Interstitial Lung Disease Epidemiology Summary

• According to DelveInsight’s analysis, ILD reported more than 1.3 million diagnosed prevalent cases in the 7MM (the United States, the EU4 (Germany, France, Italy, and Spain), the United Kingdom, and Japan) in 2025.
• ILD encompasses a heterogeneous group of diffuse parenchymal lung disorders characterized by inflammation, fibrosis, and progressive lung damage, resulting in impaired gas exchange and respiratory insufficiency. 
• Etiologies of ILD include idiopathic conditions, autoimmune diseases, environmental and occupational exposures, drug or radiation injury, and genetic predisposition. Common symptoms include exertional dyspnea, persistent dry cough, and fatigue, often delaying diagnosis.
• In 2025, idiopathic pulmonary fibrosis (IPF) represented the largest share of ILD cases in the US with approximately 125,000 cases, underscoring its central role in driving the overall ILD disease burden. This was followed closely by connective tissue disease–associated ILD (CTD-ILD) with nearly 120,00 cases, highlighting the substantial contribution of immune-mediated and systemic disorders to the ILD landscape.
• Aging populations, cumulative environmental and occupational exposures, and broader adoption of high-resolution computed tomography (HRCT) and multidisciplinary evaluation are improving the detection of mild and early-stage ILD, while greater recognition of overlapping phenotypes, including progressive pulmonary fibrosis, emphysema, and autoimmune-associated ILD, is increasing diagnostic complexity.

DelveInsight’s “Interstitial Lung Disease (ILD) – Epidemiology Forecast – 2036” report delivers an in-depth understanding of ILD, historical and forecasted epidemiology in the United States, EU4 (Germany, France, Italy, and Spain), the United Kingdom, and Japan.

Geography Covered 

North America: The United States 

Europe: Germany, France, Italy, Spain and the UK

Asia-Pacific: Japan 

Interstitial Lung Disease (ILD) Understanding 

Interstitial Lung Disease (ILD) Overview and Diagnosis

ILD, also known as diffuse parenchymal lung diseases, represents a heterogeneous group of lung disorders characterized by shared clinical, radiographic, physiologic, or pathologic features. Understanding ILD is challenging due to complex terminology and broad disease diversity. Pathologically, these conditions involve inflammatory and fibrotic processes that extend beyond the interstitium to affect the lung parenchyma, including alveoli, alveolar ducts, and bronchioles. 

The diagnosis of ILD requires a comprehensive and multidisciplinary approach, as ILD encompasses a broad and heterogeneous group of disorders with overlapping clinical, radiologic, and histopathologic features. Rather than relying on a single test, diagnosis is achieved through the integration of clinical history, physiologic assessment, imaging, laboratory evaluation, and, when necessary, tissue sampling, with the ultimate goal of identifying the underlying disease process and defining disease behavior.

Further details are provided in the report.

Interstitial Lung Disease (ILD) Epidemiology

Key Findings from Interstitial Lung Disease (ILD) Epidemiological Analysis and Forecast 

• According to DelveInsight’s estimates, in 2025, the US reported nearly 520,000 diagnosed prevalent cases of ILD.
• The US ILD patient population showed a slight female predominance in 2025, with females accounting for approximately 55% of cases compared with 45% among males.
• In 2025, sarcoidosis represented the most prevalent ILD subtype across EU4 and the UK, accounting for the largest share of diagnosed patients with approximately 180,000 cases, highlighting the significant contribution of inflammatory and immune-mediated lung disease to the regional ILD burden. This was followed by IPF with about 120,000 patients, underscoring the continued clinical and healthcare impact of progressive fibrotic ILD.
• DelveInsight’s 2025 assessment highlights a modest gender disparity in ILD in Japan, with males accounting for approximately 52% of cases and females comprising about 48%. This near-balanced distribution suggests that while ILD slightly predominates in men—potentially reflecting higher exposure to occupational or environmental risk factors—the disease burden remains substantial in women, underscoring the need for gender-inclusive awareness, diagnosis, and management strategies.
• The number of treated ILD cases in the United States was about 420,000 in 2025 and is projected to increase by 2036.This upward trend highlights a steadily expanding treated population, reflecting both a rising underlying disease burden and improvements in diagnosis and long-term disease management across the US healthcare system.

                                       Diagnosed Prevalent Cases of ILD in the 7MM in 2025

Industry Experts and Physician Views for Interstitial Lung Disease (ILD)

To keep up with ILD dynamic epidemiology trends, we take Key Opinion Leaders (KOLs) and Subject Matter Experts (SMEs) opinions working in the domain through primary research to fill the data gaps and validate our secondary research. Industry Experts were contacted for insights on the ILD epidemiology, including MD, PhD, Instructor, Postdoctoral Researcher, Professor, Researcher, and others. DelveInsight’s analysts connected with 15+ KOLs to gather insights at country level. Centers such as the University of Alabama, University Hospital Heidelberg , Keio University Hospital, Hannover Medical School etc. were contacted.

Their opinion helps understand, validate, highlight and provide epidemiological context in ILD. 

Scope of the Report

• The report covers a segment of key events, an executive summary, a descriptive overview of ILD, explaining their causes, signs and symptoms and pathogenesis.
• Comprehensive insight has been provided into the epidemiology segments and forecasts, the future growth potential of the diagnosis rate, and disease progression along diagnostic guidelines.
• The report provides an edge for understanding trends, expert insights/KOL views, and patient journeys in the 7MM.
• A detailed review of current challenges in establishing the diagnosis.

Report Insights

• Epidemiology‑based (Epi‑based) Bottom‑up Forecasting
• 11-year forecast 
• Patient Burden Trends (by geography)
• The 7MM Coverage

FAQs

Market Insights

• What is the forecast period covered in the report?
• How is epidemiological data collected and analyzed for forecasting purposes?
• Out of all EU4 countries and the UK, which country had the highest population of ILD cases?
• What are the disease risks and burdens of ILD? 

Reasons to Buy

• The report will help in developing business strategies by understanding the latest epidemiology trends.
• Insights on patient burden/prevalence, evolution in diagnosis, and factors contributing to the change in the epidemiology of the disease during the forecast years.
• To understand KOLs’ perspectives on the dynamic epidemiology trends.
• This Artificial Intelligence (AI) ‑ enabled report summarize and simplify complex datasets with in the report into clear, actionable insights for stakeholders, investors, and healthcare providers, enabling faster, data‑driven decisions.