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The Sister Study


The Sister Study is on Facebook!

We are excited to let you know that we have created a private Facebook group for the Sister Study to provide a forum for Sister Study participants, colleagues and friends of the study. This private group is by invitation only and not a public forum. We saw the need to have a more dynamic way of communicating with our Sister Study community than just the Sister Study website. We see the Facebook group as a real-time forum where we can post study updates, announcements, and new research findings or plans.

We know that Facebook has been in the news lately because of how they use their users’ data. We want you to know that, as a research study funded by a government entity, we will abide by all NIEHS privacy policies.exit disclaimer We will not share your information with third parties. We ourselves will never post any personal and/or identifiable information on Facebook. If you decide to use your own real name, be mindful that you are responsible for that information. We will provide guidelines for what not to post, such as personal health information, treatment recommendations, and product endorsements or posts with an intent to sell. Our staff will monitor the group to make sure that policies are followed and remove inappropriate material.

We invite you to follow this direct link exit disclaimer if you would like to join.

We hope you find this additional communication method helpful and that you enjoy connecting with other study participants, colleagues and friends of the study.

Facebook Posts

Many Sister Study participants reported exposure to artificial light while sleeping, including having a small nightlight or light from clock radios on in the room (40%), light from outside the room (31%) or a light or television on inside the room (12%). Exposure to any of these was associated with being overweight or obese upon study enrollment, with stronger associations seen for those reporting lights or television on in the room while sleeping. Women who had exposure to artificial light while sleeping were also more likely to gain weight after baseline. Though we cannot confirm that the relationship is causal, our findings provide evidence that lowering exposure to light while sleeping may be a useful intervention for obesity prevention.

Learn more here:
Sleeping with lights on and weight gain in women linked in new study. exit disclaimer

Sleeping with Artificial Light at Night Associated with Weight Gain in Women. exit disclaimer

Association of Exposure to Artificial Light at Night While Sleeping With Risk of Obesity in Women. exit disclaimer

We previously posted about our findings that higher “biological age”, which is determined by measuring molecular changes to the genome (genetic material), was associated with increased breast cancer risk. In an effort to understand what factors might influence biological age, Sister Study investigators looked for differences in biological age between those who reported doing shift work (7% of participants) versus those who did not. Those who reported doing shift work tended to have a biological age that was older than their age in calendar years, especially if they worked night shifts. On average, those who worked for more than 10 years in a job that included night shifts were 3 years “older” than their chronological age. This research helps us understand some of the chemical processes that may explain previously observed associations between shift work and chronic diseases like breast cancer.

For those interested in learning more about the association between shift work and breast cancer, the National Toxicology Program recently released a report stating that “There is strong, but not sufficient, evidence from cancer epidemiology studies that persistent night shift work (e.g., frequent and long-term, or working a large number of night shifts over a lifetime, especially in early adulthood) causes breast cancer in women.”

Read more about it here:
Shift work, DNA methylation and epigenetic age. exit disclaimer

We would like to introduce you to Dr. Nicole “Nikki” Niehoff, a new post-doctoral fellow and Sister Study researcher. Dr. Niehoff has already made major contributions to the Sister Study through her work as a doctoral student in Epidemiology at the University of North Carolina, studying air pollutants, pesticides, and physical activity in relation to breast cancer risk. In her post-doctoral position, Dr. Niehoff will continue to study environmental risk factors for breast cancer, including how obesity and other metabolic factors affect the relationship between the environment and cancer, and how multiple pollutants together influence risk.

When we talk about genetic risk factors for breast cancer, we are usually referring to how the genes we are born with can influence our risk of getting breast cancer. However, breast cancer may also be affected by change to our genes that occur after birth. Epigenetics is a term that refers to biologic changes that can affect DNA, including “DNA methylation”, which can affect which genes can be “read” and turned into proteins. In a recent publication, Sister Study authors discuss how they examined more than 400,000 known DNA methylation markers, measured in DNA from blood samples given at study enrollment. The researchers identified several thousand methylation markers associated with breast cancer. Since the associations were stronger for breast cancer diagnosed shortly after study enrollment, they hypothesize that many of these markers may be indicators of early disease. These results could help develop tools for detecting invasive breast cancer at an early stage.

Read more about it here:
Blood DNA methylation and breast cancer: A prospective case-cohort analysis in the Sister Study. exit disclaimer

As previously discussed, even though the DNA you inherit from your parents is generally not modifiable, biological changes within cells over time can affect how the body reads and processes your genetic information. Sister Study investigators are very interested in learning about what environmental and lifestyle factors might affect DNA methylation, a type of genetic alteration that serves as an indicator of which genes are turned “on” or “off”. In a recent study, we identified many such markers that may be associated with high alcohol consumption, which is a known risk factor for breast cancer and other diseases. These results may help explain how alcohol affects the body and increases disease susceptibility.

Read more about it here:
Alcohol and DNA Methylation: An Epigenome-Wide Association Study in Blood and Normal Breast Tissue. exit disclaimer

In a recently published study, Sister Study researchers found that women who ate breakfast every morning were less likely to be or become obese, compared to women who irregularly ate breakfast (3-4 days a week). On the other hand, women who never ate breakfast were also less likely to be obese than those who irregularly ate breakfast. We interpret this to mean that a regular breakfast consumption habit, whether it be eating breakfast every day or never eating breakfast, may be important for maintaining a healthy weight.

Read more about it here:
Day-to-day regularity in breakfast consumption is associated with weight status in a prospective cohort of women. exit disclaimer

The DNA you inherit from your parents is largely fixed and unchangeable. However, outside factors can alter how your body reads and uses the information coded in the genes. One such example is DNA methylation, where the presence of certain molecules (a “methyl” group) on the strand of DNA can affect whether the gene is turned “on” (i.e. it can be read) or “off”. We recently found that Sister Study participants who were born to older mothers had different DNA methylation patterns than those with younger mothers. We do not yet know what this means in terms of health or breast cancer risk, specifically, but it could be a clue as to why some conditions or diseases are more common in individuals born to older mothers.

Read more about it here:
Persistent epigenetic changes in adult daughters of older mothers. exit disclaimer

In a recently published study led by Sister Study investigators Symielle Gaston and Chandra Jackson, women who averaged less than 7 hours of sleep per night and who had difficulty falling or staying asleep were more likely to have metabolic disorders like high blood pressure and obesity. These associations were usually stronger in premenopausal women than postmenopausal women. Because sleep and metabolic disorders were measured at the same time, we could not assess which occurred first. However, this work helps us to understand the biological relationship between sleep and metabolic disorders and to identify possible approaches to prevent metabolic disorders in women. As always, please consult your health care provider to tailor these findings individually.

All paper surveys and other forms you complete and return to the Sister Study are handled by this team. Your responses are securely processed into our system in preparation for their eventual analysis by our researchers. We are grateful for your diligence in completing your health update surveys! Those responses directly inform the research findings we share with you in this Facebook group. Thanks to what you share with us, researchers have published over 100 articles.

Please visit our website to view these articles:
Sister Study articles

Thanks to our Sister Study participants’ continued dedication to the study, researchers are able to publish such important findings as the ones described in this news release. We encourage you to read about "if a woman’s biologic age is older than her chronologic age, she has an increased risk of developing breast cancer."

Read more about it here:
Older biologic age linked to elevated breast cancer risk. exit disclaimer

Anti-Müllerian hormone (AMH), like estrogen, is a marker of ovarian function. Levels decrease as women approach menopause. AMH levels are thought to correspond with how many egg cells remain in the ovaries, so the measure has implications for fertility. Like estrogen, higher levels may be associated with breast cancer risk. But unlike estrogen, AMH has the advantage that levels do not change across the menstrual cycle, making it easier to use in research studies. Sister Study investigators measured AMH in blood samples collected at enrollment from a subgroup of participants who had not yet gone through menopause, and looked at how dietary factors might be related to levels. The results indicated that dietary fat intake may be associated with lower AMH, but that other factors, including protein and alcohol intake were not related to AMH levels. Please check with your health care provider about applying these results individually.

Read more about it here:
Dietary factors and serum Anti-Müllerian hormone concentrations in late premenopausal women. exit disclaimer

You may find this article on testing for BRCA1 and BRCA2 interesting and helpful. As always, please consult your health care provider to interpret and apply specifics to your own health.

Read more about it here: Taking the Uncertainty Out of Interpreting BRCA Variants. exit disclaimer

Fruits and vegetables contain nutrients called antioxidants, which may counteract cell damage caused by harmful substances. Green and black tea contain some types of antioxidants, but their specific health benefits are not fully understood. In a small study that included 889 Sister Study participants, we looked at whether consumption of black or green tea was associated with biologic measures of oxidative stress, a measure of the balance between the body’s potentially harmful (oxidative) and potentially beneficial (antioxidant) chemicals. We found that while black tea may be associated with lower levels of oxidative stress, green tea was not. Related research is looking at whether tea consumption is related to breast cancer risk.

Read more about it here:
Tea consumption and oxidative stress: a cross-sectional analysis of 889 premenopausal women from the Sister Study. exit disclaimer

Did you know that the average age of women in the Sister Study is now 67 years of age? Our youngest Sister participant is just 44 years young and our “wisest” participant is going strong at 89!

Research has shown that engaging regularly in exercise reduces breast cancer risk generally, but it was not clear whether the benefit would also apply to women with a family history of breast cancer. Our research in the Sister Study, where all women have a family history of breast cancer, showed that being more physically active was associated with a reduction in postmenopausal breast cancer, but not premenopausal breast cancer. Please check with your health care provider about applying these results individually.

Read more about the research here:
Adult Physical Activity and Breast Cancer Risk in Women with a Family History of Breast Cancer. exit disclaimer

Heart disease is the leading cause of death for women in the United States. Over the years, we have asked you questions about your cardiovascular health and disease history. We are excited to let you know that we are working with cardiovascular disease experts to study environmental contributors to stroke, heart attack, and congestive heart failure. As part of that effort, in October we started requesting medical records to confirm diagnoses and obtain needed details about reported heart conditions such as results of tests performed and disease subtypes. Our goal is to identify preventable environmental causes of cardiovascular disease. We have reached out to some of you for more information about your health history. If you were contacted and returned your authorization forms, we thank you! But if you haven’t yet done so we encourage you to sign and mail your forms soon. Thank you again for your contributions to the Sister Study. We couldn’t do this research without your willingness to participate!

We would like to introduce you to Dr. Symielle Gaston, a post-doctoral research fellow working with the Sister Study. Dr. Gaston is interested in studying how the physical and social environments contribute to racial/ethnic and socioeconomic disparities in cardiovascular health. For instance, how living in neighborhoods with social and physical disorder may negatively affect cardiovascular health. She recently received a grant to support this research. In the Sister Study, she has several ongoing projects, including a study of the association between racial/ethnic discrimination and poor sleep, an understudied contributor to cardiovascular health and other health conditions.

Read more here:
Postdoc awards reflect strong research potential exit disclaimer

We would like to announce that Dr. Alexandra White joined the Sister Study as a Stadtman Tenure-Track Investigator. exit disclaimer Dr. White's research will focus on identifying environment and lifestyle risk factors for cancer and understanding the biologic mechanisms that allow cancer to develop. She has already worked for three years as a post-doctoral fellow on the Sister Study, publishing research on factors that may influence breast cancer risk, such as alcohol consumption, smoking, physical activity, and obesity. She is particularly excited to expand her research to examine the effects of exposure to toxic metals and air pollution on breast density and breast cancer risk.

In the first study to make use of the data from the “Sisters Changing Lives” sub-study, we measured the concentrations of 16 trace elements in each of two sets of toenail samples – the first collected at enrollment and the second in 2013-2014. We found that concentrations of most of the elements decreased over time, with the biggest decreases seen for lead, cadmium and chromium. This was true for women who were diagnosed with breast cancer between enrollment and 2013 and women who were not. This work was led by Drs. Katie O’Brien and Clarice Weinberg, both NIEHS investigators.

Read more about it here:
Do Post-breast Cancer Diagnosis Toenail Trace Element Concentrations Reflect Prediagnostic Concentrations? exit disclaimer

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