Micronutrient intake and the risk of herpes zoster: a case-control study.

BACKGROUND: Herpes zoster can seriously impair quality of life and may also be a marker for age-related immune decline (immunosenescence). Diets low in micronutrients may increase the risk of zoster by temporarily compromising cell-mediated immune function or by hastening immunosenescence. METHODS: Primary objectives were to examine the association between risk of zoster and (i) dietary intake of vitamins A, B(6), C, E, folic acid, zinc, and iron, and (ii) fruit and vegetable consumption. We conducted a community-based case-control study. Cases were adults with incident zoster presenting to 22 general practices in London. Controls were individuals with no zoster history, matched to cases by age, sex, and general practice. Diet was ascertained for 243 cases and 483 controls using an interviewer-administered food-frequency questionnaire. We used conditional logistic regression to estimate odds ratios. RESULTS: There was a strong graded association between lower fruit intake and increasing zoster risk; in adjusted analysis, individuals who ate less than one piece of fruit per week had more than three times the risk of zoster compared with individuals who ate more than three portions per day. None of the dietary intakes of the seven micronutrients examined had a statistically significant association with zoster risk when considered singly. However, amongst individuals aged >60 years, a measure of combined micronutrient intake and vegetable intake showed similar dose-related associations with zoster risk. CONCLUSION: A cocktail of nutrients such as those found in fruit and vegetables may act together, particularly in older individuals, to maintain immune health and prevent zoster.