Persistent or chronic, but not acute, viral infections significantly increase the risk of developing idiopathic pulmonary fibrosis (IPF), according to the results of a meta-analysis published in the journal CHEST.

Viral loads from patients diagnosed with IPF as measured by laboratory methods were compared with healthy controls in this meta-analysis of controlled trials. Analyzed viruses included Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpesvirus 7 (HHV7) and HHV8. Furthermore, data about acute exacerbations of IPF were also collected and compared with viral load.

Of the 48 full text articles examined, 20 met the inclusion and exclusion criteria and were included in the analysis. These 20 studies included 1287 patients from 10 countries. The mean patient age was 59.75 years and 69% were men. A total of 19 virus species were detected in 634 patients using various laboratory examinations.

EBV, CMV, HHV7 and HHV8 were found to be associated with increased IPF risk (pooled odds ratio, 3.48; 95% CI, 1.61-7.52; P =.001). However, multiple viral infections did not increase the risk for IPF. In addition, viral infections did not increase the risk for IPF exacerbations (odds ratio, 0.99; 95% CI, 0.46-2.12; P =.988).

The researchers noted that the exact etiology and pathogenesis of IPF is still unclear, and studies have focused on the role of viral infection, but the interpretation of said studies was hindered by the smaller sample sizes and differing populations.

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“Given these challenges, large-scale samples and higher quality studies are needed in the future to draw conclusions on the exact causal relationship between the virus and IPF and/or virus and acute exacerbation of IPF,” the researchers concluded.

Reference

Sheng G, Chen P, Wei Y, et al. Viral infection increases the risk of idiopathic pulmonary fibrosis: A meta-analysis [published November 12, 2019]. CHEST. doi:10.1016/j.chest.2019.10.032