Nav: Home

High body fat levels associated with increased breast cancer risk in women with normal BMI

January 26, 2018

AUSTIN, Texas -- Among postmenopausal women with normal body mass index (BMI), those with higher body fat levels had an increased risk for invasive breast cancer, according to data presented at the American Association for Cancer Research Special Conference Obesity and Cancer: Mechanisms Underlying Etiology and Outcomes, held Jan. 27-30.

"It was previously unknown whether individuals who have a normal BMI but increased body fat have an increased risk of developing cancer," said Neil Iyengar, MD, medical oncologist at Memorial Sloan Kettering Cancer Center. "Our findings show that the risk of invasive breast cancer is increased in postmenopausal women with normal BMI and higher levels of body fat, meaning that a large proportion of the population has an unrecognized risk of developing cancer."

"Body fat levels are typically measured via BMI, which is a ratio of weight to height. While BMI may be a convenient method to estimate body fat, it is not an exact way to determine whole body fat levels, as muscle mass and bone density cannot be distinguished from fat mass," said Thomas Rohan, MBBS, PhD, DHSc, professor and chair, Department of Epidemiology and Population Health at Albert Einstein College of Medicine. Dual energy X-ray absorptiometry (DXA) is a technology that can specifically measure for fat content, resulting in a more accurate assessment of total body fat levels, he explained.

The investigators analyzed data from the Women's Health Initiative (WHI), an observational study that follows the health of postmenopausal women ages 50-79. The study included participants who had a normal BMI (between 18.5 to <25.0) with baseline DXA measurements and no history of breast cancer.

During the median 16 years of follow-up, study participants were assessed for the development of invasive breast cancer, and cancer cases were evaluated for estrogen receptor (ER) positivity. Of the 3,460 participants in the study, 182 developed invasive breast cancer during follow-up; 146 of these cases were ER-positive.

In multivariable analysis, compared to women in the lowest quartile of whole body fat mass, women in the highest quartile had approximately a doubling in the risk for ER-positive breast cancer.

Iyengar and colleagues also found that the risk of ER-positive breast cancer increased by 35 percent for each 5-kilogram increase in whole body fat, despite having a normal BMI. "It is also notable that the level of physical activity was lower in women with higher amounts of body fat," said Iyengar. "This suggests that physical activity may be important even for those who are not obese or overweight."

"These findings will probably be surprising to many doctors and patients alike, as BMI is the current standard method to assess the risks for diseases related to body weight," said Andrew Dannenberg, MD, associate director of Cancer Prevention at the Sandra and Edward Meyer Cancer Center of Weill Cornell Medicine. "We hope that our findings will alert women to the possibility of increased breast cancer risk related to body fat, even if they have a healthy weight."

A limitation to the study is that the researchers were unable to analyze how changes in body fat over time related to breast cancer risk. The authors noted that findings from this study are limited to postmenopausal women and are not generalizable to other populations or other cancers.
-end-
Several authors of this study are supported by the Breast Cancer Research Foundation. The WHI program is funded by the National Heart, Lung, and Blood Institute, National Institutes of Health, U.S. Department of Health and Human Services. The investigators declare no conflicts of interest.

American Association for Cancer Research

Related Epidemiology Articles:

Understanding the epidemiology of sarcopenia throughout the lifecourse
Recent definitions of sarcopenia have integrated information on muscle mass, strength, and physical function.
Dentists in good compliance with American Heart Association guidelines, according to Rochester epidemiology project
In the first study examining dental records in the Rochester Epidemiology Project, results show that dentists and oral surgeons are in good compliance with guidelines issued by the American Heart Association (AHA) in 2007, describing prophylactic antibiotic use prior to invasive dental procedures.
Spatial epidemiology used to identify 3 key hepatitis C hotspots in Massachusetts
Public health researchers from Tufts and colleagues conducted a spatial epidemiology study to identify hotspot clusters of hepatitis C infections in Massachusetts.
Large integrated health outcomes study reveals shifting epidemiology in drug-resistant organisms
A first-of-its-kind study of 900,000 hospital admissions from an integrated health system has yielded insights into shifts in the epidemiology of multi-drug resistant organisms in the community.
Understanding the epidemiology of fractures in diabetes
The paper reports on the complexity of fracture epidemiology in diabetes, and makes recommendations for the clinician and for future research.
A broken bone may lead to widespread body pain -- not just at the site of the fracture
Breaking a major bone may increase risk of widespread chronic body pain in later life, a new study has found.
Epidemiology of HIV-1 transmitted drug resistance
Only a limited number of surveillance drug-resistance mutations are responsible for most instances of non-nucleoside reverse transcriptase inhibitor- and nucleoside reverse transcriptase inhibitor-associated resistance, and most strains of HIV-1 transmitted drug resistance in sub-Saharan Africa and south/southeast Asia arose independently, according to a study led by Soo-Yon Rhee of Stanford University, published this week in PLOS Medicine.
Healthcare workers wash hands more often when in presence of peers
Nationally, hand hygiene adherence by healthcare workers remains staggeringly low despite its critical importance in infection control.
MRSA colonization common in groin and rectal areas
Colonization of methicillin-resistant Staphylococcus aureus allows people in the community to unknowingly harbor and spread this life-threatening bacteria.
Exercise associated with reduced risk of breast cancer in African-American women
Regular exercise, including brisk walking, is associated with a decrease in the incidence of breast cancer in African American women.

Related Epidemiology Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Bias And Perception
How does bias distort our thinking, our listening, our beliefs... and even our search results? How can we fight it? This hour, TED speakers explore ideas about the unconscious biases that shape us. Guests include writer and broadcaster Yassmin Abdel-Magied, climatologist J. Marshall Shepherd, journalist Andreas Ekström, and experimental psychologist Tony Salvador.
Now Playing: Science for the People

#513 Dinosaur Tails
This week: dinosaurs! We're discussing dinosaur tails, bipedalism, paleontology public outreach, dinosaur MOOCs, and other neat dinosaur related things with Dr. Scott Persons from the University of Alberta, who is also the author of the book "Dinosaurs of the Alberta Badlands".