BACKGROUND
We recently reported an increased risk of herpes zoster (shingles or zoster) in children with asthma, but little is known about whether it is true for adults with asthma. We determined whether asthma is associated with an increased risk of zoster in adults.
METHODS
This study was designed as a population-based case-control study. Zoster cases during the study period were identified among adults (aged ≥ 50 years) who resided in Olmsted County, Minnesota. We compared the frequency of asthma between zoster cases and birthday- and gender-matched controls (1:2 matching) without a history of zoster. Asthma status was ascertained by predetermined criteria. Conditional logistic regression model was used to assess the association of asthma with risk of zoster.
RESULTS
A total of 371 zoster cases and their 742 matched controls were enrolled. Of the 371 cases, 246 (66%) were females, 348 cases (94%) were Caucasians, and the mean (± standard deviation) age was 66.8±10.7 years. Twenty-three percent (N=87) of zoster cases had a history of asthma, compared to 15% (N=114) in controls. Controlling for pertinent covariates and confounders, there was a significant association between a history of asthma and risk of zoster (adjusted odds ratio: 1.70, 95% CI: 1.20–2.42, p=0.003). Population-attributable risk percent for asthma was about 10%.
CONCLUSIONS
Asthma is an unrecognized risk factor for zoster in adults. Consideration for immunizing adults with asthma aged over 50 years as a target group should be given.