Herpes zoster and the subsequent risk of prostate cancer in an Asian population: A nationwide population-based cohort study

It has been suggested that herpes zoster may increase the risk of subsequent prostate cancer (PCa). We aimed to assess the risk of PCa following herpes zoster by the population-based follow-up study. This is a retrospective study and data are from the Taiwan National Health Insurance Research Database (NHIRD). The study cohort comprised all patients with a diagnosis of herpes zoster (International Classification of Diseases, 9th Revision, Clinical Modification code 053.0–053.9) and followed for PCa from 1997 to 2013 (n = 11,376). Subjects younger than 20 years of age were excluded. The match-control cohort was identified from the Registry of Beneficiaries of the NHIRD and randomly selected by matching with the study cohort at a 3:1 ratio based on age (every 5-year span), and year of herpes zoster diagnosis (n = 34,128). We used Cox proportional hazards regression models to estimate the hazard ratios (HRs) for subsequent PCa, after controlling for potential cormobidities. Men with and without herpes zoster had similar age and comorbidity distributions. Among the 45,504 sampled patients, 1011 (2.22%) developed PCa during the 10 years of follow-up, 276 (2.43%) from the study cohort and 735 (2.15%) from the match-control cohort and the incidence rate was 3.13 and 2.72 per 1000 person years respectively. Patients with herpes zoster were more likely to develop PCa than patients in the match-control cohort (HR = 1.15; 95% confidence interval (CI) = 1.00–1.32, P value = .045). After adjusting for age and comorbidities, herpes zoster was associated with a 1.15 increased risk of PCa (adjusted HR = 1.15, 95% CI = 0.99–1.32, P value = .054). Our study indicates that preceding herpes zoster infection is a suggestive risk marker for subsequent PCa after controlling for potential confounders. Further prospective studies are needed to determine the relationship between herpes zoster and PCa.