# Catholic University of Korea tracks early cancer risk across 6 313 338 adults

- Published: 2026-11-10 09:51 UTC
- Section: Life & Health › Medicine
- Tags: early-onset cancer risk, body mass index, abdominal obesity, waist circumference, cumulative cancer incidence, Annals of Internal Medicine
- URL: https://realtech.media/news/rt-6e5d69b6047a6b78cb2e7670_catholic_university_of/

**A nationwide cohort study evaluated obesity and cancer incidence in young adults over an 11.2-year mean follow-up.**

![Catholic University of Korea tracks early cancer risk across 6 313 338 adults](https://realtech.media/media/2026/11/e2d41296f5b929ee.jpg)
*Goleisureintl, Wikimedia Commons, CC BY 4.0*

Researchers from The Catholic University of Korea and affiliated institutions evaluated the link between body mass index, waist circumference, and early-onset cancer risk in young adults using the Korean National Health Insurance Service database from 2009 to 2021 [1]. The nationwide population-based cohort study tracked 6 313 338 individuals aged 20 to 39 years who had no prior cancer diagnosis at baseline. As reported in Annals of Internal Medicine, a total of 151 893 incident cancer cases were recorded during a mean follow-up period of 11.2 years [1]. Body mass index was classified into five categories from underweight to class II obesity based on Asian-specific criteria.

## Cumulative incidence rates

The 10-year cumulative incidence of cancer was 1.84% (95% CI, 1.83% to 1.86%) in the normal-weight group, 2.24% (CI, 2.22% to 2.27%) in the class I obesity group, and 2.62% (CI, 2.56% to 2.68%) in the class II obesity group [1]. Compared with the normal-weight cohort, absolute risk differences were 0.40% (CI, 0.39% to 0.41%) for class I obesity and 0.78% (CI, 0.73% to 0.82%) for class II obesity [1]. The relative association was more pronounced in men, whereas absolute risk differences were greater among women.

## Body mass index and abdominal measures

Combined evaluations of body mass index and waist circumference showed that individuals with class I obesity and abdominal obesity had a higher 10-year cumulative incidence of 2.45% (CI, 2.41% to 2.50%) compared to 2.13% (CI, 2.10% to 2.16%) for those without abdominal obesity [1]. This rate also exceeded the 2.20% (CI, 2.03% to 2.36%) documented for individuals with class II obesity who did not have abdominal obesity [1].

By tumor type, the highest cumulative incidence was identified for thyroid, endometrial, and ovarian cancer [1]. Obesity was not associated with an increased risk for breast cancer diagnosed by age 50 years [1]. The authors noted study limitations, including an observational design, a sample restricted to health screening participants, and unmeasured confounding factors such as smoking burden.

## Sources

1. [Annals of Internal Medicine](https://doi.org/10.7326/ANNALS-25-02612)
2. [endocrinologyadvisor.com](https://www.endocrinologyadvisor.com/news/obesity-linked-to-early-onset-cancer-risk-in-young-adults)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-6e5d69b6047a6b78cb2e7670_catholic_university_of/