Risk of Advanced Adenomas in Siblings of Individuals with Advanced Adenomas: A Cross-Sectional Study

Abstract

Background & Aims The risk of colorectal neoplasms among siblings of patients with advanced adenomas is not clear. We determined the prevalence of advanced adenomas in the siblings of patients with advanced adenomas and compared it with that of siblings of individuals without these lesions. Methods In a blinded, cross-sectional study, colonoscopies were performed (from 2010 through 2014), at 2 hospitals in Hong Kong on 200 asymptomatic siblings of patients with advanced adenomas (exposed; mean age, 58.2 ± 6.3 years; adenomas ≥10 mm, high-grade dysplasia, villous, or tubulovillous) and 400 age- and sex-matched siblings of subjects with normal findings from colonoscopies and no family history of colorectal cancer (unexposed; mean age, 58.1 ± 6 years). We recruited 1 sibling per family. The primary outcome was prevalence of advanced adenomas. Results Baseline demographics (ie, aspirin use, smoking, body mass index, and metabolic diseases) did not differ significantly between exposed and unexposed individuals. The prevalence of advanced adenoma was 11.5% among the exposed subjects and 2.5% among the unexposed subjects (matched odds ratio [mOR] = 6.05; 95% confidence interval [CI]: 2.74-13.36; P