Risk Factors for Herpes Zoster Among Adults.

Background.  The causes of varicella-zoster virus reactivation and herpes zoster (HZ) are largely unknown. We assessed potential risk factors for HZ, the data for which cannot be obtained from the medical sector. Methods.  We conducted a matched case-control study. We established active surveillance in Olmsted County, Minnesota to identify HZ occurring among persons age ≥50 years during 2010-2011. Cases were confirmed by medical record review. Herpes zoster-free controls were age- and sex-matched to cases. Risk factor data were obtained by telephone interview. Results.  We enrolled 389 HZ case patients and 511 matched controls; the median age was 65 and 66 years, respectively. Herpes zoster was associated with family history of HZ (adjusted odds ratio [aOR] = 1.65); association was highest with first-degree or multiple relatives (aOR = 1.87 and 3.08, respectively). Herpes zoster was also associated with prior HZ episodes (aOR = 1.82), sleep disturbance (aOR = 2.52), depression (aOR = 3.81), and recent weight loss (aOR = 1.95). Stress was a risk factor for HZ (aOR = 2.80), whereas a dose-response relationship was not noted. All associations indicated were statistically significant (P < .05). Herpes zoster was not associated with trauma, smoking, tonsillectomy, diet, or reported exposure to pesticides or herbicides (P > .1). Conclusions.  We identified several important risk factors for HZ; however, the key attributable causes of HZ remain unknown.