Superoxide imbalance triggered by Val16Ala‐SOD2 polymorphism increases the risk of depression and self‐reported psychological stress in free‐living elderly people

Abstract

Abstract Background Oxidative stress and chronic inflammatory states triggered by a single‐nucleotide polymorphism (SNP) in superoxide dismutase manganese‐dependent gene (Val16Ala‐SOD2) have been associated with the risk of developing several chronic, nontransmissible diseases. However, it is still not clear whether the VV‐SOD2 genotype that causes higher basal superoxide anion levels has any impact on the risk for depression and self‐reported psychological stress in elderly people. Methods In the present study, we tested this hypothesis using a case‐control study where depression was detected using the Geriatric Depression Scale‐15 (GDS‐15). A total of 612 Brazilian free‐living elderly subjects with a mean age of 67.1 ± 7.1 years old (number of controls, C = 497, and depressive individuals, D = 115) were included in this study. All participants had similar social, health, and lifestyle variables, with the exception of polypharmacy (≥5 medicines daily intake), which was higher in the D group, compared to C subjects. Results Our results showed that the VV‐SOD2 genotype significantly increased the risk for depression and psychological stress in the elderly subjects, independently of sex/gender, age, and other prior diseases and health indicators (depression risk = 1.842, 1.109–3.061 95% CI, p = .018). VV‐subjects also had a higher daily intake of antidepressants, anxiolytics, and anti‐inflammatory drugs than A‐allele subjects. Conclusion Our findings support the hypothesis that genetically induced oxidative superoxide‐hydrogen peroxide imbalance may be involved in an increased risk for developing depression and psychological stress in free‐living elderly people without other chronic nontransmissible diseases.

Keywords

• depression
• elderly
• psychological stress
• superoxide dismutase polymorphism