confirmed incident PC cases and 801 population controls matched by age (±5 y). The usage frequency (daily, weekly, or less, and non-use) of deodorant, body lotion, shampoo, perfume, and shaving or after-shaving products was evaluated based on a structured questionnaire. Using the K-means approach, we selected three patterns according to the usage frequency and number of PCPs used: high, intermediate, and low. Multivariable non-conditional logistic regression models adjusted by selected confounders were conducted to estimate the association between the use of PCPs (patterns, individual products, and number of products used daily) and PC, as well as PC histological differentiation.

RESULTS

Compared to the low exposure pattern, the high (OR: 2.6 95% CI: 1.8-3.8) and intermediate (OR: 1.3 95% CI: 1.0-1.8) PCPs patterns were associated with higher odds of PC. Similarly, the intermediate exposure pattern was significantly associated with poorly differentiated PC (OR: 1.8 95% CI: 1.1-2.9). The daily use of perfume was the most consistent PCP associated with PC (OR high vs. low: 1.9 95% CI: 1.3-2.8; p for trend = 0.001) and PC poor differentiation (OR: 2.0, 95% CI: 1.1-3.6; p for trend = 0.013). In addition, a dose-response relationship was observed with the number of personal care products used daily.

IMPACT STATEMENT

This study provided evidence that high exposure to personal care products (PCPs) is associated with prostate cancer. Our findings are consistent with those observed regarding hormone-sensitive female cancer and suggest the potential contribution of PCPs to prostatic carcinogenesis.

Ultrasound-based versus immediate biopsy-based management of postmenopausal bleeding in non-Hispanic Black and non-Hispanic White individuals

BACKGROUND

Ultrasound-based evaluation of endometrial thickness to rule out endometrial cancer in patients with postmenopausal bleeding (PMB) is not sufficiently validated in the non-Hispanic Black (NHB) population. Differences in ultrasound performance between NHB and non-Hispanic White (NHW) patients may contribute to documented disparities in cancer-associated survival.

METHODS

We developed a decision-tree model, informed by literature and institutional data, comparing an immediate biopsy-based strategy (BBS) to an ultrasound-based strategy (UBS) to evaluate PMB in NHB and NHW patients. Primary outcomes were the probability of a missed cancer diagnosis and incremental biopsies per additional cancer detected. Fibroid prevalence, endometrial visibility, and race were modeled using institutional patient-level data. Prompt endometrial sampling following abnormal ultrasound (perfect follow-up) was assumed; institutionally observed follow-up rates were alternatively modeled.

RESULTS

In a simulated cohort of 10,000 patients with PMB, UBS missed 109 (95 % prediction interval (PI) 85-159) cancer diagnoses compared to 70 missed for BBS. Compared to UBS, BBS resulted in 123 (95 % PI 45-265) biopsies/additional cancer detected for NHB and 155 (95 % PI 47-398) for NHW. Under observed follow-up rates, BBS resulted in 33 (95 % PI 26-38) biopsies/additional cancer detected for NHB and 44 (95 % PI 30-54) for NHW. NHB derived higher value (fewer biopsies/additional cancer detected) from BBS than NHW, particularly with fibroids present.

CONCLUSION

BBS has higher value compared to UBS under observed/imperfect levels of follow-up and enhanced value when fibroids are present and among NHB patients. These results suggest that endometrial sampling should be offered at time of initial evaluation for PMB.

Evaluating personal care product use by Environmental Working Group hazard scores in relation to consumers' sociodemographic characteristics, purchasing behaviors, and product safety perceptions

BACKGROUND

Personal care products (PCPs) are a source of environmental chemical exposures. Little research has examined the specific PCPs people use, the environmental hazards posed by those PCPs, and factors informing PCP selection.

OBJECTIVE

To examine chemical hazards of the specific products used in relation to sociodemographic factors, purchasing behaviors, and perceptions about PCP safety.

METHODS

In a cross-sectional, university-based sample (NJ, USA, N = 593), participants reported on sociodemographics, PCP purchasing behaviors and perceptions, and PCP use in the last 24-48 h (including brand and product name). Those PCPs were linked to product hazard scores (1=least hazardous, 10=most hazardous) in the Environmental Working Group's Skin Deep® database. For each participant, we calculated average hazard scores across all PCPs used and by category (e.g., haircare, skincare) and evaluated use of PCPs with high hazard scores (7-10). We fitted adjusted regression models examining associations of sociodemographic factors and participants' perceptions and purchasing behaviors with product hazard scores.

RESULTS

Of 9349 unique PCPs used by participants, 68% matched to Skin Deep®. Average hazard scores varied by participant characteristics (e.g., age) for perfumes/colognes, beauty, and skin care products. The relative risk (RR) of recent use of a hair product with a high hazard score was twice as high in non-Hispanic Black women compared to non-Hispanic White women (RR:1.99; 95%CI:1.37, 2.89). Frequent use of healthy product apps (β = -0.49, 95%CI:-0.77, -0.21), reading product ingredient labels (β = -0.26; 95%CI:-0.82, -0.30), and seeking eco-friendly products (β = -0.17; 95%CI:-0.36, -0.01) were associated with use of skin care products with lower hazard scores. Results for hair and beauty products were similar. Concerns about PCP health impacts and regulation were associated with using products with lower hazard scores.

IMPACT STATEMENT

Personal care products (PCPs) can contain numerous endocrine disrupting and carcinogenic chemicals. In a U.S. university-based sample, we linked the PCPs used by participants in the last 24-48 h to hazard scores in the Skin Deep® database. Average hazard scores of the PCPs used by participants varied by sociodemographic factors. Participant behaviors (e.g., use of healthy product apps) and perceptions of PCP safety and regulation were associated with the average hazard scores of the PCPs they used. Our findings suggest that education and tools to inform PCP choice may help consumers choose safer products and potentially, reduce chemical exposures.

Racial and ethnic differences in prenatal exposure to environmental phenols and parabens in the ECHO Cohort

BACKGROUND

Research suggests racial/ethnic disparities in prenatal exposure to endocrine disrupting environmental phenols (EPs) in limited populations. However, no studies have investigated racial/ethnic disparities in prenatal EP exposure across the U.S.

OBJECTIVES

To estimate demographic differences in prenatal urinary EPs among participants in the Environmental influences on Child Health Outcomes (ECHO) Cohort.

METHODS

An analysis of 4006 pregnant ECHO participants was performed, with 7854 specimens collected from 1999-2020. Racial/ethnic identity was self-reported. Urinary levels of 2,4-dichlorophenol (2,4-DCP), 2,5-dichlorophenol (2,5-DCP), benzophenone-3 (BP-3), bisphenols A (BPA), F (BPF), and S (BPS), and methyl- (MePb), ethyl- (EtPb), propyl- (PrPb), and butyl- (BuPb) parabens were measured at one or more time points during pregnancy. Effect estimates were adjusted for age, pre-pregnancy body mass index, educational level, gestational age and season at urine collection, and ECHO cohort.

RESULTS

Participants were classified as Hispanic of any race (n = 1658), non-Hispanic White (n = 1478), non-Hispanic Black (n = 490), and non-Hispanic Other (n = 362), which included individuals of multiple races. Urinary 2,4-DCP and 2,5-DCP concentrations were 2- to 4-fold higher among Hispanic, non-Hispanic Black, and non-Hispanic Other participants relative to non-Hispanic White participants. MePb was ~2-fold higher among non-Hispanic Black (95% confidence interval (CI): 1.7-3.1) and non-Hispanic Other (95% CI: 1.5-2.8) participants. PrPb was similarly higher among non-Hispanic Black (95% CI: 1.7-3.7) and non-Hispanic Other (95% CI: 1.3-3.1) participants. EtPb was higher among non-Hispanic Black participants (3.1-fold; 95% CI 1.7-5.8). BP-3 was lower in Hispanic (0.7-fold; 95% CI: 0.5-0.9), non-Hispanic Black (0.4-fold; 95% CI: 0.3-0.5), and non-Hispanic Other (0.5-fold; 95% CI: 0.4-0.7) participants. Urinary BuPb, BPA, BPF, and BPS were similar across groups.

IMPACT STATEMENT

This multisite, observational cohort study investigated whether there are racial and ethnic differences in prenatal exposure to endocrine disrupting environmental phenols and parabens. Among 4006 participants from multiple U.S. cohorts who provided urine specimens during pregnancy, those who self-reported a racial and ethnic identity other than non-Hispanic White had higher urinary concentrations of 2,4-dichlorophenol, 2,5-dichlorophenol, methyl paraben, ethyl paraben, and propyl paraben and lower urinary concentrations of benzophenone-3 than those reporting as non-Hispanic White. These data show differences in prenatal concentrations of endocrine disrupting environmental phenols and parabens by racial and ethnic identity.

Systematic Review of the Epidemiology of Hair Relaxer Use and Hormone-Sensitive Reproductive Outcomes Among Black Adult Women in the United States

Hair relaxers are predominantly used by Black women in the United States. It has been recently suggested that exposure to potential endocrine-disrupting compounds from the use of these products may be associated with the development of gynecological and breast cancers and anatomically relevant nonmalignancies. We conducted a systematic literature review using PubMed to identify original studies reporting measures of association between hair relaxer use and relevant adverse outcomes, focusing specifically on Black women in the United States. A total of 1382 studies were initially identified, and after consideration of the exclusion and inclusion criteria, the final set of studies consisted of seven cohort studies and one case-control study. The overall findings suggest that Black women in the United States do not experience an increased risk of breast cancer, ovarian cancer, or uterine cancer due to hair relaxers. One study found a statistically significant association between hair relaxer use and uterine leiomyomata, but there were no other studies identified to support these findings. None of the studies characterized the chemical constituents of hair relaxers. From an epidemiologic perspective, the weight of the evidence does not support the hypothesis that the use of hair relaxers is a risk factor for gynecological and breast cancers in US Black women.

Hair Straightener Use in Relation to Prevalent and Incident Fibroids in the Sister Study with a Focus on Black Women

BACKGROUND

Uterine fibroids disproportionately affect Black women, and exposure to chemicals from hair relaxers or straighteners ("straighteners") may contribute to fibroid development.

OBJECTIVES

We examined the association between straightener use and prevalent young-onset uterine fibroids (diagnosed before age 36 y), as well as incident fibroids (diagnosed age 36-60 y), with a focus on Black women. We also examined differences in associations across birth cohorts as proxies for formulation changes.

METHODS

Data from 4,162 Black women in the Sister Study, a prospective cohort of women 35-74 y of age (enrolled 2003-2009), were analyzed. We used logistic regression to estimate odds ratios (ORs) for the association of straightener use at 10-13 y of age and self-reported young-onset fibroids. We used Cox regression to assess hazard ratios (HRs) for straightener use (age 10-13 y and in 12 months before enrollment) and incident fibroids among 779 premenopausal Black women. Similar analyses were conducted in 40,782 non-Hispanic White women.

RESULTS

Over 70% of Black women used straighteners. In comparison with no use, any [OR = 1.15 ; 95% confidence interval (CI): 0.96, 1.36] and frequent use (OR = 1.18 ; 95% CI: 0.99, 1.42) of straighteners at 10-13 y of age were associated with young-onset fibroids. This association was most apparent among those born between 1928 and 1945 (OR = 1.78 ; 95% CI: 1.15, 2.74) and 1965-1974 (OR = 1.64 ; 95% CI: 0.82, 3.29). Fibroid incidence from 36 to 60 y of age was modestly associated with use of straighteners at 10-13 y of age [hazard ratio ( HR ) = 1.14 ; 95% CI: 0.81, 1.63] and in the 12 months prior to enrollment (HR = 1.32 ; 95% CI: 0.88, 2.00). Among non-Hispanic White women, straightener use at 10-13 y of age was similarly associated with young-onset fibroids (OR = 1.23 ; 95% CI: 1.03, 1.47) despite lower use (≤ 5 % ) of straighteners. Sensitivity analyses indicated a potential for bias due to fibroid misclassification, with an overestimation of the effect likely if nulliparous women or women from households with lower education reported their fibroid status less accurately.

DISCUSSION

Hair straightener use may be positively associated with fibroid risk. https://doi.org/10.1289/EHP14493.

The Impact of Environmental Health Determinants in Surgical Oncology

Environmental determinants of health refer to external factors in our surroundings that influence health outcomes. It is estimated that healthier environments could prevent almost one-quarter of the global burden of disease. Additionally, environmental factors, including lifestyle factors, air pollution, chemical exposures, and natural exposures, are responsible for a significant incidence of cancers and premature cancer deaths. Minority populations, low-income populations, children, and older adults are at increased risk for oncologic risks secondary to environmental factors.

Hepatocellular carcinoma antibodies preferably identify nitro-oxidative-DNA lesions induced by 4-Chloro-orthophenylenediamine and DEANO

The widespread use of oxidative hair colouring cosmetics threatens public health. Phenylenediamine derivatives serve as the main pigment in permanent hair colours. They interact with biological macromolecules, altering their functional and structural physiology. The study aimed to investigate the effect of a typical synthetic hair dye pigment, 4-Chloro-orthophenylenediamine (4-Cl-OPD), under a nitrating environment of DEANO on the calf thymus DNA molecule. The results showed single-stranded regions, base/sugar-phosphate backbone alterations, molecular changes, and nitro-oxidative lesions. These modifications are referred to as neo-epitopes on the DNA molecule. IgGs from cancer patients with a history of permanent hair dye use were screened for the recognition of neo-epitopes on DNA molecules. Hepatocellular carcinoma IgG showed the highest binding with 56% inhibition in the competition ELISA. The immune complex formation was observed through electrophoretic mobility shift assay. In conclusion, synthetic hair dye users are likely to present with heightened immunological triggers under elevated nitric oxide levels. The study reports chronic hair dye exposure as one of the factors responsible for altering the intricacies of the DNA's microarchitectural structure and inducing neo-epitopes on the molecule. The physiological status of NO may define the susceptibility towards 4-Cl-OPD and humoral response in hair dye users. Persistent nitro-oxidative stress due to 4-Cl-OPD and NO may induce a heightened immune response against neoepitopes in the nitro-oxidatively modified DNA. Therefore, chronic hair dye exposure may be identified as a risk to human health. These findings may contribute to a better understanding and reinforcement of hair dye as one of the modifiable risk factors responsible for the pro-inflammatory carcinogenic environment.

Asking Why Is Necessary to Address Health Disparities: A Critical Approach for Solution-Oriented Environmental Epidemiological Research

BACKGROUND

In environmental epidemiology, we use an array of tools from various, related disciplines to answer key questions about environmental exposures in relation to health outcomes. Typically, we ask questions related to what, who, where, when, and how. We value these questions because they contribute to novel scientific discovery and our understanding of disease etiology linked to environmental exposures. In addition, these questions help us better understand who might be at highest risk of exposure and subsequent risk of disease. Although necessary for the goals of environmental epidemiology, these questions are insufficient for addressing environmental health disparities. Specifically, these questions may be able to help us describe exposure-health outcome associations but are limited in their ability to move beyond identification to intervening on observed disparities to achieve environmental health equity.

OBJECTIVES

We sought to emphasize the need to value and routinely add the key question of "Why?" in environmental epidemiological studies. In asking this additional critical question, we can identify and incorporate the structural determinants and drivers of environmental exposure disparities and determine whether these factors are linked to existing and historically recalcitrant health disparities. Further, we can design effective studies that build on existing frameworks to address the fundamental causes of environmental health disparities.

DISCUSSION

This commentary underscores the need to routinely incorporate "why" questions in the practice of environmental epidemiology. By asking and addressing "Why?" we can employ better, more solution-oriented study designs, improve data collection, and enhance our ability to collaborate with diverse study populations through trust-building and community-engaged research. Incorporating these approaches will move environmental epidemiology forward from mostly documenting to actively addressing environmental health disparities. https://doi.org/10.1289/EHP14513.

Environment and gynaecologic cancers

In the current era, environmental factors are well established as major causative agents for all cancers especially lung and breast cancer. We sought to review the current available literature on the topic pertaining to gynaecologic cancers. Although a few factors are well established in literature, others need more research to conclude.

Changing human hair fibre colour and shape from the follicle

INTRODUCTION

Natural hair curvature and colour are genetically determined human traits, that we intentionally change by applying thermal and chemical treatments to the fibre. Presently, those cosmetic methodologies act externally and their recurrent use is quite detrimental to hair fibre quality and even to our health.

OBJECTIVES

This work represents a disruptive concept to modify natural hair colour and curvature. We aim to model the fibre phenotype as it is actively produced in the follicle through the topical delivery of specific bioactive molecules to the scalp.

METHODS

Transcriptome differences between curly and straight hairs were identified by microarray. In scalp samples, the most variable transcripts were mapped by in situ hybridization. Then, by using appropriate cellular models, we screened a chemical library of 1200 generic drugs, searching for molecules that could lead to changes in either fibre colour or curvature. A pilot-scale, single-centre, investigator-initiated, prospective, blind, bilateral (split-scalp) placebo-controlled clinical study with the intervention of cosmetics was conducted to obtain a proof of concept (RNEC n.92938).

RESULTS

We found 85 genes transcribed significantly different between curly and straight hair, not previously associated with this human trait. Next, we mapped some of the most variable genes to the inner root sheath of follicles, reinforcing the role of this cell layer in fibre shape moulding. From the drug library screening, we selected 3 and 4 hits as modulators of melanin synthesis and gene transcription, respectively, to be further tested in 33 volunteers. The intentional specific hair change occurred: 8 of 14 volunteers exhibited colour changes, and 16 of 19 volunteers presented curvature modifications, by the end of the study.

CONCLUSION

The promising results obtained are the first step towards future cosmetics, complementary or alternative to current methodologies, taking hair styling to a new level: changing hair from the inside out.

Particles and Prejudice: Nanomedicine Approaches to Reducing Health Disparities in Endometrial Cancer

Endometrial cancer is the most common gynecological malignancy worldwide and unfortunately has a much higher mortality rate in Black women compared with White women. Many potential factors contribute to these mortality rates, including the underlying effects of systemic and interpersonal racism. Furthermore, other trends in medicine have potential links to these rates including participation in clinical trials, hormone therapy, and pre-existing health conditions. Addressing the high incidence and disparate mortality rates in endometrial cancer requires novel methods, such as nanoparticle-based therapeutics. These therapeutics have been growing in increasing prevalence in pre-clinical development and have far-reaching implications in cancer therapy. The rigor of pre-clinical studies is enhanced by the likeness of the model to the human body. In systems for 3D cell culture, for example, the extracellular matrix mimics the tumor more closely. The increasing emphasis on precision medicine can be applied to cancer using nanoparticle-based methods and applied to pre-clinical models by using patient-derived model data. This review highlights the intersections of nanomedicine, precision medicine, and racial disparities within endometrial cancer and provides insights into reducing health disparities using recent scientific advances on the nanoscale.

Evaluation of dermal exposure to phthalates and parabens resulting from the use of hair relaxers

Hair relaxers have been suggested as a source of exposure to parabens and phthalates. However, dermally absorbed doses of these chemicals resulting from consumer use of hair relaxers have yet to be quantified, and results from epidemiological studies have consistently demonstrated that there is no increased risk for hormone-sensitive, reproductive cancers associated with use of hair relaxers among Black women. Therefore, dermal absorption of parabens and phthalates associated with hair relaxer use for several commercially available hair relaxer kits was modeled using IH SkinPerm™. The chemicals detected in the hair relaxer kits included methylparaben (MP), ethylparaben (EP), butylparaben (BP), diethyl phthalate (DEP), bis(2-ethylhexyl) phthalate (DEHP), and the phthalate substitute bis(2-ethylhexyl) adipate (DEHA). The daily absorbed dose ranges (mg/kg/day), standardized over a year of product use, were as follows: 8.64 × 10-5-0.00116 MP, 2.30 × 10-8-3.07 × 10-6 EP, 3.24 × 10-8-4.33 × 10-6 BP, 8.65 × 10-9-1.15 × 10-6 DEP, and 8.94 × 10-7-0.000119 DEHP for Kit #1; 8.44 × 10-5-0.00113 MP and 7.91 × 10-5-0.00106 DEP for Kit #2; and 2.49 × 10-6-3.33 × 10-5 MP, 1.52 × 10-8-2.03 × 10-6 EP, 3.29 × 10-9-4.39 × 10-7 DEP, and 3.11 × 10-6-4.14 × 10-5 DEHA for Kit #3. These absorbed doses were well below applicable health-based guidance values, indicating consumer exposure from product use is not expected to pose a health risk. These results provide valuable information for health risk evaluations for hair relaxer use.

Environmental Racism and Child Health

Environmental racism poses a significant threat to child health. It is a major contributor to disproportionate exposure to environmental hazards that are linked to adverse health outcomes. This narrative review shows the profound impact that environmental racism poses to healthy child development through 3 examples. Historical redlining provides compelling evidence of how historical policies continue to influence neighborhoods' physical and social conditions. Exploring chemicals in beauty products reveals how anti-Black perceptions of beauty work to expose children of color to endocrine-disrupting chemicals. Finally, by exploring childhood lead exposure, we see how decades of inequitable implementation of lead exposure prevention policies contribute to persistent disparities in the United States today. Fixing these structural issues is complex and will require political will and investment. Yet, individual clinicians play an important role in their local communities in protecting children from the harms of environmental racism, through education, genuine collaboration with the community, and advocacy.

Hair product use and urinary biomarker concentrations of non-persistent endocrine disrupting chemicals among reproductive-aged Black women

BACKGROUND

Studies have shown an association between hair product use and adverse health outcomes. Scientists have hypothesized that exposure to endocrine-disrupting chemicals (EDCs) drives these associations, but few studies have directly evaluated associations between hair product use and biomarkers of EDCs. Even more limited are studies of Black women, who frequently use EDC-containing products (e.g., hair relaxers).

OBJECTIVE

We estimated associations between hair product use and EDC biomarker concentrations.

METHODS

We leveraged cross-sectional data from the Study of Environment, Lifestyle, and Fibroids, a cohort of females aged 23-34 years who self-identified as Black/African American from the Detroit-metropolitan area (USA; n = 425). On structured questionnaires, participants reported their past 24-h and past 12-month use of hair products, including relaxers/straighteners/perms, styling products, moisturizers, oils, and hair food. We quantified urinary concentrations of 19 phthalate/phthalate alternative metabolites, 7 phenols, and 4 parabens using high performance liquid chromatography isotope dilution tandem mass spectrometry. EDC biomarker concentrations were creatinine-adjusted and natural log-transformed. We used multivariable linear regression to estimate mean percent differences in EDC biomarker concentrations and 95% confidence intervals (CIs) associated with hair product use, adjusting for sociodemographic confounders.

RESULTS

Hair product use was associated with greater concentrations of multiple EDC biomarkers. Notably, use of hair products in the previous 24 h (compared with non-use) was associated with 16.2% (95% CI = 0.7%, 35.9%), 35.0% (95% CI = 2.6%, 77.6%), and 32.3% (95% CI = 8.8%, 92.0%) higher concentrations of mono-isobutyl phthalate, methyl paraben, and ethyl paraben, respectively. Use of hair relaxers/straighteners/perms, styling products, moisturizers, oils, and hair food in the past 12 months was also associated with higher concentrations of multiple phthalate, phenol, and paraben biomarkers.

CONCLUSION

Hair product use was associated with higher biomarker concentrations of multiple phthalates, phenols, and parabens. These findings suggest that hair products are potentially important exposure sources for hormonally-active chemicals among Black women.

Fabrication of innovative multifunctional dye using MXene nanosheets

The increasing demand for natural and safer alternatives to traditional hair dyes has led to the investigation of nanomaterials as potential candidates for hair coloring applications. MXene nanosheets have emerged as a promising alternative in this context due to their unique optical and electronic properties. In this study, we aimed to evaluate the potential of Ti3C2Tx (Tx = -O, -OH, -F, etc.) MXene nanosheets as a hair dye. MXene nanosheet-based dyes have been demonstrated to exhibit not only coloring capabilities but also additional properties such as antistatic properties, heat dissipation, and electromagnetic wave shielding. Additionally, surface modification of MXene using collagen reduces the surface roughness of hair and upregulates keratinocyte markers KRT5 and KRT14, demonstrating the potential for tuning its physicochemical and biological properties. This conceptual advancement highlights the potential of MXene nanosheets to go beyond simple cosmetic improvements and provide improved comfort and safety by preventing the presence of hazardous ingredients and solvents while providing versatility.

Frequency of personal care product use among reproductive-aged Black individuals and associations with socio-demographic characteristics

BACKGROUND

Compared to White women, Black women in the United States are more likely to use personal care products (PCPs) with higher concentrations of endocrine-disrupting chemicals (EDCs) and harsher chemical formulations. This may contribute to differential health outcomes in Black women such as increased risk of breast cancer, cardiometabolic outcomes, adverse birth outcomes, and uterine fibroids.

OBJECTIVE

Classify distinct PCP use patterns across multiple types of products and examine how patterns vary by socio-demographic characteristics.

METHODS

The Study of Environment, Lifestyle and Fibroids is a cohort study of reproductive-aged Black individuals living around Detroit, Michigan. Using self-reported data on frequency of PCP collected between 2013-2018, we employed latent class analysis to identify distinct groups of participants with similar PCP use. Socio-demographic characteristics were compared across latent classes.

RESULTS

Among 1562 participants, we identified 6 latent classes: Lower Overall; Higher Nailcare; Higher Skincare; Moderate Overall; Higher Makeup/Haircare/Skincare; Higher Overall. Makeup and nailcare usage were the most predictive for classifying participants into groups. Participants in classes with less frequent use of all PCPs and those with only high use of nailcare products, were more likely to report lower socio-economic status (SES), be current smokers, have a body mass index of ≥35 kg/m2, and have ≥3 births. In comparison, participants in classes with average and more frequent use of PCPs were more likely to report higher SES, be non-smokers, be nulliparous, and have ever used oral contraceptives.

IMPACT STATEMENT

This study is one of the first detailed assessments of PCP usage among a large cohort of young adult Black women that considers multiple product categories including makeup, hair, skin, nail, and vaginal products. Latent class analysis was used to capture complex patterns of PCP use and identify distinct groups of individuals with similar product use. Although the latent classes are specific to this study population, the identified socio-demographic characteristics or behaviors associated with latent classes may inform targeted and impactful exposure reduction strategies in similar populations.

Combined Exposures and Mixtures Research: An Enduring NIEHS Priority

BACKGROUND

The National Institute of Environmental Health Sciences (NIEHS) continues to prioritize research to better understand the health effects resulting from exposure to mixtures of chemical and nonchemical stressors. Mixtures research activities over the last decade were informed by expert input during the development and deliberations of the 2011 NIEHS Workshop "Advancing Research on Mixtures: New Perspectives and Approaches for Predicting Adverse Human Health Effects." NIEHS mixtures research efforts since then have focused on key themes including a) prioritizing mixtures for study, b) translating mixtures data from in vitro and in vivo studies, c) developing cross-disciplinary collaborations, d) informing component-based and whole-mixture assessment approaches, e) developing sufficient similarity methods to compare across complex mixtures, f) using systems-based approaches to evaluate mixtures, and g) focusing on management and integration of mixtures-related data.

OBJECTIVES

We aimed to describe NIEHS driven research on mixtures and combined exposures over the last decade and present areas for future attention.

RESULTS

Intramural and extramural mixtures research projects have incorporated a diverse array of chemicals (e.g., polycyclic aromatic hydrocarbons, botanicals, personal care products, wildfire emissions) and nonchemical stressors (e.g., socioeconomic factors, social adversity) and have focused on many diseases (e.g., breast cancer, atherosclerosis, immune disruption). We have made significant progress in certain areas, such as developing statistical methods for evaluating multiple chemical associations in epidemiology and building translational mixtures projects that include both in vitro and in vivo models.

DISCUSSION

Moving forward, additional work is needed to improve mixtures data integration, elucidate interactions between chemical and nonchemical stressors, and resolve the geospatial and temporal nature of mixture exposures. Continued mixtures research will be critical to informing cumulative impact assessments and addressing complex challenges, such as environmental justice and climate change. https://doi.org/10.1289/EHP14340.

Monitoring human exposure to four parabens and triclosan: comparing silicone wristbands with spot urine samples as predictors of internal dose

BACKGROUND

People are exposed to a variety of chemicals each day as a result of their personal care product (PCP) use.

OBJECTIVE

This study was designed to determine if silicone wristbands provide a quantitative estimate of internal dose for phenols commonly associated with PCPs, with a focus on triclosan and four parabens: methyl-, ethyl-, propyl-, and butylparaben. Uptake of these compounds into wristbands and correlations with internal dose were assessed.

METHODS

Ten adults from central North Carolina wore five silicone wristbands, with one wristband removed each day for 5 days. Each participant provided a 24 h urine sample and a random spot urine sample each day, in which paraben and triclosan metabolites were evaluated.

RESULTS

All parabens and triclosan were detected frequently in wristbands and, except for butylparaben, in urine samples. Wristband and spot urine concentrations of parabens and triclosan were both compared to a measurement of internal dose (i.e., the total metabolite mass excreted over 5 days as a measurement of internal dose).

IMPACT STATEMENT

The two most hydrophobic compounds investigated, butylparaben and triclosan, displayed significant linear uptake in wristbands over 5 days, whereas concentrations of methyl- and ethylparaben displayed a steady state concentration. In general, wristbands and spot urine samples were similarly correlated to internal dose for frequently detected parabens and triclosan.  However, wristbands have additional advantages including higher detection rates and reduced participant burden that may make them more suitable tools for assessing exposure to PCPs.

Associations between use of chemical hair products and epigenetic age: Findings from the Sister Study

Background

Hair products may be a source of harmful chemicals and have been linked to age-related health outcomes. We investigated whether the use of hair products is related to epigenetic age in a sample of Black (both Hispanic and non-Hispanic) and non-Hispanic White women.

Methods

In a subset of 4358 participants aged 35-74 years from the Sister Study, we estimated cross-sectional associations between self-reported use of four chemical hair products (permanent dye, semipermanent dye, straighteners/relaxers, and hair permanents/body waves) in the year before enrollment (2003-2009) and three DNA methylation-based measures of epigenetic age (DunedinPACE, GrimAge age acceleration [GrimAgeAccel], and PhenoAge age acceleration [PhenoAgeAccel]) using survey-weighted multivariable linear regressions. Associations were estimated both overall and by self-identified race and ethnicity, adjusting for chronological age, socioeconomic and lifestyle factors, body mass index, menopausal status, and DNA methylation platform.

Results

Associations between the use of hair products and the three epigenetic age measures were largely null. Use of hair permanents/body waves was modestly associated with higher DunedinPACE among all participants (βever-never = 0.010; 95% confidence interval [CI] = 0.001, 0.019) and with lower PhenoAgeAccel among Black women (βever-never = -1.53; 95% CI = -2.84, -0.21).

Conclusion

In this US-based study, we found little evidence of associations between chemical hair product use and epigenetic age in Black and non-Hispanic White women. Observed associations were modest and largely not supported by dose-response relationships or were inconsistent across epigenetic age measures. Previously observed associations between chemical hair product use and aging-related health outcomes may not be explained by the biological aging pathways captured by DunedinPACE, GrimAgeAccel, or PhenoAgeAccel. Alternative biological pathways are worth investigating in racially diverse samples.

Risk perception and use of personal care products by race and ethnicity among a diverse population

Personal care products can contain phthalates, parabens and other endocrine-disrupting chemicals. However, information on perception of risks from personal care product use and how use varies by race and ethnicity is limited. We evaluated differences in personal care product use and risk perception in a diverse sample of participants recruited from a US college campus and online. A self-administered questionnaire captured information on sociodemographic factors, personal care product use trends and perception of risk associated with them. Pearson's chi-square and Fisher's exact tests were used to determine differences in personal care product use and risk perception by race and ethnicity. Ordered logistic regressions were performed to measure associations between personal care product use frequency across racial/ethnic categories. Participant (n = 770) mean age was 22.8 years [standard deviation ± 6.0]. Daily use of make-up (eye = 29.3%; other = 38.0%; all = 33.7%) and skincare products (55%) was most frequently reported among Middle Eastern and North African participants. Non-Hispanic Black participants reported the highest daily use of hairstyling products (52%) and lotion (78%). Daily make-up use was more frequently reported among females (41%) than males (24.6%). Levels of agreement were similar across racial and ethnic groups, that personal care product manufacturers should be required to list all ingredients (≥87%). There were significant associations between the frequency of use of some personal care products and racial/ethnic categories when the use frequencies of participants from other racial/ethnic categories were compared to the use frequency of non-Hispanic White participants. There were significant differences in daily use frequency, levels of trust, perception of safety and health risks associated with personal care products by race and ethnicity, underscoring that there may be different sources of exposure to chemicals in personal care products by race and ethnicity.

A systematic review of association between use of hair products and benign and malignant gynecological conditions

Hair products often contain chemicals like para-phenylenediamine (PPD) and endocrine-disrupting chemicals (EDCs); giving rise to concerns about the possible adverse effects such as hormonal disturbances and carcinogenicity. The objective of this systematic review was to evaluate the association between the use of different hair products and benign and malignant gynecological conditions. Studies were identified from three databases including PubMed, Embase, and Scopus, and evaluated in accordance with PRISMA guidelines. The risk of bias was assessed using the Newcastle-Ottawa Scale. A total of 17 English-language studies met the inclusion criteria. Associations of hair relaxer or hair dye use with breast and ovarian cancer were observed in at least one well-designed study, but these findings were not consistent across studies. Further sub-analysis showed 1.08 times (95 % CI: 1.01-1.15) increased risk of breast cancer in females with permanent hair dye use. Chang et al. reported strong association between uterine cancer risk and hair relaxer use (HR 1.8, 95 % CI: 1.12-2.88), with no observed association with hair dye use. Studies conducted by Wise et al. and James-Todd et al. for benign gynecological conditions; including uterine leiomyoma (IRR 1.17, 95 % CI: 1.06-1.30), early onset of menarche (RR 1.4, 95 % CI: 1.1-1.9), and decreased fecundability (FR 0.89, 95 % CI: 0.81-0.98) revealed positive associations with hair relaxer use, but these findings were based on small sample sizes. In summary, the available evidence regarding personal use of hair products and gynecological conditions is insufficient to determine whether a positive association exists.

Gynecologic Care of Black Breast Cancer Survivors

Purpose of Review

Black patients suffer from breast cancer-related racial health disparities, which could have implications on their gynecologic care. This review explores considerations in the gynecologic care of Black breast cancer survivors.

Recent Findings

Black people have a higher risk of leiomyoma and endometrial cancer, which could confound bleeding patterns such as in the setting of tamoxifen use. As Black people are more likely to have early-onset breast cancer, this may have implications on long-term bone and heart health. Black patients may be more likely to have menopausal symptoms at baseline and as a result of breast cancer treatment. Furthermore, Black patients are less likely to utilize assisted reproductive technology and genetic testing services.

Summary

It is important for healthcare providers to be well-versed in the intersections of breast cancer and gynecologic care. Black breast cancer survivors may have unique considerations for which practitioners should be knowledgeable.

A Public Health Emergency: Breast Cancer Among Black Communities in the United States

While Black people have a similar incidence of breast cancer compared to White people, they have a 40% increased death rate. Black people are more likely to be diagnosed with aggressive subtypes such as triple-negative breast cancer. However, despite biological factors, systemic racism and social determinants of health create delays in care and barriers to treatment. While genetic testing holds incredible promise for Black people, uptake remains low and results may be challenging to interpret. There is a need for more robust, multidisciplinary, and antiracist interventions to reverse breast cancer-related racial disparities.

Incidence and health care burden of uterine fibroids among female service members in the active component of the U.S. Armed Forces, 2011-2022

Uterine fibroids are the most common benign tumors of the uterus among women of reproductive age, disproportionally affecting non-Hispanic Black women compared to other races and ethnicities. This report is an update of a 2011 MSMR report that examined uterine fibroids among female active component service members in the U.S. Armed Forces from 2001 to 2010. Incident uterine fibroids were identified for this report from inpatient and outpatient medical encounter data from 2011 to 2022. Health care burden was estimated utilizing uterine fibroid-related inpatient and outpatient diagnostic and procedure codes. Crude incidence rates and incidence rate ratios were calculated to compare rate differences between subpopulations. A total of 16,046 new uterine fibroid cases were identified, with an incidence rate of 63.5 cases per 10,000 person-years (95% confidence interval: 62.5-64.5). The highest incidence rates were observed among service women 40 years and older, non-Hispanic Black women, and those who served in the Army. Health care burden analysis showed that, even with increases in medical encounters and individuals affected, the numbers of hospital bed days declined over time. The decline in uterine fibroid-related hospital bed days could be attributed to early diagnoses and minimally-invasive treatments. Continued promotion of uterine fibroid awareness can potentially help further reduce uterine fibroid-related impacts on military readiness.

Broadening the Environmental Lens to Include Social and Structural Determinants of Women's Health Disparities

BACKGROUND

Due to the physical, metabolic, and hormonal changes before, during, and after pregnancy, women-defined here as people assigned female at birth-are particularly susceptible to environmental insults. Racism, a driving force of social determinants of health, exacerbates this susceptibility by affecting exposure to both chemical and nonchemical stressors to create women's health disparities.

OBJECTIVES

To better understand and address social and structural determinants of women's health disparities, the National Institute of Environmental Health Sciences (NIEHS) hosted a workshop focused on the environmental impacts on women's health disparities and reproductive health in April 2022. This commentary summarizes foundational research and unique insights shared by workshop participants, who emphasized the need to broaden the definition of the environment to include upstream social and structural determinants of health. We also summarize current challenges and recommendations, as discussed by workshop participants, to address women's environmental and reproductive health disparities.

DISCUSSION

The challenges related to women's health equity, as identified by workshop attendees, included developing research approaches to better capture the social and structural environment in both human and animal studies, integrating environmental health principles into clinical care, and implementing more inclusive publishing and funding approaches. Workshop participants discussed recommendations in each of these areas that encourage interdisciplinary collaboration among researchers, clinicians, funders, publishers, and community members. https://doi.org/10.1289/EHP12996.

Exploring the perspectives of underrepresented voices: Perceptions and experiences of uterine cancer for black African, Caribbean, black British, and mixed-black women in the UK to develop strategies for early symptom presentation

OBJECTIVES

The uterine cancer (UC) mortality rate in the UK is significantly higher for women who belong to a Black ethnic group compared to those from other ethnic groups. This study aimed to understand the views and experiences of UC amongst Black ethnic minority women in the UK, with a focus on awareness and presentation of red-flag symptoms.

METHODS

Women of Black African, Caribbean, Black British and Mixed-Black ethnicity were purposefully recruited to participate in focus groups and individual semi-structured interviews.

RESULTS

Twenty women from different regions in England participated in the study. Reflexive thematic analysis of the data led to the identification of three main themes: 1) Healthcare inequities; 2) Support and sense making with other Black women; and 3) Knowledge dissemination, mobilisation, and empowerment. Perceptions of inequitable healthcare provision and distrust influenced how participants, and their peer networks, approached seeking assistance from healthcare professionals. Concerns were also raised about culturally insensitive information resources, including issues of language, literacy, and representation, all of which served as potential barriers for women within Black ethnic minority groups.

CONCLUSIONS

The deficiency of targeted knowledge mobilisation and specific UC information aimed at Black ethnicity women living in the UK, reportedly contributes to the dissemination of misconceptions and an atmosphere of apprehension around a UC diagnosis. The insights from this study highlight the significance of designing culturally sensitive strategies to promote informed decision-making and empower the dissemination of accurate health knowledge amongst Black women.

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.

Beauty Beware: Associations between Perceptions of Harm and Safer Hair-Product-Purchasing Behaviors in a Cross-Sectional Study of Adults Affiliated with a University in the Northeast

(1) Background: Widespread personal care product (PCP) use can expose individuals to endocrine-disrupting chemicals (EDCs) associated with adverse health outcomes. This study investigated the association between harm perceptions and hair-product-purchasing behaviors in adults enrolled in a cross-sectional study. (2) Methods: Respondents rated their agreement with five PCP-related harm statements using a five-point Likert scale. Multivariable-adjusted logistic regression models were used to examine the associations between harm perceptions with hair-product-purchasing behaviors and hair product use (i.e., number of products used). (3) Results: Among 567 respondents (non-Hispanic White, 54.9%; non-Hispanic Black, 9.5%; Hispanic/Latinx, 10.1%; Asian American/Pacific Islander, 20.1%; and multiracial/other, 5.5%), stronger harm perceptions around PCP use were associated with potentially "safer" hair-product-purchasing behaviors. Respondents who strongly agreed that consumers should be concerned about the health effects of PCPs had more than fourfold increased odds of always/usually using healthy product apps (OR 4.10, 95% CI: 2.04-8.26); reading ingredient labels (OR 4.53, 95% CI: 2.99-6.87); and looking for natural, non-toxic, or eco-friendly product labels (OR 4.53, 95% CI: 2.99-6.88) when buying hair products. (4) Conclusions: Promoting environmental health literacy and raising awareness of potential PCP use-related harms might encourage healthier hair product use behaviors.

Assessment of personal care product use and perceptions of use in a sample of US adults affiliated with a university in the Northeast

Evidence supports unequal burdens of chemical exposures from personal care products (PCPs) among some groups, namely femme-identifying and racial and ethnic minorities. In this study, we implemented an online questionnaire to assess PCP purchasing and usage behaviors and perceptions of use among a sample of US adults recruited at a Northeastern university. We collected PCP use across seven product categories (hair, beauty, skincare, perfumes/colognes, feminine hygiene, oral care, other), and behaviors, attitudes, and perceptions of use and safety across sociodemographic factors to evaluate relationships between sociodemographic factors and the total number of products used within the prior 24-48 h using multivariable models. We also summarized participants' perceptions and attitudes. Among 591 adults (20.0% Asian American/Pacific Islander [AAPI], 5.9% Hispanic, 9.6% non-Hispanic Black [NHB], 54.6% non-Hispanic White [NHW], and 9.9% multiracial or other), the average number of PCPs used within the prior 24-48 h was 15.6 ± 7.7. PCP use was greater among females than males (19.0 vs. 7.9, P < 0.01) and varied by race and ethnicity among females. Relative to NHWs, AAPI females used fewer hair products (2.5 vs. 3.1) and more feminine hygiene products (1.5 vs. 1.1), NHB females used more hair products (3.8 vs. 3.1), perfumes (1.0 vs. 0.6), oral care (2.3 vs. 1.9), and feminine hygiene products (1.8 vs. 1.1), and multiracial or other females used more oral care (2.2 vs. 1.9) and feminine hygiene products (1.5 vs. 1.1) (P-values <0.05). Generally, study participants reported moderate concern about exposures and health effects from using PCPs, with few differences by gender, race, and ethnicity. These findings add to the extant literature on PCP use across sociodemographic characteristics. Improving the understanding of patterns of use for specific products and their chemical ingredients is critical for developing interventions to reduce these exposures, especially in vulnerable groups with an unequal burden of exposure.

Endometrial cancer risk and trends among distinct African descent populations

BACKGROUND

Endometrial cancer (EC) is the fourth most common cancer among Black women in the United States, a population disproportionately affected by aggressive nonendometrioid subtypes (e.g., serous, carcinosarcoma). To examine EC vulnerability among a wider spectrum of African descent populations, a comparison between Black women residing in different countries, rather than in the United States alone, is needed.

METHODS

The authors analyzed 34,789 EC cases from Florida (FL) (2005-2018), Martinique (2005-2018), and Guadeloupe (2008-2018) based on cancer registry data. Age-adjusted incidence rates, incidence rate ratios (IRRs), and annual percent changes (APC) in trends were estimated for Black populations residing in the United States (non-Hispanic Blacks [NHB]) and Caribbean. The US non-Hispanic White (NHW) population was used as a reference.

RESULTS

Caribbean Black women had the lowest rates for endometrioid and nonendometrioid subtypes. Nonendometrioid types were most common among US (FL) NHBs (9.2 per 100,000), 2.6 times greater than NHWs (IRR, 2.60; 95% confidence interval [CI], 2.44-2.76). For endometrioid EC, rates increased 1.8% (95% CI, 0.1-3.5) yearly from 2005 to 2018 for US (FL) NHBs and 1.2% (95% CI, 0.9-1.6) for US (FL) NHWs whereas no change was observed for Caribbean Blacks. For nonendometroid carcinomas, rates increased 5.6% (95% CI, 4.0-7.2) among US (FL) NHB, 4.4% (95% CI, 0.3-8.6) for Caribbean Black, and 3.9% for US (FL) NHW women (95% CI, 2.4-5.5).

CONCLUSIONS

Lower rates of nonendometrioid EC among Caribbean Black women suggest that vulnerability for these aggressive tumor subtypes may not currently be an overarching African ancestry disparity. Most importantly, there is an alarmingly increasing trend in nonendometrioid across all populations studied, which warrants further surveillance and etiological research for this particular subtype.

PLAIN LANGUAGE SUMMARY

We analyze population-based incidence rates and trends of endometrial cancer (EC) for African descent populations residing in different countries (i.e., United States, Martinique, Guadeloupe) to examine whether EC vulnerability among Black women is socio-environmental or more ancestry-specific in nature. The increased EC risk was not uniform across all Black women since the Caribbean had the lowest rates (for endometrioid and nonendometrioid histology subtypes). Regardless, from 2005 to 2018, there was an increasing trajectory of nonendometrioid EC for all groups, regardless of race.

The Person Beneath the Hair: Hair Discrimination, Health, and Well-Being

Discrimination toward black hair is pervasive in today's society. Hair discrimination is negative bias manifested toward black natural or textured hair styles typically worn by persons of African descent. This commentary discusses the potential effects of hair discrimination on the health and well-being of persons of African descent. Specifically, it explores the mental and physical health implications of hair discrimination and situates it within the broader context of social determinants of health. The Creating a Respectful and Open World for Natural Hair Act has been recently passed in the United States House of Representatives, but more work is needed to eliminate hair discrimination and its negative effects.

Use of Chemical Hair Straighteners and Fecundability in a North American Preconception Cohort

Chemical hair straighteners ("relaxers") are used by millions of North Americans, particularly women of color. Hair relaxers may contain endocrine-disrupting compounds, which can harm fertility. We evaluated the association between hair relaxer use and fecundability among 11,274 participants from Pregnancy Study Online (PRESTO), a North American preconception cohort study. During 2014-2022, participants completed a baseline questionnaire in which they reported their history of relaxer use and completed follow-up questionnaires every 8 weeks for 12 months or until pregnancy, whichever came first. We used multivariable-adjusted proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs). Relative to never use, fecundability was lower among current (FR = 0.81, 95% CI: 0.64, 1.03) and former (FR = 0.89, 95% CI: 0.81, 0.98) users of hair relaxers. FRs for first use of hair relaxers at ages <10, 10-19, and ≥20 years were 0.73 (95% CI: 0.55, 0.96), 0.93 (95% CI: 0.83, 1.04), and 0.85 (95% CI: 0.74, 0.98), respectively. Fecundability was lowest among those with longer durations of use (≥10 years vs. never: FR = 0.71, 95% CI: 0.54, 0.91) and more frequent use (≥5 times/year vs. never: FR = 0.82, 95% CI: 0.60, 1.11), but associations were nonmonotonic. In this preconception cohort study, use of chemical hair straighteners was associated with slightly reduced fecundability.

Exposomics as a tool to investigate differences in health and disease by sex and gender

The health and disease of an individual is mediated by their genetics, a lifetime of environmental exposures, and interactions between the two. Genetic or biological sex, including chromosome composition and hormone expression, may influence both the types and frequency of environmental exposures an individual experiences, as well as the biological responses an individual has to those exposures. Gender identity, which can be associated with social behaviors such as expressions of self, may also mediate the types and frequency of exposures an individual experiences. Recent advances in exposome-level analysis have progressed our understanding of how environmental factors affect health outcomes; however, the relationship between environmental exposures and sex- and gender-specific health remains underexplored. The comprehensive, non-targeted, and unbiased nature of exposomic research provides a unique opportunity to systematically evaluate how environmental exposures interact with biological sex and gender identity to influence health. In this forward-looking narrative review, we provide examples of how biological sex and gender identity influence environmental exposures, discuss how environmental factors may interact with biological processes, and highlight how an intersectional approach to exposomics can provide critical insights for sex- and gender-specific health sciences.

A Comprehensive Review of Mammalian Pigmentation: Paving the Way for Innovative Hair Colour-Changing Cosmetics

The natural colour of hair shafts is formed at the bulb of hair follicles, and it is coupled to the hair growth cycle. Three critical processes must happen for efficient pigmentation: (1) melanosome biogenesis in neural crest-derived melanocytes, (2) the biochemical synthesis of melanins (melanogenesis) inside melanosomes, and (3) the transfer of melanin granules to surrounding pre-cortical keratinocytes for their incorporation into nascent hair fibres. All these steps are under complex genetic control. The array of natural hair colour shades are ascribed to polymorphisms in several pigmentary genes. A myriad of factors acting via autocrine, paracrine, and endocrine mechanisms also contributes for hair colour diversity. Given the enormous social and cosmetic importance attributed to hair colour, hair dyeing is today a common practice. Nonetheless, the adverse effects of the long-term usage of such cosmetic procedures demand the development of new methods for colour change. In this context, case reports of hair lightening, darkening and repigmentation as a side-effect of the therapeutic usage of many drugs substantiate the possibility to tune hair colour by interfering with the biology of follicular pigmentary units. By scrutinizing mammalian pigmentation, this review pinpoints key targetable processes for the development of innovative cosmetics that can safely change the hair colour from the inside out.