Compiler: Gongzi Xin
Colorectal cancer is the third most common cancer worldwide and the second leading cause of cancer deaths worldwide, with more than 1.9 million cases and nearly 1 million deaths in 2020. There is evidence that people who are overweight or obese (BMI≥25 kg/m²) have a higher risk of colorectal cancer.
Waist circumference, hip circumference, waist-to-hip ratio represent surrogate markers of body fat distribution and are similar to BMI, showing an association with the risk of colorectal cancer, but not providing additional insight into the etiology or risk of colorectal cancer. Considering these anthropometric characteristics together can provide information about the role of body type in cancer development and further understand how obesity subtypes correlate with colorectal cancer risk differences.
A few days ago, a large international medical research team assessed the size and genetic predisposition of tens of thousands of people to understand the risk of colorectal cancer. It was found that people with average obesity and tall "apple" size were more likely to develop colorectal cancer than people with other body types. The study was published in the journal Science Advances.
In 2016, a group of researchers proposed a promising approach to body type definition, hoping to provide information about the role of body type in the development of colorectal cancer. The method was derived from data from 170,000 individuals of European ancestry and was based on principal component analysis of 6 anthropometric characteristics (BMI, weight, height, waist circumference, hip circumference, and waist-to-hip ratio).
In observational analysis, two distinct and orthogonal body types characterized the body types of common obesity and tall central obesity, respectively, and both were strongly positively correlated with colorectal cancer risk. These preliminary findings need to be replicated in different study populations and their potential causal basis assessed. Moreover, the occurrence of colorectal cancer is characterized by various genetic and molecular changes, and body type may play a role through this unique but currently unknown molecular pathway. To that end, in the new study, the team conducted a similar study on a larger population.
A flowchart summarizing the research methodology
The study, the largest of its kind to date, involved collecting and studying data from 550,000 adults recorded in the UK Biobank. Genetic data from tissue samples collected from an additional 800 donors were also studied.
The team found that taller people with an "apple" size were more likely to develop colorectal cancer than people with other genetically encoded body types. An "apple" shape means that they are genetically inclined to gain weight around the waist. The team also found that tall, "apple"-shaped people tend to have more digestive health-related health problems. In addition, the average obese person, who is prone to becoming obese due to an unhealthy diet, is also more likely to develop colorectal cancer.
The researchers noted that the body type of generalized obesity was associated with gene expression patterns in tissues with a high proportion of nerve cells, while the body type of tall central obesity was associated with gene expression patterns in mesenchymal cells. This suggests that these two different body types may work through different downstream molecular pathways through which they affect the risk of colorectal cancer.
Data Diagram and Reference Sources:
https://www.science.org/doi/10.1126/sciadv.adj1987
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