The effect of pre-pregnancy hair dye exposure on infant birth weight: a nested case-control study

Pre- and postnatal maternal hair dye use and risk of wheeze and asthma in 5-year-old Japanese children: the Kyushu Okinawa Maternal and Child Health Study

The present study investigated the association between pre- and postnatal maternal hair dye use and the risk of wheeze and asthma in Japanese children aged 5 years. Study participants were 1199 mother-child pairs. Information on the variables under study was obtained using repeated questionnaires completed by parents. Prenatal maternal hair dye use was associated with an increased risk of current wheeze and ever doctor-diagnosed asthma; the adjusted odds ratios (ORs) (95% confidence intervals [CIs]) were 1.44 (1.02-2.02) and 1.51 (1.00-2.25), respectively. Postnatal maternal hair dye use was related to the risk of doctor-diagnosed asthma; the adjusted OR (95% CI) was 1.58 (1.03-2.40). Children who were exposed to maternal hair dye use both prenatally and postnatally had an increased risk of childhood current wheeze and ever doctor-diagnosed asthma; the adjusted ORs (95% CIs) were 1.59 (1.03-2.42) and 1.76 (1.06-2.88), respectively. Our findings suggest that perinatal maternal hair dye use is associated with the risk of wheeze and asthma in children.

Dermatological adverse effects of hair dye use: A narrative review

Hair dyeing is a popular practice dating back to ancient Egyptian times. Initially, hair dye use was restricted to concealing grey and white hairs of the elderly population. However, in recent times, its use is common among the younger generation as a fashion statement. Hair dye contact dermatitis is a common dermatological condition encountered by dermatologists. It is a delayed type of hypersensitivity reaction that commonly affects the scalp and the vicinity of hair line and neck. Para-phenylenediamine (PPD), a synthetic aromatic amine is the most common allergen specifically implicated in hair dye contact dermatitis. Para-phenylenediamine was announced as the allergen of the year in 2006 by the American Contact Dermatitis Society. Contact allergy to para-phenylenediamine can occur in 0.1-2.3% of the general population. Epicutaneous patch testing is the gold standard test for the diagnosis of hair dye contact dermatitis. However, para-phenylenediamine carries a risk of cross-sensitivity and co-sensitization to other allergens. Apart from contact dermatitis, hair dye use is also associated with various other cutaneous adverse effects such as pigmentary changes, hair loss, skin malignancies and autoimmune disorders. Due to the various adverse effects associated with hair dye use, it is prudent to look for safer alternatives to allergenic hair dyes. In this article, we review the epidemiology, cutaneous and systemic adverse effects associated with hair dye use, patch testing, preventive strategies to minimize the risk of hair dye contact dermatitis, and treatment aspects.

Gender-specific effects of prenatal mixed exposure to serum phthalates on neurodevelopment of children aged 2-3 years:the Guangxi Birth Cohort Study

Phthalates have been shown to have adverse effects on neurodevelopment, which may be gender-specific. However, the association between prenatal mixed exposure to phthalates and children's neurodevelopment remains inconsistent. We measured 15 prenatal serum phthalate levels and evaluated children's neurodevelopmental indicators using Gesell Developmental Schedule (GDS) (n = 750). Generalized linear regression was fitted to examine the association. Among boys, mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP) had adverse effects on gross motor [odds ratio (OR): 7.38, 95% confidence interval (CI):1.42, 38.46]. For gross motor in boys, joint effect was discovered between mono-2-ethylhexyl phthalate (MEHP) and MEHHP. Moreover, synergistic effects were found for MEHP with vanadium and cadmium, and antagonistic effects for MEHP with magnesium, calcium, titanium, iron, copper, selenium, rubidium, and strontium. We did not find statistically significant relationships in girls. In the 1st trimester, adverse effects were identified between mono-2-ethyl-5-oxoyhexyl phthalate (MEOHP) and adaptation (P = 0.024), and monomethyl phthalate (MMP) with social area (P = 0.017). In the 2nd trimester, MEHHP had adverse effects on social area (P = 0.035). In summary, we found boys may be more vulnerable to the neurotoxicity than girls in gross motor, and we also discovered the detrimental effects of phthalates on children's neurodevelopment in the 1st and 2nd trimesters. Therefore, the supplementation of appropriate elements in the 1st and 2nd trimesters may help reduce the adverse effects of phthalates on children's neurodevelopment, especially among boys.

Hair Dye Ingredients and Potential Health Risks from Exposure to Hair Dyeing

Given the worldwide popularity of hair dyeing, there is an urgent need to understand the toxicities and risks associated with exposure to chemicals found in hair dye formulations. Hair dyes are categorized as oxidative and nonoxidative in terms of their chemical composition and ingredients. For several decades, the expert panel's Cosmetic Ingredient Review (CIR) has assessed the safety of many of the chemicals used in hair dyes; however, a comprehensive review of hair dye ingredients and the risk of exposure to hair dyeing has not been documented. Herein, we review the safety of the various chemicals in oxidative and nonoxidative hair dyes, toxicities associated with hair dyeing, and the carcinogenic risks related to hair dyeing. While many compounds are considered safe for users at the concentrations in hair dyes, there are conflicting data about a large number of hair dye formulations. The CIR expert panel has ratified a number of coloring ingredients for hair dyes and banned a series of chemicals as carcinogenic to animals and unsafe for this application. The use of these chemicals as raw materials for producing hair dyes may result in the synthesis of other contaminants with potential toxicities and increased risk of carcinogenesis. It is an open question whether personal or occupational hair dyeing increases the risk of cancer; however, in specific subpopulations, a positive association between hair dye use and cancer occurrence has been reported. To address this question, a better understanding of the chemical and mechanistic basis of the reported toxicities of hair dye mixtures and individual hair dye ingredients is needed. It is anticipated that in-depth chemical and systems toxicology studies harnessing modern and emerging techniques can shed light on this public health concern in the future.

Personal care products: Demographic characteristics and maternal hormones in pregnant women from Puerto Rico

Personal care products (PCPs) refer to a wide variety of items commonly characterized as health or beauty products. PCPs contain a number of ingredients, often including a wide range of endocrine disrupting chemicals such as phthalates and parabens. The present study examines the association between self-reported PCP use and prenatal sex-steroids and thyroid hormones levels in women from Puerto Rico. We recruited pregnant women (n = 1070) through the Puerto Rico PROTECT Cohort and collected blood, demographic and pregnancy-related data at recruitment and subsequent visits. PCP use in the 48-h preceding the blood sample was collected through self-reported questionnaires. Nine hormones (corticotropin-releasing hormone [CRH], sex-hormone binding globulin [SHBG], estriol [E3], progesterone, testosterone, thyroid-stimulating hormone [TSH], total triiodothyronine [T3], total thyroxine [T4], and free thyroxine [fT4]) were measured in maternal serum samples at two points during pregnancy. Linear mixed models with random intercepts were used to examine associations between PCP use and serum hormone levels. Use of cosmetics significantly increased with age, household income and education level (p < 0.01). Use of hair products, such as hair dyes and bleach, relaxers, and mousse, was associated with lower levels of all sex steroid hormones compared to non-use: SHBG (%Δ = -7.1, 95%CI: -12.4,-1.8), E3 (%Δ = -23.2, 95%CI: -32.2,-13.0), progesterone (%Δ = -21.5, 95%CI: -29.4,-12.9) and testosterone (%Δ = -21.5, 95%CI: -33.1,-7.8) adjusted for maternal age, education and pre-pregnancy body mass index. Our findings suggest that household income and education level influence PCP use among pregnant women in this study. Use of certain hair products was associated with lower concentrations of sex steroid hormones. Although there are limitations to questionnaire data, characterizing PCP use is inexpensive and may represent exposure from multiple classes of chemicals, including chemicals that may not specifically appear on product labels and/or have not been tested for endocrine disrupting potential, making it a useful complement to chemical biomarker data.

Endocrine disrupting chemical-associated hair product use during pregnancy and gestational age at delivery: a pilot study

BACKGROUND

Prenatal endocrine disrupting chemical (EDC) exposure has been associated with increased risk of preterm birth. Non-Hispanic Black women have higher incidence of preterm birth compared to other racial/ethnic groups and may be disproportionately exposed to EDCs through EDC-containing hair products. However, research on the use of EDC-associated hair products during pregnancy and risk of preterm birth is lacking. Therefore, the objective of this pilot study was to estimate associations of prenatal hair product use with gestational age at delivery in a Boston, Massachusetts area pregnancy cohort.

METHODS

The study population consisted of a subset of participants enrolled in the Environmental Reproductive and Glucose Outcomes (ERGO) Study between 2018 and 2020. We collected self-reported data on demographics and hair product use using a previously validated questionnaire at four prenatal visits (median: 12, 19, 26, 36 weeks' gestation) and abstracted gestational age at delivery from medical records. We compared gestational age and hair product use by race/ethnicity and used linear regression to estimate covariate-adjusted associations of product use and frequency of use at each study visit with gestational age at delivery. Primary models were adjusted for maternal age at enrollment and delivery method.

RESULTS

Of the 154 study participants, 7% delivered preterm. Non-Hispanic Black participants had lower mean gestational age at delivery compared to non-Hispanic White participants (38.2 vs. 39.2 weeks) and were more likely to report ever and more frequent use of hair products. In regression models, participants reporting daily use of hair oils at visit 4 had lower mean gestational age at delivery compared to non-users (β: -8.3 days; 95% confidence interval: -14.9, -1.6). We did not find evidence of associations at earlier visits or with other products.

CONCLUSIONS

Frequent use of hair oils during late pregnancy may be associated with shorter gestational duration. As hair oils are more commonly used by non-Hispanic Black women and represent potentially modifiable EDC exposure sources, this may have important implications for the known racial disparity in preterm birth.

Exposure to N-monoacetyl-p-phenylenediamine impaired ovarian function in mice

p-Phenylenediamine (PPD) is the main constituent of permanent hair dye and is also widely used in the photographic and rubber industries. PPD and its metabolites have been shown to increase the risk of cancer (especially ovarian cancer); however, their effect on female reproduction is unclear. We investigated the effects of the PPD metabolite N-monoacetyl-PPD (MAPPD) on mouse blastocyst development and ovarian function. Sixty 8-week-old female Kunming mice were administered at 0-, 100-, and 300-mg/kg/day MPPD by gavage for 28 days. KGN (human ovarian granulosa cells) were treated with MAPPD at concentrations of 0, 50, 100, and 300 μg/ml for 48 h. The number of abnormal blastocysts increased on gestation day 3.5 in all treatment groups. Compared with the control group, in MAPPD exposed group, the number of antral follicles decreased, the levels of E₂ and P₄ decreased in ovarian tissue, the serum levels of E₂ , P₄ , luteinizing hormone (LH), and T decreased, and follicle-stimulating hormone (FSH) increased. The expression of FSH receptor (FSHR) and LH receptor (LHR) was significantly downregulated, and the level of oxidative stress was significantly increased. In KGN cells, the level of reactive oxygen species increased in a dose-dependent manner, and the mRNA levels of FSHR, LHR, and aromatase increased. These results suggest that MAPPD inhibits FSH- and LH-induced aromatase activity by causing oxidative stress, which decrease hormone levels, leading to abnormal follicle development. Meanwhile, MAPPD exposure could affect early embryonic development abnormalities by affecting the quality of ovum.

Chemical/straightening and other hair product usage during childhood, adolescence, and adulthood among African-American women: potential implications for health

Few studies have characterized life course hair product usage beyond ever/never. We investigated hair product use from childhood to adulthood, usage patterns in adulthood, and socioeconomic status (SES) correlates among African-American (AA) women. Using self-reported data from 1555 AA women enrolled in the Study of Environment, Lifestyle, and Fibroids (2010-2018), we estimated the usage frequency of chemical relaxer/straightener (≥twice/year, once/year, and rarely/never) and leave-in/leave-on conditioner (≥once/week, 1-3 times/month, and rarely/never) during childhood, adolescence, and adulthood. Latent class analysis was used to identify patterns of adulthood usage of multiple hair products. SES was compared across latent classes. With a mean age of 33 ± 3.4 years, most women reported ever using chemical relaxers/straighteners (89%), and use ≥twice/year increased from childhood (9%) to adolescence (73%) but decreased in adulthood (29%). Leave-in/leave-on conditioner use followed the same pattern. Each of three identified latent classes reported frequent styling product use and infrequent relaxer/straightener use. Class One was unlikely to use any other products, Class Two moderately used shampoo and conditioner, and Class Three frequently used multiple product types (e.g., moisturizers and conditioners). Participants in the latter two classes reported higher SES. Ever/never characterization may miss important and distinctive patterns of hair product use, which may vary by SES.

Associations between multiple serum metal exposures and low birth weight infants in Chinese pregnant women: A nested case-control study

To investigate the associations between prenatal exposure to single metal and multiple metals and the risk of low birth weight (LBW), we conducted a nested case-control study of 246 LBW and 406 NBW mother-infant pairs based on a prospective birth cohort study. 22 serum metals were detected by inductively coupled plasma quadruple mass spectrometry (ICP-MS). Categorical analyses showed serum Co and Ti were associated with LBW (Co: 3rd vs 4th. quartile: OR = 1.83, 95%CI: 1.14-2.92, P_trend = 0.043; Ti: 2nd vs. 4th quartile: OR = 0.51, 95% CI: 0.32-0.81, P trend = 0.051), especially gestational age >13 weeks (Co: 3rd vs. 4th quartile: OR = 1.94, 95% CI: 1.13 - 3.32, Ptrend = 0.043; Ti: 2nd vs. 4th quartile: OR = 0.50, 95% CI: 0.30 - 0.84, P trend= 0.073). Cubic spline analyses showed serum Co and serum Ti had non-linearity associations with LBW (Co: P for overall = 0.048, P-nonlinearity = 0.014; Ti: P for overall = 0.015, P- nonlinearity = 0.008). In multi-metal compound exposure model, 15 metals selected by elastic net model were significantly associated with the increased risk of LBW and OR (95%CI) was 5.14 (2.81-9.40). Our study suggested that lower level serum Co was positively associated with LBW and lower level serum Ti was negatively associated with LBW, especially gestational age >13 weeks, and both of them had non-linearity dose-relationships with LBW. And multi-metal compound model was significantly associated with LBW compared with single metal model.

Serum multiple cytokines for the prediction of spontaneous preterm birth in asymptomatic women: A nested case-control study

BACKGROUND

Current biomarkers such as fetal fibronectin and cervical length are accurate predictors of spontaneous preterm birth (sPTB) in women with clinically suspected preterm risk; however, these are not effective for predicting the risk of sPTB in asymptomatic women. Therefore, we performed this study with the objective of determining whether the combinations of specific serum cytokines could accurately predict the sPTB risk in asymptomatic women.

METHODS

We conducted a nested case-control study with 129 incident sPTB cases and 258 individually matched controls who participated in an ongoing birth cohort study. The maternal serum levels of the selected 35 cytokines were measured. We evaluated the relationship between the multiple cytokines and sPTB risk using conditional logistic regression and elastic net model.

RESULTS

A panel of cytokines was significantly associated with an increased risk of sPTB. The odds ratio (OR) of sPTB per standard deviation (SD) increase of the predictive model score was 1.57 (95% CI 1.25-1.97) for the cytokines model. The combination of the selected serum cytokines was substantially more effective in predicting the risk for sPTB, as the receiver-operator characteristic curve (AUC) values were 0.546 and 0.559 in the single cytokine model and it improved to 0.642 in the multiple cytokines model (PAUC difference = 0.02 for TNF-α vs. multiple cytokines; PAUC difference = 0.05 for TRAIL vs. multiple cytokines). Moreover, the prediction was more accurate in overweight pregnant women, with an AUC = 0.879.

CONCLUSIONS

The current study suggested that the combination of selected serum cytokines can more effectively predict the risk of sPTB in asymptomatic women compared with the use of single cytokine.

The associations between maternal lifestyles and antenatal stress and anxiety in Chinese pregnant women: A cross-sectional study

The study aimed to investigate the associations between maternal lifestyles and antenatal stress and anxiety. 1491 pregnant women were drawn from the Guangxi birth cohort study (GBCS). A base line questionnaire was used to collect demographic information and maternal lifestyles. The Pregnancy Stress Rating Scale (PSRS) and Self-Rating Anxiety Scale (SAS) were used to assess prenatal stress and anxiety, respectively. Regression analyses identified the relationship between maternal lifestyles and prenatal stress and anxiety: (1) Hours of phone use per day was positively correlated to prenatal stress and anxiety and increased with stress and anxiety levels (all P trend < 0.05). In addition, not having baby at home was positively correlated to prenatal stress. (2) Self-reported sleep quality was negative with prenatal stress and anxiety, and decreased with stress and anxiety levels (all P trend < 0.01). Moreover, not frequent cooking was negatively correlated to prenatal stress and having pets was negatively correlated to prenatal anxiety (P < 0.05). However, having pets was not correlated to prenatal stress (P > 0.05). Our results showed that adverse lifestyles increase the risk of antenatal stress and anxiety, a regular routine and a variety of enjoyable activities decreases the risk of prenatal stress and anxiety.