Perceived psychological stress and risk of herpes zoster: a nationwide population-based cohort study

Background Psychological stress may reduce cellular immunity, but its role in triggering latent infections, including herpes zoster (HZ), is controversial. Objectives To examine the association between perceived psychological stress and risk of HZ. Methods In a linked registry-based cohort study, we followed 77 310 persons aged 40 years or older who participated in the 2010 Danish National Health Survey from 1 May 2010 until HZ diagnosis, death, emigration or 1 July 2014, whichever occurred first. We computed hazard ratios (HRs) of HZ associated with Cohen's Perceived Stress Scale (PSS) score (range 0-40) using Cox regression with age as the timescale, adjusted for sex, immunosuppressive and selected chronic conditions, immunosuppressive drugs, and sociodemographic, lifestyle and anthropometric factors. The PSS measures chronic stress perceived by an individual in response to various demands of daily life. We modelled the PSS score using quintiles and a restricted cubic spline function. Results The unadjusted rate of HZ varied from 5 center dot 53 to 7 center dot 20 per 1000 person-years from the lowest to the highest PSS score quintile. Compared with the lowest PSS score quintile, the adjusted HR for HZ was 1 center dot 00 [95% confidence interval (CI) 0 center dot 86-1 center dot 16], 1 center dot 08 (95% CI 0 center dot 92-1 center dot 26), 1 center dot 05 (95% CI 0 center dot 90-1 center dot 23) and 1 center dot 14 (95% CI 0 center dot 97-1 center dot 34) for the second to the fifth quintile, respectively. In cubic spline analyses, PSS scores < 20 were not associated with increased HR of HZ, but thereafter the HR increased linearly from 1 center dot 10 (95% CI 0 center dot 85-1 center dot 41) to 2 center dot 22 (95% CI 1 center dot 32-3 center dot 75). Conclusions Our study indicated that high levels of psychological stress are associated with increased risk of HZ.