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Did you know that there is a link between excess weight and increased risk of getting cancer? The International Agency for Research on Cancer has recognized a link between being overweight and having an increased risk of cancer in 13 sites of the body. Strikingly, the CDC reported that of all of the cancer cases that were diagnosed in 2014, approximately 40% of them were associated with overweight/obesity (55% of cancer cases diagnosed in women and 24% of those diagnosed in men).
To give you an idea of the true extent of that risk, here are some numbers from the cancer.gov factsheet on the current scientific evidence on weight status and cancer risk: Women who are overweight (BMI 25-30) or who have obesity (BMI>30) are about 2 to 4 times as likely to develop endometrial cancer compared to women with normal BMI (18.5-25). People who are overweight or have obesity are 4x as likely to develop esophageal cancer, 2x as likely to develop stomach cancer or liver cancer, 1.5x as likely to develop meningioma (a type of brain cancer) or pancreatic cancer, and 1.3x as likely to develop colorectal cancer. As demonstrated by these statistics, there is a general trend that suggests a direct association between being overweight and being at critical risk of developing several types of cancer.
To address the correlation between obesity and cancer surgence, and the central question of links between age and cancers across sex and race/ethnicity, Koroukian et al. have published a research study. In this work, the authors investigate how the patient populations for obesity associated cancers (OACs) have been changing over time. This is an important question to consider because in the past, OACs were diagnosed most frequently among people above the age of 65. When the investigators pulled data from 6 million cancer patients from a database providing clinical records of cancer cases in the USA, they found that the prevalence of OAC in patients between the ages of 50-64 has recently increased by 25% in white women and nearly 200% in Hispanic men between 2000 and 2016. Overall, they measured a 51.8% increase in OAC cases for all patients between 50 and 64 years of age, and a 43% increase in OAC for patients 65 or older.
The authors suggested that public health interventions are sorely needed to prevent and reduce the epidemic of obesity and overweight, because the implications of an increasingly overweight population are profound. A recent CDC report used data from the National Health and Nutrition Examination Survey to find that, in the time-span from the early 90s until 2016, the prevalence of obesity doubled in the 20 to 39-year-old age group (from 18 to 36%), increased from 28% to 43% in the 40-59 age group, and increased from 24% to 41% for adults over 60. Overall, an estimated 39.8% of U.S. adults over 20 have obesity (BMI>30), and another 31.8% are overweight (BMI 25-30). Unfortunately, we can only hypothesize that these rising numbers will be mirrored by rising incidence of OAC in years to come. Although extensive guidelines on dietary therapy, physical activity, and behavioral therapy have been published, successfully putting them into practice has proved to be a challenging task for our country.
The World Health Organization (WHO) categorizes overweight and obesity (as well as their related diseases) as being largely preventable. At a basic level, the WHO describes only one truly necessary condition for patients to lose weight: consume fewer calories than they spend in a given time period. The WHO recommends that this can be accomplished either by eating fewer calories, spending more calories (by increasing physical activity), or, ideally, both. Reducing the frequency of obesity could have wide-ranging impacts beyond reducing the incidence of OACs, such as leading to beneficial changes to the gut microbiome, reducing cardiovascular disease rates, and extending anticipated life spans.
What types of societal shifts or legislative actions do you think would be necessary to reverse the obesity epidemic? What would it take to reduce our current 72% prevalence of overweight/obesity in adults over 20? We are curious to hear your thoughts! Let us know on twitter @Oncobites.
Edited by: Payal Yokota
Koroukian, S. M., Dong, W., & Berger, N. A. (2019). Changes in Age Distribution of Obesity-Associated Cancers. JAMA Netw Open, 2(8), e199261. doi: 10.1001/jamanetworkopen.2019.9261
Renée Gordon (FDA)
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