Chronic viral infection a risk factor for idiopathic pulmonary fibrosis

Persistent or chronic viral infections, such as Epstein-Barr virus (EBV) and cytomegalovirus (CMV), may promote the development, but not exacerbation, of idiopathic pulmonary fibrosis (IPF), according to the results of a meta-analysis.

Researchers searched multiple online databases for studies evaluating the effect of viral infection on IPF. They estimated statistical heterogeneity by using I2 and Cochran Q tests, as well as assessed publication bias using the funnel plot, Begg test, Egger test, and trim-and-fill methods. Regression, sensitivity and subgroup analyses were conducted to examine the effects of confounding factors, such as sex and age.

The meta-analysis included 20 case-control studies from 10 countries, with a total of 1,287 participants (mean age, 59.75 years; 69 percent male). All studies were deemed high-quality. There were 19 virus species detected using various laboratory examinations, including EBV, CMV, human herpesvirus (HHV)-6, HHV-7 and HHV-8.

Pooled data revealed that the odds of developing IPF were thrice as great in the presence of a viral infection (odds ratio [OR], 3.48, 95 percent confidence interval [CI], 1.61–7.52; p=0.001). This association was not observed for exacerbation of IPF (OR, 0.99, 95 percent CI, 0.46–2.12; p=0.988).

The findings validate the hypothesis implicating virus infection in the pathogenesis of IPF, the researchers said. Additional higher-quality studies with larger-scale samples are needed to draw conclusions about the exact causal relationship between the virus and IPF and/or the virus and acute exacerbation of IPF.