Colorectal cancer (CRC)

• Context (TH): Obesity rates are increasing globally, including in India.
• A 2022 study in The Lancet found that 9.8% of Indian women and 5.4% of men are obese.
• Obesity is linked to higher risks of heart disease, diabetes, and colorectal cancer (CRC).

Obesity & Fat distribution

• Obesity is typically defined using the body mass index (BMI), which considers height and weight.
• A BMI of 25 kg/m2 or higher indicates overweight, while 30 kg/m2 or higher indicates obesity.
• However, BMI doesn’t account for how fat is distributed in the body. Scientists use measures like waist circumference, hip circumference, and waist-to-hip ratio to assess fat distribution.

Colorectal Cancer (CRC)

• CRC refers to cancers of the colon or rectum.
• CRC incidence in India is relatively low, but survival rates after diagnosis are under 40%.
• Indian CRC patients are often young and diagnosed at advanced stages, according to a 2017 study.

Who is at risk of colorectal cancer (CRC)?

• Scientists identified four body shape groups:
  • PC1 (generally obese).
  • PC2 (tall with a low waist-to-hip ratio).
  • PC3 (tall with central obesity).
  • PC4 (athletic body shape).
• PC2 and PC4 individuals showed no significant association with CRC risk.
• A gene called AKT was associated with higher colorectal cancer (CRC) risk in generally obese individuals.
• Another gene, RAF1, was linked to CRC risk in tall and centrally obese individuals.