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The Link between Obesity and Cancer

The Link between Obesity and Cancer



Obesity is a ‘condition’ characterised by an unhealthy amount or distribution of fat in the body. Obesity leads to various other medical problems, including diabetes, hypertension, heart disease, etc. 


Researchers typically use a scale known as the body mass index (BMI) to measure obesity. A person's BMI is calculated by multiplying their weight (in kilogrammes) by their height (in metres) squared (usually stated as kg/m2). BMI is a more accurate measure of obesity than weight alone, and it is a fairly decent (although indirect) estimate of body fat for the majority of people.


Obesity and cancer risk

Obesity has been found to be associated with an increased risk of cancers, including endometrial cancer (cancer of the lining of the uterus), cancer of the food pipe, stomach cancer, liver cancer, kidney cancer, pancreatic cancer, colorectal cancer, gall bladder cancer, breast cancer, ovarian cancer, thyroid cancer, etc.  Obesity increases the risk of cancer by two to seven fold for these various types of cancer.


How does obesity increase the risk of cancer?


Several possible mechanisms have been suggested to explain how obesity might increase the risks of some cancers.


  1. Chronic low-level inflammation can cause DNA damage over a period of time.
  2. The excess hormones released from the fat tissue, such as oestrogen, have been associated with an increased risk of breast, endometrial, ovarian, and some other cancers in women.
  3. There are several other factors, like insulin-like growth factor-1 and certain other chemicals known as adipokines (produced from fat tissue), which interfere with normal cell growth.


How much these factors contribute to the increased cancer risk is still not known for sure, and there is research going on to understand more about how obesity increases the risk of cancer.


Effect of weight loss on cancer risk:


It has been seen, though, that people who have lower weight gain during adulthood have lower risks of colon cancer, kidney cancer, and—for postmenopausal women—a lower risk of breast, endometrial, and ovarian cancers. Weight loss can help decrease the risk of some of these cancers, and interestingly, it has been seen that obese people who undergo bariatric surgery appear to have lower risks of obesity-related cancers than obese people who do not have bariatric surgery. If someone has a family history of cancer and suffers from obesity, they need to strongly treat obesity, whether that is with diet modification and exercise or bariatric surgery.


Obesity and cancer survivorship:


Obesity not only increases the risk of certain cancers but may also worsen other aspects related to cancer, like quality of life, complications associated with that, recurrence rate, progression, and overall prognosis. 


Overall, if we were to look at things from a brighter perspective, although obesity is associated with increased cancer risk, it certainly is a modifiable factor and prevention is the key. In order to curb this pandemic of obesity and its associated medical problems, we need to educate our children today for a better tomorrow!


Key takeaways

  • Several cancers are associated with an increased risk of several folds with obesity.
  • Obese patients respond unfavourably to cancer treatments and often have a higher relapse risk.
  • If you have a strong family history of cancer, you need to seek obesity treatment early.
  • Prevention is better than a cure!



Dr. Vikas Singhal
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