Self-reported reasons for colonoscopy among adults aged 45-49 versus 50 years and older from 2010-2018.

Background: In May of 2018, the American Cancer Society lowered the age of colorectal cancer (CRC) screening initiation from 50 to 45 years and in October 2020, United States Preventive Services Task Force published draft guidelines also lowering age of screening initiation to 45 years. Evaluating guideline adherence is needed; however, the majority of prior research on cancer screening do not distinguish whether colonoscopy was performed for true screening purposes or for post-symptomatic diagnosis.

Methods: Using data from the National Health Interview Survey between 2010 to mid-2018, we assessed response to the question "What was the MAIN reason you had [last] colonoscopy?" stratified by age (45-49 versus 50+ years). Multivariable logistic regression defined adjusted odds ratios of receiving last colonoscopy for screening controlling for relevant demographic characteristics. To estimate the cost burden of colonoscopy, the proportion of respondents reporting paying out of pocket for their last colonoscopy was assessed.

Results: Among 29,074 participants who had undergone a colonoscopy, 44.4 % of those aged 45-50 reported routine procedure as the reason for their most recent colonoscopy, as compared to 82.4 % in the 50+ age group (p < 0.001). Characteristics associated with undergoing colonoscopy as a routine procedure included Black race and male sex for both age cohorts (p < 0.01 for all). Notably, almost half (46.9 %) of participants younger than 50 years paid part of or the full cost of their colonoscopy, as compared to 30.7 % over the age of 50 (p < 0.001).

Conclusions: The majority of adults aged 45-49 self-report that last colonoscopy was not performed for screening, which is unsurprising given guidelines for screening for individuals under 50. As guidelines change, continued surveillance of colonoscopy patterns across age cohorts is needed, and studies should also incorporate reasons for testing.