A descriptive epidemiological study of interstitial lung disease in the United Kingdom general population

Interstitial lung disease (ILD) is a heterogeneous group of parenchymal lung disorders having varied histopathologies. Although histologically different, the ILDs have rather similar clinical presentations consisting of increasing dyspnea, a restrictive lung function, impaired gas exchange, and widespread shadowing on chest radiography. Approximately two-thirds of ILD cases have no known etiology. The remaining one-third is either associated with connective tissue disease (CTD) or caused by various environmental or occupational exposures including inhalation of asbestos or other inorganic particles, inhalation of inorganic agents, certain drugs and radiation therapy. It is widely accepted that prevention, improved prognosis and quality of healthcare are dependent on a better understanding of disease epidemiology, and it is to this end that the present research contributes.
This doctoral research project makes use of a large and well-validated primary care database to investigate the frequency of ILD, the incidence of comorbidity after diagnosis, and characteristics of ILD patients at diagnosis compared to a general population control group. For many ILD subgroups an increase in incidence density and prevalence over time was observed, however it is uncertain to what extent secular trends played a role in these findings. Rates for all-cause mortality and comorbidities varied greatly across ILD subgroups, as did patient characteristics at diagnosis. This research project also delved deeper into specific epidemiological topics relating to certain ILD subgroups within the more broadly-classified, non-idiopathic ILD disease category.