What Your Bathroom Scale Tells You About Your Cancer Risk

What to know & what to do about your cancer risk if you are obese.

No one likes being overweight.  Apart from the social stigma of being “fat,” everyone knows that being overweight is unhealthy.  Most have heard that obesity increases your risk of high blood pressure and heart disease (there is increased risk of heart attack, heart failure, sudden cardiac death, and arrhythmias).  And many appreciate that greater than 80% of Type II diabetics are overweight (by 2030, there will be more than 366 million diabetics worldwide, 90% of whom will be Type II diabetics, the vast majority of whose diabetes results from obesity).

  Being overweight also increases your risk of stroke.

But most people, including some physicians, do not truly appreciate the direct relationship that obesity has on your risk of developing cancer.

First, let’s all get on the same page as to what we mean by “obesity.”  We estimate body fat through a calculation called Body Mass Index, or BMI.  BMI takes into account both your weight and height (and for those under twenty, your specific age and gender).  BMI calculation using is quick and easy and results in a specific number.  For adults age twenty and over, a BMI of 18.5 to 24.9 is “Normal” (below 18.5 being “Underweight,” which has its own health risks); 25.0 to 29.9 is “Overweight;” and greater than 30.0 is “Obese.”

Obesity is clearly directly related to an increased risk of several types of malignancies, including cancer of the esophagus, pancreas, colon, rectum, breast (in post-menopausal women), endometrium (the lining of the uterus), thyroid, kidney, and gallbladder.

  In some cases (esophageal and endometrial malignancies), obesity is the cause of as many as 40% of cancer cases.

Recent estimates of obesity with the American population are alarming:  greater than 35% of adults, 17% of youth ages two to nineteen, and 8% of infants and toddlers are obese.  And check out the sobering cancer-related impact of these numbers:  in 2007 in the United States, 34,000 newly diagnosed cancers in men and 50,500 in women (4% of new male and 7% of new female cancer cases, respectively) were related to these folks’ obesity.

Given the horrific projections, based on current obesity trends, in 2030, fully 500,000 (yes, half-a-million) new cases of cancer in the United States will be attributable to obesity.

Not only does being obese increase your risk for numerous malignancies, living above normal weight also impacts your survival once you develop certain cancers.  For example, a report from the Fox Chase Cancer Center (to be published in the journal, Cancer) found that increasing BMI was associated with poorer outcomes (including death) for a population of prostate cancer patients.

While we are not certain exactly why obesity increases the risk of cancer development, there are several theories, one, some, or all of which may be true.  Extra fatty tissue leads to excessive estrogen production, and high levels of estrogen in the bloodstream are associated with an increased risk of breast, endometrial, and some other types of malignancies.  Type II diabetes is the result of “insulin resistance,” which stimulates the pancreas to release additional insulin.

  Increased levels of circulating insulin has been implicated in the development of tumors.  Fat cells also release hormones and other proteins which some believe interfere with normal body cell regulation, thus increasing the likelihood of uncontrolled cell growth (a cancer characteristic).  And there are many more theories.

But in the end, what matters is simply this:  if you are obese, you are more likely to develop many cancer (including some malignancies which are notoriously hard to defeat).

So what should you do if you are challenged in controlling your weight?  The no-brainer is to reduce your carbohydrates and general caloric intake as well as increase your physical activity.  However, I have no additional dietary or exercise “secrets” for you.  But what I can do is remind you that if you are obese, you must be especially diligent in your cancer screening and surveillance.  Make certain that you regularly have a colonoscopy to identify and remove colon and rectal pre-cancerous polyps before they develop into invasive tumors.  Commit to annual breast examinations by a physician, routine mammograms, and monthly breast self-exams.  Don’t ignore or delay in seeing your physician for new vaginal or rectal bleeding (even minor), abdominal pain, possible yellowing of the whites of your eyes or skin (jaundice), a change in how it feels to swallow, a lump in your neck.

Just like people who know that they have a genetic mutation that increases their risk of cancer, if you are obese, you now know that you are a person at increased risk of developing cancer.  So while you are trying to reduce your weight and increase your physical activity, keep vigilant for early signs and symptoms of malignancy, and work with your physician partner to stay on schedule with regular cancer screenings.

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