Study demonstrates role of exercise in modifying melatonin levels

December 01, 2005

Toronto, ON - December 1, 2005: Moderate physical activity, which is believed to help reduce the risk of breast cancer, may do so because it increases production of a hormone believed to have protective effects against the disease, a Canadian research team has learned.

Researchers at Mount Sinai Hospital's Samuel Lunenfeld Research Institute in Toronto have completed a study of how light and other factors, such as physical activity, influence the production of melatonin - a hormone released mainly at night in the absence of light and believed to protect against breast cancer. The findings of the study have been published in the December 1, 2005 edition of the American Journal of Epidemiology.

The study is among the first to demonstrate the role of physical activity in potentially modifying melatonin levels, thus creating biological evidence for a reduced risk of breast cancer among women who exercise regularly.

"If we know that increased melatonin production could be an underlying reason for the protective effects of physical activity against breast cancer, then there is great opportunity for the scientific community to build on this knowledge and help women understand what steps they can take to reduce their risk of developing the disease," said Dr. Julia Knight, the study's lead investigator at the Samuel Lunenfeld Research Institute at Mount Sinai Hospital and a University of Toronto professor in the Department of Public Health Sciences.

The study, funded through the Canadian Breast Cancer Research Alliance with special funding from the Canadian Breast Cancer Foundation - Ontario Chapter to study the modifiable risk factors for breast cancer, took place between 2002 and 2004 and involved the participation of 213 female volunteers whose melatonin levels were monitored over time.

"Our focus on primary prevention research was initiated with the long-term goal of building knowledge about how to stop breast cancer before it starts," said Sharon Wood, Executive Director of the Canadian Breast Cancer Foundation - Ontario Chapter. "We are encouraged by the findings of Dr. Knight's work, which could provide momentum for lifestyle changes that could lead to a healthier population and potentially reduce the incidence of breast cancer."
-end-
About the Canadian Breast Cancer Research Alliance
The Canadian Breast Cancer Research Alliance is the primary granting agency for breast cancer research in Canada. Since its inception in 1993, CBCRA has awarded $138 million to support 414 projects spanning the spectrum of breast cancer research, including prevention, early detection, treatment and care. CBCRA is a unique Canadian partnership of groups from the public, private and non-profit sectors committed to reducing the incidence of breast cancer, increasing survival, and enhancing the lives of those affected by the disease. CBCRA's members include: the Avon Flame Foundation, Canadian Breast Cancer Foundation, Canadian Breast Cancer Network, Canadian Cancer Society, Canadian Institutes of Health Research, Health Canada, the Public Health Agency of Canada, and the National Cancer Institute of Canada.

About the Canadian Breast Cancer Foundation
As the leading national volunteer-based organization dedicated to creating a future without breast cancer, the Canadian Breast Cancer Foundation works collaboratively to fund, support and advocate for relevant and innovative breast cancer research; meaningful education and awareness programs; early diagnosis and effective treatment; and a positive quality of life for those living with breast cancer. Since 1986, the Foundation has allocated millions of dollars to breast cancer research, projects and support services. It is supported by four regional Chapters: BC/Yukon, Prairies/NWT, Ontario, and Atlantic. Fundraising is done on a regional basis, with funds allocated for programs unique to the needs and priorities of each region.

About Mount Sinai Hospital
Mount Sinai Hospital is recognized nationally and internationally for its excellence in the provision of compassionate patient care, teaching and research. Its key priority programs are Women's and Infants' Health, Surgical Subspecialties and Oncology, Internal Medicine and Subspecialties, and the Samuel Lunenfeld Research Institute. It is a University of Toronto-affiliated patient care, teaching and research centre.

About The Samuel Lunenfeld Research Institute
Established in 1985, the SLRI at Mount Sinai Hospital in Toronto is one of the world's leading centres for biomedical research. The Institute is part of Mount Sinai Hospital, an internationally recognized 440-bed acute care academic health centre affiliated with the University of Toronto. SLRI has 513 research, administrative and support staff, 100,000 square feet of laboratory space and a 25,000-square-foot pre-clinical research lab. For more information about SLRI research, visit www.mshri.on.ca.

Media contacts: Joanne Woodward Fraser
Mount Sinai Hospital
416-586-4800 x8306
jwoodward@mtsinai.on.ca

Lisa Marchitto
Canadian Breast Cancer Foundation
416-815-1313 x500
lmarchitto@cbcf.org

University of Toronto

Related Breast Cancer Articles from Brightsurf:

Oncotarget: IGF2 expression in breast cancer tumors and in breast cancer cells
The Oncotarget authors propose that methylation of DVDMR represents a novel epigenetic biomarker that determines the levels of IGF2 protein expression in breast cancer.

Breast cancer: AI predicts which pre-malignant breast lesions will progress to advanced cancer
New research at Case Western Reserve University in Cleveland, Ohio, could help better determine which patients diagnosed with the pre-malignant breast cancer commonly as stage 0 are likely to progress to invasive breast cancer and therefore might benefit from additional therapy over and above surgery alone.

Partial breast irradiation effective treatment option for low-risk breast cancer
Partial breast irradiation produces similar long-term survival rates and risk for recurrence compared with whole breast irradiation for many women with low-risk, early stage breast cancer, according to new clinical data from a national clinical trial involving researchers from The Ohio State University Comprehensive Cancer Center - Arthur G.

Breast screening linked to 60 per cent lower risk of breast cancer death in first 10 years
Women who take part in breast screening have a significantly greater benefit from treatments than those who are not screened, according to a study of more than 50,000 women.

More clues revealed in link between normal breast changes and invasive breast cancer
A research team, led by investigators from Georgetown Lombardi Comprehensive Cancer Center, details how a natural and dramatic process -- changes in mammary glands to accommodate breastfeeding -- uses a molecular process believed to contribute to survival of pre-malignant breast cells.

Breast tissue tumor suppressor PTEN: A potential Achilles heel for breast cancer cells
A highly collaborative team of researchers at the Medical University of South Carolina and Ohio State University report in Nature Communications that they have identified a novel pathway for connective tissue PTEN in breast cancer cell response to radiotherapy.

Computers equal radiologists in assessing breast density and associated breast cancer risk
Automated breast-density evaluation was just as accurate in predicting women's risk of breast cancer, found and not found by mammography, as subjective evaluation done by radiologists, in a study led by researchers at UC San Francisco and Mayo Clinic.

Blood test can effectively rule out breast cancer, regardless of breast density
A new study published in PLOS ONE demonstrates that Videssa® Breast, a multi-protein biomarker blood test for breast cancer, is unaffected by breast density and can reliably rule out breast cancer in women with both dense and non-dense breast tissue.

Study shows influence of surgeons on likelihood of removal of healthy breast after breast cancer dia
Attending surgeons can have a strong influence on whether a patient undergoes contralateral prophylactic mastectomy after a diagnosis of breast cancer, according to a study published by JAMA Surgery.

Young breast cancer patients undergoing breast conserving surgery see improved prognosis
A new analysis indicates that breast cancer prognoses have improved over time in young women treated with breast conserving surgery.

Read More: Breast Cancer News and Breast Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.