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2025
Iran J of Pub Health
This study of nearly 5,000 U.S. women found that exposure to triclosan—an antibacterial chemical once commonly found in soaps, toothpaste, and other personal care products—was associated with more than double the breast cancer risk at moderate exposure levels, while propylparaben (a preservative in cosmetics and foods) showed a protective association. However, when researchers examined the combined effect of multiple phenols and parabens together, they found no significant association with breast cancer, suggesting these chemicals may have complex and sometimes opposing effects. These mixed findings highlight the need for more research to understand how individual chemicals versus chemical mixtures affect breast cancer risk, especially since people are typically exposed to multiple chemicals simultaneously in everyday products.
2025
Ecotoxicol Environ Saf
This study analyzed six xenoestrogens (hormone-disrupting chemicals including phthalates, BPA, and alkylphenols) in atmospheric particles at a university campus in China from 2021 to 2023. BPA was the most prevalent xenoestrogen detected, with concentrations of these chemicals being significantly higher in winter than summer, and the overall cancer and non-cancer health risks were below threshold limits for the general population. However, infants and young children showed significantly higher risk values compared to other age groups, indicating they face greater health risks from atmospheric exposure to these endocrine disruptors. The research provides important data for developing policies to reduce health risks from airborne xenoestrogen exposure, particularly for vulnerable populations like children.
2025
Environ Health
This case-control study of 942 Brazilian women (471 with breast cancer and 471 matched controls) found that higher blood levels of certain per- and polyfluoroalkyl substances (PFAS)—persistent environmental chemicals found in products like non-stick cookware and food packaging—were significantly associated with increased breast cancer risk. Specifically, elevated concentrations of n-perfluoroheptane sulfonate (n-PFHpS) doubled the breast cancer risk, and this association was particularly strong for hormone receptor-positive breast cancers and varied by ethnicity. The study emphasizes the importance of analyzing specific PFAS chemical variants (isomers) rather than treating all PFAS as identical, as different forms showed different associations with breast cancer risk across ethnic groups. These findings add to growing evidence that PFAS exposure may be a modifiable environmental risk factor for breast cancer, though the researchers note that previous studies have shown mixed results.
2024
Environ Health Perspect
A nationwide study using CDC biomonitoring data found that California’s Proposition 65, which requires warnings about chemicals that cause cancer or reproductive harm, led to reduced exposures to listed chemicals across the entire United States, not just California. While blood and urine concentrations of 37 monitored chemicals generally declined over time, the researchers found evidence of problematic chemical substitution—for example, after bisphenol A (BPA) was listed, its concentrations dropped 15% but levels of the unlisted substitute bisphenol S (BPS) increased 20%. Californians generally had lower levels of harmful chemicals in their bodies compared to residents of other states, suggesting the law had additional protective effects. The findings indicate that transparency laws like Prop 65 can drive manufacturers to reformulate products nationwide, but regulations need to address entire chemical classes rather than individual substances to prevent companies from simply switching to similar but unlisted toxic chemicals.
2024
Sci Total Environ
A Chinese study of 226 breast cancer cases and 990 controls found that exposure to certain perfluoroalkyl substances (PFAS), particularly perfluorononanoic acid (PFNA) and perfluoroheptanoic acid (PFHpA), was associated with increased mitochondrial DNA copy number (mtDNAcn) in blood, which in turn was linked to breast cancer risk. Women with the highest mtDNAcn levels had a 234% increased risk of breast cancer and a 271% increased risk of postmenopausal breast cancer compared to those with the lowest levels. The study found that mtDNAcn mediated about 15% of the relationship between PFHpA exposure and breast cancer, suggesting that PFAS may increase breast cancer risk partly by affecting mitochondrial function. These findings provide new insights into how PFAS chemicals may contribute to breast cancer development through effects on cellular energy production and mitochondrial health.
2024
Environ Res
A decade-long study of 135 breast cancer cases and 540 controls found that exposure to PFAS (perfluoroalkyl substances) was strongly associated with increased breast cancer risk, with mixed PFAS exposure showing more than double the odds of developing the disease. Several specific PFAS compounds—including PFBA, PFOS, PFHxS, and PFDA—were identified as particularly significant risk factors, with some associations appearing exclusively in premenopausal women. The findings suggest that premenopausal women should be especially cautious about PFAS exposure, as these persistent “forever chemicals” may pose a substantial breast cancer risk.
2024
Am J Epidemiol
This systematic review of 18 epidemiological studies evaluated whether exposure to PFAS—measured in blood or plasma—is associated with breast cancer risk. Across 11 of the studies included in the meta-analysis, higher concentrations of common PFAS such as PFOA and PFOS were not associated with increased breast cancer risk (per-log-unit RR for PFOA = 0.95, 95% CI: 0.77–1.18; PFOS = 0.98, 95% CI: 0.87–1.11). When analyses were restricted to studies where PFAS levels were measured before diagnosis, risk estimates were slightly higher (for PFOA: RR = 1.16, 95% CI: 0.96–1.40), but still not statistically significant. Overall, the evidence suggests that current PFAS exposures measured do not show a consistent link to breast cancer, though the authors note substantial study variability and the need for better prospective data.
2024
Sci Total Environ
This large prospective cohort study investigated the association between DEHP exposure and breast neoplasms in 273,295 women from the UK Biobank, using modeled DEHP levels from environmental data and Cox regression analysis. Results showed that higher baseline and long-term DEHP exposure was positively associated with increased risk of malignant neoplasm, carcinoma in situ, and benign breast neoplasms, with suggestive higher risk in younger women and oral contraceptive users.
2023
J Endocrinol Invest
A comprehensive literature review examining environmental endocrine-disrupting chemicals (EDCs) and hormone-related cancers concludes that several EDCs can be definitively classified as carcinogenic, including dioxin and cadmium for breast and thyroid cancer, arsenic and dioxin for prostate cancer, and organochlorines for testicular cancer. The review highlights that fetuses and newborns are most vulnerable to endocrine disruption, with adverse effects potentially manifesting at different ages throughout life, making it difficult to assess the full health impact of EDC exposure. The authors emphasize that EDCs represent a major environmental health issue requiring effective prevention policies, increased public awareness, and protective measures—particularly for pregnant women—along with standardized testing criteria to evaluate the carcinogenic potential of new chemicals before they enter widespread use.
2023
Int J Cancer
This study of over 1,200 postmenopausal women found that higher blood levels of PFOS (a common “forever chemical” found in items like stain-resistant fabrics and food packaging) were associated with 59-134% increased risk of hormone receptor-positive breast cancers, while PFOA (another widespread PFAS chemical) showed modest associations with hormone receptor-negative tumors. PFAS are called “forever chemicals” because they persist indefinitely in the environment and human body, and these findings suggest they may contribute to breast cancer through hormone disruption. These results add to growing concerns about PFAS exposure from contaminated water, food packaging, and consumer products, though the different associations for PFOS and PFOA by tumor subtype require further investigation to fully understand how these chemicals affect breast cancer development.
2023
Environ Sci Poll Res
This meta-analysis pooled data from 17 epidemiological studies to examine whether exposure to the dioxin compound 2,3,7,8-TCDD or to per- and polyfluoroalkyl substances (PFAS) is associated with breast cancer risk. The authors found evidence of a modest but statistically significant increased breast cancer risk associated with TCDD levels in the body,
2022
Crit Rev Food Sci Nutr
A systematic review of 131 epidemiological studies examining endocrine-disrupting chemicals (EDCs) and breast cancer risk found evidence that exposure to various EDCs—including pesticides (DDT/DDE, atrazine, dioxin), synthetic chemicals (BPA, phthalates, PFAS, PCBs, PBDEs), and other compounds found in everyday products—may elevate breast cancer risk, particularly when exposure occurs during early life. The review identified food as a major route of EDC exposure and emphasized that because most EDCs persist in the environment and accumulate in the body over time, long-term multi-generational health impacts need to be assessed. The authors call for improved exposure assessments of EDCs in food and food packaging, along with careful evaluation of their links to breast cancer development to inform policy-making and regulations aimed at protecting public health.
2022
Chemosphere
Researchers measured 41 endocrine-disrupting chemicals (EDCs) in women living in the Greater Manila Area, Philippines, comparing those with and without breast cancer. They found that certain perfluoroalkyl substances (PFAS) were significantly associated with breast cancer, with some chemicals showing dramatically increased risk: PFDoA was associated with a 1,263% increased risk, PFDA with an 826% increased risk, and PFHxA with a 166% increased risk. Long-chain PFAS levels were higher in women from heavily industrialized areas compared to the National Capital Region. This study provides the first baseline data on EDC exposure levels in Filipino women, filling a critical gap in knowledge about chemical exposures in Southeast Asian populations and suggesting that industrial pollution may be contributing to elevated PFAS levels and breast cancer risk.
2022
Toxics
A meta-analysis of eight studies examining the relationship between PFAS chemicals and breast cancer found that two specific PFAS compounds—PFOA and PFHxS—were associated with significantly increased breast cancer risk, showing 32% and 79% elevated risk respectively. Surprisingly, PFNA showed a protective association with 24% reduced risk, while PFOS showed no association with breast cancer risk, though all findings had substantial statistical heterogeneity between studies. The researchers concluded that certain PFAS compounds may be potential breast cancer risk factors, with concerning evidence that even low-level exposures could have harmful impacts on human health, highlighting the need for further research to clarify the varied effects of different PFAS chemicals on breast cancer development.
2022
Cancer Epiemiol
The first Indian case-control study examining phthalates (chemicals widely used in plastics, cosmetics, and food packaging) and breast cancer found that women with higher urinary levels of di-butyl phthalate (DBP) had 1.5 times increased breast cancer risk, while those with higher DEHP levels had nearly 3 times increased risk. Analysis of breast tumor tissue revealed mutations in several genes known to respond to phthalate exposure, affecting pathways involved in hormones, metabolism, and cancer development. These findings suggest that exposure to certain phthalates may increase breast cancer risk through genetic changes, though larger studies are needed to confirm these results and understand how early-life exposures might contribute to cancer development later in life.
2022
Environ Health
This large Chinese case-control study of 373 breast cancer patients and 657 controls found that higher plasma levels of PFOA and PFDA were positively associated with breast cancer risk, with PFOA showing particularly strong associations with hormone receptor-positive and HER2-positive breast cancers (47%, 36%, and 62% increased odds, respectively). Interestingly, the study found that PFTrDA (a longer-chain PFAS) was inversely associated with breast cancer risk, though the reasons for this protective effect are unclear. The findings add to growing international evidence linking PFAS exposure to breast cancer, demonstrating that these “forever chemicals” pose breast cancer risks not just in Europe and America but also in Asian populations. These results are concerning because PFOS was found at the highest concentrations in blood samples from both cases and controls, indicating widespread population exposure to these persistent environmental contaminants in Chin
2022
Environ Pollut
This Chinese prospective study of over 1,200 women found that higher baseline plasma concentrations of PFOA and PFHpA (a shorter-chain PFAS) were associated with 35% and 20% increased risk of developing breast cancer, respectively, with similar or stronger associations seen in postmenopausal women. When researchers examined the combined effect of all perfluorinated carboxylic acids together, they found a 19% increased breast cancer risk for each quartile increase in exposure, with PFOA accounting for more than half of this effect. Importantly, this is the first study to identify PFHpA—a shorter-chain PFAS increasingly used as a replacement for longer-chain compounds—as a breast cancer risk factor, raising concerns that newer “replacement” PFAS chemicals may not be safer alternatives. These prospective findings strengthen the evidence that PFAS exposure is a modifiable risk factor for breast cancer and support the need to regulate PFAS as an entire chemical class rather than individual compounds.
2022
Environ Res
This case-only study included 2,998 women with breast cancer from the Women’s Circle of Health Study and examined how characteristics of hair dye and hair relaxer use were related to tumor features. Compared with women who only used salon-applied permanent hair dye, those using home dye kits or both salon and home dye had higher odds of having poorly differentiated (more aggressive) tumors, especially among Black women (for Black women: home kits OR 2.22, 95% CI: 1.21–5.00; combination use OR 2.46, 95% CI: 1.21–5.00) and among women with ER-positive tumors (combination use OR 2.98, 95% CI: 1.62–5.49). Combination use of hair relaxers was also associated with larger tumors (>2.0 cm vs <1.0 cm; OR 1.82, 95% CI: 1.23–2.69). Although some associations did not remain statistically significant after strict multiple-comparison correction, the overall pattern suggests that frequent, mixed use of hair dyes and relaxers may be linked to more aggressive breast tumor characteristics.
2022
Chemosphere
This case-control study found that higher urinary bisphenol A (BPA) levels were significantly associated with increased breast cancer (BC) risk, with a 54% higher risk per 1-unit increase in log-transformed BPA (95% CI: 1.34–1.77, P < 0.001). Additionally, genetic variation in the CYP17A1 gene (rs743572) significantly modified this association, with individuals carrying both high BPA levels and the GA+AA genotype showing a 2.49-fold increased BC risk (P interaction = 0.020).
2021
Environ Res
This large U.S. study using NHANES data found that multiple PFAS chemicals were associated with increased odds of both breast and ovarian cancer, with dose-response relationships showing dramatically higher risks at the highest exposure levels—women in the highest quartile of exposure had 130% increased odds for breast cancer (up to 607% for PFHxS) and 77-125% increased odds for ovarian cancer compared to those in the lowest quartile. Different PFAS chemicals showed stronger correlations with different cancers: PFOA was most strongly correlated with breast cancer while PFHxS was most strongly correlated with ovarian cancer, suggesting these endocrine-disrupting chemicals may affect different hormone-sensitive tissues through distinct mechanisms. No associations were found with prostate or uterine cancers. These findings are particularly concerning because PFAS are ubiquitous environmental contaminants found in everyday products and the water supply, and the strong dose-response relationships suggest that reducing PFAS exposure could potentially lower the risk of these estrogen-related cancers in women.
2021
Cancer Epi
This study of nearly 48,000 women found that frequent use of chemical hair straighteners and perms during adolescence (ages 10-13) was associated with more than double the risk of premenopausal breast cancer, though no increased risk was seen for postmenopausal breast cancer. Black women who used permanent hair dye during adolescence had a 77% increased breast cancer risk, though permanent dye use was uncommon overall in the study population. The findings are particularly concerning because adolescence is a critical developmental window when breast tissue may be more vulnerable to chemical exposures, and these hair products contain hormonally active and potentially carcinogenic compounds that may have long-lasting effects on breast cancer risk decades later.
2021
Int J Cancer
In a nested case-control study of over 1,000 breast cancer cases and matched controls from the Multiethnic Cohort, pre-diagnostic urinary concentrations of bisphenol A (BPA), triclosan, and parabens were evaluated in relation to breast cancer risk. BPA was not significantly associated with risk; the highest tertile of total parabens had OR ≈ 0.77 (95% CI: 0.62–0.97) relative to the lowest tertile, indicating a modest inverse association. These results suggest that the relationships between common endocrine-disrupting chemicals and breast cancer may be more complex than anticipated and vary by exposure type.
2021
Sci Total Environ
This Japanese case-control study of 405 matched pairs of women found that higher serum concentrations of PFAS chemicals were generally associated with reduced breast cancer risk rather than increased risk, with women in the highest exposure quartile showing 79-85% lower odds of breast cancer for linear isomers of PFOS and PFOA. However, the study revealed important differences between chemical structures: among postmenopausal women, while the linear form of one PFAS (PFTrDA) was protective, the branched form showed a marginally increased risk (74% higher odds approaching significance at medium exposure levels). These unexpected inverse associations contrast with several other studies showing increased breast cancer risk from PFAS exposure, highlighting the complexity of PFAS research and the importance of distinguishing between different chemical structures (branched vs. linear isomers) that may have opposite health effects, though the reasons for these protective associations remain unclear and warrant further investigation.
2021
Int Arch Occup Environ Health
This case–control study in Northern Mexican women (394 breast cancer cases, 404 matched controls) measured urinary free-BPA (BPA‑F) and found that the highest exposure group had a statistically significant 2.31‑fold increased odds of breast cancer (95% CI: 1.43–3.74) compared to the lowest group. The authors concluded that BPA‑F may act as an environmental cofactor in breast carcinogenesis, although findings need replication.
2020
Int J Cancer
his French study of 388 women found that higher blood levels of PFOS (a “forever chemical”) were associated with 122-133% increased breast cancer risk for estrogen receptor-positive tumors and 147-176% increased risk for progesterone receptor-positive tumors, with a clear dose-response relationship showing increasing risk at higher exposure levels. Interestingly, the study found different patterns for hormone receptor-negative tumors, where only low-to-moderate levels of PFOS and PFOA were associated with dramatically increased risk (up to 1,440% for estrogen receptor-negative tumors at moderate PFOS levels). These findings suggest that PFAS chemicals—which are widespread in human blood worldwide due to contamination from products like stain-resistant fabrics, non-stick cookware, and food packaging—may contribute to breast cancer through different mechanisms depending on tumor type, highlighting the complexity of how these persistent environmental chemicals affect breast cancer risk.
2020
Environ Int
This Taiwanese study of 239 women found that higher plasma levels of PFOS (a “forever chemical”) were associated with 134% increased breast cancer risk in women aged 50 and younger, with each natural log unit increase in exposure more than doubling the odds of developing the disease. Both PFOS and PFHxS (another PFAS chemical) showed positive associations specifically with estrogen receptor-positive breast tumors in younger women, suggesting these endocrine-disrupting chemicals may particularly affect hormone-sensitive breast cancers during reproductive years. These findings are concerning because PFAS are ubiquitous environmental contaminants found in water, food packaging, and consumer products, and the study adds to growing evidence that these persistent chemicals may contribute to rising breast cancer rates among younger women. The results highlight the potential health consequences of widespread PFAS contamination, particularly for women of reproductive age who may face elevated risk of hormone-driven breast cancers.
2020
Int Arch Occup Environ Health
This Swedish study of 2,400 postmenopausal women found that those exposed to chemicals in the workplace had a 59% increased risk of breast cancer, with the risk increasing with longer duration of exposure. Women exposed to chlorinated hydrocarbon solvents or oil mist for more than 10 years had approximately triple the breast cancer risk compared to unexposed women. The study used individualized exposure assessments based on specific work tasks rather than just job titles, providing stronger evidence that workplace chemical exposures—particularly to organic solvents and oil mist commonly found in manufacturing and industrial settings—may be important contributors to breast cancer risk.
2019
Environ Int
This population-based case-control study investigated whether occupational exposure to alkylphenolic compounds—endocrine-disrupting chemicals widely used in industry—is associated with breast and prostate cancer. The study included over 5,600 participants and found that occupational exposure to alkylphenolic compounds was modestly associated with increased breast cancer risk (23% increase), particularly from exposure to domestic cleaning products and nonylphenol ethoxylates. No significant associations were found between alkylphenolic compound exposure and prostate cancer overall, except among men exposed through cosmetics and personal hygiene products. The authors conclude these findings suggest a modest link between occupational alkylphenolic compound exposure and breast cancer that requires further confirmation in additional studies.
2019
Environ Int
A population-based study of 711 breast cancer cases and 598 controls from the Long Island Breast Cancer Study Project measured seven urinary phenol biomarkers (environmental endocrine disruptors from personal care and consumer products) in spot urine samples collected within three months of diagnosis, with 17.6-year median follow-up identifying 271 deaths including 98 from breast cancer. The highest versus lowest quintiles of methylparaben, propylparaben, and sum of parabens (Σparabens) were associated with 31-50% increased breast cancer risk (ORs: 1.31-1.50) but paradoxically with 23-32% reduced all-cause mortality after diagnosis (HRs: 0.68-0.77), with associations for incidence stronger among women with BMI <25 kg/m² and associations for mortality stronger among women with BMI ≥25 kg/m². These findings—the first to examine phenol biomarkers in relation to both breast cancer incidence and subsequent mortality—reveal complex differential associations suggesting that select parabens may increase risk of developing breast cancer but be associated with better survival outcomes, though the mechanisms underlying these paradoxical associations remain unclear and may relate to BMI-dependent metabolic or hormonal factors, reverse causation, or unmeasured confounding.
2019
Int J Cancer
A large prospective study of 182,145 women in the Nurses’ Health Study found that higher fruit and vegetable consumption was associated with an 11% lower risk of invasive breast cancer, with the strongest benefits from cruciferous vegetables (like broccoli and cabbage) and yellow/orange vegetables (like carrots and squash). Women consuming more than 5.5 servings per day had significantly lower breast cancer risk compared to those eating 2.5 servings or less, with particularly strong protective effects against aggressive tumor types including estrogen receptor-negative (16% risk reduction per 2 additional servings/day), HER2-enriched (21% reduction), and basal-like (16% reduction) breast cancers. The protective associations were most pronounced for tumor subtypes that tend to be more aggressive and harder to treat. These findings suggest that a diet rich in fruits and vegetables, especially cruciferous and yellow/orange varieties, may help prevent breast cancer and particularly reduce the risk of developing more aggressive forms of the disease.
2018
Cancer Epidemiol Biomarkers Prev
This study examined how exposure to endocrine-disrupting chemicals (EDCs) during puberty affects breast tissue development in 200 Chilean girls by measuring urinary concentrations of phenols and phthalates at two stages of breast development and assessing breast density. The researchers found that certain phthalate metabolites were associated with increased breast density measures – specifically, higher levels of monocarboxyisooctyl phthalate were linked to 7% higher percent dense breast tissue, and monoethyl phthalate was associated with increased fibroglandular volume. Bisphenol A showed a U-shaped relationship with fibroglandular volume, where girls with middle-level exposures had at least 10% lower fibroglandular volume compared to those with low or high exposures. The findings suggest that developing breast tissue is vulnerable to certain EDCs during childhood and adolescence, which may have implications for future breast cancer risk since breast density is a known risk factor.
Cancer Epidemiol
A study of 46,709 women in the Sister Study found that use of permanent hair dye and chemical straighteners was associated with increased breast cancer risk, with particularly strong associations among Black women. Permanent hair dye use was linked to a 45% increased risk in Black women, while chemical straightener use showed an 18% increased risk overall, with higher risks associated with more frequent use. Women who applied semipermanent dyes to others showed a 28% increased risk. These findings suggest that endocrine-disrupting chemicals and carcinogens in hair products, which are often present at higher concentrations in products marketed to Black women, may contribute to breast cancer development.
2025
Int J Hyg Environ Health
New research highlights the link between endocrine-disrupting chemicals (EDCs) and earlier breast development in girls. A systematic review of 68 studies found that 10 out of 14 high-quality studies linked prenatal and postnatal exposure to EDCs like organohalogenated compounds and phthalates to earlier thelarche. With thelarche now occurring nearly three months earlier per decade, these findings raise serious concerns about long-term health risks, including breast cancer. Reducing exposure to harmful chemicals in everyday products is crucial to protecting hormonal health and preventing early puberty.
2025
Sci Totl Environ
This study investigated the effects of three common plastic additives (DEHP, BPA, and benzotriazoles) on Atlantic cod liver tissue using precision-cut liver slices exposed to various concentrations of these chemicals individually and in mixtures. The researchers found that BPA and chemical mixtures caused estrogenic effects, significantly increasing vitellogenin (a female egg protein) production and related gene expression in male juvenile cod. The study also observed changes in liver metabolism genes, with mixture exposures showing potentially different effects than individual chemical exposures. The results suggest these plastic additives can disrupt hormone systems in fish, with BPA being the primary driver of estrogenic effects, though the interaction effects between chemicals require further investigation.
2025
Sci Rep
A large U.S. study of 4,455 people found that exposure to triclosan (TRS)—an antibacterial chemical commonly found in soaps, toothpaste, and personal care products—was associated with more than double the risk of breast cancer at moderate exposure levels, with the relationship following an inverted U-shape pattern. The association was strongest among overweight individuals, people under 60 years old, and white participants, while other tested chemicals (including bisphenol A, benzophenone-3, and parabens) showed no significant link to breast cancer risk. These findings suggest that triclosan exposure may be an important modifiable risk factor for breast cancer, particularly for certain population groups, though more research is needed to understand the underlying mechanisms and confirm causality.
2025
J Hazard Mater
This study investigated whether DEHCH, a newly developed alternative plasticizer, has safer endocrine-disrupting effects compared to conventional phthalates and other alternative plasticizers using computer modeling, cell studies, and zebrafish testing. The researchers found that DEHCH showed lower binding affinity to hormone receptors and did not affect hormone-related gene expression or neurosteroid levels in zebrafish, unlike the other tested plasticizers. In contrast, conventional phthalates (DEHP, DINP) and previously proposed alternatives (DINCH, DEHTP) caused hyperactivity in zebrafish and altered hormone-related gene expression and neurosteroid concentrations. The results suggest that DEHCH may be a safer alternative to both conventional phthalates and previously proposed substitutes in terms of endocrine disruption and neurological effects.
2024
Environ Health Perspect
Researchers analyzed 279 chemicals known to cause mammary tumors in rodents and identified 642 additional chemicals that activate estrogen or progesterone signaling, finding that tumor-causing chemicals were significantly more likely to stimulate hormone production, activate estrogen receptors, or damage DNA—characteristics that likely increase breast cancer risk in humans. The study found that more mammary carcinogens worked by increasing hormone production than by directly activating estrogen receptors, with chemicals showing stronger hormone-disrupting effects being most likely to cause tumors, demonstrating a clear dose-response relationship. These findings suggest that hundreds of chemicals currently in use may pose unrecognized breast cancer risks and should not be assumed safe without specific testing for breast effects, with the strongest evidence chemicals prioritized for exposure reduction and improved testing methods needed to identify additional hazardous substances. The research provides a framework for identifying and regulating chemicals that may contribute to breast cancer through hormone disruption and genetic damage—mechanisms supported by both animal and human studies.
2024
Int J Env Res Pub Health
This study surveyed 746 Kenyan women about their hair product use and found that nearly 60% had used chemical relaxers and one-third had used hair dyes, despite many expressing concerns about health risks including breast cancer. Older women and those working in sales and service industries were more likely to use these products, which may contain endocrine-disrupting chemicals linked to breast cancer. Surprisingly, women’s awareness of potential health risks did not consistently lead to reduced use of these products, suggesting that concern alone may not be enough to change behavior. These findings are particularly important for Kenya, where breast cancer rates are rising, and highlight the need for better education about chemical exposures in hair products and strategies to reduce potentially harmful exposures.
2024
Environ Sci Technol
A study of 751 reproductive-aged Black women found that the relationship between personal care product (PCP) use and exposure to endocrine-disrupting chemicals (EDCs) varied significantly by socioeconomic status (SES), with different patterns of chemical exposure from the same products depending on women’s education, income, and employment. For example, vaginal powder use was associated with higher phenol exposure (a class of EDCs) among lower SES women but showed no such association in higher SES women, suggesting that product formulations, brands, or usage patterns may differ across SES groups. These findings highlight that Black women face inequitable EDC exposures that are influenced by both race and socioeconomic factors, underscoring the need for targeted public health interventions that address these intersecting disparities in chemical exposures from everyday products
2024
J Hazard Mater
A study analyzing 162 non-alcoholic beverages found that 63 endocrine-disrupting chemicals (EDCs) were present in 144 products, with concentrations highest in metal-canned beverages and significantly lower or absent in glass, plastic, and carton packaging. Bisphenol A (BPA) levels were notably elevated in canned drinks compared to identical products from the same manufacturers packaged in glass or plastic, and researchers identified two previously unknown BPA structural isomers in beverages for the first time. The calculated daily BPA exposure from average beverage consumption (364 mL/day) exceeded the European Food Safety Authority’s revised safety guideline by up to 2,000-fold, suggesting that regular consumption of canned non-alcoholic beverages—particularly by young children—poses a potential health hazard due to EDC exposure from packaging materials.
2024
PNAS
This study examined the health impacts of three major plastic-associated chemicals—BPA, DEHP, and PBDEs—across 38 countries representing one-third of the global population. The researchers found that in 2015, these chemicals were linked to approximately 5.4 million cases of heart disease, 346,000 strokes, 164,000 deaths among older adults, and 11.7 million lost IQ points in children due to prenatal exposure. The total economic cost of these health impacts was estimated at $1.5 trillion. The study suggests that if exposure levels had been reduced earlier, hundreds of thousands of deaths and millions of IQ points could have been prevented.
2024
Environ Res
Endocrine Disrupting Chemicals (EDCs)—including bisphenol A, phthalates, parabens, pesticides, and heavy metals commonly found in pharmaceuticals, cosmetics, and packaging—are widespread environmental pollutants that interfere with the body’s hormone system. Research shows EDCs have harmful effects on women’s reproductive health, contributing to conditions such as endometriosis, polycystic ovary syndrome, uterine fibroids, premature ovarian failure, menstrual irregularities, and infertility. This review emphasizes the need for healthcare professionals to consider environmental exposures when evaluating patients, highlights potential mechanisms by which EDCs affect female reproduction, and discusses how nutritional interventions and stricter environmental regulations could help reduce EDC-related health risks. Understanding the link between EDCs and women’s health is crucial for developing protective strategies, informing treatment approaches, and shaping public policies to safeguard reproductive and overall well-being. The study seeks to advise that couples attempting to conceive should avoid endocrine disrupting chemicals (EDCs) such as BPA, pesticides, and phthalates. Following this advice is found to be crucial during the prenatal and periconceptional periods, where fetal development and growth are critical in this window.
2024
Crit Rev Toxicol
A meta-analysis of 13 observational studies through May 2022 examined the dose-response relationship between per- and polyfluoroalkyl substances (PFAS) exposure—including PFOS, PFOA, PFNA, PFDA, and PFHxS—and risk of breast, prostate, colorectal, and ovarian cancers. The highest versus lowest exposure analysis found no significant associations between any PFAS compound and breast cancer (ORs ranging from 0.88-1.29), ovarian cancer (OR = 1.43), prostate cancer (OR = 1.05), or colorectal cancer (OR = 0.77). However, linear dose-response analysis revealed unexpected inverse associations, with each 1 ng/ml increase in PFNA and 2 ng/ml increase in PFOA associated with significant decreases in breast cancer risk (RR = 0.67 and 0.94, respectively), though non-linear analysis found no significant changes. The findings provide no evidence that PFAS exposure increases cancer risk for these sites, and the unexpected inverse associations observed in linear dose-response analyses—suggesting potential protective effects—are unexplained and may reflect study artifacts, reverse causation, or confounding factors rather than true biological protection, warranting further investigation to clarify these paradoxical relationships and determine whether they reflect real phenomena or methodological limitations.
2024
Environ Int
A study in mice found that exposure to DEHP—a common chemical used to make plastics flexible—disrupts the gut-mammary connection, causing changes in gut bacteria, intestinal inflammation, and direct damage to mammary (breast) tissue that could impair milk production. DEHP altered gut microbiome composition (increasing some bacteria while decreasing others), changed blood metabolite levels, and its breakdown product (MEHP) triggered cell death in mammary tissue through multiple pathways. These findings raise concerns about DEHP exposure from plastics affecting both human breast health and dairy production in livestock, while identifying potential therapeutic targets to counteract the chemical’s harmful effects on the gut-breast axis.
2024
Heliyon
A mouse study found that ginger volatile oil (GVO) reduced triple-negative breast cancer tumor growth in animals exposed to bisphenol A (BPA), a common plastic chemical known to promote cancer, with the effect linked to restoration of healthy gut bacteria. BPA exposure disrupted the gut microbiome by reducing bacterial diversity and beneficial bacteria like Lactobacillus, but treatment with ginger oil reversed these changes and increased the ratio of beneficial bacteria while decreasing harmful bacteria. The findings suggest that ginger compounds may counteract BPA’s cancer-promoting effects through their impact on the gut microbiome, offering a potential dietary strategy to mitigate harm from plastic chemical exposure, though human studies are needed to confirm these results.
2024
Environ Health Perspect
A mouse study examining DNA methylation changes from lead and DEHP (phthalate) exposure during pregnancy and early development found that the brain (cerebral cortex) showed the most epigenetic changes (66% for lead, 57% for DEHP), with alterations concentrated in gene regulatory regions that control gene expression. The research identified imprinted genes—particularly Gnas and Grb10—as targets of both chemical exposures across multiple tissues, with some DNA methylation signatures in blood matching those in target organs like liver and brain, suggesting blood tests could potentially detect toxic exposures affecting other organs. Notably, lead exposure caused consistent hypermethylation of the Grb10 gene’s control region in both blood and liver of male offspring, providing preliminary evidence that epigenetic changes in easily accessible blood samples might serve as biomarkers for chemical exposures affecting critical organs like the brain. These findings are significant for breast cancer prevention because early-life exposures to lead and phthalates can alter epigenetic programming in ways that may increase disease risk decades later, and identifying blood-based biomarkers could enable early detection of harmful exposures during vulnerable developmental windows.
2023
Environ Sci Technol
The following study discusses a strategic framework to improve how chemicals are managed in North America. The Essential-Use Approach is a policy that prioritizes restricting the use of chemicals based on necessity and safety. It proposes three guiding questions: Is the chemical essential to the product’s function? Is it the safest option? Is it necessary for health and safety? They also prioritize speed of assesments so that chemicals can be quickly phased out if evidence suggests danger to human health. This study is a call for change and aims to become a tool to simplify decision-making for regulating organizations, help businesses avoid liability related to harmful chemicals, and ultimately improve public health by ensuring only the safest substances are used in consumer products.
2023
Toxicol Sci
A high-throughput transcriptomic study using MCF-7 breast cancer cells exposed to BPA and 15 alternative chemicals (0.0005-100 µM for 48 hours) found that 8 alternative chemicals activated estrogen receptor alpha (ERα), with bisphenol AF identified as the most potent, followed by BPA and bisphenol C, and benchmark concentration analysis revealing that BPA and transcriptionally active alternatives enriched similar gene sets associated with increased cell division and cancer-related processes at comparable concentrations. Global transcriptomic and ERα-specific points of departure produced highly consistent potency rankings, and pathway analysis showed that active alternatives induced hazards similar to BPA through shared molecular mechanisms. These findings reveal that many BPA replacement chemicals used since initial 2010 Canadian regulatory action are not safer alternatives and may pose similar or greater hazards at comparable exposure levels despite being data-poor compounds with limited toxicological assessment, supporting the use of transcriptomic profiling for read-across risk assessment of structurally related chemicals and raising concerns about regrettable substitution in which one harmful chemical is simply replaced with equally harmful alternatives.
2023
Reprod Toxicol
A review of epidemiologic literature examining environmental chemical exposures during pregnancy and three maternal health outcomes (preeclampsia, gestational diabetes, and breast cancer) found that pregnancy represents a unique critical period when biological changes can heighten women’s susceptibility to chemicals from air, food, water, and consumer products—including flame retardants, plasticizers, pesticides, and lead—though research has disproportionately focused on fetal outcomes rather than maternal health risks, which remain poorly characterized for most chemicals. While evidence shows that lead exposure increases risk of pregnancy-induced hypertensive disorders and pregnancy can amplify women’s vulnerability to environmental chemicals, variations in study design, exposure assessment methods, and inconsistent adjustment for confounders limited comparability across studies. The authors emphasize that future research must recognize pregnancy as a critical window for women’s lifelong health, calling for incorporation of biomarkers of exposure and effect, deliberate timing and methods of measurement, and consistent confounder adjustment to strengthen understanding of the pregnancy exposome and its impacts on maternal health outcomes beyond the immediate postpartum period.
2023
Chemosphere
A community-based intervention study (REDUXE) examined the effects of discontinuing paraben and phthalate-containing personal care products over 28 days by collecting paired fine needle aspirates of breast tissue from healthy volunteers before and after intervention, finding striking reversal of cancer-associated phenotypes including PI3K-AKT/mTOR pathway alterations, autophagy, and apoptotic signaling networks, along with significant reductions in urinary paraben and phthalate metabolites. Post-intervention breast tissue showed “normalizing” changes in estrogen-modulated gene expression pathways, estrogen receptor alpha:beta ratios, and cell cycle S-phase fraction when treated with 17β-estradiol in vitro, demonstrating functional improvement in cellular responses. This paradigm-shifting study reveals that persistent exposure to xenoestrogens from daily-use personal care products produces unfavorable pro-carcinogenic cellular changes in human breast tissue that can be reversed through short-term avoidance, suggesting that reducing xenoestrogen exposure from consumer products may suppress cancer-promoting phenotypes and represents a viable approach for breast cancer prevention.