This study found a positive correlation between risk for colorectal cancer and early life body size owing to the retention of large body size into adulthood.
Childhood obesity has an increasing prevalence across most geographic regions and serves as a major public health challenge globally. A Mendelian randomization study suggested a positive correlation between the risk for colorectal cancer and early-life body size owing to retained large body size into adulthood. These findings are published in the journal BMC Medicine.
Early Life Body Size and Its Association With Colorectal Cancer Risk
Mendelian randomization estimates suggest that genetically-determined early life body size tends to increase the odds of risk for colorectal cancer, particularly for distal colon and colon cancer. Early-life body size does not directly influence the risk for colorectal cancer, except for distal colon cancer. This study demonstrated insufficient evidence to support the positive relationship between the risk for colorectal cancer in later life and early-life body size.
Early Life Body Size May Indirectly Influence Colorectal Cancer Risk in Later Life
Despite the lack of evidence supporting a positive relationship between colorectal cancer risk in later life and early-life body size, this study suggested that the retention of early life obesity through adulthood may contribute to the risk for the development of colorectal cancer. According to the current study, adult body size directly affects the risk for colorectal cancer in both men and women, with a P value of 0.02.
Link Between Adult Body Size and Colorectal Cancer, Particularly in Men
The study also reported that adult body size might increase the risk of colorectal cancer, particularly in men. In the sex-combined model, adult body size increased the risk of colorectal, colon, and proximal colon cancer, with smaller effects observed for distal and rectal cancers. Women with larger adult body sizes also had an increased risk of colon, proximal colon, and rectal cancers, but the estimates were imprecise. Notably, opposing estimates were observed for the direct effect of adult body size on distal colon cancer in men and women.
Research Calls for Genetic Exploration of BMI’s Link to Colorectal Cancer Risk
One of the limitations of the current study was the lack of identifying genetic determinants of body mass index (BMI) associated with the risk for colorectal cancer. This may aid in minimizing the heterogeneity in the study results.
The study determined a positive correlation between colorectal cancer risk and early life body size associated with retained weight into adulthood.
Papadimitriou, N., Bull, C. J., Jenab, M., Hughes, D. J., Bell, J. A., Sanderson, E., Timpson, N. J., Smith, G. D., Albanes, D., Campbell, P. T., Küry, S., Le Marchand, L., Ulrich, C. M., Visvanathan, K., Figueiredo, J. C., Newcomb, P. A., Pai, R. K., Peters, U., Tsilidis, K. K., . . . Murphy, N. (2023). Separating the effects of early and later life adiposity on colorectal cancer risk: a Mendelian randomization study. BMC Medicine, 21(1), 5. https://doi.org/10.1186/s12916-022-02702-9