Obesity may predispose individuals to early-onset colorectal adenocarcinoma

Individuals with obesity are at higher risk of developing early-onset colorectal adenocarcinoma compared with their normal-weight counterparts, as reported in a study.

Researchers used data from the Kaiser Permanente Southern California database to identify invasive colorectal adenocarcinoma cases diagnosed between ages 15 and 49 years from 2008 to 2018. Patients with a history of inflammatory bowel disease were excluded. A group of individuals without cancer was also established, with five controls matched for each case according to age, sex, and length of membership prior to index date.

The study population included 1,032 patients and 5,128 controls. The exposures of interest were obesity, type II diabetes, hypertension, and dyslipidaemia, assessed from ≥1 year prior to early-onset colorectal adenocarcinoma diagnosis or index date.

In conditional logistic regression models, obesity contributed to an increased risk of colorectal adenocarcinoma (odds ratio [OR], 1.41, 95 percent confidence interval [CI], 1.15–1.74). There was no association observed for diabetes, hypertension, or dyslipidaemia.

In an analysis stratified by tumour location, obesity showed a strong association with the risk of colon adenocarcinoma (OR, 1.56, 95 percent CI, 1.17–2.07). Its association with rectal adenocarcinoma, on the other hand, was less clear (OR, 1.19, 95 percent CI, 0.85–1.68).

There was no significant interaction detected between obesity and age (≥40 vs <40 years) and between obesity and sex.

The present data should help inform early-onset colorectal adenocarcinoma screening and prevention recommendations.