1 Clinical College of Neurology, Neurosurgery and Neurorehabilitation, Tianjin Medical University, 300070 Tianjin, China
2 Department of Neurology and Tianjin Key Laboratory of Cerebrovascular Disease and Neurodegenerative Disease, Tianjin Dementia Institute, Tianjin Huanhu Hospital, Tianjin University, 300350 Tianjin, China
3 Department of Neurology, Cangzhou People's Hospital, 061000 Cangzhou, Hebei, China
Abstract
Mild cognitive impairment is one of the non-motor symptoms in Parkinson's disease (PD) and multiple system atrophy (MSA). Few studies have previously been conducted on the correlation between serum uric acid (SUA) and lipid levels and mild cognitive impairment in PD and MSA.
Participants included 149 patients with PD and 99 patients with MSA. The Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were used to evaluate cognitive function. Evaluations were conducted on SUA and lipid levels, which included triglyceride, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and total cholesterol (TC).
Patients with PD and MSA diagnosed with mild cognitive impairment demonstrated multiple cognitive domain impairment when compared with patients with normal cognition. Attentional impairment was more pronounced in patients with MSA when compared with PD (p = 0.001). In PD, the risk of mild cognitive impairment was lower in the highest quartiles and secondary quartile of SUA than in the lowest quartiles (odds ratio [OR] = 0.281, 95% confidence intervals [CI]: 0.097–0.810, p = 0.019; and OR = 0.317, 95% CI: 0.110–0.911, p = 0.033). In MSA, the risk of mild cognitive impairment was lower in the third and highest quartile of SUA than in the lowest quartile (OR = 0.233, 95% CI: 0.063–0.868, p = 0.030; and OR = 0.218, 95% CI: 0.058–0.816, p = 0.024). In patients with PD, the MoCA scores were negatively correlated with TC levels (r = –0.226, p = 0.006) and positively correlated with SUA levels (r = 0.206, p = 0.012). In MSA, the MoCA scores were positively correlated with SUA levels (r = 0.353, p = 0.001).
Lower SUA levels and higher TC levels are a possible risk factor for the risk and severity of mild cognitive impairment in PD. Lower SUA levels are a possible risk factor for the risk and severity of mild cognitive impairment in MSA.
Keywords
- cognition
- Parkinson's disease
- multiple system atrophy
- uric acid
- serum lipid levels
Parkinson’s disease (PD) is a neurodegenerative disorder. The existence of motor symptoms, such as bradykinesia, stiffness and tremor, is necessary for PD diagnosis [1]. Additional to these well-known motor features, non-motor symptoms such as cognitive dysfunction are common and potentially occur at any disease stage [2, 3]. Multiple system atrophy (MSA) is a neurodegenerative disease and Parkinsonism, cerebellar ataxia, autonomic dysfunction and pyramidal dysfunction are its main symptoms. Some studies suggest that the incidence of mild cognitive impairment in MSA may be higher than previously thought [4, 5]. Alpha-synuclein cytoplasmic inclusions are a common feature in PD and MSA. Additionally, along with the clinical features typically observed during a neurological or physical examination, cognitive symptoms are often present in the early stages of all Parkinsonism [6].
It has been shown that serum uric acid (SUA) functions as a natural antioxidant [7]. Cao et al. [5] found low SUA plays a role in decreasing cognitive disorder in patients with MSA. Annanmaki et al. [8] also found that low SUA level predicted worse performance in neuropsychological tests in PD patients. Luca et al. [9] found a negative relationship between executive function and low-density lipoprotein cholesterol (LDL-C) levels in male patients with PD. Conversely, Choe et al. [10] found no relation between lipid levels and cognitive performance in a long-term investigation involving individuals with advanced PD. According to previous studies, low serum lipid levels are linked to a higher risk of MSA, although they have no impact on how severe or how quickly MSA develops [11, 12].
How SUA and lipid levels influence cognitive function in PD and MSA remains unclear. To investigate the hypothesis that SUA and serum lipid levels are related to cognitive changes in PD and MSA patients, a retrospective study involving 149 patients with PD and 99 patients with MSA was undertaken.
In Tianjin (China), between January 2021 and August 2023, 149 patients with a diagnosis of PD and 99 patients with a diagnosis of MSA were recruited from Tianjin Huanhu Hospital. PD patients were clinically diagnosed using the Movement Disorder Society Clinical Diagnostic Criteria for PD [13]. According to the updated Gilman criteria, patients with MSA were clinically diagnosed with possible or probable MSA-P or MSA-C [14]. Individuals with diagnoses of the following illnesses that could affect SUA and lipid levels were excluded: (1) Patients who had surgery within the previous three months, or who have acute or persistent infections; (2) Patients suffering from acute or chronic renal and liver disease; (3) Patients receiving lipid-lowering and SUA-lowering therapy; (4) Patients who could not complete or declined a cognitive test.
A brain magnetic resonance imaging (MRI) was performed on each patient to rule out other neurological disorders. All patients gave informed consent and the study (No. 2020-100) was authorized by the Tianjin Huanhu Hospital Medical Ethics Committee.
Age, sex, education, onset age, disease duration and other demographic
information, were gathered. All patients underwent a detailed assessment
performed by specialists in movement disorders. Motor symptoms were assessed
using part III of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) [15].
The clinical phenotype includes tremor-dominant, rigid-dominant and mixed
subtype. The severity of MSA was evaluated using the Unified MSA Rating Scale
(UMSARS) [16]. Cognitive function was assessed using the Mini-Mental State
Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). Patients who
reached MMSE scores for dementia were excluded from the study. MoCA is a more
sensitive measure of cognitive function than MMSE. Education-specific cutoff
values for the total MoCA score were used to identify mild cognitive impairment.
The specific total MoCA score for a diagnosis of mild cognitive impairment is
After an 8–12 hour fast at the time of admission, fasting blood samples were taken. The antecubital vein was used to extract peripheral blood. Blood samples were placed into serum separator tubes for centrifugation. Levels of total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and LDL-C, serum creatinine (SCr) and SUA were measured within two hours of collection.
Normally distributed data are given as mean
Base characteristics of participants with PD and MSA are given in Table 1. PD participants had higher levels of SCr, LDL-C, HDL-C and TC than MSA participants. PD participants with mild cognitive impairment had significantly lower levels of SUA and SCr and higher levels of TC and LDL-C than participants without mild cognitive impairment. More women had mild cognitive impairment than men among participants with MSA. In MSA, participants with mild cognitive impairment had significantly lower SUA and SCr than participants without such impairment. No significant difference in TC, LDL-C, HDL-C, or triglyceride level was found between these two groups. Compared with participants who had normal cognition, participants with PD and MSA who had mild cognitive impairment declined in multiple domains of cognition. The impairment in attention was more pronounced in participants with MSA who had mild cognitive impairment, as compared with participants with PD who had mild cognitive impairment, with no significant differences in other domains of cognition (Table 2).
| PD | MSA | PD vs. MSA | |||||||
| Total (n = 149) | PD-MCI (n = 84) | PD-NC (n = 65) | p-value | Total (n = 99) | MSA-MCI (n = 56) | MSA-NC (n = 43) | p-value | p-value | |
| Age (years) | 67.00 (60.00–71.00) | 67.00 (60.50–71.00) | 66.00 (59.00–71.00) | 0.254 | 62.00 (53.00–68.00) | 64.00 (54.00–69.00) | 60.00 (53.00–65.00) | 0.108 | 0.001 |
| Men (n %) | 76 (51.0) | 36 (42.9) | 40 (61.5) | 0.024 | 51 (51.5) | 22 (39.3) | 29 (67.4) | 0.005 | 0.937 |
| Duration (years) | 4.00 (2.00–6.00) | 4.00 (2.00–6.00) | 3.00 (2.00–6.00) | 0.948 | 2.00 (2.00–4.00) | 2.00 (2.00–4.00) | 2.00 (2.00–4.00) | 0.402 | 0.001 |
| Clinical phenotype MSA-C (n %) | 50 (50.5) | 23 (41.1) | 27 (62.8) | 0.032 | |||||
| Clinical phenotype MSA-P (n %) | 49 (49.5) | 33 (58.9) | 16 (37.2) | ||||||
| Clinical phenotype Tremor (n %) | 44 (29.5) | 24 (28.6) | 20 (30.8) | 0.671 | |||||
| Clinical phenotype Rigid (n %) | 51 (34.2) | 27 (32.1) | 24 (36.9) | ||||||
| Clinical phenotype Mixed (n %) | 54 (36.3) | 33 (39.3) | 21 (32.3) | ||||||
| Education (years) | 9.00 (6.00–12.00) | 9.00 (6.75–10.00) | 12.00 (6.00–12.00) | 0.014 | 9.00 (7.00–12.00) | 9.00 (7.00–11.00) | 10.00 (6.00–12.00) | 0.915 | 0.631 |
| Smoker (n %) | 28 (18.8) | 13 (15.5) | 15 (23.1) | 0.239 | 28 (28.3) | 16 (28.6) | 12 (27.9) | 0.942 | 0.080 |
| Alcohol (n %) | 16 (10.7) | 6 (7.1) | 10 (15.4) | 0.107 | 26 (26.3) | 16 (28.6) | 10 (23.3) | 0.551 | 0.001 |
| Hypertension (n %) | 53 (35.6) | 30 (35.7) | 23 (35.4) | 0.967 | 29 (29.3) | 19 (33.9) | 10 (23.3) | 0.247 | 0.303 |
| Diabetes (n %) | 28 (18.8) | 18 (21.4) | 10 (15.4) | 0.349 | 19 (19.2) | 13 (23.2) | 6 (14.0) | 0.246 | 0.937 |
| MDS-UPDRS III | 35.00 (19.00–50.00) | 40.00 (22.00–56.75) | 31.00 (17.50–47.00) | 0.057 | |||||
| UMSARS | 38.00 (35.00–42.00) | 38.50 (34.00–41.00) | 37.00 (35.00–43.00) | 0.969 | |||||
| Fazekas scales | 1.00 (1.00–2.00) | 1.00 (1.00–2.00) | 1.00 (1.00–2.00) | 0.839 | 1.00 (1.00–2.00) | 1.00 (1.00–2.00) | 1.00 (1.00–2.00) | 0.722 | 0.493 |
| MMSE | 25.00 (23.00–28.00) | 23.00 (20.00–24.00) | 28.00 (27.00–29.00) | 0.001 | 26.00 (22.00–28.00) | 23.00 (20.00–24.00) | 28.00 (27.00–29.00) | 0.001 | 0.992 |
| MoCA | 22.00 (18.00–25.00) | 18.50 (15.00–20.00) | 25.00 (25.00–26.00) | 0.001 | 21.00 (17.00–25.00) | 18.00 (15.00–20.00) | 25.00 (25.00–26.00) | 0.001 | 0.729 |
| SUA (µmol/L) | 293.00 (245.00–342.50) | 283.00 (228.50–329.25) | 296 (269.00–363.00) | 0.018 | 273.90 (236.00–323.40) | 257.90 (218.75–289.18) | 300.00 (258.00–346.00) | 0.001 | 0.116 |
| SCr (µmol/L) | 65.60 (57.05–76.10) | 63.90 (56.25–73.33) | 68.20 (58.10–78.50) | 0.050 | 56.61 (50.20–72.89) | 53.38 (47.90–62.80) | 67.10 (54.46–80.50) | 0.002 | 0.004 |
| LDL-C (mmol/L) | 3.02 (2.44–3.55) | 3.10 (2.57–3.88) | 2.88 (2.26–3.40) | 0.020 | 2.63 (2.14–3.29) | 2.57 (2.20–3.35) | 2.67 (1.90–3.22) | 0.887 | 0.001 |
| HDL-C (mmol/L) | 1.33 (1.15–1.56) | 1.34 (1.16–1.62) | 1.30 (1.12–1.51) | 0.324 | 1.11 (0.94–1.36) | 1.18 (0.97–1.38) | 1.05 (0.92–1.30) | 0.192 | 0.001 |
| Triglyceride (mmol/L) | 1.09 (0.78–1.55) | 1.13 (0.77–1.67) | 1.05 (0.76–1.51) | 0.230 | 1.20 (0.89–1.70) | 1.20 (0.89–1.66) | 1.19 (0.90–1.76) | 0.718 | 0.218 |
| Total cholesterol (mmol/L) | 4.93 (4.10–5.66) | 5.14 (4.29–6.27) | 4.82 (3.73–5.33) | 0.010 | 4.30 (3.60–5.08) | 4.34 (3.61–5.08) | 4.20 (3.52–5.11) | 0.777 | 0.001 |
PD, Parkinson’s disease; MSA, multiple system atrophy; MCI, mild cognitive impairment; NC, normal cognition; MDS-UPDRS, Movement Disorder Society Unified Parkinson’s Disease Rating Scale; UMSARS, Unified MSA Rating Scale; LDL-C, low-density-lipoprotein cholesterol; HDL-C, high-density-lipoprotein cholesterol; SCr, serum creatinine; SUA, serum uric acid; MMSE, Mini-Mental State Examination; MoCA, Montreal Cognitive Assessment; PD vs. MSA, Total PD participants vs. total MSA participants.
| PD-NC and MSA-NC (n = 108) | PD-MCI (n = 84) | p-value (PD-MCI vs. NC) | MSA-MCI (n = 56) | p-value (MSA-MCI vs. NC) | p-value (PD-MCI vs. MSA-MCI) | |
| MoCA | 25.00 (25.00–26.00) | 18.50 (15.00–20.00) | 0.001 | 18.00 (15.00–20.00) | 0.001 | 0.417 |
| Visual perception and Executive function (5) | 5.00 (4.00–5.00) | 1.00 (1.00–3.00) | 0.001 | 2.00 (1.00–2.00) | 0.001 | 0.844 |
| Naming (3) | 3.00 (3.00–3.00) | 3.00 (2.00–3.00) | 0.001 | 3.00 (2.00–3.00) | 0.001 | 0.770 |
| Attention (3) | 3.00 (2.00–3.00) | 2.00 (2.00–3.00) | 0.001 | 1.00 (1.00–3.00) | 0.001 | 0.001 |
| Calculation (3) | 3.00 (3.00–3.00) | 2.00 (2.00–3.00) | 0.001 | 3.00 (2.00–3.00) | 0.001 | 0.098 |
| Language (3) | 2.00 (2.00–3.00) | 1.00 (1.00–2.00) | 0.001 | 1.00 (1.00–2.00) | 0.001 | 0.316 |
| Conceptual thinking (2) | 2.00 (1.00–2.00) | 1.00 (1.00–2.00) | 0.001 | 1.00 (1.00–2.00) | 0.001 | 0.398 |
| Memory (5) | 3.00 (3.00–4.00) | 1.00 (1.00–2.00) | 0.001 | 1.00 (1.00–2.00) | 0.001 | 0.913 |
| Orientation (6) | 6.00 (5.00–6.00) | 5.00 (5.00–6.00) | 0.001 | 5.00 (5.00–6.00) | 0.001 | 0.414 |
For PD and MSA, Table 3 lists the adjusted ORs for patients with mild cognitive impairment based on the SUA and lipid quartiles. After controlling for sex, MDS-UPDRS III and education, the regression analysis in PD revealed that the probability of mild cognitive impairment was lower in the highest quartiles and secondary quartile of SUA than in the lowest quartiles (OR = 0.281, 95% CI: 0.097–0.810, p = 0.019; and OR = 0.317, 95% CI: 0.110–0.911, p = 0.033, respectively). Moreover, the risk of mild cognitive impairment was higher in the highest quartile of LDL-C and TC than in the lowest quartile (OR = 4.075, 95% CI: 1.407–11.80, p = 0.010; and OR = 4.135, 95% CI: 1.422–12.03, p = 0.009, respectively). There was no significant difference in the probability of mild cognitive impairment between the HDL-C and SCr quartiles. In MSA, the risk of mild cognitive impairment was significantly lower in the third and highest quartile of SUA than in the lowest quartile after controlling for sex and MSA subtypes (OR = 0.233, 95% CI: 0.063–0.868, p = 0.030; and OR = 0.218, 95% CI: 0.058–0.816, p = 0.024, respectively).
| PD | |||||
| n (%) | p-value | OR | 95% CI | ||
| SUA, µmol/L | p-value for trend 0.030 | ||||
| 38 (25.5) | 1.00 | reference | |||
| 245–293 | 36 (24.2) | 0.033 | 0.317 | 0.110–0.911 | |
| 294–342 | 39 (26.2) | 0.658 | 0.786 | 0.270–2.286 | |
| 36 (24.2) | 0.019 | 0.281 | 0.097–0.810 | ||
| LDL–C (mmol/L) | p-value for trend 0.015 | ||||
| 34 (22.8) | 1.00 | reference | |||
| 2.44–3.02 | 40 (26.8) | 0.226 | 1.844 | 0.684–4.971 | |
| 3.03–3.60 | 37 (24.8) | 0.726 | 1.193 | 0.444–3.203 | |
| 38 (25.5) | 0.010 | 4.075 | 1.407–11.80 | ||
| TC (mmol/L) | p-value for trend 0.022 | ||||
| 35 (23.5) | 1.00 | reference | |||
| 4.10–4.93 | 37 (24.8) | 0.023 | 3.214 | 1.173–8.804 | |
| 4.94–5.65 | 41 (27.5) | 0.248 | 1.764 | 0.674–4.623 | |
| 36 (24.2) | 0.009 | 4.135 | 1.422–12.03 | ||
| MSA | |||||
| n (%) | p-value | OR | 95% CI | ||
| SUA (µmol/L) | p-value for trend 0.019 | ||||
| 27 (27.3) | 1.00 | reference | |||
| 239–274 | 23 (23.2) | 0.222 | 0.436 | 0.115–1.652 | |
| 275–322.7 | 22 (22.2) | 0.030 | 0.233 | 0.063–0.868 | |
| 27 (27.3) | 0.024 | 0.218 | 0.058–0.816 | ||
| SCr (µmol/L) | p-value for trend 0.115 | ||||
| 18 (23.7) | 1.00 | reference | |||
| 50–56.7 | 21 (27.6) | 0.789 | 0.822 | 0.196–3.445 | |
| 56.8–72.27 | 19 (27.6) | 0.855 | 0.865 | 0.182–4.112 | |
| 18 (23.7) | 0.123 | 0.243 | 0.040–1.470 | ||
LDL-C, low-density-lipoprotein cholesterol; TC, total cholesterol; SUA, serum uric acid; SCr, serum creatinine; OR, odds ratio; CI, confidence intervals. PD: Adjusted for sex, education and MDS-UPDRS III. MSA: Adjusted for sex and MSA subtypes.
Table 4 gives the correlation analysis of MoCA scores with SUA levels. In PD participants, MoCA score was positively related to SUA level (r = 0.206, p = 0.012). SUA levels were positively related to visual perception and executive function (r = 0.194, p = 0.018), language (r = 0.278, p = 0.001), and memory (r = 0.216, p = 0.008). In MSA participants, MoCA score was positively related to SUA level (r = 0.353, p = 0.001). SUA levels were positively related to visual perception and executive function (r = 0.301, p = 0.002), naming (r = 0.251, p = 0.012), attention (r = 0.257, p = 0.010), language (r = 0.342, p = 0.001), memory (r = 0.323, p = 0.001), and orientation (r = 0.219, p = 0.029).
| PD | MSA | |||
| r | p-value | r | p-value | |
| MoCA | 0.206 | 0.012 | 0.353 | 0.001 |
| Visual perception and Executive function (5) | 0.194 | 0.018 | 0.301 | 0.002 |
| Naming (3) | 0.004 | 0.963 | 0.251 | 0.012 |
| Attention (3) | 0.158 | 0.054 | 0.257 | 0.010 |
| Calculation (3) | 0.069 | 0.402 | 0.126 | 0.215 |
| Language (3) | 0.278 | 0.001 | 0.342 | 0.001 |
| Conceptual thinking (2) | 0.032 | 0.694 | 0.172 | 0.088 |
| Memory (5) | 0.216 | 0.008 | 0.323 | 0.001 |
| Orientation (6) | 0.109 | 0.187 | 0.219 | 0.029 |
Table 5 gives the correlation analysis of MoCA scores with TC and LDL-C levels. In PD participants, MoCA was negatively related to TC level (r = –0.226, p = 0.006). TC levels were negatively related to visual perception and executive function (r = –0.207, p = 0.011), calculation (r = –0.214, p = 0.009) and orientation (r = –0.228, p = 0.005). LDL-C levels were negatively related to visual perception and executive function (r = –0.170, p = 0.038).
| LDL-C | TC | |||
| r | p-value | r | p-value | |
| MoCA | –0.130 | 0.113 | –0.226 | 0.006 |
| Visual perception and Executive function (5) | –0.170 | 0.038 | –0.207 | 0.011 |
| Naming (3) | –0.017 | 0.836 | –0.105 | 0.202 |
| Attention (3) | 0.055 | 0.502 | –0.065 | 0.432 |
| Calculation (3) | –0.065 | 0.431 | –0.214 | 0.009 |
| Language (3) | –0.045 | 0.582 | –0.124 | 0.133 |
| Conceptual thinking (2) | –0.066 | 0.427 | –0.109 | 0.187 |
| Memory (5) | –0.066 | 0.424 | –0.134 | 0.102 |
| Orientation (6) | –0.106 | 0.196 | –0.228 | 0.005 |
In this study the characteristics of cognitive decline in PD and MSA were explored. When compared with patients with normal cognition, patients with PD and MSA who had mild cognitive impairment demonstrated a total field of cognitive decline, not limited to one field. Although the decline in attention was more marked in patients with MSA who had mild cognitive impairment than PD patients who had mild cognitive impairment, there were no obvious changes in other areas of cognition. Mild cognitive impairment in PD and MSA demonstrates a broad range of affected cognitive fields.
The relationships among SUA, lipid levels and cognitive function in PD and MSA were also explored. This study showed that PD patients with mild cognitive impairment had lower SUA level than patients without such impairment. The same results were found in MSA patients. In the case of PD, patients with mild cognitive impairment had higher TC and LDL-C than patients without mild cognitive impairment. After adjusting for confounders, results showed that low SUA levels were still related to the risk of mild cognitive impairment in PD and MSA. High TC and LDL-C levels were significantly related to the risk of mild cognitive impairment in PD. Both PD MoCA scores and MSA MoCA scores were positively correlated with SUA levels. Further, MoCA scores of PD were negatively correlated with TC levels.
There are some similarities between PD and MSA, such as abnormal accumulation of
Here, a retrospective investigation was undertaken to understand the connection between lipid levels and cognitive function in MSA and PD. The study demonstrated that high TC and LDL-C were significantly related to mild cognitive impairment in patients with PD. The role that cholesterol has on cognition is controversial. However, the findings reported here raise the possibility that TC and LDL-C may play a detrimental role in cognitive function in PD. High levels of TC and LDL-C have an impact on cerebral blood supply. Elevated TC and LDL-C leads to the development of lipid plaques, which impact cognitive performance by causing cerebral ischemia and hypoxia [21]. The blood–brain barrier can be damaged by high TC levels. Elevated TC levels have been linked to elevated metabolites, such as 24S-hydroxycholesterol and 27S-hydroxycholesterol, which both impair the barrier and allow the entry of inflammatory factors and serum cholesterol [22]. Also, oxidative stress brought on by elevated TC levels damages the membranes of neurons [23].
This study showed a positive relation between the SUA level and the MoCA score in PD and MSA patients, a finding consistent with previous studies [5, 24]. Even with relatively high significance, SUA level had relatively weak-to-moderate correlations with wide ranges of cognitive domains in PD and MSA. One possible reason is that MoCA is not the optimal option for certain cognitive domains. For every cognitive domain, there are more thorough assessments. Future research on every domain of cognition is worthwhile. McFarland et al. [25] explored a negative correlation between SUA levels and PD risk and progression rates, supporting the theory that SUA might have a neuroprotective effect on cognitive function [26, 27]. Huang et al. [28] showed that SUA improved cognitive performances of PD mice and enhanced tyrosine hydroxylase (TH)-positive dopaminergic neurons in the substantia nigra. This neuroprotective function may be explained by the antioxidant and iron-scavenging effects of SUA [7, 28, 29]. When compared to healthy controls, PD patient serum and the substantia nigra had lower levels of uric acid (UA), which made dopamine more vulnerable to oxidative stress [30]. A previous study has demonstrated that urate protects PC12 cells from oxidative damage, which might include the mechanisms that underlie the link between high SUA and lower risk of PD [31]. Cognitive dysfunction in MSA may share a similar pathway.
There were several limitations in this study. First, due to its cross-sectional design, it was difficult to determine whether SUA is a cause of, or results from mild cognitive impairment. Second, the study sample size was relatively small. Third, information about the long-term residence, eating habits and exercise routines of participants was not collected, so the impact of these factors on cognitive function cannot be ruled out.
Patients with PD and MSA who had mild cognitive impairment experienced multiple cognitive domain impairment. Attentional impairment was more pronounced in patients with MSA than in PD. The present results show that a low SUA level was a possible risk factor of mild cognitive impairment in patients with PD and MSA. Additionally, high levels of TC and LDL-C might increase the risk of mild cognitive impairment in PD patients. To clarify the effect of SUA and lipid levels on cognitive decline in PD and MSA, larger clinical and prospective studies are required.
The data that support the findings of this study are available from the corresponding author Zhihong Shi upon reasonable request.
Conceptualization: ZS and XR; methodology: XR, ZS and YJ; formal analysis: XR, XL, YJ and HW; investigation: ZS, XR, PW, XL, JZ and SL; resources: ZS, XR, JZ, SL and YJ; writing original draft preparation: XR, and ZS; writing, review and editing: ZS and XR, PW; supervision: ZS and YJ; funding acquisition, YJ, ZS and PW. All authors contributed to editorial changes in the manuscript. All authors read and approved the final manuscript. All authors have participated sufficiently in the work and agreed to be accountable for all aspects of the work.
All patients gave informed consent and the study (No. 2020-100) was authorized by the Tianjin Huanhu Hospital Medical Ethics Committee.
Not applicable.
This work was supported by the Tianjin Science and Technology Plan Project (grant number 22ZYCGSY00840), Tianjin Health Research Project (TJWJ2023QN060), National Natural Science Foundation of China (grant number 82171182), and Tianjin Key Medical Discipline (Specialty) Construction Project (grant number TJYXZDXK-052B).
The authors declare no conflict of interest.
References
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