Risk Factors for Herpes Zoster
Background: The causes for herpes zoster (HZ) are largely unknown. Older age and diminished cell mediated immunity are well-documented risk factors but cannot explain by themselves the epidemiology of HZ. Several other factors have been evaluated but are unconfirmed or of insufficient prevalence to explain most episodes. During a community-based study, we assessed potential HZ risk factors for which data cannot be obtained from medical records.
Methods: We conducted a matched case-control study. Cases were identified through active surveillance among persons age ≥50 years with HZ onset and health-care encounters during 2010-2011 in Olmsted County, Minnesota and confirmed by medical record review. Controls were persons without an HZ diagnosis in the past 3 years, age- and sex-matched to cases. Data on potential risk factors for HZ were obtained via telephone interview.
Results: 389 HZ case-patients and 511 matched controls were enrolled; median age was 65/66 years and 62%/65% were female. Case-patients were more likely than controls to report a previous episode of HZ (odds ratio [OR]=1.88, 95% confidence interval [CI] 1.16-3.03) and blood relatives with a history of HZ (OR=1.57, 95% CI 1.16-2.12). Additionally, regarding family history, the risk was greater for subjects who reported first degree relatives with HZ (OR=1.75, 95% CI 1.27-2.41) or multiple blood relatives with HZ (OR=3.06, 95% CI 1.79-5.21) compared with subjects with no family history. Case-patients were also more likely to report new/increased stress in the 3 months before HZ (OR=2.86, 95% CI 2.11-3.87) however, there was no dose-response relationship between HZ and severity of stress. No association was found between HZ and trauma, smoking, tonsillectomy, diet, or self-assessed exposure to pesticides/herbicides or other chemicals (p>0.1).
Conclusion: Our findings suggest that family history is a risk factor for HZ. Family history could confound determinations of vaccine effectiveness if it prompts vaccination among family members. We found no risk factors that could individually contribute much to the total burden of HZ in the population.
J. Zhang, None
P. Wollan, None
S. R. Bialek, None
B. Yawn, Merck: Consultant , Consulting fee and Research grant
GSK: Consultant , Consulting fee