Associations between obesity, smoking and colorectal pathology in a clinical cohort

Background: Obesity and smoking are known risk factors for colorectal cancer (CRC) and other gastrointestinal pathologies. However, their combined effects in Middle Eastern clinical cohorts remain incompletely understood.
Objective: To determine associations between obesity (BMI) and smoking with various colorectal diseases in patients attending a major tertiary care centre in Jordan.
Methods: A retrospective cohort analysis included 1,207 patients who underwent colonoscopy at King Hussein Medical Centre (January 2021–December 2023). Data extracted included smoking history, BMI, colonoscopy findings, and histopathology. Multivariate logistic regression adjusted for age, sex, and family history.
Results: Among 1,207 patients, 32.4% were current smokers and 39.2% were obese (BMI ≥30 kg/m²). Overall, 46.3% had clinically significant colorectal pathology. Obesity was associated with adenoma (aOR=1.68, 95% CI: 1.24–2.28) and CRC (aOR=2.15, 95% CI: 1.42–3.25). Current smoking was associated with adenoma (aOR=1.92, 95% CI: 1.40–2.64) and CRC (aOR=2.45, 95% CI: 1.58–3.80). The highest risk was observed in obese current smokers (aOR=3.85, 95% CI: 2.40–6.18 for CRC), with significant synergy beyond additive effects.
Conclusion: Obesity and smoking were independently and synergistically associated with higher rates of colorectal pathology, especially neoplastic lesions. Targeted lifestyle modification programmes and incorporation of these risk factors into screening decisions are warranted.