Depression and Related Factors in Patients with Parkinson's Disease at High Altitude

Depression seems to aggravate progression of Parkinson's disease (PD). Hypoxia stress may be one of the pathogenic factors leading to PD. We investigated the characteristics of PD and factors related to Parkinson's disease depression (PDD) at high altitude (mean altitude ≥2300 m).

Totally 221 PD patients of three different nationalities (Han, Hui, and Tibetan) were recruited in a high-altitude hospital. Depression was present in 55.6% of them. Patient data were examined, including demographic information, medical history, disease duration and family history. Psychopathological characteristics and motor signs were assessed by the Hamilton Depression scale (HAMD) and scales for motor and non-motor symptoms in the Unified Parkinson's Disease Rating Scale (UPDRS). Progression of PD was evaluated by the modified Hoehn and Yahr (H-Y) staging system.

Mean age (47.1% men) was 68.25±13.67 years old, with disease duration of 4.18±5.13 years and median H-Y scores 2.07±0.97 points. Among three different nationalities, PD rate was 69.2% in Han nationals, 17.6% in Hui nationals and 13.1% in Tibetans of 221 PD patients. Compared with the non-depressed PD group, female, no-smoking and living alone rates, and dysphagia, pain, H-Y stage, ADL, UPDRS-I, UPDRS-III, HAMA, and PSQI scores were significantly increased in the PDD group, while MMSE scores were significantly decreased (P<0.05 or P<0.01). PD patients of Han and Hui nationalities had increased depression rates compared with Tibetan individuals (P<0.05). Compared with the mild depression group, the moderate and severe depression groups had significantly increased salivation, dysphagia, H-Y stage, UPDRS-I, UPDRS-III, HAMA, and PSQI scores (P<0.05 or P<0.01). Living alone rates and ADL scores were increased in the severe depression group (P<0.05). Logistic regression analysis showed that living alone (OR=19.833, 95% CI: 2.758-142.624, P<0.01), UPDRS-III score (OR=1.079, 95% CI: 1.009-1.153, P<0.05), and PSQI score (OR=1.538, 95% CI: 1.347-1.755, P<0.001) were risk factors for PDD. Male gender (OR=0.292, 95% CI: 0.112-0.763, P<0.05) was a protective factor in PDD.

PDD is associated with gender, ethnicity, loneliness, non-motor symptoms (NMSs), motor symptoms, and disease severity, and depression severity. Living alone, dyskinesia, and sleep disorder are risk factors for PDD at high altitude. A relative protection against depression was observed in the Tibetan population.