Impact of obesity and lifestyle-associated risk factors on outcomes of early-onset colorectal cancer in patients younger than 50 years old: A propensity-matched analysis.

Abstract

3582 Background: Early-onset colorectal cancer (CRC) incidence is rising in individuals under 50 years old. This study aims to understand the factors influencing outcomes in this population. We evaluated the impact of obesity and other lifestyle-associated risk factors, such as smoking, alcohol use, and diabetes mellitus, on outcomes in patients with early-onset CRC. Methods: A comprehensive retrospective cohort study using the TriNetX database identified adults aged 18–49.9 diagnosed with CRC. Using propensity score matching (PSM), we compared patients with obesity (body mass index [BMI] ≥30 kg/m²) and other lifestyle-associated risk factors (smoking, alcohol use, and diabetes mellitus) to those without any risk factor, while accounting for demographics, comorbidities, and treatment. The primary outcome is the 10-year mortality in obese patients as compared to non-obese patients. Secondary outcomes included the 10-year mortality in patients with other lifestyle-associated risk factors. Results: A total of 10,220 matched pairs of obese and non-obese patients were included. Before matching, obese CRC patients were older, more likely to be male, Hispanic, or non-Hispanic Black, and had higher rates of colonoscopy, surgery, and comorbidities (p < 0.001). After PSM, obese CRC patients had significantly lower odds of 10-year mortality compared to non-obese patients (7.9% vs. 14%; adjusted odds ratio [aOR] = 0.53; 95% confidence interval [CI]: 0.47–0.60). Diabetes, smoking, and alcohol use showed no significant association with 10-year mortality in patients with early-onset CRC (e.g., diabetes: aOR = 0.96; 95% CI: 0.73–1.26). Conclusions: Our study suggests that obesity may confer a protective effect on 10-year mortality in patients with early-onset CRC, whereas other lifestyle-associated risk factors showed limited-to-no significant impact. These findings underscore the need for targeted strategies to improve access to CRC screening and treatment, particularly in younger patients with obesity, and they also open up new avenues for research into the potential mechanisms underlying these associations. Prospective studies are warranted to validate these results and explore these potential implications, further enriching our understanding of this complex disease and potentially leading to novel approaches for its management. Incidence % (N) Propensity score matching analysis Lifestyle risk factors CRC< 50 + risk factor CRC<50 - risk factor Adjusted odds ratio (aOR)* [95%CI] Obesity (BMI ≥ 30) 7.9% (406) 14.0% (714) 0.53 [0.47 - 0.60] Propensity matching analysis assessing the odds of 10-year mortality when comparing patients with early-onset colorectal cancer (< 50 years) with lifestyle-associated risk factors (e.g., obesity (N=5110) compared to equal numbers of patients without lifestyle-associated risk factors.