IL-2 and IL-10 gene polymorphisms are associated with respiratory tract infection and may modulate the effect of vitamin E on lower respiratory tract infections in elderly nursing home residents

Vitamin E supplementation may be a potential strategy to prevent respiratory tract infections {(RIs)} in the elderly. The efficacy of vitamin E supplementation may depend on individual factors including specific single nucleotide polymorphisms {(SNPs)} at immunoregulatory genes.

We examined whether the effect of vitamin E on {RIs} in the elderly was dependent on genetic backgrounds as indicated by {SNPs} at cytokine genes.

We used data and {DNA} from a previous vitamin E intervention study (200 {IU} vitamin E or a placebo daily for 1 y) in elderly nursing home residents to examine vitamin E-gene interactions for incidence of {RI.} We determined the genotypes of common {SNPs} at {IL-1beta,} {IL-2,} {IL-6,} {IL-10,} {TNF-alpha,} and {IFN-gamma} in 500 participants. We used negative binomial regression to analyze the association between genotype and incidence of infection.

The effect of vitamin E on lower {RI} depended on sex and the {SNP} at {IL-10} {-819G–>A} {(P} = 0.03 for interaction for lower {RI).} Furthermore, we observed that subjects with the least prevalent genotypes at {IL-2} {-330A–>C} {(P} = 0.02 for upper {RI),} {IL-10} {-819G–>A} {(P} = 0.08 for upper {RI),} and {IL-10} {-1082C–>T} {(P} < 0.001 for lower {RI} in men) had a lower incidence of {RI} independent of vitamin E supplementation.

Studies that evaluate the effect of vitamin E on {RIs} should consider both genetic factors and sex because our results suggest that both may have a significant bearing on the efficacy of vitamin E. Furthermore, common {SNPs} at cytokine genes may contribute to the individual risk of {RIs} in the elderly. This trial was registered at clinicaltrials.gov as NCT00758914.