Junkfood Science: The compassionate message was lost

April 24, 2008

The compassionate message was lost

Cancer patients became another target of the war on obesity in the cruelest imaginable way when a new study was released this week in Cancer, the journal of the American Cancer Society.

To say that the conclusions of this study and its spin in the news were grossly overstated and bore little resemblance to the actual study, is an understatement.

Before going into detail, let’s put it in the simplest language possible. Physical education and recreation professors took data from the 2005 Canadian Community Health Survey, which included computerized interviews on 114,355 adults who had self-reported if they had cancer or had ever been diagnosed with cancer and what type; their height, weight, age and gender; and how often and long they engaged in leisure time activity (sports, exercises, weight training, yard work etc.) in the past 3 months. The authors calculated the metabolic equivalent task value and labeled as “desirable” amounts of physical activity the equivalent of 1 hour/day of moderate-intensity activity such as brisk walking. They then plotted BMIs and physical activity and looked for correlations between “BMI and participation in various leisure-time activities. That’s it. To put it simply, they were said to have found:

Fat people were more likely to be cancer survivors.

Sedentary people were more likely to be cancer survivors.

This was seen as bad news. They concluded that population-wide interventions were necessary to encourage weight loss and more physical activity in cancer survivors to promote a ‘healthy’ body weight.

But they had just shown that:

Fat people were more likely to be cancer survivors.

Sedentary people were more likely to be cancer survivors.

Their conclusions proposed negating what their own study had supposedly just found.

The press release issued with this study, from which the media took its script, actually condemned fat cancer survivors as being irresponsible for having poor lifestyle habits, because “obesity and physical inactivity are known to be detrimental to health.” [emphasis added] Worse, they reprimanded fat cancer survivors for not changing their ways even after being diagnosed with cancer, saying that “a cancer diagnosis does not appear to prompt significant behavior change.”

Blame is one of the most tragic and hurtful consequences of today’s popular beliefs that eating and living ‘right’ ensures health and helps prevent diseases, such as cancers. Such blame causes pain and anxiety for cancer survivors and cancer patients at a time when they most need support; or worse, could lead them to make diet and health decisions that might jeopardize their health.

This study is the weakest of all types of studies, a data dredge through unsubstantiated and highly selective data looking for correlations. It did not follow a single patient — or even examine a single patient — or make any attempt to verify any information, or learn the cause or time frame for weight gain. It made no effort to gather, consider or adjust for significant known survival measures, such as tumor type or stage. It did not examine a single health outcome to support its sweeping conclusions and recommendations, or for anyone to credibly interpret the correlations. What purpose did this study serve to improve public health or advance our understanding of cancers? Or was its purpose to heighten support for the war on obesity?**

Here are just a few examples of information that wasn’t reported in the news, but can help us see why the news was only worth lining the bird cage.

The claims that everybody “knows” fat is unhealthy and associated with poorer cancer outcomes is not evidence-based research. As JFS readers know, there is no credible evidence to support beliefs that obesity is associated with a greater risk of dying from cancers or of cancer recurrence. In fact, the evidence continues to refute this fear.

Senior research scientists of the Centers for Disease Control and Prevention at the National Center for Health Statistics, for example, recently compiled the mortality data from the National Health and Nutrition Examination Surveys from 1971 through 2000 and U.S. vital statistics on the causes of death. They found: “Our results showed little or no association of excess all-cancer mortality with any of the BMI categories. None of the estimates of excess deaths was statistically significantly different [from null].”

Also recently reported, being fat has not been shown to reduce a woman’s chances of surviving hormone-mediated cancers. The most important factors have been shown to be the grade and stage of the cancer, followed by age at diagnosis.

In actuality, this study was unable to find any tenable correlations between obesity and cancer survival among the cancers they examined (it was another case of splitting hairs) — for ‘obese’ women relative risks (RR=0.88-1.26) ranged from 12% lower (colorectal) to 19% higher (skin nonmelanoma) — for ‘obese’ men relative risks (RR=0.86-1.34) ranged from 14% lower (colorectal) to 34% higher (skin melanoma). All hugging either side of null and within the margin of error and random chance.

In actual proportions of those surviving any cancer at various BMIs compared with matching peers without cancer in the general public, there was a higher percentage of ‘obese’ survivors than those of ‘healthy’ weight. Obesity had 1.2% (for men) to 4.1% (for women) higher rates of cancer survival; ‘healthy weight had a 3.7% (for men) and 5.3% (for women) lower rates of cancer survival. (These were uncontrolled for age, cancer stage, etc.)

But which came first, the weight or the cancer? There’s no way to know from this study. Besides the fact that there is no evidence that being fat spells death from cancer, and plenty of evidence for a survival benefit in many conditions (see Obesity Paradoxes), we could also look at this study’s results in another way.

This study made absolutely no attempt to consider or account for obvious treatment-related factors that result in weight gain and diminished exercising during or after cancer treatments. In any case, this study could have provided a valuable opportunity to give the public sound and helpful information that could increase understanding and compassion for cancer patients and survivors, of all sizes.

For example, according to the National Cancer Institute, weight gain during chemotherapy is especially common for breast, prostate and ovarian cancers; as a side effect for patients given certain chemotherapeutic drugs; and those given hormones. Many anticancer drugs are also given with massive doses of steroids, which can lead to significant weight gain. Anti-cancer medications can also cause fluid retention. In this study, the authors took particular note of fat women breast cancer survivors, without mentioning that women undergoing chemotherapy for breast cancer gain 5 to 8 pounds on average. Some may gain less, while others can gain as much as 25 pounds over the course of their treatments. Blaming cancer patients for the side effects of chemotherapy is beyond heartless.

There are numerous other side effects of cancer treatments that can leave patients with diminished ability to engage in prolonged or intense physical activity. Long-term debilitating exhaustion and need for rest is extremely common as their bodies need time to recover, heal and regain strength. Chemotherapy and radiation treatments can take very hard tolls on the body, damaging the thyroid and affect energy levels and weight, and/or result in heart damage, loss of muscle mass, nerve damage and cognitive deficits. Blaming cancer patients for the side effects of chemotherapy is beyond uncaring. Whether they’re a few pounds heavier is the very least important worry.

Most oncologists, concerned for their patients’ health and wellbeing, in fact, do not encourage patients to try and lose weight. Their bodies are already under incredible stress and need more energy and nutrients to improve their chances for survival.

An additional point is worthy of note: their claim that “fewer than 22% of cancer survivors were physically active at the desired level.” As we learned in a previous post, how physical activity is defined can create a false perception of a group of sloths. These authors’ unusual definition not only included only leisure time activity — disregarding work-related physical activity — but also created a definition of ideal physical activity as 1 hour/day. While it might be understandable that university faculty of physical education and recreation might believe sports and exercise to be the most important activity in life, it is widely recognized (and found in most government guidelines, including the U.S.), that the amount of physical movement offering health benefits is achieved in 30 minutes most days of the week of any moderate activity.

As the authors acknowledged, while the measures aren’t precisely comparable, “our moderately active cutpoint is more comparable to the U.S. studies and showed that about 46% of Canadian cancer survivors were at least minimally active.” Also, not accurately reported in the news, there was “no differences between the cancer survivors as a group and [the general public] in prevalences of physical activity.”

Also not mentioned, is that for most of the cancer survivors, moderate-level activity was associated with greater survival than the high amount of activity that these authors considered as ideally “active.”

The cancer survivors in this study were people. They survived — months to years of biopsies, surgeries, endless tests, chemotherapy, radiation, hair loss, side effects and emotional rollercoasters of fear. They survived. They’re here for those who love them. That’s more important than what dress or pants size they wear or what they look like.

Maybe, there is a valuable message in this study and it’s the cancer patients who can teach us something. After a cancer diagnosis, the fact that they didn’t increase their physical activity to one hour a day may also indicate other priorities proved more important. Maybe, they’ve learned just how precious time is and that the meaning of life isn’t in obsessively exercising and dieting trying to become thin.

Maybe, just maybe, there’s more to life than what we look like.

© 2008 Sandy Szwarc

** All of the study authors worked for universities (University of Alberta and Queen’s University) that are partners in the Canadian Obesity Network (CON). Additionally, Dr. Peter Katzmarzyk Ph.D., is a personal member of CON listed under its experts on the “costs of obesity” and epidemiology. For more information on CON, the lobbying organization for obesity, weight loss and bariatric industry interests, government and policy makers and universities, see here.

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