• Idiopathic pulmonary fibrosis
• Smoking
• Clinical Epidemiology

IPF is increasing in incidence globally.1 Epidemiological studies have identified a number of risk factors for the development of idiopathic pulmonary fibrosis (IPF) including male sex, advancing age, and a history of working in dusty industrial environments or of agricultural exposures.2 3 Smoking has also long been considered a risk factor, but definitive proof has been difficult to come by, as smoking behaviour is also associated with increased risk of other exposures because of sociodemographic factors. Disentangling the relative contributions of each risk factor is therefore tricky.

Over recent years, a number of genome wide association studies (GWAS) have also identified genetic risk factors for developing IPF4 5 and in addition genetic risk factors associated with rates of disease progression have been found. Variant to gene mapping approaches have implicated a number of genes likely to underpin these genetic associations including MUC5B, TERT, TERC and KIF15 for disease initiation and PCSK6 for disease progression.6

The likelihood of an individual taking up smoking long term is also in part genetically determined, and a large number of genetic variants have been identified linked to smoking behaviour. Variant to gene mapping has in general identified genes involved in central nervous system reward and addiction pathways, or variants directly linked with the actions and metabolism of nicotine, including the well-studied CHRNA3/5 …