# Combined effect of diabetes and obesity on cancer risk in chronic kidney disease: a nationwide population-based study

## TL;DR

This study finds that diabetes and obesity together increase cancer risk in people with chronic kidney disease, especially for gastrointestinal and female-specific cancers.

## Contribution

The study identifies combined effects of diabetes and obesity on cancer risk in CKD patients using a large nationwide cohort.

## Key findings

- Diabetes and obesity independently increase overall cancer risk in CKD patients.
- Combined diabetes and obesity amplify cancer risks for gastrointestinal and female-specific cancers.
- Higher BMI and waist circumference are linked to increased hepatobiliary and kidney cancer risks.

## Abstract

The effects of diabetes and obesity on cancer risk in patients with chronic kidney disease (CKD) remain unclear. We examined the independent and combined effects of diabetes, body mass index (BMI), and waist circumference (WC) on overall and site-specific cancer risk in CKD.

Overall, data from 1,955,504 adults aged ≥ 20 years who underwent health checkups (2012–2017) were analyzed using the Korean National Health Insurance Service database. CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73m² or proteinuria. Participants were stratified using glycemic status (normal, impaired fasting glucose [IFG], and diabetes), BMI (<18.5, 18.5–23, 23–25, 25–30, ≥30 kg/m²), and sex-specific WC categories.

During a median 7.7-year follow-up, 162,463 new cancer cases (8.3%) were identified among 1,955,504 participants with CKD. Compared with individuals with normal fasting glucose (NFG), those with IFG and diabetes had significantly higher overall cancer risk (adjusted HR [aHR] 1.025, 95% CI 1.012–1.037 and aHR 1.176, 95% CI 1.162–1.190, respectively). Higher BMI and WC were associated with cancer risk, with the highest categories showing aHRs of 1.080 (95% CI 1.056–1.105) and 1.128 (95% CI 1.106–1.152), respectively. Site-specific analyses showed diabetes was strongly associated with liver, gallbladder, and pancreatic cancers. Higher BMI and WC increased hepatobiliary, kidney, and female-specific cancer risks. Combined diabetes and obesity amplified risks, especially for gastrointestinal and female-specific cancers, while prostate cancer risk declined with lower BMI or WC regardless of diabetes.

In this large CKD cohort, diabetes and obesity independently and jointly increased overall and site-specific cancer risk, particularly gastrointestinal and female-specific cancers.