Central Obesity Linked to Colorectal Cancer Risk

Context

Colorectal cancer (CRC) is a significant health concern globally, with rising incidence rates. Recent studies have highlighted a connection between obesity and an increased risk of developing CRC. This article delves into the nuances of this relationship, focusing on general and central obesity as distinct risk factors.

Recent Findings

• The research study which was published in the issue of Science Advances in the April month of 2022 and mentioned that there is no direct relation between the obese and the tumour of colorectal cancer (CRC) for all the people.
• And in patients with a generally high risk the risk will be higher among those who are obese (both general and central) and those who are tall and centrally obese.
• This fact means that in the cancer of the colon and rectum, genetically influenced mechanisms may affect development of the disease in the way that is different among obese individuals dependent on the subtype of obesity.

Types of Obesity

Obesity is considered as a number attached to the individual’s height and weight, and this number is called the “body mass index” or BMI. Individuals at or above the BMI of 25 kg/m2 are classified as ‘overweight’ and those at 30 kg/m2 or more as ‘obesity’. Having said that, the aforementioned definition is always devoid of how a specific kind of fat is distributed.

• General Obesity: General obesity is a situation where a person has excess body fat, in normally an amount that doesn’t look very attractive. Hence BMI above 25 kg/m² is calculated as overweight, whereas the BMI sufficing over above 30 kg/m² falling in obese category. 
• Central Obesity: Central obesity unlike widespread obesity is seen as fat accumulation in the central area of the body close to the abdomen. It has sometimes been measured by means of direct measure of the waist circumference and waist-to-hip ratio. Central obesity, in addition to metabolic disorders, represents an increasing risk of CRC. 

Colorectal Cancer

Colorectal cancer (CRC) is a term used to denote cancerous tumours that occur in the colon or the rectum. The incidence of colon and rectal cancer (CRC) in India is low but still low, and the percentage of mortality of people diagnosed five years before (survival) is less than 40 percent – which is one of the lowest in the world.

Link Between Obesity and Colorectal Cancer

• High susceptibility of colorectal cancer (CRC) together with other diseases is associated with obesity. The research was known as one of the factors, which obese people have a higher risk of colorectal cancer (CRC). In April of 2024, a Science Advances Study reported that not all obesity levels lead to the same risk of having colon cancer.
• Obesity is the main danger factor for various most severe diseases (heart disease, diabetes, cancers of certain types) For CRC, not all individuals at risk of obesity have the same risk. More specifically, central and general obesity are risk factors associated with taller than average individuals.
• Another possible association that is worth explaining between obesity and CRC is fat distribution that can vary depending on the level of metabolic health. Metabolically healthy obesity (MUHNW), metabolically healthy obesity (MHO), and metabolically unhealthy obesity (MUHO) are at different risks of colorectal cancer and have distinct metabolic phenotypes.
• The overweight or obesity is in a direct relationship with the risk of CRC regardless of metabolic health. Although the danger of excessive levels of insulin is more pronounced in individuals with metabolic abnormalities when they are obese or not.

Genetic Variations

• With the approach called genome-wide association study (GWAS), they explored whether 570 novel variations of DNA picture four body shapes or not. They evaluated data from more than 400,000 participants of the Biobank database.
• In another case, an AKT gene variant was found which is responsible, to some extent, for the increase of CRC risk in the PC1 group.
• AKT leads to modulation of a cell’s survival, insulin signalling and joining of new vessels and tumours in people. Connecting the dots, a type of RAF1 mutation also has been proven to be in the risk profiles of CRC patients with PC3 tumours already present.
• RAF1 also deletes the codes that differentiate between normal and cancerous cells during the process of cell genesis.

Conclusion

The link between obesity and CRC is complex and influenced by various factors, including body shape, fat distribution, and metabolic health. Understanding these nuances is crucial for developing targeted prevention strategies and improving screening protocols to reduce the burden of CRC.

Source: The Hindu

UPSC Mains Practice Question

Q. Discuss the correlation between central obesity and the risk of colorectal cancer. What are the underlying mechanisms that contribute to this association? Suggest preventive measures that could be implemented at the individual and public health levels to mitigate this risk.

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