Diabetes and breast cancer mortality in Black women.

PURPOSE: Breast cancer mortality is higher in Black women than in White women. The prevalence of type 2 diabetes mellitus is also higher, yet data on whether diabetes affects breast cancer mortality in this population are lacking. We investigated the relation of diabetes at the time of breast cancer diagnosis to breast cancer mortality in the Black Women's Health Study, a prospective cohort study. METHODS: 1,621 Black women with invasive breast cancer diagnosed in 1995-2013 were followed by mailed questionnaires and searches of the National Death Index. Multivariable Cox regression analysis was used to compute hazard ratios (HRs) for diabetes in relation to breast cancer mortality and all-cause mortality, with adjustment for age, stage, treatment modality, estrogen receptor (ER) status, and body mass index. RESULTS: There were 368 deaths during follow-up, of which 273 were due to breast cancer. Breast cancer mortality was significantly increased in women who had been diagnosed with diabetes at least 5 years before breast cancer occurrence, HR 1.86 (95% CI 1.20-2.89), with elevations observed for both ER+ and ER- breast cancer. All-cause mortality was also higher in diabetics, with HRs of 1.54 (95% CI 1.12-2.07) overall and 2.26 (95% CI 1.62-3.15) for ≥5-year duration of diabetes relative to non-diabetics. CONCLUSIONS: Our results present the first solid evidence of a positive association of type 2 diabetes with breast cancer mortality in Black women. Given the higher prevalence and earlier onset of type 2 diabetes in Black women, it is likely that diabetes contributes to racial disparities in breast cancer mortality.

Higher diet quality is inversely associated with mortality in African-American women.

BACKGROUND: Diet quality has been inversely associated with overall mortality in white populations, but the evidence in African-American populations is limited. OBJECTIVE: The goal of the present study was to assess diet quality in relation to all-cause mortality in the Black Women's Health Study, a follow-up study of African-American women begun in 1995. METHODS: Data used in this study were obtained via biennial questionnaires from 1995 to 2011. Based on food-frequency questionnaire data collected in 1995 and 2001, we calculated an index-based diet quality score [Dietary Approaches to Stop Hypertension (DASH)] and derived dietary patterns (prudent and Western) with the use of factor analysis. We followed 37,001 women who were aged 30-69 y and free of cancer, cardiovascular disease, and diabetes at baseline for mortality through 2011. Multivariable Cox regression was used to estimate HRs and 95% CIs. Analyses were conducted in 2014. RESULTS: Based on a total of 1678 deaths during 16 y of follow-up, higher DASH scores were associated with reduced all-cause mortality (HR: 0.75; 95% CI: 0.63, 0.89 for highest vs. lowest quintiles). The DASH components most strongly associated with lower mortality were high intake of whole grains and low intake of red and processed meat. A Western dietary pattern, characterized by high intake of red and processed meat, was associated with increased all-cause mortality rates (HR: 1.37; 95% CI: 1.17, 1.60 for highest vs. lowest quintiles of score); a prudent dietary pattern was not associated with risk. CONCLUSION: A DASH-style diet high in intake of whole grains and low in consumption of red meat is associated with reduced mortality rates in healthy African-American women.

Type 2 diabetes and the risk of colorectal adenomas: Black Women's Health Study.

Evidence for the association of type 2 diabetes mellitus (DM) with colorectal neoplasms is contradictory, and African Americans have been underrepresented in the studies published to date. In a nested case-control study (1995-2009), we examined DM and insulin therapy as risk factors for colorectal adenomas in African American women enrolled in the ongoing Black Women's Health Study. From women reporting ever having undergone a gastrointestinal endoscopy, 917 cases of colorectal adenoma were compared with 2,751 controls without a colorectal polyp, matched on age and follow-up time. Cases were verified by medical record review. We used multivariable logistic regression analyses that included DM exposures and selected confounders. There were no overall associations between DM and adenoma risk or between insulin use and adenoma risk. However, DM without insulin use was inversely associated with risk of colon adenomas (odds ratio (OR) = 0.71, 95% confidence interval (CI): 0.52, 0.97) but not rectal adenomas. DM was inversely associated with adenoma risk in women older than 55 years (OR = 0.64, 95% CI: 0.44, 0.91) but not in women 55 years or younger (OR = 1.24, 95% CI: 0.81, 1.89). Future research should attempt to replicate the unexpected inverse association of DM with colon adenoma risk among older African American women.

General and abdominal obesity and risk of death among black women.

BACKGROUND: Recent pooled analyses show an increased risk of death with increasing levels of the body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) of 25.0 or higher in populations of European ancestry, a weaker association among East Asians, and no association of an increased BMI with an increased risk of death among South Asians. The limited data available on blacks indicate that the risk of death is increased only at very high levels of BMI (≥35.0). METHODS: We prospectively assessed the relation of both BMI and waist circumference to the risk of death among 51,695 black women with no history of cancer or cardiovascular disease who were 21 to 69 years of age at study enrollment. Our analysis was based on follow-up data from 1995 through 2008 in the Black Women's Health Study. Multivariable proportional-hazards models were used to estimate hazard ratios and 95% confidence intervals. RESULTS: Of 1773 deaths identified during follow-up, 770 occurred among 33,916 women who had never smoked. Among nonsmokers, the risk of death was lowest for a BMI of 20.0 to 24.9. For a BMI above this range, the risk of death increased as the BMI increased. With a BMI of 22.5 to 24.9 as the reference category, multivariable-adjusted hazard ratios were 1.12 (95% confidence interval [CI], 0.87 to 1.44) for a BMI of 25.0 to 27.4, 1.31 (95% CI, 1.01 to 1.72) for a BMI of 27.5 to 29.9, 1.27 (95% CI, 0.99 to 1.64) for a BMI of 30.0 to 34.9, 1.51 (95% CI, 1.13 to 2.02) for a BMI of 35.0 to 39.9, and 2.19 (95% CI, 1.62 to 2.95) for a BMI of 40.0 to 49.9 (P<0.001 for trend). A large waist circumference was associated with an increased risk of death from any cause among women with a BMI of less than 30.0. CONCLUSIONS: The risk of death from any cause among black women increased with an increasing BMI of 25.0 or higher, which is similar to the pattern observed among whites. Waist circumference appeared to be associated with an increased risk of death only among nonobese women. (Funded by the National Cancer Institute.).

Bilateral oophorectomy and risk of cancer in African American women.

PURPOSE: African American women are more likely to undergo hysterectomy, with or without bilateral oophorectomy, at younger ages than white women. It is well established that women who have a bilateral oophorectomy at younger ages are at reduced risk of breast cancer, and there is some evidence of an increased risk of colorectal and lung cancer. METHODS: Using data from 44,514 women in the Black Women's Health Study, we prospectively investigated the relation of hysterectomy and oophorectomy to incidence of breast, colorectal, and lung cancer and to mortality from cancer. Hazard ratios (HRs) and 95 % confidence intervals (CIs) were estimated using Cox proportional hazards regression with control for confounding factors. RESULTS: During 16 years of follow-up, hysterectomy alone, relative to no hysterectomy, was not associated with risk of breast, lung, or colorectal cancer. Bilateral oophorectomy, relative to hysterectomy with ovarian conservation, was inversely associated with risk of estrogen receptor-positive (ER+) breast cancer (HR 0.62; 95 % CI 0.45-0.85) but not with ER-negative breast cancer; age at surgery and menopausal hormone use did not modify the associations. HRs for the association of bilateral oophorectomy with incidence of colorectal and lung cancer were nonsignificantly increased for women who had surgery before age 40 years and had used menopausal hormones for less than 2 years (HR 1.65; 95 % CI 0.73-3.73 for colorectal cancer and HR 1.71; 95 % CI 0.68-4.31 for lung cancer). Bilateral oophorectomy was not associated with cancer mortality. CONCLUSIONS: Bilateral oophorectomy was associated with reduced risk of ER+ breast cancer regardless of age at surgery and use of menopausal hormones. There were nonsignificant increases in risk of colorectal and lung cancer for women with oophorectomy at younger ages and short duration of menopausal hormone use.

Estrogen receptor positive tumors: do reproductive factors explain differences in incidence between black and white women?

PURPOSE: The incidence of estrogen receptor positive (ER+) breast cancer is higher among white women relative to black women. In two large prospective cohorts, the Black Women's Health Study (BWHS) and the Nurses' Health Study II (NHSII), we investigated whether reproductive factors explain the difference. METHODS: During 1,582,083 person-years of follow-up of 140,914 women observed from 1995 to 2007, 327 ER+ breast cancers were identified among black women in BWHS and NHSII and 1,179 among white women in NHSII. Cox proportional hazards regression models, stratified by race and pooled, were used to estimate hazard ratios (HR) and 95 % confidence intervals (CI) for the association of race, parity, age at first birth, and lactation in relation to risk of ER+ cancer with adjustment for age and other breast cancer risk factors. RESULTS: Age at first birth differed markedly in the two groups, with 66 % of parous black women having their first child before age 25 as compared with 36 % of white women. Each additional year of age at first birth was associated with a 4 % increased risk of ER+ breast cancer among both racial groups. Relative to nulliparous women, parous women were at decreased risk of ER+ breast cancer (HR 0.59, 95 % CI 0.20, 1.77), in black women and (HR 0.63, 95 % CI 0.45, 0.87) in white women. The HR for the association of black race with ER+ cancer was 0.67 (95 % CI 0.53, 0.84) in a model that adjusted for age only, 0.77 (95 % CI 0.61, 0.99) in a model that controlled for parity, age at first birth, and other reproductive/hormonal factors, and 0.83 (95 % CI 0.70, 0.98) in a model that additionally controlled for other breast cancer risk factors such as alcohol consumption and use of hormone supplements. Similar associations were seen among premenopausal women and in an analysis restricted to ER+PR+ tumors. CONCLUSIONS: Reproductive factors explained some of the higher incidence of ER+ tumors among white women as compared to black women.

A prospective study of smoking and breast cancer risk among African-American women.

PURPOSE: Active smoking and passive smoking have been associated with increased risk of breast cancer. The purpose of the present study was to prospectively assess associations of smoking with breast cancer and identify subgroups at higher risk among African-American women. METHODS: Based on 1,377 incident cases identified during 14 years of follow-up in the Black Women's Health Study, we assessed active and passive smoking in relation to breast cancer incidence by menopausal status, estrogen receptor status, and other factors. Incidence rate ratios (IRR) and 95 % confidence intervals (CI) for categories of smoking relative to no active or passive smoking were calculated from Cox proportional hazards models, controlling for breast cancer risk factors. RESULTS: Active smoking was associated with increased risk of premenopausal breast cancer. The IRR was 1.21 (95 % CI 0.90-1.62) for premenopausal breast cancer overall and 1.70 (95 % CI 1.05-2.75) for premenopausal breast cancer associated with beginning smoking before age 18 together with accumulation of ≥20 pack years. The positive association with premenopausal breast cancer was most apparent for estrogen-receptor-positive cancer. Passive smoking was also associated with increased risk of premenopausal breast cancer (IRR = 1.42, 95 % CI 1.09-1.85), based on information on passive smoking at home and work. Neither active nor passive smoking was associated with increased risk of postmenopausal breast cancer. CONCLUSION: These results strengthen the evidence that both active and passive smoking increase the incidence of premenopausal breast cancer.

Prenatal DES exposure in relation to breast size.

PURPOSE: Prenatal DES exposure has been associated with increased risk of breast cancer, but the mechanisms are unknown. Larger bra cup size has also been associated with increased breast cancer risk, although not consistently. We investigated the relation of prenatal DES exposure to mammary gland mass, as estimated by bra cup size. METHODS: In 2006, 3,222 DES-exposed and 1,463 unexposed women reported their bra cup size, band size (chest circumference), and weight at age 20. Prevalence ratios (PR) were calculated for DES exposure in relation to large bra cup size, with control for year of birth and study cohort. Primary analyses were carried out among women who reported a chest circumference of no more than 32 inches because their cup size would be less influenced by fat mass. RESULTS: Within this group, DES-exposed women had an estimated 45% increased prevalence (95% CI 0.97-2.18) of large cup size (C or greater) relative to unexposed women. The PR was further increased among women in this group who had a body mass index of < 21 at age 20: PR = 1.83 (95% CI 1.11-3.00). The PR for high-dose DES exposure relative to no exposure was 1.67, 95% CI 1.02-2.73, whereas there was no association of bra cup size with low-dose exposure. CONCLUSIONS: These results provide support for the hypothesis that in utero DES exposure may result in greater mammary gland mass. Taken together with previous research on bra size and breast cancer risk, these findings suggest a mechanism for a possible association of in utero DES exposure with increased risk of breast cancer.

Long-term diet quality is associated with lower obesity risk in young African American women with normal BMI at baseline.

The prevalence of obesity [body mass index (BMI) ≥30 kg/m2] is high among African American women, with most weight gain occurring before middle age. We assessed diet quality, as measured by the Alternate Healthy Eating Index-2010 (AHEI-2010) and the Dietary Approaches to Stop Hypertension (DASH) diet score in relation to incident obesity in the Black Women's Health Study. Prospective data were collected via biennial questionnaires from 1995 to 2011. AHEI-2010 and DASH scores were calculated from food-frequency questionnaire data collected in 1995 and 2001. We restricted the analysis to 19,885 nonobese women aged 21-39 y at baseline. Multivariable Cox regression was used to estimate HRs and 95% CIs. Among women with consistent diet scores in 1995 and 2001, higher diet quality scores were inversely associated with obesity incidence: the multivariable HRs comparing highest with lowest quintiles of the AHEI-2010 and DASH scores were 0.76 (95% CI: 0.58, 0.98) and 0.68 (95% CI: 0.53, 0.88), respectively, among women with a BMI in the normal range (18.5-24.9 kg/m2) at baseline. There were no significant associations among women who were overweight at baseline. The findings suggest that a high-quality diet that is sustained over time is associated with reduced obesity risk among young African American women with a normal BMI at baseline.

Restaurant foods, sugar-sweetened soft drinks, and obesity risk among young African American women.

BACKGROUND: The prevalence of obesity is disproportionately high in African American women, and consumption of fast foods and sugar-sweetened soft drinks is also especially high among African Americans. OBJECTIVE: We investigated the relation of intakes of sugar-sweetened soft drinks and specific types of restaurant foods to obesity in the Black Women's Health Study. DESIGN: In this prospective cohort study, 19,479 non-obese women aged 21-39 years at baseline were followed for 14 years (1995-2009). Dietary intake was assessed by validated food frequency questionnaire in 1995 and 2001. MAIN OUTCOME MEASURES: Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association of intakes of restaurant foods and sugar-sweetened soft drinks with incident obesity. RESULTS: Higher intakes of burgers from restaurants and sugar-sweetened soft drinks were associated with greater risk of becoming obese. The associations were present in models that included both factors and adjusted for overall dietary pattern. The HR of obesity in relation to restaurant burger consumption of > or = 2 times/week compared with < 5 times/year was 1.26 (95% CI: 1.14-1.40; P-trend<.001). For sugar-sweetened soft drink intake, the HR was 1.10 (95% CI: .99-1.23; P-trend = .14) for > or = 2 drinks/day compared with < 1 drink/month. The associations were stronger among women younger than age 30 with normal weight at baseline. CONCLUSIONS: Frequent consumption of burgers from restaurants and sugar-sweetened soft drinks contribute to obesity among young African American women.

Individual and neighborhood socioeconomic status in relation to breast cancer incidence in African-American women.

Socioeconomic status (SES) for both individuals and neighborhoods has been positively associated with incidence of breast cancer, although not consistently. The authors conducted an assessment of these factors among African-American women, based on data from the Black Women's Health Study, a prospective cohort study of 59,000 African-American women from all regions of the United States. Individual SES was defined as the participant's self-reported level of education, and neighborhood SES was measured by a score based on census block group data for 6 indicators of income and education. Analyses included 1,343 incident breast cancer cases identified during follow-up from 1995 through 2009. In age-adjusted analyses, SES for both individuals and neighborhoods was associated with an increased incidence of estrogen receptor-positive breast cancer. The associations were attenuated by control for parity and age at first birth, and there was no association after further control for other breast cancer risk factors. These findings suggest that the observed associations of breast cancer with SES may be largely mediated by reproductive factors that are associated with both estrogen receptor-positive breast cancer and SES.

Reproductive and hormonal factors in relation to incidence of sarcoidosis in US Black women: The Black Women's Health Study.

The authors assessed the relation of hormonal and pregnancy-related factors to the incidence of sarcoidosis in the Black Women's Health Study. On biennial questionnaires, participants (US black women aged 21-69 years at baseline) reported data on diagnoses of sarcoidosis, reproductive history, and medication use. Cox regression models, adjusted for age, education, geographic region, smoking, and body mass index, were used to estimate incidence rate ratios and 95% confidence intervals. During 694,818 person-years of follow-up from 1995 through 2009, 452 incident cases of sarcoidosis were identified. The incidence of sarcoidosis decreased as age at menopause increased (P-trend = 0.03). Both later age at first full-term birth and having a more recent birth were associated with a reduced incidence of sarcoidosis. In models that included both factors, the incidence rate ratios were 0.60 (95% confidence interval: 0.37, 0.97) for age at first birth ≥30 years versus <20 years (P-trend = 0.05) and 0.73 (95% confidence interval: 0.43, 1.24) for <5 years since last birth versus ≥15 years (P-trend = 0.15). No significant associations were observed with age at menarche, parity, lactation, oral contraceptive use, or female hormone use. These results suggest that later full-term pregnancy and longer exposure to endogenous female hormones may be related to a reduced risk of sarcoidosis.

Cardiometabolic factors and breast cancer risk in U.S. black women.

Previous studies have suggested that metabolic syndrome may be associated with an increased risk of breast cancer, particularly in postmenopausal women, but U.S. black women have not been assessed. We examined the associations of abdominal obesity, type 2 diabetes, hypertension, and high cholesterol individually and in combination with breast cancer incidence in the Black Women's Health Study. By means of Cox regression models, we estimated incidence rate ratios (IRR) and 95 % confidence intervals (CI) for the associations of baseline and time-dependent values of self-reported abdominal obesity, type 2 diabetes, hypertension, and high cholesterol with breast cancer incidence. During 516,452 person years of follow-up (mean years = 10.5; standard deviation = 2.9) from 1995 to 2007, 1,228 breast cancer cases were identified. After adjustment for age, education, body mass index at age 18, physical activity, and individual cardiometabolic factors, neither individual nor combinations of cardiometabolic factors were associated with breast cancer incidence overall; the multivariable IRR was 1.04 (95 % CI 0.86-1.25) for the combination of ≥3 factors relative to the absence of all factors, and 1.17 (0.85-1.60) for having all four factors. Among postmenopausal women, however, the comparable IRRs were 1.23 (0.93-1.62) and 1.63 (1.12-2.37), respectively. Our findings provide some support for an association between cardiometabolic factors and breast cancer incidence among postmenopausal U.S. black women.

Abuse victimization and risk of breast cancer in the Black Women's Health Study [corrected].

Few studies have examined the relation between abuse victimization and breast cancer, and results have been inconclusive. Using data from 35,728 participants in the Black Women's Health Study, we conducted multivariable Cox regression to estimate incidence rate ratios (IRRs) and 95% confidence intervals (CI) for the association of abuse across the life span (childhood, adolescence, and adulthood) with breast cancer. Incident breast cancer diagnoses were reported during 1995-2009, and abuse histories were reported in 2005. No associations were found between abuse victimization in either childhood or adolescence and breast cancer. We found a weak positive association between abuse in adulthood and breast cancer (IRR = 1.18, 95% CI = 1.03-1.34). IRRs for physical abuse only, sexual abuse only, and both physical and sexual abuse in adulthood, relative to no abuse, were 1.28 (95% CI = 1.09-1.49), 0.96 (95% CI = 0.76-1.20), and 1.22 (95% CI = 1.00-1.49), respectively. IRRs for low, intermediate, and high frequencies of physical abuse in adulthood, relative to no abuse, were 1.28 (95% CI = 1.07-1.52), 1.37 (95% CI = 1.04-1.79), and 1.24 (95% CI = 0.95-1.62), respectively. Our data suggest an increased risk of breast cancer among African-American women who reported physical abuse in adulthood, but there was little evidence of a dose-response relation. These results require confirmation in other studies.

Regular aspirin use and breast cancer risk in US Black women.

BACKGROUND: Epidemiologic studies have yet to provide consistent evidence to support a protective effect of aspirin and other non-steroidal anti-inflammatory drugs (NSAID) on the incidence of breast cancer. OBJECTIVE: We evaluated the relations of current use of aspirin, non-aspirin NSAIDs, and acetaminophen with breast cancer incidence in the Black Women's Health Study. METHODS: Biennial follow-up of 59,000 study participants began in 1995. During 558,600 person-years of follow-up through 2007, 1,275 breast cancer cases were identified. Using Cox proportional hazards regression, we estimated incidence rate ratios (IRR) and 95% confidence intervals (CI) for associations of current and former use of aspirin, other NSAIDs, and acetaminophen with incident breast cancer. RESULTS: After adjustment for age, education, body mass index at age 18, physical activity, female hormone use, current smoking, and other NSAID use, the IRRs were 0.79 (95% CI = 0.66, 0.95) for current aspirin use and 0.68 (95% CI = 0.50, 0.92) for ≥5 years of aspirin use. Similar associations were observed for acetaminophen use. CONCLUSIONS: Both aspirin and acetaminophen use were inversely associated with breast cancer incidence in the present study. Reasons for the association with acetaminophen use are unclear, given that acetaminophen has very weak anti-inflammatory effects.

Use of a web-based questionnaire in the Black Women's Health Study.

The authors assessed the utility and cost-effectiveness of using a World Wide Web-based questionnaire in a large prospective cohort study, the Black Women's Health Study (BWHS). In 1995, 59,000 African-American women were recruited into the BWHS through a paper questionnaire. Follow-up paper questionnaires have been mailed every 2 years since then. During the 2003, 2005, and 2007 questionnaire cycles, participants were given the option of completing a Web-based questionnaire. The cost of developing and processing a returned paper questionnaire was 4 times that of a returned Web questionnaire, primarily because of return postage costs and greater processing time for paper questionnaires. The proportion of respondents who completed a Web questionnaire doubled from 2003 to 2007, from 10.1% to 19.9%, but the characteristics of those completing the Web questionnaire remained the same. Web response was greatest at younger ages (20.9% of those aged <30 years) and declined with age to 3.6% among women aged 60 years or more. Web questionnaires were filled out more completely than paper questionnaires, regardless of the sensitivity of a question. The use of a Web questionnaire in the BWHS resulted in cost savings and more complete responses. Although there are advantages to using a Web questionnaire, the use of multiple means of soliciting questionnaire responses is still needed.

Fruit and vegetable intake in relation to risk of breast cancer in the Black Women's Health Study.

The authors prospectively examined the relation of fruit and vegetable intake to breast cancer risk among 51,928 women aged 21-69 years at enrollment in 1995 in the Black Women's Health Study. Dietary intake was assessed by using a validated food frequency questionnaire. Cox proportional hazards models were used to estimate incidence rate ratios and 95% confidence intervals, adjusted for breast cancer risk factors. During 12 years of follow-up, there were 1,268 incident cases of breast cancer. Total fruit, total vegetable, and total fruit and vegetable intakes were not significantly associated with overall risk of breast cancer. However, total vegetable consumption was associated with a decreased risk of estrogen receptor-negative/progesterone receptor-negative breast cancer (incidence rate ratio = 0.57, 95% confidence interval: 0.38, 0.85, for ≥2 servings/day relative to <4/week; P(trend) = 0.02). In addition, there was some evidence of inverse associations with breast cancer risk overall for cruciferous vegetable intake (P(trend) = 0.06) and for carrot intake (P(trend) = 0.02). Study findings suggest that frequent consumption of vegetables is inversely associated with risk of estrogen receptor-negative/progesterone receptor-negative breast cancer, and that specific vegetables may be associated with a decreased risk of breast cancer overall.

Genetic variants on chromosome 5p12 are associated with risk of breast cancer in African American women: the Black Women's Health Study.

Two single nucleotide polymorphisms (SNPs), rs4415084, and rs10941679 on chromosome 5p12 were associated with risk of breast cancer in a recent genome-wide association study (GWAS) of women of European ancestry. Both SNPs are located in a large high-LD region and the causal variant(s) are still unknown. We conducted a nested case-control study in a cohort of African American women to replicate and narrow the region carrying the causal variant(s). We evaluated 14 tagging SNPs in a 98 kb LD block surrounding the index SNPs in 886 breast cancer cases and 1,089 controls from the Black Women's Health Study. We used the Cochran-Armitage trend test to assess association with breast cancer risk. Odds ratios were derived from logistic regression analyses adjusted for potential confounders including percent European admixture. We confirmed the reported association of rs4415084 SNP with overall risk of breast cancer (P = 0.06), and, as in the original study, observed a stronger association with estrogen receptor positive tumors (P = 0.03). We identified four other SNPs (rs6451770, rs12515012, rs13156930, and rs16901937) associated with risk of breast cancer at the nominal alpha value of 0.05; all of them were located in a 59 kb HapMap YRI LD block. After correction for multiple testing, the association with SNP rs16901937 remained significant (P permutated = 0.038). The G allele was associated with a 21% increased risk of breast cancer overall and with a 32% increase in tumors positive for both estrogen and progesterone receptors. The present results from an African ancestry (AA) population confirm the presence of breast cancer susceptibility genetic variants in the chromosome 5p12 region. We successfully used the shorter range of LD in our AA sample to refine the localization of the putative causal variant.

Tea and coffee intake in relation to risk of breast cancer in the Black Women's Health Study.

OBJECTIVE: Prospective studies of tea and coffee intake and breast cancer risk have yielded inconsistent results. None of these studies has reported separately on African-American women. We prospectively examined the relation of tea and coffee consumption to risk of breast cancer among 52,062 women aged 21-69 at enrollment in 1995 in the Black Women's Health Study. METHODS: Dietary intake was assessed in 1995 and 2001 using a validated food frequency questionnaire. Cox proportional hazards models were used to estimate incidence rate ratios (IRR) and 95% confidence intervals (CI), adjusted for breast cancer risk factors. RESULTS: During 12 years of follow-up through 2007, there were 1,268 incident cases of breast cancer. Intakes of tea, coffee, and caffeine were not significantly associated with the risk of breast cancer overall. The IRRs for consumption of ≥4 cups/day compared with none were 1.13 (95% CI 0.78-1.63) for tea and 1.03 (95% CI 0.77-1.39) for caffeinated coffee, and the IRR for the top quintile relative to the bottom quintile of caffeine intake was 1.04 (95% CI 0.87-1.24). Consumption of tea, coffee, and caffeine was not significantly associated with breast cancer risk according to menopausal status or hormone receptor status. CONCLUSION: Our findings suggest that intakes of tea, coffee, and caffeine are not associated with the risk of breast cancer among African-American women.