Positive family history of herpes zoster as a risk factor for the disease: a case-control study

In addition to the age and immune suppression, several risk factors for herpes zoster have been studied. The aim of this study was to evaluate the family history of herpes zoster as a risk factor for this disease. This case-control study was conducted at Farshchian hospital, Hamedan, Iran. The cases were patients with confirmed diagnosis of herpes zoster. The controls were chosen from individuals with minor or chronic dermatologic diseases or their companions, who had no history of herpes zoster. Immune deficiency was the main exclusion criteria. Information was asked using special questionnaires administered by blinded investigators. Data were analyzed using chi squared test. Odds ratios (OR) with 95% confidence interval (95% CI) were calculated to compare proportions in two groups. Case and control groups included 217 and 200 participants, respectively. The mean ± standard deviation of ages in case and control groups were 49.08±15.59 and 49.96±15.54 years, respectively (P=0.936). 53.5% of cases and 54.5% of controls were women (P=0.845). The frequency of herpes zoster in first-degree relatives in cases and controls was 65/217 (30%) and 16/200 (8%) respectively (OR [95%CI] = 4.91 [2.73-8.85]). Positive history for second degree relatives was 36 (16.6%) and 8 (4%) in cases and controls, respectively (OR [95%CI] = 4.77 [2.16-10.54]). This proportion for at least one relatives was 101 (46.6%) and 24 (12%) in cases and controls, respectively (OR [95%CI] = 6.26 [3.79-10.36]). This study suggests that positive family history is a risk factor for herpes zoster.