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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
CA Cancer J Clin
Every two years, the ACS releases a report of updates on statistics on breast cancer among women. One in eight U.S. women will be diagnosed with invasive breast cancer, a 13% lifetime risk. From 2012 to 2021, diagnoses rose by 1% annually, with a 1.4% increase for women under 50. Asian American and Pacific Islander (AAPI) women saw the fastest rise in diagnoses. Despite a 44% drop in mortality since 1989, disparities persist—mortality rates remain highest among Black women, and there’s been no improvement for American Indian/Alaska Native women. These findings highlight the urgent need for equitable breast cancer diagnosis and treatment.
2024
BMC
A 2021 survey of over 5,000 U.S. women found that only about one-quarter were aware that alcohol consumption increases breast cancer risk, while 40% were unsure and over one-third believed there was no connection. Awareness was higher among younger women (18-25), college graduates, and those with alcohol use disorder symptoms, but lower among Black women compared to white women. These findings reveal a significant knowledge gap about an established and modifiable breast cancer risk factor, highlighting the need for targeted education campaigns to increase awareness across different demographic groups.
2024
Healthcare
This article highlights the disparities in the treatment of breast cancer based on various demographic factors. In terms of prevention and screening, people of minority groups such as African American and Hispanic women face challenges in accessing preventative measures like mammograms, mostly because of inequitable access to healthcare, financial constraints, and inadequate insurance coverage. These disparities also lead to delayed diagnoses and therefore worse outcomes in the treatment of these cancers. Additionally, provider bias, patient mistrust in the healthcare system, and systemic inequalities in the healthcare infrastructure cause inefficient treatment of breast cancer in these minority groups as well.
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.
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
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
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
Breast Cancer Res
A meta-analysis combining data from three cohort studies and one case-control study (3,793 estrogen receptor positive [ER+] and 627 ER- breast cancer cases) examined whether stopping alcohol consumption affects breast cancer risk by hormone receptor subtype. The study found that women who stopped drinking alcohol had a 12% lower risk of developing ER+ breast cancer compared to those who continued drinking (RR = 0.88), but cessation was not associated with reduced risk of ER- breast cancer (RR = 1.23). These findings suggest that quitting alcohol may reduce the risk of ER+ breast cancer specifically, which is noteworthy given that alcohol is an established risk factor for breast cancer, particularly hormone-receptor positive subtypes. The authors note that further research examining how long women have abstained from alcohol is needed to better understand the relationship between cessation duration and breast cancer risk.
2024
Front Glob Women’s Health
A systematic review of 51 studies (2 RCTs and 49 observational studies) examined the association between modern contraceptive use and the risk of breast and reproductive cancers in women of reproductive age. The review found that hormonal contraceptive use significantly reduced the risk of ovarian cancer by 36% and endometrial cancer, while cervical cancer rates were lower among contraceptive users compared to non-users; notably, no increased breast cancer risk was found among healthy women (RR 1.00), but BRCA1/2 mutation carriers using oral contraceptives showed a 39% increased risk of breast cancer. These findings highlight the complex cancer-related effects of hormonal contraceptives: while they offer protective benefits against ovarian and endometrial cancers for most women, BRCA mutation carriers face elevated breast cancer risk, emphasizing the need for personalized contraceptive counseling that accounts for individual genetic risk factors. The study underscores the importance of healthcare providers considering family history and genetic profiles when discussing contraceptive options with women, particularly those with hereditary cancer susceptibility.
2024
BMC Cancer
A case-control study of 133 breast cancer cases and 266 controls in Tehran, Iran used a food frequency questionnaire and the NOVA classification system to examine the association between processed foods (PFs) and ultra-processed foods (UPFs) consumption and breast cancer risk. In the initial model, women in the highest tertile of UPF consumption had nearly double the odds of breast cancer compared to the lowest tertile (OR = 1.93; 95% CI: 1.08-3.45), though this association was no longer significant after additional adjustments in a second model. However, when stratified by menopausal status, premenopausal women in the highest tertile of UPF consumption had more than 3.5 times higher odds of breast cancer (OR = 3.66; 95% CI: 1.33-10.08) in the fully adjusted model. These findings suggest that high consumption of ultra-processed foods may be particularly associated with increased breast cancer risk among premenopausal women, adding to the limited and sometimes contradictory evidence on the relationship between ultra-processed food intake and breast cancer.
2024
Ann Med
A study of 1,789 participants (including 263 breast cancer patients) from the National Health and Nutrition Examination Survey (NHANES) examined the associations between sleep duration, depression, and breast cancer risk, and developed machine learning algorithms to predict breast cancer. The study found that participants with depression had nearly double the odds of breast cancer (OR = 1.99; 95% CI: 1.55-3.51), while no significant association was observed between sleep duration (<7 hours, >9 hours compared to 7-9 hours) and breast cancer risk. Among six machine learning algorithms tested, the AdaBoost model performed best in predicting breast cancer with an area under the curve (AUC) of 0.84 (95% CI: 0.81-0.87), demonstrating good predictive capability. These findings suggest that depression, but not sleep duration, is significantly associated with increased breast cancer risk, providing new insights into the relationship between mental health and breast cancer while highlighting the need for further research into the underlying pathological mechanisms connecting depression and breast cancer development.
2024
Cancer Epidemiol
A large collaborative study of 609,880 women from 16 prospective studies, including 9,956 breast cancer cases before age 55, examined when the relationship between body mass index (BMI) and breast cancer risk transitions from protective (before menopause) to harmful (after menopause). During the critical age window of 45-55 years, the study found that a five-unit BMI increment remained associated with reduced or neutral breast cancer risk across all menopausal status groups: HR=0.87 for premenopausal women, HR=1.00 for women after natural menopause, HR=0.99 after interventional loss of ovarian function, and HR=0.88 after hysterectomy without bilateral oophorectomy. The findings indicate that the well-documented reversal from BMI being protective to being a risk factor for breast cancer occurs after age 55, later than previously thought, suggesting that the transition to increased risk with higher BMI is not directly tied to the menopausal transition itself but occurs in the years following menopause. This timing provides important insight into how adiposity influences breast cancer risk across the lifespan and suggests that the hormonal and metabolic changes associated with higher BMI have different effects on breast tissue depending on age and years since menopause.
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
Breast Cancer Res
A nested case-control study within the French E3N-Generations cohort examined 523 breast cancer cases and 523 matched controls to investigate whether thirteen metabolic health biomarkers mediate the relationship between exposure to three air pollutants (nitrogen dioxide, PCB153, and benzo[a]pyrene) and breast cancer risk. The study found that benzo[a]pyrene exposure was associated with a significant 2.32-fold increased breast cancer risk (highest vs. lowest quartile), PCB153 showed inconsistent positive associations, and nitrogen dioxide showed no association; among biomarkers, estradiol was associated with increased breast cancer risk (OR = 1.22 per SD). Four-way decomposition mediation analysis revealed suggestive evidence that albumin, HDL and LDL cholesterol, parathormone, and estradiol may partially mediate the associations between all three pollutants and breast cancer risk, though findings were limited by statistical power. These results provide preliminary mechanistic insights suggesting that air pollutants may influence breast cancer risk through alterations in metabolic biomarkers—particularly lipid metabolism and hormone regulation—though larger studies are needed to confirm these pathways and establish the clinical significance of these mediating effects in the relationship between environmental exposures and breast cancer development.
2024
Ecotoxicol Public Health
A case-control study of 758 women in southwestern Paraná, Brazil—a region with intensive pesticide use and 41% higher breast cancer rates than the national average—found that even women not working in fields but handling contaminated equipment and laundry tested positive for Glyphosate, atrazine, and 2,4-D. While the overall breast cancer risk association with pesticide exposure was non-significant after adjustment (OR = 1.30), exposed women had significantly higher risk of lymph node metastasis (OR = 2.19; 95% CI: 1.31-3.72), indicating more aggressive disease. These findings suggest pesticide exposure in agricultural communities may be associated with development of more aggressive breast cancer, highlighting the need for monitoring both occupational and household pesticide exposure in rural populations.
2024
Maturitas
A prospective study of 24,892 Spanish women (639 breast cancer cases) from the EPIC cohort examined associations between three dietary patterns (Western, Prudent, Mediterranean) and breast cancer risk over time. Women with moderate-to-high adherence to the Western dietary pattern showed a non-linear 37% increased breast cancer risk compared to those with lowest adherence (HR = 1.37; 95% CI: 1.07-1.77 for third quartile and HR = 1.37; 95% CI: 1.03-1.83 for fourth quartile), with particularly strong associations in postmenopausal women (HR = 1.42; 95% CI: 1.04-1.94 in highest quartile) and for ER+/PR+/HER2- tumors (HR = 1.71; 95% CI: 1.11-2.63 in highest quartile), while Prudent and Mediterranean patterns showed no clear associations. The findings suggest that Western dietary patterns characterized by high-fat dairy, red and processed meats, refined grains, sweets, caloric drinks, and convenience foods may increase breast cancer risk, especially for hormone receptor-positive tumors in postmenopausal women.
2024
J Women's Health
A prospective cohort study of 39,811 women followed for a median 25 years documented 2,830 breast cancer cases (including 237 deaths) and found that each additional alcoholic drink per day was associated with a 10% higher breast cancer rate (HR = 1.10; 95% CI: 1.04-1.16) in a linear dose-response manner, with the association significant for ER+ tumors (HR = 1.12; 95% CI: 1.06-1.18) but not ER- tumors (HR = 0.95; 95% CI: 0.82-1.10). Modeling 100,000 women over 10 years revealed that compared to rarely/never drinking, at-least-monthly consumption would result in 64 additional cases (NNH = 1,567) and >1 drink/day would result in 279 additional cases (NNH = 358), with approximately 4.1% of breast cancer cases attributable to alcohol consumption exceeding one drink per month. The study demonstrates that alcohol consumption increases breast cancer risk in a linear fashion even within recommended limits of up to one drink per day, particularly for ER+ tumors, and quantifies the substantial population-level burden of alcohol-attributable breast cancer among women.
2024
Maturitas
A comprehensive review of breast cancer disparities highlights that Non-Hispanic Black women experience markedly elevated breast cancer mortality due to multifactorial causes, including unique risk profiles such as higher prevalence of early-onset triple-negative breast cancer, specific reproductive risk factors, obesity patterns traced to infant feeding practices, and barriers to genetic risk assessment and high-risk referrals. The authors propose risk- and race-based screening strategies given the prevalence of aggressive early-onset disease in young Black women, emphasize the importance of early hereditary/familial risk identification while addressing challenges in interpreting uncertain genetic results, and stress the need for culturally sensitive approaches to healthy lifestyle promotion and clinical trial participation. Addressing breast cancer disparities requires tackling social determinants of health, educating patients and clinicians about factors driving outcome inequities, building trust to foster adherence and follow-up, and encouraging participation in targeted research to better serve all communities and reduce the disproportionate burden of breast cancer mortality in Black women.
2024
Environ Int
A study of 1,031 pregnant women from the socioeconomically diverse CANDLE cohort in the urban South found that ultra-processed foods constituted 38.6% of participants’ diets on average, with each 10% higher dietary proportion of ultra-processed foods associated with 13.1% higher urinary concentrations of DEHP phthalate metabolites, while specific foods like hamburgers, French fries, soda, and cake showed 6-10.5% higher DEHP per standard deviation increase in consumption. Causal mediation analyses revealed that lower income and education levels were associated with 1.9% and 1.4% higher DEHP exposure respectively, mediated through increased ultra-processed food consumption, indicating that ultra-processed foods contribute to socioeconomic disparities in phthalate exposure during pregnancy. The findings demonstrate that consuming ultra-processed foods increases exposure to endocrine-disrupting phthalates from food contact materials, and because socioeconomic barriers can prevent dietary modifications, policies to reduce phthalates in food packaging and processing are needed rather than relying solely on individual dietary recommendations to reduce prenatal phthalate exposures.
2024
Thorac Cancer
A study combining genetic analysis and bacterial sequencing in East Asian women found that specific oral bacteria may causally influence breast cancer risk, with 30 tongue bacteria and 37 saliva bacteria showing significant associations. The research identified seven bacterial genera present in both tongue and saliva samples that appear to affect breast cancer risk, and found that breast cancer patients had higher levels of certain bacterial families (Pasteurellaceae and Streptococcaceae) but lower levels of others (Bacteroidaceae) compared to healthy women. These findings suggest that the composition of bacteria in the mouth may not just be associated with breast cancer but could actually play a causal role in disease development, though more research is needed to understand the underlying mechanisms.
2024
Cancer Med
A mouse study found that exposure to bacterial toxins (lipopolysaccharides or LPS) during puberty—a critical period for breast development—caused lasting inflammation and changes in gene expression that increased breast cancer risk later in life. Researchers discovered that a prebiotic supplement derived from shiitake mushrooms (AHCC) could counteract these harmful effects by reducing inflammation, regulating immune signaling molecules, and blocking cancer-promoting gene activity in mammary tissue. The findings suggest that gut health and inflammation during puberty may influence long-term breast cancer risk, and that dietary interventions like prebiotics might offer a preventive strategy, though human studies are needed to confirm these results.
2024
Front Public Health
DDT, a highly persistent organochlorine pesticide comprising mainly p,p’-DDT (77%) and o,p’-DDT (15%), was widely used in agriculture and disease vector control with India being the primary consumer for malaria and leishmaniasis control, though global usage declined from ~5,388 metric tons annually (2001-2007) to ~3,772 metric tons (2008-2014) following the Stockholm Convention. As a xenoestrogen that bioaccumulates in fatty tissues and breast milk, DDT disrupts the endocrine system and enters the human circulatory system, causing reproductive toxicity, increased cancer risk (particularly threatening infants consuming contaminated breast milk), and carcinogenic effects, while also devastating wildlife populations through eggshell thinning in birds like pelicans and eagles. Prolonged DDT exposure causes cumulative toxicity that can alter morphogenesis, induce cancer, and cause reproductive system failure, yet its exceptional persistence and resistance to biodegradation means it continues to accumulate in the food chain and pose ongoing health threats despite reduced usage.
2024
Cancer Epidemiol Biomarkers Prev
While breast tissue was once thought to be sterile, the past decade has revealed it harbors unique bacterial communities, with growing evidence that breast tumor tissue has different microbiome compositions compared to healthy breast tissue. However, despite numerous studies examining breast cancer patients, research has been inconsistent in methodology and sample sizes, making it difficult to identify specific bacterial patterns reliably associated with breast cancer risk or outcomes. Only one large prospective study has linked breast microbiome composition to cancer prognosis, highlighting the need for larger, long-term studies to determine whether the breast microbiome could serve as a tool for predicting breast cancer risk, progression, or treatment response.
2024
Int J Mol Sci
This comprehensive review covers breast cancer biology from classification and risk factors through diagnosis and treatment, highlighting how the disease varies by subtype and between racial groups. The review examines both traditional factors like staging systems and molecular subtypes (Luminal A/B, Triple Negative, HER2-enriched) as well as emerging research on genetic mutations, epigenetic changes, and microbiome imbalances that may contribute to breast cancer development and progression. Recent evidence suggests that disruptions in the body’s microbial communities may play a role in breast cancer, with patterns potentially differing across populations, adding a new dimension to understanding racial disparities in breast cancer outcomes.
2024
Environ Toxicol Pharmacol
A comprehensive review examines endocrine-disrupting chemicals (EDCs) classified as carcinogens—compounds recognized for decades as top priority toxicants and persistent organic pollutants due to their ability to disrupt endocrine signaling—analyzing their hazard identification, human exposure routes, carcinogenic potency, and mechanisms of action across different organs. The review discusses major endocrine-disrupting carcinogens and their cancer-causing potential while identifying critical research gaps, methodological bottlenecks, and limitations in analytical detection techniques. This analysis underscores the serious public health concern posed by EDCs with carcinogenic properties, highlighting the need for improved understanding of their mechanisms, better analytical methods for detection and measurement, and addressing research limitations to protect human health from these ubiquitous environmental contaminants that can both disrupt hormonal systems and initiate cancer development.
2024
Breast Cancer Res
An ecological study using SEER Cancer Registry data examined correlations between alcohol consumption patterns and breast cancer diagnosed in women under age 40, accounting for a 10-year latency period and conducting cumulative 10-year aggregate exposure analyses. Both moderate (≥1 drink/day) and heavy (≥2 drinks/day) alcohol consumption were associated with 5% increased rates of early-onset Luminal A breast cancer (IRR = 1.05 for both), while binge drinking was associated with 6% increased rates of Luminal A BC in the lag model (IRR = 1.06; 95% CI: 1.02-1.11) and 4-5% increases in both Luminal A and Luminal B BC in cumulative models, with no associations found for ERBB2-enriched or triple-negative subtypes. These findings support the hypothesis that increasing alcohol consumption and binge drinking trends may be contributing to the observed rise in early-onset breast cancer among young U.S. women, particularly hormone receptor-positive Luminal A and B subtypes that have been increasing fastest in this population. The study highlights alcohol—especially binge drinking—as a modifiable risk factor that may be driving concerning upward trends in breast cancer incidence among young women, with effects appearing specifically for hormone-responsive cancer subtypes consistent with alcohol’s known estrogenic mechanisms.
2024
Cancer Med
A Mendelian randomization study using genetic variants associated with sedentary behaviors from genome-wide association studies examined causal relationships between leisure television watching, computer use, and cancer risk (breast, colorectal, prostate). Univariable analysis found that each 1-standard deviation (1.5 hours/day) increase in television watching increased breast cancer risk by 15% (OR=1.15; 95% CI: 1.05-1.26) and colorectal cancer risk by 32% (OR=1.32; 95% CI: 1.16-1.49) with little evidence for prostate cancer (OR=0.94; 95% CI: 0.84-1.06), but these associations were substantially attenuated and became non-significant after adjusting for years of education (breast cancer OR=1.08; colorectal cancer OR=1.08), suggesting education may act as both a confounder and mediator. The findings indicate that while sedentary television watching appears associated with increased breast and colorectal cancer risk in univariable analyses, these relationships are largely explained by educational attainment and associated lifestyle factors rather than representing direct causal effects of sedentary behavior itself, highlighting the need for future studies using objective exposure measures and better control for socioeconomic and lifestyle confounders to clarify whether sedentary behavior truly plays a causal role in cancer development.
2024
Br J Cancer
A large prospective study of 1,275,783 women aged 45+ years followed for a median 12.7 years from 2004 examined associations between menopausal hormone therapy (HT) types and breast cancer risk, finding that oral estrogen combined with daily progestin carried the highest risk (HR=2.42; 95% CI: 2.31-2.54), with drug-specific hazard ratios ranging from Cliovelle® (HR=1.63) to Kliogest® (HR=2.67), while vaginal estradiol showed no association with breast cancer. The associations varied substantially by molecular subtype (stronger for luminal A: HR=1.97 vs. other subtypes), detection mode (stronger for interval-detected: HR=2.00 vs. screen-detected cancers: HR=1.33 in women 50-71), and BMI (decreasing hazard ratios with increasing BMI). These contemporary findings confirm that oral and transdermal HT use increases breast cancer risk with important variation by specific formulations, administration routes, tumor characteristics, and patient factors, providing critical updated evidence for clinical decision-making about menopausal hormone therapy use and emphasizing the need for individualized risk-benefit assessment accounting for HT type, body weight, and cancer screening participation.
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.
2023
Environ Res
A nationwide Danish study of 55,745 breast cancer cases matched with controls found that each 10 μg/m³ increase in fine particulate matter (PM₂.₅) air pollution exposure over 20 years was associated with a 21% increased breast cancer risk, with the association particularly strong (32% increased risk) among women diagnosed before age 55. While elemental carbon and nitrogen dioxide also showed modest associations initially, these disappeared in multi-pollutant models, suggesting PM₂.₅ is the primary air pollutant linked to breast cancer risk. These findings add breast cancer to the growing list of cancers associated with air pollution exposure and suggest that younger women may be especially vulnerable, though the authors caution that unmeasured confounding factors may influence the results.
2023
JAMA Oncol
A retrospective analysis of 60,137 women with early-stage, ER-positive, node-negative breast cancer found that Black women had an 82% increased risk of breast cancer death compared to White women, with social determinants of health (neighborhood disadvantage and insurance status) mediating 19% of this disparity and tumor biological characteristics (including genomic recurrence scores) mediating 20%. When all factors were combined in a fully adjusted model, 44% of the racial survival disparity was explained, suggesting that social determinants and aggressive tumor biology contribute roughly equally to worse outcomes in Black women, though over half of the disparity remains unexplained. Notably, neighborhood disadvantage itself mediated 8% of racial differences in high-risk recurrence scores, indicating that social factors may influence tumor biology, and highlighting that addressing breast cancer disparities requires dual approaches targeting both structural barriers to healthcare access and quality while investigating the biological mechanisms—including ancestry-related genetic variants and molecular pathways—that may drive more aggressive disease in Black women.
2023
Cancer Epidemiol Biomark Prev
A pooled analysis of six European cohorts including 199,719 women followed for 3.6 million person-years found that long-term exposure to fine particulate matter (PM₂.₅) was associated with a 6% increased breast cancer risk per 5 μg/m³ increase. The association was strongest among middle-aged women (ages 50-54) and never-smokers, and notably, the cohorts studied represented the lower range of air pollution concentrations in Europe, suggesting that even relatively low levels of air pollution may contribute to breast cancer risk. These findings add to mounting evidence that air pollution—particularly fine particulate matter from traffic, industry, and combustion sources—is an environmental breast cancer risk factor operating independently of established risk factors, with important implications for public health policy, urban planning, and air quality regulations aimed at reducing population-level cancer burden, especially given that air pollution exposure is largely involuntary and affects entire populations.
2023
Environ Res
A meta-analysis of 17 epidemiological studies examining cadmium exposure and breast cancer risk found no statistically significant associations overall or when examining specific exposure routes separately (dietary cadmium or biomarker-based studies), with substantial heterogeneity between studies and no clear patterns by menopausal status. The inconclusive findings leave critical questions about whether specific exposure routes (occupational, air pollution, smoking) pose different risks than dietary intake or whether residual confounding by tobacco smoke constituents may influence observed associations. These results highlight the need for future research with better exposure assessment methods that can distinguish between different cadmium sources and routes of exposure, particularly occupational and environmental air pollution exposures that may be more relevant than diet for populations living near industrial areas where cadmium contamination is prevalent.
2023
Eur J Nutr
A large prospective cohort study of 67,879 French women followed for 21 years found that higher dietary inflammatory potential was associated with a 4% increased breast cancer risk per standard deviation increase in DII score, with women in the highest versus lowest quintile showing a 13% increased risk in a linear dose-response relationship. The association was slightly stronger among non-smokers (6% increased risk per standard deviation) and low alcohol consumers (5% increased risk per standard deviation), suggesting that inflammatory diet effects may be most pronounced in women without other pro-inflammatory exposures. These findings from one of the largest and longest prospective studies provide strong evidence that promoting anti-inflammatory dietary patterns—rich in fruits, vegetables, whole grains, legumes, nuts, and fish while limiting processed foods, red meat, refined carbohydrates, and saturated fats—could contribute meaningfully to breast cancer prevention as part of comprehensive public health strategies.
2023
Frontiers
A meta-analysis of 21 studies including 734,372 participants worldwide found that light at night (LAN) exposure was associated with a 12% increased breast cancer risk overall, with case-control studies showing 16% increased risk and cohort studies showing 8% increased risk. The association was particularly pronounced in Asian populations (24% increased risk) and for ER-positive breast cancers (10% increased risk), while outdoor LAN specifically showed a 7% increased risk. These findings support the hypothesis that artificial light exposure at night disrupts circadian rhythms and suppresses melatonin production—a hormone with anti-cancer properties—though the authors caution against taking melatonin supplements for prevention without medical advice until mechanisms are better understood, and emphasize the need for high-quality research accounting for environmental confounding factors to clarify the role of light pollution in breast cancer development.
2023
Cancer Epidemiol Biomark Prev
A systematic review and meta-analysis of 34 observational studies and 3 Mendelian randomization studies found that women with the highest levels of C-reactive protein (CRP)—a marker of systemic inflammation—had a 13% increased breast cancer risk compared to those with the lowest levels, though the quality of evidence was rated as very low to moderate. While adiponectin showed a protective association (24% reduced risk), this finding was not supported by genetic evidence from Mendelian randomization studies, and there was little evidence that other inflammatory markers like TNFα and IL-6 affected breast cancer risk. These findings suggest that while chronic low-grade inflammation measured by CRP may modestly increase breast cancer risk, the overall role of inflammation in breast cancer development remains unclear, with limited support beyond CRP—highlighting the need for higher-quality prospective studies and mechanistic research to clarify whether inflammation is truly causal or merely a marker of other underlying processes that drive breast carcinogenesis.
2023
Breast Cancer Res Treat
A study of 1,398 Black women (567 breast cancer cases, 831 controls) found preliminary evidence of gene-environment interactions between genetic variants in the mTOR signaling pathway and vigorous physical activity affecting breast cancer risk, though results did not survive correction for multiple testing. Specific variants in AKT1 were associated with 49-85% reduced ER-positive breast cancer risk only among physically active women, while an MTOR variant showed a 124% increased ER-positive cancer risk and an EIF4E variant showed dramatically elevated ER-negative cancer risk (over 20-fold), but only in the context of vigorous physical activity. These exploratory findings suggest that the relationship between physical activity and breast cancer may vary by genetic background in Black women, potentially explaining some of the heterogeneity in physical activity-breast cancer associations, though larger studies with multiple testing correction are needed to confirm whether these gene-exercise interactions truly modify breast cancer risk.
2023
Eur J Clinc Nutr
A prospective study of 65,574 postmenopausal French women followed for 20 years found that high adherence to a Paleolithic diet—characterized by high intake of fruits, vegetables, nuts, fish, and lean meat while limiting dairy, grains, legumes, refined sugar, and alcohol—was associated with a 17% reduced breast cancer risk compared to low adherence. Each standard deviation increase in Paleolithic diet score was associated with an 8% lower breast cancer risk, and notably, the protective association was consistent across all breast cancer subtypes, suggesting involvement of non-hormonal mechanisms. These findings provide the first long-term evidence linking Paleolithic dietary patterns to breast cancer prevention and suggest that this eating pattern—which emphasizes whole, unprocessed foods while restricting potentially inflammatory foods—may offer protective benefits beyond what has been observed with other dietary patterns, though further research is needed to identify the specific biological mechanisms involved.
2023
Occup Environ Med
A prospective cohort study of 33,359 Finnish public sector workers followed until 2016 found that shift work—both with and without night shifts—was associated with approximately double the breast cancer risk among women aged 50 or older after 10 or more years of follow-up (101% and 105% increased risk, respectively). However, no overall association was found when examining the entire cohort regardless of age or duration, and when historical shift work exposure data were available in a subgroup, the association with longer exposure duration was not statistically significant. These findings suggest that the breast cancer risk from shift work may primarily affect older women with prolonged exposure, though the authors acknowledge that incomplete information on the intensity and patterns of night work exposure may have weakened the observed associations.
2023
Ann Agric Environ Med
A case-control study of 111 postmenopausal women with breast cancer and 111 controls found that shift work was associated with a 165% increased breast cancer risk, but this risk was dramatically amplified by body weight status. Overweight shift workers showed a staggering 884% increased breast cancer risk compared to normal-weight women who had never worked shifts, indicating a powerful synergistic effect between shift work and excess body weight. With 72% of breast cancer cases having a history of shift work compared to 49% of controls, these findings suggest that the combination of circadian disruption from shift work and metabolic dysfunction from excess weight creates a particularly high-risk scenario, highlighting the urgent need for targeted prevention strategies—including weight management and lifestyle interventions—specifically for women working non-standard hours.
2023
Res Square
A study of 104 drinking water sources across Iranian cities found dangerous levels of arsenic and chromium exceeding safety standards in some locations, with the highest arsenic concentrations in Bashet (15.47 µg/L) and chromium in Behmai (292.21 µg/L), both significantly above acceptable limits. Health risk assessments showed that arsenic exposure in Bashet and chromium exposure in Behmai posed definite cancer risks (risk factors exceeding 1), with cancer risks from contaminated drinking water confirmed in multiple cities including Bashet, Gachsaran, and Behmai. These findings highlight a serious public health concern, as chronic exposure to these carcinogenic heavy metals through drinking water can increase risks for various cancers including breast cancer, underscoring the urgent need for water treatment interventions and alternative water sources in affected communities.
2023
Environ Pollut
A 2022 study tested 571 cash register receipts from U.S. retailers to assess endocrine-disrupting chemicals in thermal paper and compared findings to a 2017 study. Bisphenol S (BPS) was found in 85% of receipts, Pergafast 201 in 12%, and bisphenol A (BPA) in only 1%, indicating a shift away from BPA. National retailers were more likely than local ones to use non-bisphenol alternatives. These findings highlight potential health risks from handling receipts, as BPS and other chemicals can still pose significant exposure concerns.
2023
Endocrinology
Methylparaben (MP) and propylparaben (PP) are preservatives commonly found in food, and cosmetics which activate estrogen receptors (ER) in the body. Research shows that these parabens can promote mammary tumor growth and metastasis. This study tested female mice with exposure to MP and PP within levels deemed safe by the FDA. Even within FDA approved levels, there was significant increase in mammary tumor volume. Cellular analysis revealed that these parabens affected the expression of genes, some linked to breast cancer. This research highlights potential risks of parabens in promoting breast cancer.
2023
Sci Total Environ
In a transgenic mouse model (MMTV-Erbb2) that naturally develops mammary tumors, mice given oral cadmium (3.6 mg/L in drinking water for 23 weeks) developed palpable tumors significantly earlier and showed accelerated tumor growth compared with unexposed controls. Cadmium exposure increased the proliferation marker Ki-67, enhanced focal necrosis and new blood vessel formation in mammary tumors, and triggered greater intratumoral glutamine metabolism. Notably, disrupting gut microbiota with antibiotics delayed tumor onset and reduced tumor weight, implicating gut-microbiome–mediated metabolic reprogramming in cadmium-driven mammary tumorigenesis.
2023
Environ Sci Technol
This review investigates the migration of bisphenols and alternative color developers from thermal labels on cling-wrapped fresh food, identifying them as significant dietary sources of these compounds. While no BPA was found in packaging, high concentrations of bisphenol S (BPS) and other alternatives were detected, particularly in thermal labels. Migration studies revealed that BPS and related compounds leach into food, especially fish, raising potential health concerns. These findings highlight the need for further risk assessments regarding these alternative chemicals in food packaging due to past findings about BPA being an endocrine disruptor. This will help mitigate exposure risks and ensure consumer safety.
2023
Frontiers
This meta-analysis aimed to evaluate the association between exposure to endocrine-disrupting chemicals (EDCs), including phthalates and other common environmental pollutants, and breast cancer risk. The study found that certain EDCs—such as p,p′-DDT, chlordane, HCH, and specific PCBs—were positively associated with increased breast cancer risk, while a few compounds like BBP and PFDoDA showed a negative association.
2023
Breast Cancer Res
A study of over 3,000 Ghanaian women found that using insect repellent room sprays was associated with a 42% increased breast cancer risk compared to women who didn’t use any mosquito control products, while widely-used mosquito coils and insecticide-treated bed nets showed no significant association with breast cancer. The lack of association with bed nets and coils is reassuring given their critical importance for preventing malaria in regions where mosquito-borne diseases are a major health threat, but the findings regarding repellent sprays—used by about half of participants—require further investigation to understand which chemical ingredients may be driving the increased risk. The study had limited ability to assess repellent skin creams due to low usage, and researchers could not determine whether more frequent spray use increased risk, highlighting the need for additional research on insecticide exposures and breast cancer in low- and middle-income countries where these products are essential for disease prevention.
2023
Foods
A review of regulations for endocrine-disrupting chemicals and persistent organic pollutants in infant formula found that while breast milk remains the healthiest option, infant formula must be strictly monitored to ensure it is pollutant-free, particularly given the vulnerability of newborns to chemical exposures. Current regulations and upper limits for contaminants in infant formula vary worldwide, though standardized policies exist to protect infants, and continuous monitoring is required to maintain safety standards. The authors emphasize that risk assessment studies are limited but urgently needed to better understand exposure variations and evaluate the health risks infants face from dietary exposure to pollutants during this critical developmental period.
2023
Environ Health Perspect
A case-cohort study within the prospective Cancer Prevention Study II (CPS-II) LifeLink cohort examined associations between serum per- and polyfluoroalkyl substances (PFAS) concentrations and cancer risk by analyzing blood samples collected 1998-2001 from 999 randomly selected participants and 3,762 cancer cases (breast, bladder, kidney, pancreas, prostate, and hematologic cancers), with particular attention to histologic subtypes. The study found that higher serum PFOA concentrations were positively associated with renal cell carcinoma in women (HR per PFOA doubling: 1.54; 95% CI: 1.05-2.26) but not men, while higher PFHxS concentrations were associated with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) in men (HR per PFHxS doubling: 1.34; 95% CI: 1.02-1.75), with some variation in associations observed across histologic subtypes within cancer sites. These findings in a general population cohort support previous observations linking PFOA to kidney cancer in women and identify a new association between PFHxS and CLL/SLL in men, highlighting the importance of considering both sex differences and specific histologic cancer subtypes when evaluating PFAS-cancer relationships. The study demonstrates that PFAS exposure at levels found in the general U.S. population may be associated with increased risk of certain cancers, extending concerns beyond highly exposed occupational or community populations.