The multicenter team of researchers, led by Anne McTiernan, M.D., Ph.D., of Fred Hutchinson Cancer Research Center, found that women who had the lowest body-mass index, or BMI, and the highest physical-activity levels had the lowest levels of circulating estrogens, sex hormones that can fuel breast-cancer growth.
Specifically, they found a significant decrease in the two most common, biologically active forms of estrogen, estrone and estradiol, among the most active, lean women studied. The researchers found that women with high BMI and low physical-activity had mean estrogen concentrations that were 50 percent to 100 percent higher than that of women with low BMI and high activity levels.
"Women with high levels of estrogens have a two-to-four-times-higher risk of breast cancer than women with very low levels," said McTiernan, a member of the Hutchinson Center's Public Health Sciences Division and co-investigator of the Women's Health Initiative Clinical Coordinating Center, which is based at the Center. "If a woman can keep her own natural estrogens lower after menopause, it is probably going to be beneficial in terms of reducing her risk of breast cancer."
The study, based on a random sample of 267 postmenopausal women nationwide selected from the WHI Dietary Modification Trial, is the first of its kind to examine the dual impact of body weight and physical activity on levels of various circulating sex hormones thought to impact cancer risk.
"Other studies have looked at the impact of body weight by itself or physical activity by itself but this is the first to look at both together regarding their influence on hormone levels," McTiernan said. "This gives us a new understanding that combining weight control with high levels of physical activity is necessary for keeping estrogens at a healthy level in postmenopausal women." Exercising vigorously for 30 to 60 minutes a day, five days a week would achieve this benefit, McTiernan said.
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New malaria analysis method reveals disease severity in minutes
14.08.2017 | University of British Columbia
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
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