Chronic obstructive pulmonary disease (COPD) is a severe systemic disease leading to circulatory and respiratory failure. COPD is also a risk factor for the onset of anxiety and mood disturbances. Identification of the correlates of emotional disturbances in the course of COPD can make it possible, on the one hand, to prevent mental and behavioral disorders early in the course of this serious somatic disease, and on the other hand, to institute appropriate treatment. The aim of the study was to determine the correlation between the polymorphism of manganese superoxide dismutase signal peptide and the severity of anxiety and depression in COPD patients.
Material and methods: The study group consisted of 57 patients with grade I, II and III COPD according to GOLD criteria. The control group consisted of 63 healthy nicotine addicts. In all the subjects, the genotype of position 9 of manganese superoxide dismutase signal peptide was determined, depression severity was measured with Beck Depression Scale, and anxiety as a trait and as a state was measured with Spielberg State/Trait Anxiety Inventory (STAI).
Results: Among COPT patients, 16 subjects were found to have Ala/Ala genotype, 23 Val/Ala and 18 Val/Val. In the smokers' group Ala/Ala genotype was found in 29 cases, Val/Ala in 27 and Val/Val in 7. The distribution of genotype frequencies differed between the groups. In COPD patients, the mean depression severity assessed according to Beck Scale amounted to (16.52 +/- 5.63) and was higher than in smokers without COPD (13.85 +/- 4.24, p = 0.003828). The average severity of anxiety as a trait and as a state did not differ significantly in both groups. Among COPD patients, the mean severity of depressive disorders in subjects with Val/ Val genotype was 21.27 +/- 4.32 and was significantly higher than in those with Val/Ala (15.22 +/- 5.29) and Ala/Ala (12.87 +/- 3.72) genotypes. The severity of anxiety as a trait in COPD patients reached 7.72 +/- 1.21 in the subgroup with Val/Val genotype and was also higher than in those with Val/Ala genotype (6.69 +/- 1.48) and with Ala/Ala genotype (5.87 +/- 1.14). A similar correlation was observed for anxiety as a state (subjects with Val/Val genotype 6.78 +/- 1.06, with Val/Ala genotype 6.18 +/- 1.01 and with Ala/ Ala genotype 5.88 +/- 1.41). Among healthy smokers, the mean severities of depression, anxiety as a trait and anxiety as a state did not differ in subjects with different genotypes.
Conclusions: The study has demonstrated that the severity of depression is higher in COPD patients than in the group of healthy smokers. In the group of patients with COPD, Val/Val genotype at position 9 of MnSOD signal peptide is associated with more severe depression, anxiety as a trait and anxiety as a state in comparison with patients who have Val/Ala and Ala/Ala genotypes. No similar correlations were found in healthy smokers.