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2023
Breast Cancer Res
This large study of over 181,000 women from the UK Biobank examined whether allostatic load (AL)—a measure of cumulative physiological stress on the body over time—is associated with breast cancer risk. Women with higher AL scores had a significantly increased risk of developing breast cancer, with each one-unit increase in AL associated with a 5% higher risk, and women in the high AL group showing a 17% increased risk compared to those in the low AL group, even after accounting for known risk factors like family history, lifestyle, and genetic factors. The association was found across multiple subgroups and appeared independent of traditional breast cancer risk factors, suggesting that chronic physiological stress may contribute to breast cancer development. These findings indicate that AL could serve as a valuable biomarker for predicting and stratifying breast cancer risk in women.
2023
PLOS Med
A large UK study of nearly 10,000 breast cancer cases found that current or recent use of progestagen-only contraceptives (including pills, injections, implants, and IUDs) was associated with a 21-32% increased breast cancer risk, similar to the risk from combined oral contraceptives containing both estrogen and progestagen. The absolute risk increase is small and age-dependent: for women using hormonal contraceptives for 5 years, the excess risk translates to 8 additional breast cancer cases per 100,000 users among women aged 16-20, but rises to 265 additional cases per 100,000 users among women aged 35-39. While these findings add important evidence about hormonal contraceptive risks, the small increased risk must be weighed against the significant benefits of contraception during childbearing years, and women should discuss their individual risk-benefit profile with their healthcare providers when choosing contraceptive methods.
2020
Cancer Epidemiol
A study of 186,981 postmenopausal women in the NIH-AARP Diet and Health Study found that those living in areas with the highest levels of outdoor light at night (LAN) had a 10% increased risk of developing breast cancer over 16 years of follow-up compared to women in the darkest areas. The association was stronger for estrogen receptor-positive breast cancer (12% increased risk) and appeared to vary by individual characteristics such as smoking, alcohol consumption, sleep duration, and body mass index. These findings suggest that nighttime light pollution may disrupt circadian rhythms and contribute to breast cancer development, particularly hormone-sensitive tumors. The results highlight artificial light at night as a potentially modifiable environmental risk factor for postmenopausal breast cancer, with implications for urban planning and outdoor lighting policies.
2020
Br Med J
A large UK study of 98,611 women with breast cancer and 457,498 controls found that long-term hormone replacement therapy (HRT) use (≥5 years) was associated with significantly increased breast cancer risk, with combined estrogen-progestogen therapy showing a 79% increased risk and estrogen-only therapy showing a 15% increased risk. Among combined therapies, norethisterone carried the highest risk (88% increase) while dydrogesterone showed the lowest (24% increase), and importantly, the increased risk from past long-term combined therapy use persisted even after stopping treatment (16% increased risk). In practical terms, recent combined HRT users could expect 9-36 extra breast cancer cases per 10,000 women per year depending on age, while estrogen-only users would see 3-8 extra cases per 10,000 women per year, providing critical information for women and clinicians weighing the benefits and risks of different HRT regimens.
2025
Nutr J
A prospective cohort study of 13,567 Chinese women followed for nearly 15 years found that consuming one or more servings of sugar-sweetened beverages (SSBs) per week was associated with a 58% increased breast cancer risk compared to consuming less than one serving weekly. The association was partly mediated by body mass index (4.2%) and uric acid (18.8%), with genetic analyses identifying additional metabolic mediators including cholesterol and fatty acid ratios accounting for small portions of the effect. Interestingly, higher soy milk consumption (3-6 portions weekly) was associated with a 69% reduced breast cancer risk, while dairy milk showed a non-significant trend toward increased risk, and no associations were found for juice, coffee, tea, or alcohol, suggesting that reducing SSB consumption and addressing the associated metabolic disruptions could be effective breast cancer prevention strategies.
2025
Sci Rep
A secondary analysis of 15,536 post-menopausal women from the Alberta Tomorrow Project cohort examined whether exposure to traffic-related air pollution (TRAP), measured using nitrogen dioxide (NO₂) levels, was associated with breast cancer risk over 12.6 years of follow-up during which 523 breast cancer cases were diagnosed. After adjusting for confounders including age, education, births, diet, income, physical activity, BMI, and smoking, the study found no significant association between NO₂ exposure and post-menopausal breast cancer risk (HR = 1.10 per 10-ppb increase in NO₂; 95% CI = 0.90, 1.34). The authors suggest that while the magnitude of risk observed was similar to other studies, the lack of statistical significance may be due to the study’s sample size limitations and the fact that NO₂ levels in Alberta are lower than in many other regions globally where associations have been found. These findings indicate that traffic-related air pollution may not significantly impact post-menopausal breast cancer risk in regions with relatively low pollution levels, though larger studies in more polluted areas may be needed to fully assess this relationship.
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
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
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
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.
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
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
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
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
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.
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.
2022
Cancer Epidemiol Biomark Prev
A study of 102,572 women aged 40-69 years with normal BMI (18.5-<25 kg/m²) from the UK Biobank examined whether a healthy lifestyle index (HLI)—a composite score based on diet quality, low alcohol consumption, no smoking, moderate-to-high physical activity, and waist circumference <80 cm—was associated with breast cancer risk. Postmenopausal women with the highest HLI scores (3rd tertile) had a 24% reduced risk of breast cancer compared to those with the lowest scores (HR = 0.76; 95% CI: 0.64-0.91), while premenopausal women showed similar but non-significant trends, except when smoking was excluded from the score (HR = 0.71; 95% CI: 0.56-0.90). These findings demonstrate that even among women with normal BMI—a group traditionally considered at lower risk—adhering to multiple healthy lifestyle behaviors is associated with reduced breast cancer risk in postmenopausal women. The results suggest that maintaining a healthy lifestyle through diet, physical activity, limited alcohol, healthy waist circumference, and not smoking may provide breast cancer protection beyond weight management alone, particularly for postmenopausal women.
Risk of breast cancer in Danish women occupationally exposed to organic solvents, including ethanol.
2022
Am J Indust Med
A Danish nested case-control study of 845 breast cancer patients and 1,500 matched controls found that occupational exposure to organic solvents was associated with a 220% increased breast cancer risk among ever-exposed women compared to never-exposed women. The elevated risk was observed across all breast cancer subtypes—both estrogen receptor-positive and negative tumors—and in both pre- and postmenopausal women, though surprisingly, no dose-response relationship was detected with duration or cumulative exposure levels. Occupational ethanol exposure showed no association with breast cancer, suggesting that specific properties of other organic solvents may drive the carcinogenic effect, and highlighting the need for workplace protections and further research to identify which solvent types pose the greatest risk.
2021
Eur J Epidemiol
A large prospective study of 318,686 European women followed for 14 years found that consuming a pro-inflammatory diet was associated with a 4% increased breast cancer risk per standard deviation increase in inflammatory diet score, with women in the most pro-inflammatory diet group showing a 12% increased risk compared to those consuming the least inflammatory diets. The association was particularly strong in premenopausal women (8% increased risk per standard deviation), and notably, the pro-inflammatory diet effect was independent of body mass index, physical activity, and alcohol consumption, suggesting that dietary inflammation contributes to breast cancer risk through pathways distinct from these other established risk factors. The consistent associations across all hormone receptor-defined breast cancer subtypes suggest that dietary inflammation may promote breast cancer through non-hormonal mechanisms, reinforcing the importance of anti-inflammatory dietary patterns—rich in fruits, vegetables, whole grains, and omega-3 fatty acids while limiting processed foods, red meat, and refined carbohydrates—as a modifiable strategy for breast cancer prevention across all women, particularly those still premenopausal.
2021
Sci Rep
A combined analysis of five Finnish cohorts including 6,374 postmenopausal women examined whether adherence to three dietary quality indices—the modified Nordic Diet (mNDI), modified Mediterranean diet (mMEDI), and modified Alternative Healthy Eating Index (mAHEI)—was associated with breast cancer risk over an average 10-year follow-up during which 274 breast cancer cases were diagnosed. The study found a borderline protective association for the highest versus lowest adherence to the Nordic Diet (HR = 0.67; 95% CI 0.48-1.01), but no significant associations for the Mediterranean diet (HR = 0.88) or Alternative Healthy Eating Index (HR = 0.89). The authors note that the Nordic Diet, which is more aligned with local Finnish food culture, showed the strongest protective trend, though the association did not reach statistical significance. These findings suggest that while healthy dietary patterns have been linked to prevention of various chronic diseases, their relationship with postmenopausal breast cancer risk is not clearly established, with limited evidence for dietary factors beyond alcohol consumption affecting breast cancer risk.
2020
Int J Cancer
A nested case-control study within a large European cohort of 430 breast cancer cases and 645 controls found that while alcohol consumption was associated with a 17% increased overall breast cancer risk (36% for ER-positive tumors), individual sex hormones showed limited evidence of mediating this relationship except for a weak effect through free estradiol. However, when researchers used a sophisticated statistical approach (partial least squares regression) to create an alcohol-related hormonal signature—characterized by lower SHBG and higher estradiol and testosterone—this hormonal pattern was associated with 25% increased breast cancer risk and mediated approximately 24% of the alcohol-breast cancer association. These findings suggest that alcohol increases breast cancer risk partly through a complex hormonal mechanism involving the interplay of multiple sex hormones rather than through individual hormones alone, providing new mechanistic insight into how alcohol consumption drives breast carcinogenesis in postmenopausal women and supporting recommendations to limit alcohol intake for breast cancer prevention.
2020
Breast Cancer Res Treat
A prospective cohort study of 57,654 Swedish women aged 40-74 years found that increased alcohol consumption was associated with a 26% higher breast cancer risk, but importantly, this relationship—and the protective effect of physical activity—was consistent across women regardless of their baseline breast cancer risk level. The study used the Tyrer-Cuzick model to categorize women as below average, average, or above average risk and found that additional risk factors (such as family history, reproductive factors, or breast density) did not modify how alcohol and physical activity affected breast cancer risk. These findings support recommending reduced alcohol consumption and increased physical activity for breast cancer prevention in all women, regardless of their individual risk profile, since the lifestyle benefits apply equally whether a woman is at low, average, or high baseline risk of developing the disease.
2020
Alcohol Alcohol
A meta-analysis of 22 cohort studies including 45,350 breast cancer cases found that each 10 grams per day increase in alcohol consumption (approximately one standard drink) was associated with a 10.5% increased breast cancer risk overall, with postmenopausal women showing an 11.1% increased risk per 10 grams daily. Wine showed a similar dose-response relationship (8.9% increased risk per 10g/day), while beer and spirits did not show significant linear associations in the dose-response analysis, and the risk was particularly elevated for estrogen receptor-positive (ER+) breast cancers. The alcohol-attributable percentage of breast cancer cases was highest in Europe compared to North America and Asia, suggesting that current drinking recommendations may need to explicitly address breast cancer risk, particularly for postmenopausal women and wine drinkers.
2020
Cancer Epidemiol Biomark Prev
A large international study of BRCA1 and BRCA2 mutation carriers conducted both retrospective (9,232 carriers) and prospective (3,886 carriers) analyses to examine whether tobacco smoking and alcohol consumption affect breast cancer risk in this high-risk population. The study found that smoking for more than 5 years before a first full-term pregnancy (FFTP) was associated with increased breast cancer risk in both BRCA1 carriers (19-36% increased risk) and BRCA2 carriers (25-30% increased risk) compared to women who never smoked, while other smoking variables and alcohol consumption showed no significant associations. These findings suggest that smoking specifically during the prereproductive years may increase breast cancer risk for BRCA mutation carriers, a finding that requires further investigation given its potential public health importance for this high-risk population. This represents the largest prospective study to date examining these lifestyle risk factors in women with BRCA mutations, who already face substantially elevated lifetime breast cancer risk.
2020
Nutrients
A prospective cohort study of 10,930 Spanish female university graduates in the SUN (“Seguimiento Universidad de Navarra”) project examined whether adherence to the 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) cancer prevention recommendations was associated with breast cancer risk. The study used an 8-item score measuring compliance with recommendations including body fat, physical activity, consumption of wholegrains/vegetables/fruit/beans, avoidance of fast foods and processed meats, limited sugar-sweetened drinks and alcohol, and breastfeeding. While no significant association was found for overall breast cancer risk, women who scored highest on adherence (>5 points vs. ≤3 points) had a 73% reduced risk of postmenopausal breast cancer after adjusting for other variables. The findings suggest that following multiple WCRF/AICR lifestyle and nutritional recommendations together may significantly reduce postmenopausal breast cancer risk through their combined protective effects.
2020
J Natl Cancer Inst
A prospective study of 146,326 women in the UK Biobank found that maintaining a healthy lifestyle—combining favorable diet, physical activity, healthy weight, limited alcohol, and no smoking—was associated with 22% and 31% reduced breast cancer risk in premenopausal and postmenopausal women respectively, even among women with high genetic risk (top third of polygenic risk score). Importantly, women with high genetic risk who maintained favorable lifestyles still achieved 27-32% risk reductions across menopausal groups, and while high genetic risk doubled breast cancer risk overall, lifestyle factors provided consistent protective benefits regardless of genetic predisposition. These findings demonstrate that genetic risk is not destiny: even women with the highest genetic susceptibility to breast cancer can substantially reduce their risk through modifiable lifestyle factors, supporting the critical importance of population-wide lifestyle interventions for breast cancer prevention and providing hope that women at elevated genetic risk can take meaningful action to lower their cancer risk through behavioral changes.
2020
Cells
A comprehensive review reveals that imbalanced gut and body microbiomes are linked to nearly all established breast cancer risk factors—including obesity, aging, periodontal disease, alcohol intake, reproductive history, and elevated estrogen levels—suggesting that microbial dysbiosis may itself be an important independent risk factor. The altered bacteria can promote cancer through multiple mechanisms: producing harmful metabolic byproducts, changing how the body processes medications and environmental chemicals, disrupting immune system function, and affecting how well cancer treatments work. These findings suggest that maintaining a healthy microbiome through diet, lifestyle, or therapeutic interventions could potentially reduce breast cancer risk and improve treatment outcomes, representing a promising new frontier in breast cancer prevention and management.
2020
Nutr J
A case-control study of 350 breast cancer patients and 700 controls in Iran found that women with the healthiest combined lifestyle scores—encompassing diet quality, physical activity, and non-smoking—had a 38% reduced breast cancer risk compared to those with the least healthy scores, with effects particularly pronounced in postmenopausal women who showed a 44% risk reduction. Notably, when examining individual lifestyle components, diet quality (measured by the Healthy Eating Index-2010) emerged as the strongest protective factor with a 46% risk reduction in the highest versus lowest category, while physical activity and smoking individually showed no significant associations. These findings suggest that comprehensive healthy lifestyle patterns—particularly high-quality diet—may substantially reduce breast cancer risk in postmenopausal women, though the lack of association in premenopausal women and the dominance of diet over other factors highlights the need for prospective studies to clarify whether combined lifestyle interventions offer synergistic benefits or whether specific components (like diet) drive most of the protective effect.
2019
Eur J Clinic Nutr
A meta-analysis of 23 prospective studies including 41,516 breast cancer cases and 1,171,048 individuals found that higher folate intake was associated with reduced risk of ER-/PR- breast cancer (RR = 0.82; 95% CI: 0.68-0.97), with each 100 μg/day increment decreasing risk by 6% for ER- and 10% for ER-/PR- subtypes. Additionally, high folate intake showed protective effects in premenopausal women (RR = 0.94) and individuals with moderate-to-high alcohol consumption (RR = 0.82), suggesting folate may be particularly beneficial for hormone receptor-negative breast cancers and specific high-risk populations.
2018
BMC Pub Health
A mixed ecological and case-control study in Australia found that obesity occurring between ages 31-40 was independently associated with a 250% increased breast cancer risk in middle-aged women, though no direct association was found between alcohol consumption and breast cancer in the case-control analysis despite ecological correlations. The study revealed that stress was ecologically linked to both alcohol consumption and obesity but not directly to breast cancer incidence, suggesting that stress may influence breast cancer risk indirectly through health behaviors rather than representing a “missing link” as hypothesized. These findings highlight a critical window for breast cancer prevention: obesity in the decade before age 40 appears particularly risky, supporting targeted weight management interventions for women in their 30s, while the complex interrelationships between stress, alcohol, obesity, and breast cancer warrant further investigation using longitudinal designs that can capture temporal sequences and cumulative exposures across women’s reproductive years.
2018
Breast Cancer Res Treat
A study of 27,153 postmenopausal women in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial created an estrogen-related lifestyle score (ERLS) combining four factors: estrogenic diet, alcohol intake, body mass index (BMI), and physical activity, with scores ranging from 0-6 and higher scores representing lower estrogenic lifestyle patterns. Women with ERLS scores of 4 or ≥5 had 23% and 34% lower breast cancer risk, respectively, compared to those with scores ≤2, with similar protective effects observed for invasive cases and estrogen receptor-positive subtypes. The findings indicate that adopting multiple low-estrogen lifestyle behaviors together—including a low estrogenic diet, minimal alcohol consumption, healthy body weight, and high physical activity—has a combined protective effect against postmenopausal breast cancer that is stronger than any single factor alone. The researchers suggest this combined effect likely works by influencing estrogen metabolism, highlighting the importance of addressing multiple lifestyle factors simultaneously for breast cancer prevention in postmenopausal women.
2022
PLOS Med
A large French study following nearly 103,000 adults for nearly 8 years found that people who consumed higher amounts of artificial sweeteners—particularly aspartame and acesulfame-K found in diet sodas and many processed foods—had a 13-15% increased risk of cancer overall, with specific increases in breast cancer and obesity-related cancers. The research, which carefully tracked detailed dietary records and controlled for multiple lifestyle factors, showed aspartame was associated with a 22% higher breast cancer risk among higher consumers compared to non-consumers. While the study has some limitations including potential confounding factors, these findings add to growing concerns about artificial sweetener safety and support the need for regulatory agencies to re-evaluate the safety of these widely used food additives found in thousands of products worldwide.
2019
A prospective study of 4,523 women diagnosed with invasive breast cancer (1994-1998) and followed for a median 8.6 years (1,055 deaths, 824 from breast cancer) examined pre-diagnosis alcohol consumption patterns collected through interviews shortly after diagnosis. Women with the highest average weekly alcohol consumption (≥7 drinks/week) during the 5-year period ending 2 years before diagnosis had 26% lower breast cancer-specific mortality (HR = 0.74; 95% CI: 0.57-0.95), and those with highest consumption in the 2 years immediately before diagnosis had 27% lower mortality (HR = 0.73; 95% CI: 0.56-0.95), with wine consumption showing the strongest inverse association with mortality risk. These findings indicate that while alcohol consumption is a known risk factor for developing breast cancer, pre-diagnosis alcohol consumption—especially wine—was associated with reduced breast cancer mortality rather than increased risk of death, suggesting different biological mechanisms may operate for cancer development versus progression, though no associations were observed for non-breast cancer mortality.