Research Results

Beta Version

Use the search bar below to find studies, or apply one or more filters to narrow your results. See our list of keywords to guide your search.

Search by keyword

Impact of Alcohol Consumption on Breast Cancer Incidence and Mortality: The Women’s Health Study.

Mostofsky et al,

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.

Hair Dye and Relaxer Use among Cisgender Women in Embu and Nakuru Counties, Kenya: Associations with Perceived Risk of Breast Cancer and Other Health Effects.

Llanos et al,

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.

Heavy-metal associated breast cancer and colorectal cancer hot spots and their demographic and socioeconomic characteristics.

Tomlinson et al,

2024

Cancer Causes Control

A population-based study using Kentucky cancer registry data (77,637 breast cancer and 56,598 colorectal cancer cases) found that higher ambient air concentrations of carcinogenic metals—cadmium, arsenic, nickel, and chromium(VI)—were associated with increased odds of residing in breast and colorectal cancer hotspots, independent of individual risk factors including age, race, smoking, and neighborhood socioeconomic characteristics. Cancer hotspot populations were disproportionately Black and exhibited markers of lower socioeconomic status, and importantly, the metal-cancer associations persisted even after adjusting for these factors, suggesting environmental metal exposure is an independent contributor to geographic cancer clustering. These findings provide evidence that historically marginalized communities face disproportionate exposure to carcinogenic metals through environmental pollution, likely contributing to cancer disparities, and underscore the urgent need for environmental justice interventions including stricter air quality regulations, cleanup of contaminated sites, and individual-level exposure assessments to fully understand how metal exposures drive cancer inequities in vulnerable populations.

Exposure to di-2-ethylhexyl phthalate (DEHP) increases the risk of cancer.

Yang et al,

2024

BMC Pub Health

This study used NHANES 2011–2018 data (n = 6,147) to evaluate the association between DEHP exposure and cancer risk. After adjusting for confounders, DEHP and its metabolites were significantly associated with increased risk of overall cancer prevalence, especially female reproductive system cancers (OR > 1.0, p < 0.05).

Exposure to Pesticides and Breast Cancer in an Agricultural Region in Brazil.

Panis et al,

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.

Increasing rates of early-onset Luminal A breast cancers correlate with binge drinking patterns.

Chen et al,

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.

Association between oral microbiome and breast cancer in the east Asian population: A Mendelian randomization and case-control study.

Feng et al,

2024

Thorac Cancer

Gut Health| Human| Mechanistic Studies| Microbiome

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.

Demographic disparities in the limited awareness of alcohol use as a breast cancer risk factor: empirical findings from a cross-sectional study of U.S. women.

Swahn et al,

2024

BMC

Alcohol| Human| Ethanol (alcohol)| Alcohol| Human Studies

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.

Ultra-processed and fast food consumption, exposure to phthalates during pregnancy, and socioeconomic disparities in phthalate exposures.

Baker et al,

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.

Disparities in Breast Cancer Care-How Factors Related to Prevention, Diagnosis, and Treatment Drive Inequity.

Wilkerson et al,

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.

The Genomic and Biologic Landscapes of Breast Cancer and Racial Differences.

Galappaththi et al,

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.

Light at night exposure and risk of breast cancer: a meta-analysis of observational studies.

Luo et al,

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.

Intestinal Vitamin D receptor protects against extraintestinal breast cancer tumorigenesis.

Zhang et al,

2023

Gut Microbes

A mouse study revealed that Vitamin D receptor (VDR) deficiency in the gut lining leads to bacterial imbalance (dysbiosis), increased intestinal permeability (“leaky gut”), and bacterial migration to breast tissue, significantly increasing breast tumor formation. Mice lacking intestinal VDR developed larger and more numerous breast tumors, with harmful bacteria like Streptococcus found in the tumor tissue, while beneficial bacteria that normally protect against cancer were depleted. However, treatment with butyrate (a beneficial bacterial byproduct) or the probiotic Lactobacillus plantarum reduced breast tumors by restoring gut barrier function and reducing inflammation, demonstrating a direct gut-breast axis. These findings suggest that maintaining gut health through adequate Vitamin D, beneficial bacteria, and a healthy microbiome may be a promising strategy for breast cancer prevention, though human studies are needed to confirm these results.

Cadmium exposure and risk of breast cancer: A meta-analysis.

Florez-Garcia et al,

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.

Linking Physical Activity to Breast Cancer via Inflammation, Part 2: The Effect of Inflammation on Breast Cancer Risk.

Lou et al,

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.

Dose-response Relationships Between Cigarette Smoking and Breast Cancer Risk: A Systematic Review and Meta-analysis.

Scala et al,

2023

J Epidemiol

A comprehensive systematic review and meta-analysis of 169 observational studies published through January 2020 examined the association between cigarette smoking and breast cancer risk using random-effects models and dose-response analyses. The pooled analysis found that current smokers had 7% increased breast cancer risk, former smokers 8% increased risk, and ever smokers 9% increased risk compared to never smokers, with results consistent across both case-control and cohort studies and across most covariates including genetic mutations (BRCA) and relevant polymorphisms. Importantly, breast cancer risk increased in a linear dose-response manner with both smoking intensity (12% increased risk for 20 cigarettes/day, 26% for 40 cigarettes/day) and duration (5% increased risk for 20 years, 11% for 40 years), demonstrating clear dose-response relationships. This large and comprehensive meta-analysis, which employed innovative search methods, provides strong evidence supporting a causal role of tobacco smoking in breast cancer development, resolving previous controversy on this association and establishing smoking as a modifiable risk factor for breast cancer with risks increasing proportionally to the amount and duration of smoking exposure.

Associations of Circulating Estrogens and Estrogen Metabolites with Fecal and Oral Microbiome in Postmenopausal Women in the Ghana Breast Health Study.

Wu et al,

2023

Microbiol Spectr

Gut Health| Hormones| Human| Mechanistic Studies| Microbiome

A study of 117 postmenopausal African women found significant links between blood levels of estrogens (hormones associated with breast cancer risk) and the composition of bacteria in both the gut and mouth. Higher levels of certain estrogens were associated with greater diversity of gut bacteria, while specific estrogen byproducts were linked to differences in oral bacteria composition, including bacterial families known to help metabolize estrogens. These findings suggest that gut and oral bacteria may influence breast cancer risk by affecting how the body processes estrogens, though larger studies are needed to confirm how these relationships develop over time.

mTOR pathway candidate genes and physical activity interaction on breast cancer risk in black women from the women’s circle of health study.

Ilozumba et al,

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.

Reduction of daily-use parabens and phthalates reverses accumulation of cancer-associated phenotypes within disease-free breast tissue of study subjects.

Dairkee et al,

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.

Dietary Inflammatory Index and risk of breast cancer: evidence from a prospective cohort of 67,879 women followed for 20 years in France.

Hajji-Louati et al,

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.

Ethylene oxide emissions and incident breast cancer and non-Hodgkin lymphoma in a US cohort.

Jones et al,

2023

J Natl Cancer Inst

A large cohort study of 451,945 National Institutes of Health-AARP Diet and Health Study participants used EPA Toxics Release Inventory data to estimate historical environmental ethylene oxide (EtO) exposures based on proximity to EtO-emitting facilities, wind patterns, and emission levels from enrollment in 1995-1996. Among 173,670 postmenopausal women, living within 10 km of EtO facilities was associated with statistically significant breast cancer risk for invasive disease (HR = 1.03; 95% CI: 0.97-1.09); women in the highest quartile of the airborne emissions index showed elevated risk of in situ breast cancer at 10 km (HR = 1.25; 95% CI: 1.02-1.53), with no clear patterns for non-Hodgkin lymphoma risk. These findings reveal a novel potential association between environmental EtO exposure and in situ breast cancer—but not invasive breast cancer or lymphohematopoietic cancers—contrasting with occupational studies that found associations with invasive disease. The differential association with in situ versus invasive disease suggests EtO may influence early-stage breast carcinogenesis, though the mechanism remains unclear and warrants further investigation to understand why environmental exposures show different patterns than occupational exposures and why the effect appears limited to pre-invasive lesions.

Case-Cohort Study of the Association between PFAS and Selected Cancers among Participants in the American Cancer Society’s Cancer Prevention Study II LifeLink Cohort.

Winquist et al,

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.

Endocrine-Disrupting Chemicals and Persistent Organic Pollutants in Infant Formulas and Baby Food: Legislation and Risk Assessments.

Hatzidaki et al,

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.

Association between Gut Microbiota and Breast Cancer: Diet as a Potential Modulating Factor.

Altinok Dindar et al,

2023

Nutrients

A case-control study of 42 newly diagnosed, treatment-naïve breast cancer patients and 44 age-matched cancer-free controls at Oregon Health & Science University (2020-2021) found reduced gut microbial diversity in breast cancer patients and enrichment of three specific bacterial genera—Acidaminococcus, Tyzzerella, and Hungatella—in fecal samples from cases, with these genera associated with distinct dietary patterns including vegetables and dairy (Hungatella) and whole fruits (Acidaminococcus). Breast cancer patients also had significantly higher BMI and lower physical activity levels, and microbiome analysis revealed significant differences in composition between cases and controls using 16S rRNA sequencing. These findings highlight complex interactions between the gut microbiome, dietary habits (assessed via National Cancer Institute Diet History Questionnaire), lifestyle factors like weight management and physical activity, and breast cancer risk, suggesting the gut microbiome may serve as a source of biomarkers for breast cancer risk assessment, though larger studies are needed to establish causal relationships and validate these microbial signatures.

Endocrine-disrupting chemicals and breast cancer: a meta-analysis.

Liu et al,

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.

Chronic Exposure to Low Levels of Parabens Increases Mammary Cancer Growth and Metastasis in Mice.

Tong et al,

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.

Air pollution with NO(2), PM(2.5), and elemental carbon in relation to risk of breast cancer- a nationwide case-control study from Denmark.

Poulsen et al,

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.

Association of Social Determinants and Tumor Biology With Racial Disparity in Survival From Early-Stage, Hormone-Dependent Breast Cancer.

Hoskins et al,

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.

Exposure to pesticides and breast cancer in the city of Petrópolis, Brazil.

de Rezende et al,

2023

Environ Sci Pollut Res

A hospital-based case-control study in Petrópolis, Brazil found that women exposed to pesticides for 10 or more years had elevated but non-significant breast cancer risk after adjusting for confounders (OR = 1.40; 95% CI: 0.85-2.49), while higher education and hormone replacement therapy showed significant positive associations, and having 2+ pregnancies was protective. The authors conclude that further research is needed to clarify pesticide exposure’s contribution to breast cancer development given conflicting findings in the literature.

FokI polymorphism of Vitamin D receptor gene and deficiency of serum Vitamin D increases the risk of breast cancer in North Indian women.

Chakraborty et al,

2023

Endocrine

A case-control study in North India found that breast cancer patients had significantly lower serum Vitamin D levels than healthy controls, with women in the highest Vitamin D quartile having 59% lower breast cancer risk than those in the lowest quartile (OR = 2.44; 95% CI: 1.09-5.45); additionally, women with the polymorphic T allele for VDR FokI genotype (CT/TT) had over 4-fold increased breast cancer risk compared to those homozygous for the wild C allele (OR = 4.30; 95% CI: 2.21-8.35). Vitamin D levels were significantly higher in ER+ patients and significantly lower in advanced-stage cancers, suggesting Vitamin D may serve as both a risk factor and prognostic marker. The study concludes that FokI polymorphism of the VDR gene and low circulating Vitamin D levels independently increase breast cancer risk in North Indian women.

Breast Cancer Incidence in Relation to Long-Term Low-Level Exposure to Air Pollution in the ELAPSE Pooled Cohort.

Hvidtfeldt et al,

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.

Palaeolithic diet score and risk of breast cancer among postmenopausal women overall and by hormone receptor and histologic subtypes.

Shah et al,

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.

Shift work with and without night shifts and breast cancer risk in a cohort study from Finland.

Härmä et al,

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.

Shift work, body mass index and associated breast cancer risks in postmenopausal women.

Świątkowska et al,

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.

Mosquito control exposures and breast cancer risk: analysis of 1071 cases and 2096 controls from the Ghana Breast Health Study.

Olivos et al,

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.

The impact of social and environmental factors on cancer biology in Black Americans.

Lord et al,

2023

Cancer Causes Control

A review examining how low socioeconomic status (SES) contributes to early chronic disease onset and reduced life expectancy found that neighborhood-level factors—including environmental pollutants, deprivation, social isolation, structural racism, and discrimination—create chronic life stress that affects molecular processes like DNA methylation, inflammation, and immune response, contributing to more aggressive tumor biology, particularly in Black Americans. Despite decades of research showing associations between neighborhood factors and cancer outcomes in marginalized communities, the biological mechanisms linking SES to cancer disparities remain poorly understood, though emerging evidence suggests chronic stress pathways may play a central role. The authors summarize current methods for measuring neighborhood-level deprivation, discrimination, and structural racism in cancer disparities research and recommend adopting a multi-faceted intersectional approach to reduce cancer health inequities and develop effective interventions promoting health equity.

Redlining-associated methylation in breast tumors: the impact of contemporary structural racism on the tumor epigenome.

Miller-Kleinhenz et al,

2023

Front Oncol

A study of 80 Black and White women with breast cancer at Emory University Hospitals (2008-2017) examined associations between contemporary neighborhood redlining—a structural racism measure derived from Home Mortgage Disclosure Act data—and DNA methylation patterns in breast tumor tissue. Contemporary redlining was significantly associated with aberrant methylation at 5 CpG sites (FDR<0.10) in genes implicated in breast carcinogenesis, inflammation, immune function, and stress response (ANGPT1, PRG4), with additional top sites showing interaction by ER status and association with mortality; redlining was also associated with epigenetic age acceleration (β=5.35; 95% CI: 0.30-10.4 by Hannum metric). These novel findings suggest that structural racism—manifested through discriminatory housing policies leading to inequitable social and environmental exposures—may biologically embed in the breast tumor epigenome through altered DNA methylation patterns, potentially contributing to documented racial disparities in breast cancer outcomes and highlighting the need for further research on epigenetic mechanisms linking neighborhood-level structural racism to cancer prognosis.

Dietary inflammatory index and breast cancer risk: an updated meta-analysis of observational studies.

Hayati et al,

2022

Nutr Cancer

An updated meta-analysis of 21 studies including over 346,000 participants found that the most pro-inflammatory diets were associated with a 16% increased breast cancer risk overall, with particularly strong associations among postmenopausal women (13% increased risk), obese women with BMI ≥30 kg/m² (35% increased risk), and populations in developing countries (79% increased risk). The analysis revealed important methodological influences on effect estimates, with stronger associations observed in case-control studies (50% increased risk), studies using hospital-based controls (111% increased risk), and cohort studies with prolonged follow-up (13% increased risk). These findings not only confirm that pro-inflammatory dietary patterns increase breast cancer risk but also demonstrate that the magnitude of association varies substantially by population characteristics and study design, with obesity and postmenopausal status appearing to amplify the carcinogenic effects of inflammatory diets—suggesting that anti-inflammatory dietary interventions may be particularly beneficial for overweight/obese postmenopausal women and populations in developing countries where rapid dietary transitions toward processed, inflammatory foods are occurring.

Breast Cancer Among Female Flight Attendants and the Role of the Occupational Exposures: A Systematic Review and Meta-analysis.

Weinmann et al,

2022

J Occup Environ Med

A systematic review and meta-analysis of 9 studies found that female flight attendants had a 43% increased breast cancer incidence compared to the general population, but surprisingly, neither cosmic radiation exposure nor circadian rhythm disruption—the two primary occupational hazards hypothesized to drive this excess risk—showed clear associations with breast cancer in the available studies. Three studies suggested a possible link with cosmic radiation while none found associations with circadian disruption, leaving the underlying cause of the elevated breast cancer risk among flight attendants unexplained. These findings highlight a critical gap in occupational health research: while flight attendants clearly face elevated breast cancer risk, the mechanisms remain unclear, potentially involving unmeasured factors such as reproductive patterns (delayed childbearing, fewer children), lifestyle factors associated with the profession, cumulative effects of multiple low-level exposures, or limitations in exposure assessment methods—underscoring the urgent need for studies with detailed individual-level data on occupational exposures, work schedules, and lifestyle factors to identify modifiable risk factors for this vulnerable workforce.

Association between fertility treatments and breast cancer risk in women with a family history or BRCA mutations: a systematic review and meta-analysis.

Liu et al,

2022

Front Endocrinol

A meta-analysis of 8 studies (5 cohort and 3 case-control studies) examined whether fertility treatments increase breast cancer risk in genetically susceptible women, including those with a family history of breast cancer or BRCA mutations. The analysis found no significant increase in breast cancer risk associated with fertility treatments in genetically susceptible women overall (OR 1.18), women with a family history of breast cancer (OR 1.35), or BRCA mutation carriers (OR 1.02), with similarly reassuring results across subgroups including BRCA1 carriers, BRCA2 carriers, and women treated with specific fertility medications like in vitro fertilization, clomiphene citrate, or gonadotropins. This first meta-analysis on this topic provides reassuring evidence that fertility treatments do not significantly increase breast cancer risk even in women with hereditary susceptibility, though the authors note that larger prospective studies with more detailed information are needed to fully understand potential risks. Future research should examine whether risks vary by breast cancer subtype, explore the genetic mechanisms underlying hormone-related breast cancer, and investigate the relationship between BRCA mutations and hormone receptor-positive breast cancer specifically.

Oral contraceptives and risk of breast cancer and ovarian cancer in women with a BRCA1 or BRCA2 mutation: a meta-analysis of observational studies.

Park et al,

2022

Carcinogen

A meta-analysis of 12 breast cancer studies and 8 ovarian cancer studies in women with BRCA1 or BRCA2 mutations found that oral contraceptive (OC) use was associated with a 24% increased breast cancer risk but a 47% decreased ovarian cancer risk. The increased breast cancer risk was observed only with long-term OC use (>5 years), while the ovarian cancer protection occurred regardless of duration, and these patterns were consistent when BRCA1 and BRCA2 carriers were analyzed separately. These findings present a complex risk-benefit trade-off for BRCA mutation carriers considering oral contraceptives, suggesting that while OCs provide substantial protection against ovarian cancer—a particularly deadly cancer in this high-risk population—they also modestly increase breast cancer risk with prolonged use, requiring careful individualized counseling about contraceptive choices and cancer prevention strategies.

Endocrine disrupting chemicals and breast cancer: a systematic review of epidemiological studies.

Wan et al,

2022

Crit Rev Food Sci Nutr

This systematic review of 131 epidemiological studies evaluated the association between various endocrine-disrupting chemicals, including phthalates and hormonal exposures like contraceptive pills, and the risk of breast cancer. It found that several EDCs, particularly phthalates and oral contraceptive use, were consistently associated with increased breast cancer risk across multiple studies.

Oral Contraceptive Use and Breast Cancer Risk According to Molecular Subtypes Status: A Systematic Review and Meta-Analysis of Case-Control Studies.

Barańska et al,

2022

Cancers

A meta-analysis of 19 case-control studies found that oral contraceptive (OC) use had markedly different effects on breast cancer risk depending on tumor receptor status: OC use was associated with a 37% increased risk of triple-negative breast cancer and a 20% increased risk of ER-negative breast cancer, while showing an 8% reduced risk of ER-positive breast cancer and a non-significant 5% reduced risk of HER2-positive breast cancer. These contrasting associations suggest that oral contraceptives may influence breast cancer development through different biological mechanisms depending on tumor subtype, with particularly concerning implications for triple-negative breast cancer—the most aggressive subtype with limited treatment options. The findings highlight the importance of considering breast cancer heterogeneity when evaluating hormonal contraceptive risks and suggest that women at high risk for triple-negative or ER-negative breast cancer may need alternative contraceptive counseling.

Night-shift work, breast cancer incidence, and all-cause mortality: an updated meta-analysis of prospective cohort studies.

Wei et al,

2022

Sleep Breath

A comprehensive meta-analysis of 31 prospective cohort studies including 9.3 million participants found that night-shift work was associated with a modest but statistically significant 2.9% increased breast cancer risk overall, with risk escalating to 8.6% for women working night shifts for more than 10 years and 5.3% for rotating night-shift work specifically. Night-shift workers also showed a 3.1% increased risk of cardiovascular mortality compared to day workers, highlighting broader health impacts beyond cancer. These findings provide strong epidemiological evidence that chronic circadian disruption from night-shift work increases breast cancer risk in a dose-dependent manner, with implications for the millions of women worldwide working non-standard hours in healthcare, manufacturing, transportation, and service industries—suggesting the need for policy interventions to limit long-term night-shift exposure and provide enhanced health monitoring for affected workers.

Recent Trends in Multiclass Analysis of Emerging Endocrine Disrupting Contaminants (EDCs) in Drinking Water.

Lazofsky et al,

2022

Molecules

A review of endocrine-disrupting compounds (EDCs) in drinking water examines this emerging class of environmental contaminants—ranging from naturally occurring to synthetic compounds—that exist as complex mixtures at trace levels but can cause adverse health effects even at low concentrations. The review covers the perceived and actual health risks of EDC exposure through water ingestion (a major human exposure route), regulatory efforts to limit contamination, and analytical methods including advanced sample preparation, instrumentation, and bioassays for multiclass EDC identification and quantitation. Given that human exposure to EDCs via drinking water poses significant health concerns even at trace concentrations, the ability to detect and evaluate EDC contamination with high sensitivity and accuracy is critically important for protecting public health and informing regulatory policy.

Breast Cancer Incidence among Female Workers by Different Occupations and Industries: A Longitudinal Population-Based Matched Case-Control Study in Taiwan.

Shen et al,

2022

Int J Env Res Public Health

Job| Human| Epidemiological Studies| Human Studies| Occupation

A large population-based retrospective case-control study in Taiwan examined 103,047 female workers with breast cancer diagnosed between 2008-2017 and matched controls (1:4 ratio) using lifetime labor enrollment records from 1950-2017 to investigate the association between occupational industries and breast cancer risk. The study identified slightly elevated breast cancer risk across nine major occupational classifications, with the highest risks observed in education (OR: 1.199), professional/scientific/technical activities (OR: 1.118), human health and social work (OR: 1.125), and financial/insurance activities (OR: 1.109), while manufacturing, wholesale/retail trade, information/communication, real estate, and public administration sectors showed smaller but statistically significant increases (ORs ranging from 1.027-1.074). The findings suggest that women employed in certain white-collar professions (education, healthcare, finance, professional services) and some industrial sectors (manufacturing, retail) have modestly increased breast cancer risk compared to other Occupations. The authors recommend further investigation into specific risk factors within these industries—such as work schedules, occupational exposures, socioeconomic factors, or lifestyle patterns associated with these professions—that might explain the slightly elevated breast cancer incidence among female workers in these sectors.

Breast cancer and urinary metal mixtures in Mexican women.

Mérida-Ortega et al,

2022

Environ Res

A case-control study of 499 breast cancer patients and 499 controls in Northern Mexico found that women with breast cancer had distinct patterns of urinary metal exposure, with higher concentrations of tin and lower concentrations of vanadium, cobalt, and molybdenum compared to controls. Using principal component analysis to identify metal mixtures, researchers discovered two distinct exposure patterns with opposite breast cancer associations: a mixture containing chromium, nickel, antimony, aluminum, lead, and tin showed a 15% increased risk, while a mixture of molybdenum and cobalt showed a 44% reduced risk. This is the first study to identify specific urinary metal mixture profiles associated with breast cancer, highlighting that metals may interact synergistically or antagonistically rather than acting independently, and underscoring the critical need for mixture-based approaches in environmental health research—since real-world exposures involve multiple simultaneous contaminants whose combined effects may differ substantially from predictions based on individual metals alone—along with mechanistic studies to understand how metal interactions influence breast carcinogenesis.

Consumption of ultra-processed foods and their link with increasing risk of cancer

Supe et al,

2022

BMJ

Processed Food| Food| Human| Human Studies| Processed Food

Ultra-processed foods (UPFs), commonly found in ready-to-eat items like packaged snacks, frozen meals, and sodas, are filled with added sugars, unhealthy fats, and harmful chemicals like preservatives and flavor enhancers. These foods are increasingly linked to serious health issues, including obesity and cancer. Studies show that replacing UPFs with whole, unprocessed foods can reduce the risk of disease and improve overall health. The harmful ingredients in these products, such as phthalates and bisphenols, can also disrupt the endocrine system, further increasing the risk of developing serious health problems, including cancer.

Dietary intakes of dioxins and polychlorobiphenyls (PCBs) and breast cancer risk in 9 European countries.

Fiolet et al,

2022

Environ Int

A large prospective study within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort examined 318,607 women from nine European countries over a median 14.9 years of follow-up, identifying 13,241 incident invasive breast cancer cases, to assess whether dietary intake of 17 dioxins and 35 polychlorobiphenyls (PCBs)—persistent organic pollutants with endocrine-disrupting and carcinogenic properties—was associated with breast cancer risk. Dietary exposures to dioxins, dioxin-like PCBs (DL-PCBs), non-dioxin-like PCBs (NDL-PCBs), and combined dioxins + DL-PCBs showed no associations with breast cancer incidence (all HRs approximately 1.00-1.01 per 1 SD increase), with results remaining consistent when analyzed by quintile groups, by country, by estrogen receptor status, or after adjusting for contributing food groups and nutritional factors. These findings from one of the largest prospective studies on this topic do not support an association between dietary intake of dioxins and PCBs—the main exposure route for these chemicals in the general population—and breast cancer risk. Despite the established endocrine-disrupting properties of these pollutants and some previous suggestions of positive associations, this comprehensive European study provides reassuring evidence that typical dietary exposures to dioxins and PCBs are not linked to increased breast cancer incidence.

Alcohol consumption, blood DNA methylation and breast cancer: a Mendelian randomisation study.

Zhou et al,

2022

Eur J Epidemiol

A comprehensive study combining meta-analysis of observational data with genetic (Mendelian randomization) analysis found that each 10 grams per day increase in alcohol consumption was associated with a 4% increased breast cancer risk, and importantly, genetic predisposition to problematic alcohol use showed a 76% increased risk even after accounting for alcohol quantity consumed. The study identified four specific DNA methylation sites (epigenetic modifications) affected by alcohol—near the CDC7, ZNF318, RIN3, and RP11-867G23.13 genes—where alcohol-induced changes were causally linked to increased breast cancer risk, providing mechanistic insight into how alcohol drives carcinogenesis. These findings confirm that even low-dose alcohol consumption increases breast cancer risk and suggest that the harm stems not just from the amount consumed but from pathological drinking patterns and specific epigenetic changes that could serve as targets for prevention strategies.

No results found.

Research Results

Beta Version

Search by keyword

You have Successfully Subscribed!