The duration of overweight and obesity in women's adult lives is associated with cancer risk, according to a longitudinal study published in PLOS Medicine. The study, led by Melina Arnold of the International Agency for Research on Cancer (IARC), the specialized cancer agency of the WHO, in Lyon, France, and Professor Hoda Anton-Culver at the University of California, Irvine, uses United States Women's Health Initiative (WHI) data to identify dose-response relationships between duration of high body mass index (BMI) and the risk of developing several types of cancer.
To date, most studies exploring the relationship between excess weight and cancer risk looked at cross-sectional information on overweight and obesity. Using multiple BMI measurements over time from approximately 74,000 women (with over 6,000 cancers diagnosed during the 12.6-year mean follow-up), Arnold and colleagues examined the association between duration of overweight, obesity and cancer risk, taking into account other factors related to obesity, such as physical activity, diet, smoking, hormone use, and diabetes. They found every ten-year increase in adulthood overweight duration was associated with a 7% (95% confidence interval 6%-9%) increase in the risk of all obesity-related cancers, 5% (3%-7%) increase in risk of postmenopausal breast cancer, and 17% (12%-22%) increase in the risk of developing endometrial cancer. After adjusting for the intensity of overweight, these figures rose to 8% (5%-12%) for postmenopausal breast cancer and 37% (29%-46%) for endometrial cancer.
BMI is not an ideal measure for body fat, and the WHI cohort is dominated by non-Hispanic white women. While these aspects of study design limit generalizability of the findings, the large scale of the study and longitudinal BMI data provide compelling evidence that overweight duration is an important risk factor for cancer. The authors state, "[i]f this is true, health care teams should recognize the potential of obesity management in cancer prevention and that excess body weight in women is important to manage regardless of the age of the patient."
The WHI program is funded by the National Heart, Lung, and Blood Institute, National Institutes of Health, (http://www.nhlbi.nih.gov/) US Department of Health and Human Services through contracts HHSN268201100046C, HHSN268201100001C, HHSN268201100002C, HHSN268201100003C, HHSN268201100004C, and HHSN271201100004C. Support for this research (for MA) came from the Department of Epidemiology, School of Medicine and the Genetic Epidemiology Research Institute at the University of California, Irvine. Funding for this study (for MA and IS) was also obtained from the World Cancer Research Fund International(http://www.wcrf.org/), grant number SG 2012/619. MA was supported by a Union for International Cancer Control (UICC) International Cancer Technology Transfer Fellowship (http://www.uicc.org/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
I have read the journal's policy and the authors of this manuscript have the following competing interests: ESL's institution has received grant funding from the National Institute of Health, AHRQ, Merck, Amgen, Bristol Meyers Squibb, and Astrazeneca for her research work that is unrelated to the current study.
Arnold M, Jiang L, Stefanick ML, Johnson KC, Lane DS, LeBlanc ES, et al. (2016) Duration of Adulthood Overweight, Obesity, and Cancer Risk in the Women's Health Initiative: A Longitudinal Study from the United States. PLoS Med 13(8): e1002081. doi:10.1371/journal.pmed.1002081
Section of Cancer Surveillance, International Agency for Research on Cancer, Lyon, France
Department of Epidemiology, School of Medicine, University of California, Irvine, California, United States of America
Stanford Prevention Research Center, Department of Medicine, Stanford University, Stanford, California, United States of America
Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
Department of Preventive Medicine, Stony Brook University School of Medicine, Stony Brook, New York, United States of America
Center for Health Research, Kaiser Permanente, Portland, Oregon, United States of America
Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York, United States of America
Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
Faculty of Health Sciences and Social Welfare, University of Haifa, Haifa, Israel
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