[Intrinsic](https://poal.co/u/Intrinsic) had posted the link to BrasAndBreastCancer.org a couple times already. The "organization behind it" is a nobody, the director a thief (see link). EDIT: Read my UPDATE comments. But you'd analyze new incoming information, opinion and stance anyway, so I decided to take a slightly deeper look than just [that page](https://brasandbreastcancer.org/supportive-references). **Disclaimer:** I didn't evaluate papers, authors or the accuracy. Nor did I search for citations or follow-ups. Just went by each link and read the papers' authors' summaries. **Red flag #2:** The 'cited' sources *on the website* are largely copy pasted from the article "HOW BRAS CAUSE LYMPH STASIS AND BREAST CANCER" by Sydney Ross Singer, whom I'd not consider a researcher anyway, more of an article writer in a wanna-be scientific setting if you look at his other 'publications.' Red flag because of a sloppy job by site writer, one that screams agenda. # SUMMARY OF THE BELOW Correlation between excessive bra wearing time PLUS tightness of bras and mammary lesions. - Brazillian, Iranian and Spanish studies. Think of 24/7 or >"20h/day" (sleeping in bras). The Brazillian study claims 2x increased risk. The damage is likely to be caused by **awful**, not just poor, blood circulation. - paper "Lymph stasis promotes tumor growth" The Chinese study found no single distinct correlation, I'd summarize them instead as 'stressful life' On the other hand, there could be a correlation between breast size and breast cancer, so that bras only facilitate the growth of breasts and are not the direct cause. (Yet then again, bigger breats - more weight - more pressure on skin and tissue by the bra) My conclusion: Wearing a bra for a moderate amount of time during day, and one that's not overly tight should not, if at all, increase the chance of breast cancer. Final note: The papers do not claim 90% correlation, but rather only hinting at that conclusion. And again, I didn't examine any papers of the opposing side. PS: Higher risk in tight bras makes sense. If tissue doesn't get enough blood flow, it will die off sooner, triggering an early regeneration cycle. The more cell growth (tissue regeneration) there is, the more likely some could go wrong. I'm not a scientist, definitely not a human anatomy biologist, just take it as a fancy pop-hypothesis. # Epic quotation and summaries of the summaries > Breast size, handedness and breast cancer risk TLDR: The larger breast size is probably a more likely cause, but confidence is still barely above error margins > Bra cup size and handedness were studied as possible risk factors for breast cancer. Data for 3918 cases and 11,712 controls from 7 centres were used to examine the association of handedness with laterality of breast cancer; data for 2325 cases and 7008 controls from 4 centres were used to assess the relation of bra cup size to breast cancer risk. There was a suggestive (P about 0.10) association of handedness with breast cancer laterality: odds ratio of a left-handed (or ambidextrous) woman having a left-sided cancer 1.22 (95% CI 0.96-1.56). Handedness may affect the lateral occurrence of breast cancer, although this tumour is in general more common in the left breast, possibly because this breast is usually slightly larger. Premenopausal women who do not wear bras had half the risk of breast cancer compared with bra users (P about 0.09), possibly because they are thinner and likely to have smaller breasts. Among bra users, larger cup size was associated with an increased risk of breast cancer (P about 0.026), although the association was found only among postmenopausal women and was accounted for, in part, by obesity. These data suggest that bra cup size (and conceivably mammary gland size) may be a risk factor for breast cancer. > Book "Dressed To Kill: The Link Between Breast Cancer and Bras" Well maybe again, smaller breasts = smaller risk. The more tissue there is to regenerate over life time, the more chance something will go wrong. > Book "Get It Off!" No access > "[A case-control study on risk factors of female breast cancer in Zhejiang province] " > Results: Univariate conditional logistic regression showed that family history of malignant tumor and breast cancer, housing decoration in last 10 years, mammary hyperplasia, adverse life events, bra with steel rings, sleeping with bra, high fat and pickle intake, poor sleep were positively related to breast cancer; whereas environmental friendly decoration materials, long decoration time interval, workplace condition, more lactation and parity, high fruits intake, sufficient sleep were negatively related to breast cancer. [... confidence intervals listed] > Conclusion: Hereditary,psychological factors,lifestyle,environment and diet related factors are significantly associated with risk of breast cancer. No definite answer. > Patologias mamarias generadas por el uso sostenido y seleccion incorrecta del brassier en pacientes que acuden a la consulta de mastologia > ABSTRACT > Sustained and inappropriate use of bra is an important predictor of emergence and development of breast diseases conditioned by time of use and specific characteristics for the garment accessories and fabric. > General Purpose: To determine the incidence of breast conditions generated by sustainable use and incorrect selection of bras in patients attending Mastology HUAL consultation during the period from March to June 2010. > Materials and Methods: We conducted a descriptive, non-experimental, transactional study. The sample consisted of 73 patients who responded to the Mastology HUAL consultation. The data collection was done through the application of a questionnaire addressed to them and a thorough physical exam individually, account for the results in statistical tables. > Results: 49% of the patients comprised between 33-52 years; 76% of which use half cup, full cup 62%, had breast conditions; 73% of the bra using whales showed abnormalities; 75% of the people using it more than 12 hours presented mammary lesions. > Conclusion: The incorrect selection of bra given by the use of whales, fillers and accessories that enhance the breast and combined with the prolonged use of it results in the alteration of the female breast health. Just 70 people... Well, I dont know how many other studies/papers had. Out of the 73, the selection goes down to 50% and then do you see the calculated percentages. Basically a study on 36 people, then 26 with conditions in some form. > Comparative study of breast cancer risk factors at Kenyatta NationalHospital and the Nairobi Hospital > Abstract Breast cancer rates in high-income countries increased sharply with industrialization and urbanization but are now declining. Rates in low-income countries are instead rising after adoption of western type lifestyles. > There was no difference in level of education (p=0.783), and marital status (p=0.432) between cases and controls. On theother hand intensity of brassiere use (p<0.001), occupation(p<0.001), area of residence (p=0.045) diet (p=<0.01), duration of use of hormonal contraceptives (p<0.001), and family history of breast cancer (p=0.016), had association with breast cancer occurrence. This seems to be a good one > "Wearing a Tight Bra for Many Hours a Day is Associated with Increased Risk of Breast Cancer" > Methods: In total, 152 patients with breast cancer and 152 controls were investigated regarding risk factors for breast cancer and bra-wearing habits. The bra and the chest of the patient at the bra band level were measured. The percentage obtained was multiplied by the number of hours per day that the bra is worn. The data were analysed using multivariate analysis with Poisson regression. > Results: Women who had a high daily bra wearing hours x bra stretch percentage coefficient had a frequency of breast cancer that was 2.27-fold higher compared to those who had a low coefficient. This result demonstrated that there is an association between these variables and breast cancer among pre- and postmenopausal women. > Conclusions: This study demonstrated a correlation between wearing a tight bra for several hours per day and an increased risk of developing breast cancer. Seems to start off a good premise, but I don't like how their highest-risk group has the least control samples to compare against (scroll down to results for the table) > "Brassiere wearing and breast cancer risk: A systematic review and meta-analysis" > original research studies published in English or Chinese examining the association between type and duration of brassiere-wearing and breast cancer risk. Data were abstracted by a first reviewer and verified by a second. Study quality was rated according to predefined criteria. “Fair” or “good” quality studies were included. Results were summarised by meta-analysis whenever adequate material was available. > RESULTS: Twelve case-control studies were included in the review. Meta-analysis showed brassiere wearing during sleep was associated with a two times of increased odds. > CONCLUSION: The present review demonstrates insufficient evidence to establish a positive association between the duration and type of brassiere wearing and breast cancer. Further research is essential; specifically, a large-scale epidemiological study of a better design is needed to examine the association between various forms of brassiere exposure in detail and breast cancer risk, with adequate control of confounding variables. The Chinese are often criticized for simply evaluating and summarizing existing studies. Yet their conclusion of a 2x increase seems to be consistent with the previous one from Brazil. > "Lymph stasis promotes tumor growth" > As for tumors, two vascular neoplasms of lymphatic origin, namely lymphangiosarcoma (Stewart-Treves syndrome) and Kaposi sarcoma, are the most frequent skin tumors arising on lymphedematous skin areas[...]. The reason for this probably lies in the impairment of lymph circulation that specifically promotes lymph angiogenesis in addition to causing local immune dysfunction. Furthermore, several other cutaneous malignancies have been reported to appear in the presence of lymph stasis TLDR: Blood circulation is important for the skin. No word of breasts, but applies to that anatomic area. > "HOW BRAS CAUSE LYMPH STASIS AND BREAST CANCER" Basically disqualified if you look at his other "publications". Its like they're written just to be citated like this: "Nose-Picking Pointers to Help Prevent COVID-19", "COVID-19 Survival Tips: What Doctors Should Be Telling You", "Ivanka Trump Nitpicked over Nip Pic". Though: > Looking for clues, we examined the red marks and indentations in her skin left by her bra. Most women experience these same signs of constriction. We had seen them every day, but ignored them as a normal part of bra-wearing. Now, they were clues into what might have caused Soma’s lump. This. Though we wear underwear daily and it squeezed our skin as well. **IMPORTANT!** If you look at his sources, it's all the same as presented on the dot-org website. Basically the website copy-pasted it from his work, while adding minor stuff and maybe swapping a couple citations/sources. > "WEARING BRASSIERE - A LESS WELL KNOWN FACTOR ASSOCIATED WITH BREAST CANCER IN WOMEN" > **Materials & Methods:** This case-control study was conducted on women with and without breast cancer.A total of 360(120 in the case group -240 in the control group) individuals were selected based on available sampling method. The study tools were Demographic and behavioral habits of wearing brassiere questionnaires. Data were analyzed by Descriptive (mean and standard deviation, Frequency) and analytical tests (Independent t test and Chi-square) by using SPSS version 18 software. > **Results:** Based on the results, the average hours of wearing brassiere in women with and without breast cancer was 19.2 ± 3. 21 and 17.9 ± 3.19 respectively. The mean frequency of wearing brassiere during sleep in women with and without breast cancer was 5.78 ± 1.16 and 4.18 ± 0.83 times per week. There was a significant difference between the two groups regarding the average hours of wearing brassiere, the mean frequency of wearing brassiere during sleep and the habit of wearing a tight brassiere (p<0/05). > **Conclusion:** The findings of this study revealed differences in some behavioral habits of wearing brassieres in women with and without breast cancer. So, in preventive interventions for breast cancer, women's education should be considered in order to be aware of the proper behavioral habits in wearing brassieres. Very much repeats the brazilian study in its spirit. Higher rates of breast cancer correlate with excessive bra usage.