Lifetime obesity shows increased impact in Colorectal Cancer risk: JAMA

A new study shows a higher role for cumulative lifetime excess weight in colorectal cancer (CRC) risk than previous studies based on single-point BMI measurements. The findings of this study were published in the Journal of American Medical Association - Oncology.

Excess weight is linked to an increased risk of cancer, but the danger may have been overestimated since prior research did not account for cumulative lifetime exposure. As a result, Xiangwei Li and colleagues undertook this study with the goal of determining the relationship between cumulative lifetime excess weight and the risk of colorectal cancer.

Height and self-reported weight were documented in 10-year increments starting at age 20 years up to the current age in a population-based case-control research performed in Germany since 2003, with 5635 people with CRC and 4515 people acting as controls. Body mass index (BMI), determined as weight in kilograms divided by height in meters squared, was estimated using linear interpolation for each year of age from 20 to the present. Excess BMI (eBMI) was calculated for each year of age as BMI 25 and added across ages to give the weighted number of years lived with overweight or obesity (WYOs), calculated as year eBMI. Multiple logistic regression was used to determine associations between BMI at various ages and WYOs and CRC risk. Data analysis was carried out between June 4, 2021 and December 17, 2021.

The key findings of this study are as follow:

1. The patients with CRC (n = 5635) had a mean (SD) age of 68.4 (10.9) years; 3366 were males (59.7%); the control participants (n = 4515) had a mean (SD) age of 68.5 (10.6) years; 2759 were men (61.1%).

2. WYOs and CRC risk were linked, with adjusted odds ratios (ORs) rising from 1.25 to 2.54 from the first to fourth quartile of WYOs compared to persons who stayed within the normal weight range.

3. Each SD increase in WYOs was related with a 55% increase in CRC risk.

4. This OR was greater than the OR per SD rise in eBMI at any given period, which varied from 1.04 to 1.27.

In conclusion, the use of WYOs in future research, such as prospective cohort studies, may help to more completely reveal the relationship of excess weight not just with CRC but also with other cancers and disorders.

Reference:

Li X, Jansen L, Chang-Claude J, Hoffmeister M, Brenner H. Risk of Colorectal Cancer Associated With Lifetime Excess Weight. JAMA Oncol. Published online March 17, 2022. doi:10.1001/jamaoncol.2022.006