2013

Active smoking and passive smoking (exposure to the smoke of others) have been assessed in relation to breast cancer in many studies, but rarely in Black women. There is uncertainty as to whether passive smoking is associated with increased risk.  In the BWHS, both active and passive smoking were associated with increased risk of breast cancer.  Women who smoked most heavily and who began smoking at young ages were at highest risk.  link to online article

To determine whether diet quality affects weight gain, we assessed dietary patterns in relation to weight gain among BWHS participants who were ages 21-39 at the start of follow-up.  These ages were studied because most weight gain in adults occurs before age 40. Two dietary patterns were assessed in 1995 and in 2001.  Women who maintained high quality diets over time had a lower risk of becoming obese.  The healthiest diets were low in red and processed meats and high in whole grains, fruits, and vegetables.  link to online article

With information from BWHS participants who reported a pregnancy attempt during 1995-2011, we found that heavier women were less likely to have been successful in becoming pregnant.  These findings add to the growing body of research showing that excess weight is associated with reduced success in becoming pregnant.  link to online article

In recent years, there has been increasing evidence that body fat at the waist has a worse effect on health than body fat at the hips. The BWHS contributed information to a genetic study of body fat distribution in populations of African ancestry.  Some genetic variants associated with body fat at the waist were identified.  link to online article

People who eat food from restaurants tend to consume more calories than those who prepare their food at home, because restaurant meals, particularly from fast food restaurants, often contain more fats and more calories.  Most weight gain among women in the BWHS occurs before age 45.  We found that young BWHS participants who ate meals often from restaurants, particularly meals of burgers, were at higher risk of becoming obese. This was also the case for women who frequently consumed sugar –sweetened soft drinks.  link to online article

Some evidence suggests that risk of lung cancer may be affected by body size. In the BWHS, risk of lung cancer was lower in women who were obese than in thinner women, especially among current smokers, in agreement with previous results.  It is unclear why body size would have this effect.  However, it is clear the adverse effect of smoking on lung cancer risk is far greater than any effect of weight.  link to online article

BWHS participants who exercised vigorously were less likely to become obese than less active women.   Women who walked briskly also appeared to have a lower risk, although the results were less clear than for vigorous exercise. These effects on weight were independent of dietary factors and other factors related to weight gain.  link to online article

Sarcoidosis is a chronic autoimmune disease that disproportionately affects Black women. This study found that mortality among women in the BWHS with sarcoidosis was greater than that among women free of the illness.  link to online article

This study examined possible genetic markers for sarcoidosis in the BWHS. The results support the conclusions of previous studies, which identified several specific genetic variants related to increased risk and others related to decreased risk. In addition, this study examined genetic markers of ancestry, and found that a higher percent African ancestry is related to an increased risk of sarcoidosis.  link to online article

African American women are more likely to develop uterine fibroids than other women and also more likely to be lactose intolerant and avoid dairy products.  In the BWHS, participants with low intake of dairy products were more likely to develop fibroids than women with high intake.  To see if this difference was explained by genetic factors (such as might be linked to lactose intolerance), we assessed whether % African ancestry explained the difference in fibroids risk in the BWHS between women with low and high intakes of dairy products.  This measure of ancestry did not explain the difference.  link to online article

The relation of early age at menopause to mortality has not previously been assessed among African American women. In the BWHS, having a natural menopause before age 45 was associated with a small increase in the risk of death.  link to online article

In a large analysis that gathered data from many studies of people of African ancestry, genetic variants associated with body mass index were identified.  Some variants were the same as those identified in white and Asian populations, indicating that there are shared genetic variants related to body size across populations of diverse ancestry.  link to online article

African American women on average start having periods at an earlier age than women of European ancestry.  The BWHS contributed information to a study of African American women, which included information from a large number of studies.  Several genetic variants, including some associated with age at menarche in white women, were identified.  It is hoped that studies of genetic variants will give clues as to why and how some women have an earlier age at start of periods.  link to online article

A subtype of breast cancer, estrogen receptor- positive cancer (ER+), occurs less commonly  among Black women than among white women.  In an analysis of data on risk factors for ER+ breast cancer from the BWHS and from a similar follow-up study of white women, differences in reproductive factors only partly explained the difference in incidence between the two populations.  link to online article

Breast cancer risk prediction models are used to estimate a woman’s individual risk, which in turn is used to judge whether the woman is at high enough risk to be enrolled in breast cancer prevention trials, how often she should have a mammogram, and whether she is a candidate for breast cancer chemoprevention.  The CARE model, which was developed for Black women, was assessed in the BWHS. It underestimated breast cancer risk, and its predictive ability was modest, worse for estrogen receptor-negative breast cancer than for estrogen receptor-positive breast cancer.  Further work will be focused on efforts to improve the model.  link to online article

In a study in the BWHS, both physical and sexual abuse during childhood were associated with a higher incidence of uterine fibroids, with a stronger association for sexual abuse.  These results add to the evidence that stressor may contribute to increased incidence of uterine fibroids.  link to online article

Results on the association of meat and dairy intake with the incidence of breast cancer have been conflicting. In the BWHS, neither meat consumption nor dairy consumption was materially related to the incidence of breast cancer.  Associations with specific subtypes of breast cancer, such as estrogen receptor positive and negative cancer, were also generally absent.  link to online article

Uterine sarcomas are a rare subtype of endometrial cancer (cancer of the lining of the uterus).  To study this rare subtype requires the collaboration of multiple studies in order to have sufficient cases. The BWHS contributed data to such a collaboration, which found that risk factors for uterine sarcomas are no different from those for the most common subtype of this cancer.  link to online article

Childhood abuse has been associated with a higher risk of asthma during childhood. An analysis of BWHS data found an association of asthma incidence during adulthood with both physical and sexual abuse during childhood, with a stronger association for physical abuse.   A proposed mechanism involves the effect of stress on the immune system.  link to online article

Genetic variants identified in populations of European-ancestry women were assessed in the BWHS.  Several genetic variants were associated with increased risk of breast cancer, including with the subtypes that are more aggressive and occur more commonly in African American women—the estrogen receptor-negative and triple negative subtypes.  These findings contribute to understanding of why certain breast cancer subtypes occur more commonly among Black women.  link to online article

A specific genetic variant has been associated with increased risk of breast cancer in Chinese women and women of European-ancestry, but not in women of African ancestry.  Genotyping in the BWHS indicated that a different genetic variant in the same region as the one found in Chines and European women is associated with a reduced risk in the BWHS. The finding was confirmed in another study of Black women.  link to online article

Many genetic variants have been identified as being associated with specific diseases, but they explain only a small part of the expected genetic variation and are poor predictors of disease occurrence.  This paper proposes a mathematical model involving promoters that suggests new paths of research to understand genetic effects.  link to online article

Most genetic variants that have been linked to disease occurrence have very small effects, and very large studies are needed to identify them.  Multiple studies, including the BWHS,  contributed to the present study of genetic risk factors for breast cancer in women of African ancestry. Two previously unidentified genetic variants were found to be associated with breast cancer risk.  link to online article

In previous studies, obesity measured by body mass index  has been linked to an increased risk of macrosomia (birth weight of at least 4000 grams or of at least 8 pounds 13 ounces). Such babies have a higher risk of injury during the birth and a higher chance of childhood obesity.  High waist circumference and high ratio of waist to hip circumference are measures of “central” obesity, in which body fat is more concentrated in the waist than in the hips.  In the BWHS, these measures as well as obesity measured by body mass index were all associated with a higher risk of macrosomia.  link to online article

Some previous studies that have measured neighborhood socioeconomic status (SES) with a single variable have found associations of SES with higher rates of preterm birth. Neighborhood SES  may be better captured with a variable based on multiple factors.  Using such a variable in the BWHS, we found little evidence of an association of neighborhood SES with risk of premature birth. link to online article