Asthma increases the risk of herpes zoster: a nested case-control study using a national sample cohort

Background This study aimed to complement previous studies on the risk of herpes zoster in the asthmatic adult population. Methods The Korean Health Insurance Review and Assessment Service-National Sample Cohort (HIRA-NSC) from 2002 through 2013 was used. A total of 64,152 participants with herpes zoster were matched for age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia with 239,780 participants who were included as a control group. In both the herpes zoster and control groups, previous history of asthma were investigated. The crude and adjusted odds ratios (ORs) and 95% confidence intervals (CI) of asthma for herpes zoster were analyzed using unconditional logistic regression analysis. Subgroup analyses were conducted according to age and sex. Results Approximately 16.2% (9728/59,945) and 12.8% (30,752/239,780) of participants in the herpes zoster and control groups, respectively, had a previous history of asthma (P < 0.001). The herpes zoster group demonstrated a 1.32-times higher odds of asthma than the control group (95% CI 1.28-1.35, P < 0.001). The increased odds of asthma in the herpes zoster group persisted in all the age and sex subgroups. Conclusions The odds for asthma were higher in the herpes zoster group.