Could Obesity Surgery Increase the Risk of Colon Cancer?

As for any medical treatment or surgery, the decision to undergo bariatric surgery requires that the benefits and risks are carefully evaluated by the patient and the health care team.  Amongst the list of benefits, several studies have suggested that bariatric surgery decreases the risk of cancer amongst women.   Now, a new study suggests that the risk of colorectal cancer may actually be increased after obesity surgery.

The study was an evaluation of the population database in Sweden, looking at the colon cancer incidence rates amongst men and women who had obesity surgery (gastric bypass, gastric banding, and an older procedure called vertical banded gastroplasty), compared to patients with obesity who did not have bariatric surgery.  They found that amongst those who had had bariatric surgery, the risk of colon cancer was 60% higher than those who hadn't had surgery (though the absolute numbers were fairly low - 70 out of 15,095 patients, or 0.46% of patients who had obesity surgery developed colon cancer).  Ten years after bariatric surgery, the risk of having colon cancer was double compared to people with obesity who hadn't had bariatric surgery.

These results need to be taken with a grain of salt, as there are a number of limitations to this database analysis - for example, other risk factors associated with colon cancer such as smoking, diabetes, family history etc were not available (the interested reader can read more about this here).  The study does seem to contradict the overall protective effect that bariatric surgery is thought to have on cancer risk (for women, at least) - but then again, most previous studies have not followed up patients for as long as this one, and colon cancer is known to be a very slow growing tumor.

Following gastric bypass surgery, it has been suggested that the lining of the intestine may change (called 'mucosal hyperproliferation'), and an increase in a pro-tumor chemical has been found (a cytokine called 'macrophage migration inhibitory factor'), though other tumor inducing chemicals (such as TNF alpha and interleukin 6) have been shown to decrease after bariatric surgery.  The population of intestinal bacteria change after surgery as well, and there is still much we don't know about the effects of these changes (though there appear to be metabolic benefits of these post-surgery bacterial changes).

So where does this leave us?  Well, there are still many questions to be answered about the long term efffects of bariatric surgery, which only time will teach us.  In the meantime, we must continue to carefully weigh the benefits and risks of obesity surgery, and for patients who have had bariatric surgery, colon cancer screening and surveillance should be undertaken.

@drsuepedersen

www.drsue.ca © 2013

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Weight Discrimination and Bullying

I really have to hand it to my fellow author Dr Rebecca Puhl for writing a fantastic chapter in our ‘Complications of Obesity’ textbook, about the effect of obesity stigmatization and bullying on both children and adults.  Here are some jaw-dropping and very sobering statistics and facts that she shares with us:

Discrimination in the workplace:  for the same work performed, obese women earn 6% less than healthy weight women, and obese men earn 3% less than thinner men.

Some studies have shown that managers are more willing to hire a less qualified thinner candidate, than a more qualified overweight candidate.

Health care discrimination: 69% of women report being stigmatized about their weight by their own doctor (eg feeling disrespected, dismissed, and/or upset about comments made by their MD)

One study reported that 68% of women with obesity delayed their medical care due to feeling embarrassed about being weighed, disrespected by health care providers,  and because gowns, examination tables, and other medical equipment were too small for them.

A vicious cycle:  79% of women in one study reported coping with weight stigma by eating more food.

People closest may hit the hardest: 60% of overweight people report friends, and 47% name their own spouses, as perpetrators of weight bias.

And the two that hit me the hardest:

Suicide risk in youth: over 50% of girls who experienced weight based bullying by peers or family contemplated suicide.

Suicide risk in youth: 13% of boys who were teased by family members about their weight reported attempting suicide (more than three times the risk compared to those who were not teased).

As I have blogged many times before, the stigmatization against people with obesity desperately needs to STOP.  As Dr Puhl concludes:

The stigmatization, bullying, and discrimination of obese children and adults are pervasive and lead to damaging consequences for individuals who are targeted… The adverse psychological, social, and health consequences resulting from weight stigmatization must also be prioritized in efforts to prevent and treat obesity.

@drsuepedersen

www.drsue.ca © 2013

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How Does Exercise Affect Your Hunger?

Each of us is created as a unique and beautiful person - and with that uniqueness, there is also a 'Best Weight' for each of us - a realistic weight goal (which is different for everyone) that optimizes metabolic health and overall wellbeing.  This Best Weight is at least partially genetically determined, with a number of factors likely to be players, including the weight at which the balance of our hunger and satiety hormones leave us feeling satisfied.

In keeping with this hypothesis, a new study shows us that exercise affects hunger hormones and feelings of fullness differently in people who are thin, compared to people who struggle with their weight.

The study had lean and obese participants walk for an hour on a treadmill in the evening, and served them a meal the following morning.  On a separate day, they offered the participants the same breakfast, but without exercising the night prior.

In the lean people, they found that the hunger hormone ghrelin was decreased the morning after exercise.  When the lean people were served breakfast, they felt just as full from the breakfast whether or not they had exercised the night before.

In the people with obesity, there was no decrease in the hunger hormone ghrelin after exercise (as there was for the lean people), and they felt markedly less full after breakfast when they had exercised the night prior.

The Bottom Line: another study to add to the list that teaches us that weight struggles are SO much more than calories in and calories out.

www.drsue.ca © 2013 @drsuepedersen

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