Abstract LB142: Metabolically defined body size phenotypes in relation to subsequent colorectal cancer risk
Authors: Vidman Linda , Knekta Simon , Gylling Björn , Zingmark Carl , Löfgren-Burström Anna , Palmqvist Richard , Harlid Sophia , Van Guelpen Bethany 
Published: April 2023

Abstract
Overweight and obesity have been linked to increased risk of several diseases, including colorectal cancer, but the underlying mechanisms are not fully known. An earlier study analyzed metabolically defined body size phenotypes in relation to colorectal cancer risk, using combinations of C-peptide (a marker of insulin resistance) and body mass index (BMI). Higher serum C-peptide concentrations were associated with higher colorectal cancer risk in both overweight and normal weight individuals compared to individuals with low levels of C-peptide and normal weight. The aim of the present study was to see if these results could be replicated and to further explore the role of metabolism and body size phenotypes in colorectal cancer subtypes. We conducted a nested case-control study of 1010 individuals with colorectal cancer and 1010 individually matched (age, sex, cohort, year of blood sampling and data collection, number of freeze-thaw cycles of plasma samples and fasting status at blood sampling) control participants from the population-based Northern Sweden Health and Disease Study. The blood samples and data used in our analyses were collected at a mean of 9.7 years prior to case diagnosis. Participants were categorized as (1) metabolically healthy/normal weight (BMI &lt; 25 kg/m2), (2) metabolically healthy/overweight (BMI ≥ 25 kg/m2), (3) metabolically unhealthy/normal weight (BMI &lt; 25 kg/m2), or (4) metabolically unhealthy/overweight (BMI ≥ 25 kg/m2), where metabolically healthy was defined as C-peptide in the lowest tertile, as in the previous study. We used multivariable conditional logistic regression to calculate odds ratios and confidence intervals and adjusted for tobacco smoking, recreational physical activity and alcohol consumption as potential confounders. In our preliminary results, metabolically unhealthy/overweight individuals had a significantly higher risk of developing colorectal cancer compared to metabolically healthy/normal weight individuals (adjusted odds ratio =1.44, 95% CI 1.13-1.85). The odds ratio for metabolically unhealthy/normal weight individuals was 1.23 (95% CI 0.92-1.65) and for metabolically healthy/overweight individuals 1.23 (95% CI 0.89-1.70). These results support the potential of a more nuanced analysis of metabolism and body size to better understand their etiological contribution to colorectal cancer development. To gain more knowledge about how the role of metabolism and body size might differ between tumor subtypes, we will also analyze body size phenotypes in relation to subtypes of colorectal cancer based on anatomical tumor site, KRAS and BRAF mutations and microsatellite instability status of the tumor.
Citation Format: Linda Vidman, Simon Knekta, Björn Gylling, Carl Zingmark, Anna Löfgren-Burström, Richard Palmqvist, Sophia Harlid, Bethany Van Guelpen. Metabolically defined body size phenotypes in relation to subsequent colorectal cancer risk [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB142.