Publications

Publications from the current and previous year are listed below; articles are listed chronologically within each year from the most to the least recent.

Most research articles have brief description below and a link to the published abstract (a detailed summary) through the US. National Library of Medicine.

For prior years, click on the following links:

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BWHS_Printer friendly publication list, August 2017

 (articles listed from most to least recent)

Last Updated: August 4, 2017

2017

In a collaborative study, genetic variants across the genome were assessed in relation to colorectal cancer in African Americans (AA). A novel genetic variant associated with risk in AAs was identified, as well as another variant that had a stronger association in AAs than in other ethnic groups.  link to online article

We studied the relation of reproductive factors to incidence of endometrial cancer in the BWHS, based on 300 women who were affected by the condition during  18 years of follow-up. Earlier age at start of menstruation was associated with higher risk and later age at first birth with lower risk. Women who had had children were at lower risk than those who had not had children. These results suggests that these factors have similar associations with endometrial cancer in black and white women.  link to online article

Vitamin D levels differ between African American (AA) and European Americans (EA), with many more AAs being vitamin D deficient. Vitamin D deficiency may be related to incidence of several illnesses. Levels of vitamin D (i.e., 25(OH)D) and of vitamin D-binding protein (VDBP) in AA and EA women were compared. AA women had lower levels of vitamin D but similar levels of VDBP as EA women. Demographic and lifestyle determinants of vitamin D were similar in the two populations, but genetic determinants may be ethnicity specific.  link to online article

In genetic studies, some genes in the Wnt pathway have been found to be associated with type 2 diabetes. Other genes in the pathway were assessed in a collaborative study of African Americans. A new variant that may represent a signal seen only in African ancestry populations was identified. The finding needs to be replicated.  link to online article

Numerous studies have linked heavy alcohol consumption to an increase in breast cancer incidence. In a study of data from the BWHS and three other studies of African American women, consumption of at least seven drinks per week was associated with a small increase in risk of breast cancer in the overall data. However, the results among the four studies were not consistent.  link to online article

Periodontitis (infections of the gums and bone) occur commonly. To study risk factors for periodontitis and effects of periodontitis on health requires adequate reporting of the condition. BWHS participants living in Massachusetts in the Boston metropolitan area were invited to participate in a study of the validity of reporting of dental conditions, which involved having a clinical examination by a dentist. A total of 77 BWHS participants were examined for periodontal disease, and their questionnaire responses about dental disease were compared with the clinical data. Accuracy of reporting was similar to that in other populations, and it was sufficient for studies of periodontitis in the BWHS based on self-report.  link to online article

Both mortality from breast cancer and the occurrence of diabetes are higher in black women than white women. We assessed whether diabetes may be contributing to mortality among breast cancer survivors in the BWHS. Based on over 1,600 participants who had been diagnosed with breast cancer, we found that breast cancer mortality was increased among those who had been diagnosed with diabetes at least 5 years before breast cancer occurrence. The increase was present for both estrogen rector positive and estrogen receptor negative breast cancer. The results suggest that diabetes contributes to breast cancer mortality among women with breast cancer.  link to online article

Extensive evidence in white women has linked oral contraceptive use, tubal ligation (tubes tied), and higher parity (greater number of children) with reduced risk of ovarian cancer. Results on supplemental female hormones used for the menopause are inconsistent. We studied these factors in the BWHS. The associations of oral contraceptive use, tubal ligation, and parity with ovarian cancer in the BWHS were similar to those in white women. The results suggested that use of female hormone supplements may be associated with increased risk, but more studies are needed to be certain.  link to online article

Ozone, an air pollutant, can increase insulin resistance. We assessed levels of ozone in relation to incidence of diabetes in the BWHS. Diabetes incidence was greater in areas with higher levels of ozone, and the increase was larger in areas of lower nitrogen dioxide. These findings require replication in other studies.  link to online article

Air pollutants can increase blood pressure. We studied levels of traffic-related nitrogen dioxide (NO2) and of ozone in relation to the incidence of hypertension in the BWHS. Over a period of 16 years, 9,570 new cases of hypertension were identified. Higher ozone levels were associated with increased risk of hypertension, but higher NO2 levels were associated with decreased risk.  link to online article

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Genetic studies often identify multiple genetic variants associated with a particular outcome, and methods are need to help to identify real causal variants from among chance findings. A method called the preferential LD approach was tested in genetic data derived in four studies of breast cancer in African American women, including the BWHS. The results support the use of the preferential LD approach in African American women.  link to online article

Aggressive subtypes of breast cancer, such as estrogen receptor negative (ER-) tumors, lead to higher breast cancer mortality and occur more commonly among Black women than among White women. Risk factors for ER- breast cancer are poorly understood. We assessed reproductive risk factors and body size in relation to the incidence of ER- and ER+ breast cancer in the BWHS. Higher parity (number of births) and older age at first birth were associated with increased risk of ER- breast cancer among women less than 45 years of age; breastfeeding reduced the risk associated with higher parity. Abdominal obesity (obesity around the waist as opposed to around the hips) was also associated with higher risk of ER- breast cancer among women under age 45. None of these factors was associated with ER+ breast cancer at older ages or with ER+ breast cancer. These findings indicate that risk factors vary by age and by breast cancer subtype, and that differences in reproductive factors may contribute to Black/White differences in the occurrence of aggressive forms of breast cancer.  link to online article

2016

Incidence rates for liver cancer have increased 3-fold since the mid-1970s in the United States in parallel with increasing trends for obesity and type II diabetes mellitus. In a collaborative project, the Liver Cancer Pooling Project, data from 1.57 million adults enrolled in 14 U.S.-based prospective studies, including the BWHS, were analyzed. Higher body mass index was associated with higher risk of liver cancer except among people who were sera-positive for hepatitis. Higher waist to hip ratio and history of type II diabetes were also associated with higher risk of liver cancer. These results suggests that the increasing trends for obesity and type 2 diabetes in the US are contributing to the increase in liver cancer incidence.  link to online article

Traumatic events, such as childhood abuse, may result in changes in how genes are expressed.  Using blood samples collected from BWHS participants, we assessed DNA methylation levels in a particular genetic region that has been linked to psychosocial stressors in other studies.  We found that methylation levels were greater in women who reported childhood abuse than in women who reported no abuse.  It was unclear whether childhood emotional support modified this association and resulted in less methylation.  Further studies are needed to clarify that issue.  link to online article

Air pollution levels can be measured with remote sensing devices or using ground-based information.  Both measures were associated with mortality in a large study of cancer,  but the effect estimates were generally larger when the ground-based information was used.  link to online article

We carried out the largest study to date in African American women focused on identifying new genomic regions associated with African ancestry that may be associated with risk of breast cancer. We used data from the BWHS and a collaborative study of breast cancer in Black women, the AMBER collaboration, in which the BWHS participates. We found two new regions of excess African ancestry that were associated with estrogen receptor-positive breast cancer and also confirmed two other regions identified previously. The results indicate that previously unidentified genetic variants may contribute to Black/White differences in breast cancer risk.  link to online article

The BWHS participated, together with three other studies of African American (AA) women, in a study that included 1,938 women with estrogen receptor positive (ER+) breast cancer, 1,098 with ER negative (ER-) breast cancer, and 4,687 women without breast cancer. ER- breast cancer is an aggressive breast cancer subtype that occurs more commonly in African American women. The purpose was to determine whether genetic variants in the insulin/insulin-like growth factor (IGF) system are related to the risk of developing specific types of breast cancer, especially ER-. This pathway has been shown to have a key role in cancer development. We identified several genetic variants related specifically to risk of ER- breast cancer.  link to online article

Adherence to cancer prevention recommendations may contribute to lower incidence of breast cancer, but evidence in Black women is limited. We assessed whether BWHS participants who followed recommendations from the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) had lower breast cancer incidence. In analyses that took into account changes in habits over time, we found that following recommendations to exercise and to limit alcohol, sugary beverage, and red and processed meat consumption were associated with reduced risk. However, relatively few women followed the WCRF/AICR recommendations.  link to online article

Evidence from studies of white women has suggested that physical activity may reduce the risk of developing breast cancer. In a previous study in the BWHS, vigorous exercise was associated with lower risk of breast cancer. In the present analysis based on data in the African American Breast Cancer Epidemiology and Risk Consortium of four large studies of African American women, in which the BWHS is participating, recent vigorous exercise was associated with reduced risk of estrogen receptor positive breast cancer.  link to online article

Most studies of genes involved in the occurrence of breast cancer have been conducted in women of European ancestry (white women).  We used genetic data from several studies of women of African ancestry to identify genetic variants associated with breast cancer in this population group. Several genetic variants associated with estrogen receptor negative breast cancer and estrogen receptor positive breast cancer were identified. These genetic variants may be useful in building effective breast cancer risk prediction models for African American women.Most studies of genes involved in the occurrence of breast cancer have been conducted in women of European ancestry (white women).  We used genetic data from several studies of women of African ancestry to identify genetic variants associated with breast cancer in this population group. Several genetic variants associated with estrogen receptor negative breast cancer and estrogen receptor positive breast cancer were identified. These genetic variants may be useful in building effective breast cancer risk prediction models for African American women.  link to online article

Vitamin D deficiency, which has been linked to an increased risk of colorectal cancer, is common among African Americans. Studies of vitamin D deficiency and breast cancer risk, conducted mostly in white women, have been conflicting. To study the relation of vitamin D levels to breast cancer risk in the BWHS, we first developed a vitamin D prediction model.  The model was based on comparing measured levels of vitamin D (specifically, 25-hydroxyvitamin D) in blood samples provided by BWHS participants with levels predicted by models based on participants’ vitamin D consumption in the diet and from supplements, weight, cigarette smoking, and several other factors. The model was then used to predict vitamin D levels among all women in the BWHS. Using the predicted levels of vitamin D together with information on breast cancer occurrences, we estimated that women with the lowest levels of vitamin D had an increased risk of breast cancer compared with women with higher levels. These results suggest that treating vitamin D deficiency could result in lower risk of breast cancer.  link to online article

A signaling pathway in the body, called HIPPO, regulates cell growth and survival. Based on genotyping data in the African American Breast Cancer Epidemiology and Risk Consortium of studies of African American women, in which the BWHS is participating, we found that the several genetic variants in the Hippo signaling pathway were significantly associated with estrogen-receptor negative and estrogen receptor positive breast cancer.  link to online article

Coffee consumption has been reported to be inversely associated with hepatocellular carcinoma (HCC), the most common type of liver cancer. There have been no studies of coffee and intrahepatic cholangiocarcinoma (ICC), the second most common type of liver cancer. In the Liver Cancer Pooling Project, a consortium of U.S.-based cohort studies, including the BWHS, data from 1,212,893 individuals, including 860 with HCC and 260 with ICC, were assessed. Consumption of more than 3 cups of coffee per day, relative to nondrinking, was associated with a 27% lower risk of HCC. The risk reduction was greater in women than in men. The associations were stronger for caffeinated coffee than decaffeinated coffee. There was no association between coffee consumption and ICC. These findings suggest that coffee consumption in the U.S. is associated with reduced risk of HCC.  link to online article

Experimental studies have suggested that nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin and ibuprofen, may potentially protect against liver cancer. As part of the Liver Cancer Pooling Project, we assessed data on 1,084,133 individuals (including 679 with hepatocellular carcinoma (HCC) and 225 with intrahepatic cholangiocarcinoma (ICC) from 10 U.S.-based cohort studies, including BWHS. Current aspirin use, versus nonuse, was with a 32% lower risk of HCC; the association was stronger for users who reported daily use, longer duration use, and lower dosage. Ibuprofen use was not associated with HCC risk. Aspirin use was associated with a reduced ICC risk in men but not women.  link to online article

Hepatocellular carcinoma (HCC) occurs less commonly among women than men in almost all regions of the world. The disparity in risk is particularly notable prior to menopause suggesting that hormonal exposures during reproductive life may be protective. In the Liver Cancer Pooling Project, a consortium of US-based cohort studies, data from 799,500 women in 11 cohorts, including BWHS, were assessed. Bilateral oophorectomy (removal of both ovaries) was associated with a significantly increased risk of HCC. There was no association of oral contraceptives use, parity, age at first birth, age at natural menopause, or duration of fertility with HCC. These findings do not help to explain the female/male disparity in HCC incidence.  link to online article

Evidence has been growing that sedentary behavior, such as long hours of sitting, increases the risk of several illnesses, independent of physical activity.  We evaluated whether time spent sitting at work or time spent watching television, or both combined, was associated with breast cancer risk in the BWHS.  We found that higher levels of total time sitting reported at baseline in 1995, as well as updated total time sitting based on data provided during follow-up, were associated with increased incidence of breast cancer. These association were present among women who exercised on a regular basis as well as among those who did not exercise.  In a previous BWHS study, vigorous exercise was associated with reduced risk of breast cancer.  Thus, BWHS findings suggest that high sedentary time may increase risk for breast cancer among Black women, while vigorous exercise may lower risk.  link to online article

In women of European ancestry, an association of a particular gene near the fatty acid synthase (FASN) gene has been found to occur more commonly among women with uterine fibroids. We assessed that possibility in the BWHS. We found no association with risk of fibroids overall. On average, African American women have about 20% European ancestry; we found that among women with higher European ancestry (40% or more), the genetic variant in question was associated with increased risk of fibroids.  link to online article

The influence of genetic background on risk of breast cancer has been studied mainly among European and Asian women. We conducted an analysis of rare genetic variants in relation to risk of breast cancer breast cancer in the African American Breast Cancer Epidemiology and Risk Consortium, which includes data from four large studies of African American women, including the BWHS. There were no significant associations with overall risk of breast cancer, but a gene not previously identified and a gene previously identified in women of European ancestry were significantly associated with risk of estrogen-receptor negative breast cancer and triple negative breast cancer.  link to online article

Genome-wide association studies (GWAS) of lung cancer have identified regions of genetic variants associated with lung cancer risk in Europeans and Asians. The present study was a GWAS in African Americans, who have higher rates of lung cancer despite smoking fewer cigarettes per day when compared with other population groups. We confirmed results previously reported in African Americans and other populations for two loci near plausible candidate genes that are associated with lung cancer. Additional work is required to map and understand the biological underpinnings of the strong association of these loci with lung cancer risk in African Americans.  link to online article

Previous studies have found that people who attend religious services have a lower mortality rate than non-attenders, but the meaning of this association is unclear. In the BWHS, we assessed mortality in more than 36,000 BWHS participants during eight year period after they had provided information on their religious practices in 2005.  Attending religious services several times per week was associated with lower mortality, but engaging in prayer several times per day was associated with higher mortality.  Religious coping and self-identification as a religious/spiritual person were not associated with mortality.  link to online article

We evaluated whether adherence to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) cancer prevention recommendations was associated with colorectal cancer incidence in the BWHS. The seven recommendations involved healthy weight, exercise, and dietary intake.  Adherence to cancer prevention recommendations was low and not associated with colorectal cancer risk. The validity of existing recommendations in diverse populations needs further study, as well as whether there are alternative recommendations that are more beneficial for cancer prevention in specific populations.  link to online article

Multiple myeloma (MM) is a relatively rare cancer that occurs more commonly among African Americans than among other population groups. Obesity also occurs more commonly among African Americans as well but its relation to multiple myeloma is undetermined. We combined data from seven cohort studies, including the BWHS, that tracked mortality among Africans Americans.  MM mortality increased as body mass index increased and was 43% greater among those with body mass index of 35 or more relative to individuals with healthy weights. The findings suggest that obesity is a risk factor for MM and a contributor to the rising incidence rates of MM among African Americans.  link to online article

Laboratory studies show that air pollutants can increase insulin resistance, but epidemiologic evidence on whether air pollution affects diabetes incidence is conflicting. We assessed traffic-related nitrogen dioxide (NO2) levels in relation to the incidence of type 2 diabetes in the BWHS. Based on 4387 participants who were diagnosed with diabetes during 1995 to 2011, we found no evidence of an increase in diabetes associated with levels of NO2.  link to online article

The participation of African-Americans in research involving biospecimens used in genetic studies (such as saliva/mouthwash or blood samples) has generally been low. However, in the BWHS, the response rate to an invitation to submit a saliva/mouthwash sample (which is a source of DNA) was high, 51%. The response rate was highest among older women and women who were health conscious, as indicated by a recent visit to a doctor or having had cancer screening (mammography, colonoscopy, PAP smear). The response in the BWHS is encouraging given published findings of low overall participation rates of African-Americans in genetic studies.  link to online article

In a collaborative project of four large studies of African American women, we examined associations between smoking and breast cancer. Results differed by menopausal status. Postmenopausal women who had smoked most heavily were estimated to have a 15% greater risk of breast cancer than postmenopausal women who had never smoked. Other studies have found similar results. By contrast, among premenopausal women, smokers had lower risk than nonsmokers, a finding that has not been observed before and requires confirmation.  link to online article

Animal studies and epidemiologic studies in children have suggested that air pollution might contribute to weight gain. We investigated the association between air pollution and weight gain over 16 years of follow-up in the BWHS. The air pollutants assessed were fine particulate matter, ozone, and nitrogen dioxide, with levels based on measurements from a variety of sources. Our analyses suggested that air pollution does not increase weight gain.  link to online article

Previous studies have found an association between uterine leiomyomata (fibroids in the womb) and cancer of the uterus. In the BWHS, based on 300 incident cases of endometrial cancer identified during follow-up, women with a history of uterine leiomyomata had a higher incidence of endometrial cancer compared to woman without such a history. The strongest association was observed for cancer diagnosed within two years of the diagnosis of uterine leiomyomata, suggesting that women with uterine leiomyomata may be under greater surveillance for cancer. Confirmation of these findings is needed.  link to online article

Previous studies have found that a woman’s personal socioeconomic status (e.g., income and education) is related to her risk of developing asthma, with higher risk among women with fewer socioeconomic resources. It is possible that neighborhood socioeconomic status could also contribute to risk of developing asthma, for example in neighborhoods with more older buildings with higher levels of allergens. In a study in the BWHS that included 1520 women who developed asthma during follow-up, individual and neighborhood socioeconomic status were both assessed in relation to asthma incidence. Lower personal socioeconomic status was associated with increased asthma risk, as has been seen in other studies, whereas there was no association of neighborhood with risk.  link to online article

Low neighborhood socioeconomic status (SES) is associated with higher risk of cardiovascular disease (CVD), such as heart attacks. We assessed neighborhood SES in relation to several CVD biomarkers in blood samples provided by BWHS participants. The blood samples of 418 BWHS participants were assayed for C-reactive protein (CRP), hemoglobin A1C (hgA1C), and high-density lipoprotein (HDL) cholesterol.  Women living in neighborhoods with lowest SES had the least favorable biomarker levels. These results suggest that neighborhood environments may affect physiological processes within residents independently of individual SES.  link to online article

Low neighborhood socioeconomic status (SES) is associated with poorer health. We assessed the relation of neighborhood SES to mortality in the BWHS.  Based on 2,598 deaths during 1995-2011, lower neighborhood SES was associated with increased all-cause and cancer mortality irrespective of individual level of education. The presence of the association even among women with high levels of education suggests that high individual SES may not overcome the unfavorable influence of neighborhood deprivation on mortality.  link to online article

We assessed a genetic pathways that might be involved in breast cancer occurrence, namely the fibroblast growth factor receptor (FGFR) signaling pathway. We compared genetic variants in this pathway among women with and without breast cancer in a collaborative study of the BWHS with three other studies of African American women. We found an association of the FGFR2 gene with estrogen receptor positive breast cancer, and an association of the FGFR1 gene with estrogen receptor negative breast cancer. Thus, different genes in the same pathway may be associated with different breast cancer subtypes.  link to online article

Breast cancer is not a single disease but rather is made up of various subtypes.  Based on breast cancer tumor tissue from a consortium of studies of breast cancer in Black women that included the BWHS, we compared classification into subtypes by a three-biomarker immunohistochemistry (IHC) method with classification by an RNA-based method and classification by estrogen and progesterone receptor status; the latter classification is commonly used in hospitals to guide treatment.  The IHC-based method had reasonable accuracy for distinguishing the basal-like subtype (which has a poorer prognosis) from non-basal like cancers, but addition biomarkers were needed to distinguish other subtypes.  link to online article

A woman’s family history of various cancers may be related to her chance of developing breast cancer, but evidence has been conflicting. We assessed the relation of a woman’s first-degree family history (in her mother, father, sisters, brothers, or children) of breast cancer and several other cancers (e.g., prostate, lung, colon, cervix) to her risk of developing breast cancer. This was a collaborative study of the BWHS with three other studies that included African American women.  First degree family history of breast cancer was associated with a 70% increase in a woman’s own risk of developing breast cancer, whereas having a family history of both breast cancer and prostate cancer was associated with an increase three times that great. These findings suggest that greater surveillance and screening for breast cancer may be needed for women with a family history of both breast and prostate cancer.  link to online article

Vitamin D deficiency is more common among African Americans than among other racial groups. We assessed whether vitamin D-related genetic pathways are involved in breast cancer risk in the BWHS and three other studies of African American women. To do so, we compared genetic variants in vitamin-D related pathways among women with and without breast cancer.  Several genetic variants were related to breast cancer risk, and one in particular was related to estrogen receptor negative breast cancer, a subtype that occurs more commonly among African American women. These results support a possible role for vitamin D in the occurrence of breast cancer subtypes.  link to online article

Estrogen receptor negative (ER-) breast cancer is a subtype of breast cancer that occurs more commonly in black women than white women. Because ER- cancer includes “triple negative” breast cancer, a subtype that has a poorer prognosis than other subtypes, there has been a search for genetic variants that may be associated with higher or reduced risk of ER- cancer. In the present collaborative study that involved BWHS and three other studies of African American women, we assessed genetic variants in a pathway, mTOR that might play a role in the development of breast cancer. Several variants were found to be related to risk of ER- breast cancer. If confirmed, these findings suggest a mechanism that might help to explain the occurrence of ER- breast cancer in black women.  link to online article

Medications with estrogen together with progestin, such as PremPro, are used to treat menopausal symptoms. Their use has been associated with increased incidence of estrogen receptor-positive (ER+) breast cancer in White women. Using data from the BWHS and three other large studies of Black women, we found that the incidence of ER+ cancer was increased in users of estrogen with progestin, but not in users of medications that contained estrogen alone. There is now a great deal of evidence suggesting a cause-effect relationship between combination therapy and ER+ breast cancer. A decrease in use would be expected to reduce the number of ER+ cancers. Women of any ethnic group using drugs containing estrogen with progestin for the relief of menopausal symptoms should use them for as short a time as possible.  link to online article

Numerous genetic variants are associated with body mass index (a measure of body size). It has also been found that people born with a low birth weight have an increased risk of disorders that involve weight control, which suggests that normal regulation of body weight is disrupted in people with low birth weight.  We found that certain central nervous system genetic variants associated with weight affected the relation of birth weight to adult body mass index in the BWHS. These results support the theory that low-birth weight disrupts mechanisms of body weight regulation.  link to online article

Inflammation may be a pathway involved in the development of endometrial cancer (cancer of the lining of the womb). Fatty fish contain a substance, a “fatty acid”, that is thought to reduce inflammation. If this is so, fish consumption might lower risk of developing endometrial cancer.  We assessed this possibility in the BWHS and found that fish intake was related only weakly to the overall incidence of endometrial cancer.  There was a hint of a lower risk for fish consumption among leaner women, but assessment of this possibility will require larger numbers.  link to online article

Exposure to a component of air pollution called fine particulate matter (PM2.5) has been linked to increases in insulin resistance and blood pressure, raising the possibility that PM2.5 could increase the incidence of diabetes and hypertension. In a study of BWHS participants living in 56 metropolitan areas across the US, we first estimated PM2.5 levels and then assessed whether levels were related to the occurrence of type 2 diabetes or hypertension. Our analysis suggested that PM2.5 dose not increase the incidence of either condition.  link to online article

Cancer of the endometrium (the lining of the womb) occurs more commonly among white women who are overweight or obese or have type 2 diabetes, but whether this is the case among African American women has received little study.  In an assessment of these issues within the BWHS, we found that the incidence of endometrial cancer increased as body mass index increased.  There was also an increased risk of this cancer among women who had diabetes.  Thus, overweight and diabetes appear to have similar effects on endometrial cancer incidence in black and white women.  link to online article