# Beyond the Skin: Atopic Dermatitis and Increased Gastric Cancer Risk in Korea

## TL;DR

This study finds that people with atopic dermatitis in Korea have a higher risk of gastric cancer, suggesting a need for combined skin and digestive health care.

## Contribution

The study identifies atopic dermatitis as a novel risk factor for gastric cancer in East Asian populations.

## Key findings

- Atopic dermatitis is significantly associated with increased gastric cancer risk in Korea.
- The association is stronger among older adults, men, and rural residents.
- Non-allergic rhinitis and absence of asthma are linked to higher gastric cancer risk in AD patients.

## Abstract

Atopic dermatitis (AD) is a common inflammatory skin disease that has increasingly been recognized as a systemic disorder rather than a condition limited to the skin. While previous studies from Western countries have linked AD mainly to skin cancers and lymphomas, evidence regarding its relationship with gastrointestinal cancers, particularly gastric cancer (GC), is scarce. Using a large, nationwide Korean database, we found that AD was significantly associated with an increased risk of GC, especially among older adults, men, and rural residents. These results suggest that AD may serve as a novel risk factor for GC in East Asian populations with high disease burden. Our findings highlight the need for integrated dermatologic and gastroenterologic care, and they provide important insights for cancer prevention and risk stratification strategies.

Background/Objectives: Atopic dermatitis (AD) is a prevalent chronic inflammatory skin disease, but its relationship with gastric cancer (GC) remains unclear. This study aimed to investigate the association between AD and GC using a nationwide Korean database. Methods: Using the Korean National Health Insurance Service-National Sample Cohort, we conducted a nested case–control study including 10,174 GC patients and 40,696 matched controls (1:4 by age, sex, income, and region). Overlap propensity score weighting was used to control for confounders. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated via logistic regression. Results: AD was significantly associated with an increased risk of GC (adjusted OR = 1.08; 95% CI: 1.01–1.15). Subgroup analyses revealed stronger associations among individuals aged ≥ 65 years (OR = 1.12), men (OR = 1.10), rural residents (OR = 1.14), and those without comorbidities (CCI = 0, OR = 1.15). Higher risks were also observed in participants with non-allergic rhinitis (OR = 1.43) or no asthma (OR = 1.12). Conclusions: AD may be associated with an increased risk of GC in the Korean population. These findings may highlight the importance of considering dermatological conditions in the context of systemic cancer risk.