Risk of Herpes Zoster in Relation to Body Mass Index Among Residents Aged >= 50 Years: The Shozu Herpes Zoster Study

Background: The impact of body mass index on incidence of herpes zoster is unclear. This study investigated whether body mass index was associated with a history of herpes zoster and incidence during a 3-year follow-up, using data from a prospective cohort study in Japan. Methods: In total, 12,311 individuals were included in the cross-sectional analysis at baseline, of whom 1,818 with a history of herpes zoster were excluded from the incidence analysis, leaving 10,493 individuals. Body mass index (kg/m(2)) was classified into three categories (underweight: <18.5; normal: 18.5 to <25; and overweight: >= 25). To evaluate the risk of herpes zoster, we used a logistic regression model for prevalence and a Cox proportional hazard regression model for incidence. Results: Being overweight or underweight was not associated with herpes zoster prevalence at baseline. The multivariate hazard ratios of herpes zoster incidence for overweight versus normal-weight groups were 0.67 (95% confidence interval, 0.51-0.90) in all participants, and 0.57 (95% confidence interval, 0.39-0.83) in women, with no significant difference for men. Conclusion: Being overweight was associated with a lower incidence of herpes zoster than being normal weight in older Japanese women.