Interstitial lung disease: NHLBI Workshop on the Primary Prevention of Chronic Lung Diseases

Abstract

Population-based, longitudinal studies spanning decades linking risk factors in childhood, adolescence and early adulthood to incident clinical interstitial lung disease (ILD) events in late adulthood have not been performed. In addition, no observational or randomized clinical trials have been conducted; therefore, there is presently no evidence to support the notion that reduction of risk factor levels in early life prevents ILD events in adult life. Primary prevention strategies are host-directed interventions designed to modify adverse risk factors (i.e., smoking) with the goal of preventing the development of ILD, whereas primordial prevention for ILD can be defined as the elimination of external risk factors (i.e., environmental pollutants). As no ILD primary prevention studies have been previously conducted, we propose that research studies that promote implementation of primary prevention strategies could, over time, make a subset of ILD preventable. Herein, we provide a number of initial steps required for the future implementation of prevention strategies; this statement discusses the rationale and available evidence that support potential opportunities for primordial and primary prevention, as well as fertile areas for future research of preventive intervention in ILD.

Figure 1.

The natural history of patients affected by idiopathic interstitial pneumonia has been well characterized. Clinical progression is heterogeneous, with a rate of decline in lung function that can be slowly or rapidly progressive, with a subset of patients that will develop periods of rapid decline or acute disease exacerbation. What remain poorly defined are the inciting events, disease onset, and progression from asymptomatic to symptomatic interstitial lung disease (ILD). The widespread use of high-resolution computed tomography in clinical and research settings has increased the detection of subclinical ILD in family members of affected individuals with familial pulmonary fibrosis, smokers and subjects with connective tissue disease. A better understanding of the phenotypic and molecular characteristics of subclinical ILD will increase our ability to identify at-risk populations and implement preventive strategies.

Figure 2.

Priority research areas proposed for at-risk populations. Ongoing studies have focused on defining the phenotype and endotype of populations affected with subclinical interstitial lung disease (ILD). In the short term, observational studies will enhance our ability to identify proxy measures and risk factors, which will be required to design therapeutic interventions and, in the long term, determine the longitudinal outcomes of subjects affected with subclinical ILD. FHS = Framingham Heart Study; MESA = Multi-Ethnic Study of Atherosclerosis; MRI = magnetic resonance imaging; RA = rheumatoid arthritis; RCT = randomized controlled trial; Ssc = systemic sclerosis.