STOCKHOLM, Sweden (AP) — July 24, 2025 — People with interstitial lung disease (ILD) face a significantly higher risk of developing most types of lung cancer, even after accounting for family history and other cancer-related factors. This crucial finding, derived from a large Swedish study, suggests that ILD should be a key consideration in lung cancer risk assessments.
ILD Linked to Elevated Lung Cancer Risk Across Subtypes
A new study suggests interstitial lung disease significantly increases the odds of developing various lung cancer forms.
- Interstitial lung disease (ILD) is linked to a doubled risk of lung cancer.
- The increased risk applies to all major lung cancer subtypes.
- Sibling-controlled analysis reinforces the association, minimizing genetic influence.
- ILD presence should be integrated into lung cancer risk models, researchers say.
The study, published in JAMA Network Open, analyzed data from over 5.4 million individuals in Sweden, born between 1932 and 1987, with follow-up from 1987 to 2016. Researchers found that individuals with ILD were more than twice as likely to develop lung cancer compared to the general population.
Study Design and Data
The research team, led by Weimin Ye, MD, PhD, of Karolinska Institutet in Stockholm, Sweden, and Mingqiang Kang, MD, PhD, of Fujian Medical University Union Hospital in Fuzhou, China, utilized data from the Swedish Total Population Register and the Swedish Multi-generation Register. This comprehensive dataset allowed for both population-based and sibling-controlled analyses.
In total, 5,425,976 individuals were included. Of these, 14,624 had a diagnosis of ILD, and 5,411,352 served as the general population comparison group.
Key Findings on Lung Cancer Risk
Over the nearly 30-year follow-up period, 227 cases of lung cancer were diagnosed among individuals with ILD, equating to an incidence rate of 355.4 per 100,000 person-years. In stark contrast, 40,592 lung cancer cases occurred in the general population group, with an incidence rate of 26.2 per 100,000 person-years.
After adjusting for factors such as sex, age, calendar period, educational attainment, and smoking-related diseases, individuals with ILD had a 2.16 times higher risk of developing lung cancer (HR = 2.16, 95% CI = 1.89–2.46).
The sibling-controlled analyses further strengthened these findings, revealing an even higher risk of 2.91 times (HR = 2.91; 95% CI = 1.98–4.27). This design helps to mitigate the impact of shared genetic and environmental factors within families.
Subtype Analysis Reveals Broad Impact
The increased risk associated with ILD was not confined to a single type of lung cancer. The study found elevated risks for:
- Adenocarcinoma: HR = 1.60, 95% CI = 1.28–2.01
- Squamous cell carcinoma: HR = 2.56, 95% CI = 1.99–3.29
- Small cell carcinoma: HR = 3.29, 95% CI = 2.32–4.68
- Other histologic types: HR = 2.32, 95% CI = 1.78–3.01
The sibling-controlled analyses generally supported these results across the different histological subtypes.
“This study is the first, to our knowledge, to use a sibling-controlled design, thereby incorporating genetic considerations and minimizing potential familial confounding,” the investigators commented. “Our findings indicate that ILD is associated with an elevated risk of lung cancer, even after adjusting for familial factors. Furthermore, additional analyses across different histological subtypes of lung cancer demonstrated that ILD increases the risk for all subtypes examined.”
The research was supported by a grant from the Swedish Cancer Society. The study authors declared no conflicts of interest.
