Obesity's Link To Cancer

By Masoud Rezvani, MD, FACS, FASMBS

DHMR Clinics

. https://www.dhmrclinics.com/

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Obesity's Link To Cancer

Seven out of 10 adult Americans are obese or overweight. Obesity, which is defined as a Body Mass Index (BMI) greater than 30 kg/m2, is calculated by dividing a person's weight (kilograms) by their height (meters squared). BMI provides a more accurate measure of obesity or being overweight than total body weight by itself.

Table – 1 Adult National Institutes of Health (NIH) guideline based on BMI

Being obese or overweight may cause a significant number of health issues such as diabetes, hypertension, and obstructive sleep apnea. It is also known to be a leading cause of cancer. More importantly, it seems to have a very critical role for survivors, including their risk of other chronic diseases, tolerating and minimizing the risk of surgical intervention, and chemo/radiation therapy.

With a high prevalence, high BMI puts our general population in a very high state of risk. A 2013 American Institute for Cancer Research survey found more than half of Americans are unaware that overweight and obesity are both linked to a higher risk of cancer.

Body fat is a metabolically active and essential tissue. There are distinct types of fat, each with its own characteristics and functions.

The fat located deep within our abdomen is called visceral fat. It is an independent risk factor for colorectal and breast cancers and may indicate a higher risk of metabolic abnormalities that can play a role in type 2 diabetes and other chronic diseases. Scientists report overweight people carry higher risks for cancer involvement and potentially poor treatment outcomes. That means for those who are overweight and obese, losing weight and keeping that weight off may lower cancer risk.

The percentage of cases connected to obesity varied widely for different cancer types, but it potentially could be as high as 40% for some cancers.

Several possible mechanisms have been suggested to explain the association of obesity with increased risk of cancer. The most common ones are

Fat tissues produce excess amounts of the hormone estrogen, which is associated with the risk of breast, endometrial, and some other cancers.

Obese individuals carry high levels of insulin and insulin-like growth factor-1 (known as hyperinsulinemia or insulin resistance), which may promote the development of certain tumors.

Fat cells produce hormones that may stimulate or inhibit cell growth. For example, leptin, which is more abundant in obese people, seems to promote cell reproduction, whereas adiponectin, which is less abundant in obese people, may have anti-growth effects.

Obese people often have chronic low-level inflammation, which has been associated with increased risk of cancer.

A projection of the future health and economic burden of obesity is estimated that with the continuation of existing trends in obesity will lead to about 500,000 additional cases of cancer in the United States by 2030. This analysis also found that if every adult reduced their BMI by one percent, this would prevent the increase in the number and, in fact, decrease cancer risk significantly.