Background: Even though poor metabolic health is usually associated with obesity, 30 percent of normal-weight adults are believed to be metabolically unhealthy worldwide, according to Liang.
Metabolic health is often assessed by measuring waist circumference, blood pressure, and levels of triglycerides, glucose, and high-density lipoprotein cholesterol (HDL-C, so-called "good" cholesterol) in the blood. People have metabolic syndrome if they have three or more of the following: elevated waist circumference, elevated blood pressure, elevated levels of triglycerides, elevated levels of glucose, and low levels of HDL-C. In this study, people were considered metabolically unhealthy if they had two or more of those factors excluding elevated waist circumference.
How the Study Was Conducted and Results: Liang and colleagues used data from 5,068 postmenopausal women enrolled in the Women's Health Initiative. All the women were classed as normal weight based on having a body mass index (BMI) from 18.5 kg/m2 to <25 kg/m2; 33.7 percent of them were metabolically unhealthy.
During a mean follow-up time of 14.3 years, 64 of the 3,358 women who were classed as metabolically healthy were diagnosed with colorectal cancer and 50 of the 1,710 metabolically unhealthy women. After adjusting for numerous factors that affect colorectal cancer risk, the researchers calculated that women who were metabolically unhealthy had a 49 percent increased risk for colorectal cancer relative to those who were metabolically healthy.
The researchers also found that women with metabolic syndrome had a more than two-fold higher risk for colorectal cancer relative to those who were metabolically healthy.
Author Comment: "Our finding that normal-weight U.S. women who are metabolically unhealthy have an increased risk of colorectal cancer compared with those who are metabolically healthy highlights how important it is for women to be aware of their metabolic health status, which can be assessed using standard clinical tests," said Liang.
"Colorectal cancer is the third most commonly diagnosed cancer for women in the United States," she continued. "Recognition that normal-weight women who are metabolically unhealthy may have an increased risk for colorectal cancer could result in more timely use of preventive interventions and reduce the burden of this deadly disease."
Limitations: According to Liang, the study had two main limitations. First, BMI and components of metabolic health were measured only at the time of enrollment in the Women's Health Initiative and possible changes over time could not be considered in the analysis. Second, the study population can be generalized only to postmenopausal women and not men or younger women.
###
Funding & Disclosures: The study was supported by a grant from the National Cancer Institute and the Youth Scholars Program of Beijing Normal University. Liang declares no conflicts of interest.
To interview an author on this paper, contact Julia Gunther at julia.gunther@aacr.org or 215-446-6896.
Bottom Line: Among postmenopausal women who were normal weight, those who were metabolically unhealthy had a significantly increased risk for colorectal cancer compared with those who were metabolically healthy.
Journal in Which the Study was Published: Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.
Author: Xiaoyun Liang, MD, PhD, an associate professor at Beijing Normal University in China.
Follow us: Cancer Research Catalyst http://blog.aacr.org; Twitter @AACR; and Facebook http://www.facebook.com/aacr.org
About the American Association for Cancer Research
Founded in 1907, the American Association for Cancer Research (AACR) is the world's first and largest professional organization dedicated to advancing cancer research and its mission to prevent and cure cancer. AACR membership includes more than 37,000 laboratory, translational, and clinical researchers; population scientists; other health care professionals; and patient advocates residing in 108 countries. The AACR marshals the full spectrum of expertise of the cancer community to accelerate progress in the prevention, biology, diagnosis, and treatment of cancer by annually convening more than 30 conferences and educational workshops, the largest of which is the AACR Annual Meeting with nearly 19,500 attendees. In addition, the AACR publishes eight prestigious, peer-reviewed scientific journals and a magazine for cancer survivors, patients, and their caregivers. The AACR funds meritorious research directly as well as in cooperation with numerous cancer organizations. As the Scientific Partner of Stand Up To Cancer, the AACR provides expert peer review, grants administration, and scientific oversight of team science and individual investigator grants in cancer research that have the potential for near-term patient benefit. The AACR actively communicates with legislators and other policymakers about the value of cancer research and related biomedical science in saving lives from cancer. For more information about the AACR, visit http://www.AACR.org.