Obesity and Cancer : Dr. Nilesh D. Mehta


Obesity and Cancer :  Dr. Nilesh D. Mehta : hiINDiA

Certain cancers tend to occur at a later age in life.   As one gets older, there are certain changes in our DNA and body chemistry that can increase the risk and lead to the development of cancers affecting certain organs.  There are well described risk factors for some cancers, however, it is not exactly clear what is the exact etiology of cancer. Role of genetic factors, viral infections, bacterial infections, environmental factors, dietary factors may all be contributing towards the causation of malignant diseases.  Obesity has been linked to several cancers.  A recent study published utilising the North American database of cancer Registry has shown some startling information.  The risk of developing obesity related cancer appears to be increasing in younger patients.  These are certainly some extremely disturbing trends in cancer epidemiology.  The risk of developing cancer in young adults is increasing for half of the obesity related cancers.

After carefully studying North American Cancer Registries, data was collected on 30 cancer types diagnosed in patients aged 25–84 years from Jan 1, 1995 – Dec 31, 2014. Analysis was limited to 25 US state registries that had data for all study years which essentially covered 67% of the US population. All invasive cases of 30 cancer types diagnosed in patients aged 25–84 years during the study period in these registries were included in the study. Incidence was noted to be significantly increased for six of 12 obesity-related cancers (multiple myeloma which is a bone marrow cancer, colorectal, uterus, gallbladder, kidney, and pancreatic cancer) in young adults (25–49 years).

The risk of cancer is increasing in young adults for half of the obesity-related cancers, with the increase steeper in progressively younger ages,” said Ahmedin Jemal, D.V.M., Ph.D., who is the vice president of the Surveillance and Health Services Research Program for the American Cancer Society.  The risk was increasing in a stepwise manner in successively younger people. “The findings from this study are a warning for increased burden of obesity-related cancer in older adults in the future,” commented Ahmedin Jemal.  He further expressed his concern by stating – “potentially halting or reversing the progress achieved in reducing cancer mortality over the past several decades.”

Based on some estimates, obesity has reached epidemic proportions according to the World Health Organization which estimates more than 1 billion adults are overweight and of these 300 millions of them are considered clinically obese in the world. Not all obese patients develop malignancy, but, an overweight individual is more likely to get cancer compared to their normal weighing counterparts. The exact mechanism of how obesity leads to increased cancer risk is poorly understood. Researchers believe it is largely due to the inflammation caused by visceral fat.  Adipose tissue or fat cells make extra hormones and growth factors which in turn tells our cells to divide more often.  Sometimes, this multiplication and cell division can lead to abnormal cellular proliferation which can lead to cancer.

Avoidance or elimination of potential risk factors for any disease would help in improved healthcare outcomes especially in cancer. Not smoking at all or elimination of all forms of tobacco would certainly go a long way in decreasing the number of new cancer patients globally. This is particularly a much bigger issue in India and other Asian nations.

Can we prevent obesity completely? There are certain genetic factors at play which one cannot control. And, why worry about what we cannot control and we should focus on other preventive strategies. Eating less, calorie restriction, exercise, limiting or not drinking alcohol, avoidance of all forms of nicotine are some of the factors that are in our hands. Obesity and Cancer connection has been known for decades. Now, this study is a wakeup call not only for adults but our younger generations also. We should take our caloric consumption seriously and that is the bottom line. Eat well and eat healthy.

Dr. Nilesh D. Mehta