Clinical, Biochemical and Genetic Variables Associated With Metabolic Syndrome in Patients With Schizophrenia Spectrum Disorders Using Second-Generation Antipsychotics: A Systematic Review

Global Prevalence of Metabolic Syndrome in Schizophrenia Patients: A Systematic Review and Meta-Analysis

The prevalence of metabolic syndrome in patients with schizophrenia has significantly increased and can be associated with severe complications such as chronic diseases and mortality. Despite numerous studies, a comprehensive estimate of the prevalence of metabolic syndrome in schizophrenia patients is lacking. Therefore, this study aimed to estimate the global prevalence of metabolic syndrome in schizophrenia patients through a systematic review and meta-analysis. This study was conducted as a systematic review and meta-analysis based on PRISMA guidelines without time restrictions until April 1, 2024. Relevant articles were identified through searches in databases including Scopus, Web of Science (WoS), PubMed, Science Direct, Embase, and Google Scholar, using key terms combined with AND & OR operators. After removing duplicates and conducting primary and secondary screening, 12 studies were included in the meta-analysis. Data were analysed using the random-effects model in Comprehensive Meta-Analysis Version 2 software. This analysis included 12 studies with 1,953 participants. The pooled prevalence of metabolic syndrome was 41.3% (95% CI: 28.8-55.1), with significant heterogeneity (I2: 96.3%). The highest prevalence was reported in France (79.1%) and the lowest in China (18.03%). Over one-third of patients with schizophrenia are affected by metabolic syndrome. Hence, greater attention should be paid to the prevention and reduction of complications and mortality associated with metabolic syndrome in schizophrenia patients.

Genetic predisposition and antipsychotic treatment effect on metabolic syndrome in schizophrenia: a ten-year follow-up study using the Estonian Biobank

Background

Schizophrenia (SCZ) patients exhibit 30% higher prevalence of metabolic syndrome (MetS) compared to the general population with its suboptimal management contributing to increased mortality. Large-scale studies providing real-world evidence of the underlying causes remain limited.

Methods

To address this gap, we used real-world health data from the Estonian Biobank, spanning a median follow-up of ten years, to investigate the impact of genetic predisposition and antipsychotic treatment on the development of MetS in SCZ patients. Specifically, we set out to characterize antipsychotic treatment patterns, genetic predisposition of MetS traits, MetS prognosis, and body mass index (BMI) trajectories, comparing SCZ cases (n = 677) to age- and sex-matched controls (n = 2708).

Findings

SCZ cases exhibited higher genetic predisposition to SCZ (OR = 1.75, 95% CI 1.58-1.94), but lower polygenic burden for increased BMI (OR = 0.88, 95% CI 0.88-0.96) and C-reactive protein (OR = 0.88, 95% CI 0.81-0.97) compared to controls. While SCZ cases showed worse prognosis of MetS (HR 1.95, 95% CI 1.54-2.46), higher antipsychotic adherence within the first treatment year was associated with reduced long-term MetS incidence. Linear mixed modelling, incorporating multiple BMI timepoints, underscored the significant contribution of both, antipsychotic medication, and genetic predisposition to higher BMI, driving the substantially upward trajectory of BMI in SCZ cases.

Interpretation

These findings contribute to refining clinical risk prediction and prevention strategies for MetS among SCZ patients and emphasize the significance of incorporating genetic information, long-term patient tracking, and employing diverse perspectives when analyzing real-world health data.

Funding

EU Horizon 2020, Swedish Research Council, Estonian Research Council, Estonian Ministry of Education and Research, University of Tartu.

A randomized controlled trial of Vitamin D supplementation in Iranian patients with schizophrenia: Effects on serum levels of glycogen synthase kinase-3β and symptom severity

BACKGROUND

Growing evidence has shown that hypovitaminosis D is a risk factor for developing schizophrenia and comorbid conditions. Therefore, this study aimed to examine the effect of vitamin D supplementation on serum levels of vitamin D, metabolic factors related to insulin resistance (IR) and the severity of the disorder in patients with schizophrenia.

METHODS

Forty-eight chronic male patients with schizophrenia with vitamin D deficiency (≤20 ng/mL= (≤50 nmol/l) were selected and randomly assigned to vitamin D treatment and placebo groups. Subjects were supplemented for 8 weeks with vitamin D (2000 IU/day) or placebo.

RESULTS

Within-group comparison revealed that the vitamin D group had a significant reduction in waist circumference, Positive and Negative Syndrome Scale - total score (PANSS-TS), and glycogen synthase kinase 3 beta (GSK-3β) levels (P = .022, P = <.001 and P = .013, respectively). On the other hand, the placebo group showed a significant increase in the level of fasting serum insulin and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) (P = .003 and P = .003). The between-group comparison showed a significant difference in terms of PANSS-TS, GSK-3β, fasting serum insulin (FSI), and HOMA-IR (P = .022, P = .048, P = .013 and P = .014 respectively).

CONCLUSIONS

Among vitamin D deficient patients with schizophrenia, vitamin D supplementation may affect GSK-3 β, an important biomarker in schizophrenia and insulin resistance. In addition, vitamin D supplementation in such patients may reduce the disorder's symptom severity.

The association between schizophrenia and white blood cells count: a bidirectional two-sample Mendelian randomization study

BACKGROUND

Positive associations between the risk of schizophrenia and the level of white blood cells (WBC) count have been suggested by observational studies. However, the causality of this association is still unclear.

METHODS

We used a group of bidirectional two-sample Mendelian randomization (MR) analyses to estimate the causal relationship between schizophrenia and WBC count traits (i.e., WBC count, lymphocyte count, neutrophil count, basophil count, eosinophil count, and monocyte count). The threshold of FDR-adjusted P < 0.05 was considered as showing potential evidence of a causal effect. Instrument variables were included based on the genome-wide significance threshold (P < 5 × 10^- 8) and linkage disequilibrium (LD) clumping (r² < 0.01). In total, 81, 95, 85, 87, 76, and 83 schizophrenia-related single nucleotide polymorphisms (SNPs) were used as genetic instruments from Psychiatric Genomics Consortium for six WBC count traits, respectively. And in reverse MR analysis, 458, 206, 408, 468, 473, and 390 variants extracted from six WBC count traits were utilized as genetic instruments, which were obtained from a recent large-scale Genome-Wide Association Study (GWAS).

RESULTS

Genetically predicted schizophrenia was positively associated with the level of WBC count [odds ratio (OR) 1.017, 95% confidence interval (CI) 1.008-1.026; P = 7.53 × 10^- 4], basophil count (OR 1.014, 95%CI 1.005-1.022; P = 0.002), eosinophil count (OR 1.021, 95%CI 1.011-1.031; P = 2.77 × 10^- 4), monocyte count (OR 1.018, 95%CI 1.009-1.027; P = 4.60 × 10^- 4), lymphocyte count (OR 1.021, 95%CI 1.012-1.030; P = 4.51 × 10^- 5), and neutrophil count (OR 1.013, 95%CI 1.005-1.022; P = 0.004). WBC count traits are not associated with the risk of schizophrenia in our reverse MR results.

CONCLUSION

Schizophrenia is associated with elevated levels of WBC count (i.e., higher WBC count, lymphocyte count, neutrophil count, basophil count, eosinophil count, and monocyte count).

Cell Adhesion Molecules in Schizophrenia Patients with Metabolic Syndrome

Metabolic syndrome (MetS) is a common comorbidity of schizophrenia and significantly shortens life expectancy of the patients. Intercellular (ICAM), vascular (VCAM), and neural (NCAM) cell adhesion molecules (CAMs) mediate neuroinflammatory processes, and their soluble forms (e.g., sICAM) in plasma are present in parallel with their cell-bound forms. In this study, their serum levels were examined in 211 white Siberian patients with paranoid schizophrenia (82 patients with and 129 without MetS according to the 2005 International Diabetes Federation criteria). Serum levels of CAMs were determined with Magpix and Luminex 200 (Luminex, Austin, TX, USA) using xMAP Technology. The level of sICAM-1 was significantly higher and that of sVCAM-1 significantly lower in patients with MetS compared to patients without MetS. Levels of NCAM did not differ between the groups. More pronounced Spearman’s correlations between CAMs, age, duration of schizophrenia, and body–mass index were observed among patients without MetS than among patients with MetS. Our results are consistent with MetS’s being associated with endothelial dysfunction along with other components of inflammation. Through these endothelial components of peripheral inflammatory processes, MetS might induce intracerebral neuroinflammatory changes, but further investigation is needed to confirm this.

3-year incidence and predictors of metabolic syndrome in schizophrenia in the national FACE-SZ cohort

AIMS

Metabolic Syndrome (MetS) is a major health epidemic of Western countries and patients with schizophrenia is a particularly vulnerable population due to lifestyle, mental illness and treatment factors. However, we lack prospective data to guide prevention. The aim of our study is then to determine MetS incidence and predictors in schizophrenia.

METHOD

Participants were recruited in 10 expert centers at a national level and followed-up for 3 years. MetS was defined according to the International Diabetes Federation criteria. Inverse probability weighting methods were used to correct for attrition bias.

RESULTS

Among the 512 participants followed-up for 3 years, 77.9% had at least one metabolic disturbance. 27.5% were identified with MetS at baseline and excluded from the analyses. Among the rest of participants (N = 371, mean aged 31.2 (SD = 9.1) years, with mean illness duration of 10.0 (SD = 7.6) years and 273 (73.6%) men), MetS incidence was 20.8% at 3 years and raised to 23.6% in tobacco smokers, 29.4% in participants receiving antidepressant prescription at baseline and 42.0% for those with 2 disturbed metabolic disturbances at baseline. Our multivariate analyses confirmed tobacco smoking and antidepressant consumption as independent predictors of MetS onset (adjusted odds ratios (aOR) = 3.82 [1.27-11.45], p = 0.016, and aOR = 3.50 [1.26-9.70], p = 0.0158). Antidepressant prescription predicted more specifically increased lipid disturbances and paroxetine was associated with the highest risk of MetS onset.

CONCLUSION

These results are an alarm call to prioritize MetS prevention and research in schizophrenia. We have listed interventions that should be actively promoted in clinical practice.

Associations between the number of antipsychotics prescribed and metabolic parameters in Japanese patients with schizophrenia

Aim

There is little evidence on the effects of antipsychotic polypharmacy on metabolic parameters in patients with schizophrenia. Thus, this cross-sectional study explored the associations between the number of antipsychotics prescribed and metabolic parameters in Japanese patients with schizophrenia.

Methods

We obtained metabolic parameter data from 19,675 patients with schizophrenia. Of these, 1380 (7.0%), 8422 (42.8%), 6326 (32.2%), and 3547 (18.0%) were treated with none, one, two, and three or more antipsychotics, respectively. We compared eight metabolic parameters among the four groups using univariate analyses. We then performed multiple regression analysis to assess the effect of the number of antipsychotics prescribed on metabolic parameters after controlling for the effects of age, sex, type of care (outpatient/inpatient), chlorpromazine-equivalent dose, and antipsychotic type (aripiprazole, olanzapine, and risperidone).

Results

There were significant differences in body mass index (BMI), systolic and diastolic blood pressure (dBP), total cholesterol, low-density lipoprotein cholesterol, and triglycerides among the four groups. The multiple regression analysis showed that the number of antipsychotics prescribed was significantly correlated with BMI and dBP (standardized regression coefficient = 0.031 and 0.026, respectively).

Conclusion

Our results suggested that the number of antipsychotics prescribed adversely affects BMI and dBP. Clinicians should avoid inappropriate antipsychotic polypharmacy, especially polypharmacy involving three or more antipsychotics.

Metabolic polygenic risk scores effect on antipsychotic-induced metabolic dysregulation: A longitudinal study in a first episode psychosis cohort

OBJECTIVE

Metabolic syndrome is a health-threatening condition suffered by approximately one third of schizophrenia patients and largely attributed to antipsychotic medication. Previous evidence reports a common genetic background of psychotic and metabolic disorders. In this study, we aimed to assess the role of polygenic risk scores (PRSs) on the progression of the metabolic profile in a first-episode psychosis (FEP) cohort.

METHOD

Of the 231 FEP individuals included in the study, 192-220 participants were included in basal analysis and 118-179 in longitudinal 6-month models. Eleven psychopathologic and metabolic PRSs were constructed. Basal and longitudinal PRSs association with metabolic measurements was assessed by statistical analyses.

RESULTS

No major association of psychopathological PRSs with the metabolic progression was found. However, high risk individuals for depression and cholesterol-related PRSs reported a higher increase of cholesterol levels during the follow-up (FDR ≤ 0.023 for all analyses). Their effect was comparable to other well-established pharmacological and environmental risk factors (explaining at least 1.2% of total variance).

CONCLUSION

Our findings provide new evidence of the effects of metabolic genetic risk on the development of metabolic dysregulation. The future establishment of genetic profiling tools in clinical procedures could enable practitioners to better personalize antipsychotic treatment selection and dosage.

Gene Polymorphisms of Hormonal Regulators of Metabolism in Patients with Schizophrenia with Metabolic Syndrome

Background: Metabolic syndrome (MetS) is a common complication of long-term treatment of persons with schizophrenia taking (atypical) antipsychotics. In this study, we investigated the existence of an association with polymorphisms of genes for four hormones that regulate energy metabolism. Methods: We recruited 517 clinically admitted white patients (269M/248F) with a verified diagnosis of schizophrenia (ICD-10) and with a stable physical condition. Participants were classified for having or not having MetS and genotyped for 20 single-nucleotide polymorphisms (SNPs) in the genes encoding insulin-induced gene 2 (INSIG2), ghrelin (GHRL), leptin (LEP), and leptin receptor (LEPR). Results: The 139 patients (26.9%) with MetS were significantly more likely to be women, older, and ill longer, and had a larger body mass index (BMI). Four polymorphisms (rs10490624, rs17587100, rs9308762, and rs10490816) did not meet the Hardy–Weinberg equilibrium (HWE) criterion and were excluded. Only genotypes and alleles of the rs3828942 of LEP gene (chi2 = 7.665, p = 0.022; chi2 = 5.136, p = 0.023) and the genotypes of the rs17047718 of INSIG2 gene (chi2 = 7.7, p = 0.021) had a significant association with MetS. Conclusions: The results of our study suggest that the LEP and INSIG2 genes play a certain causal role in the development of MetS in patients with schizophrenia.

Metabolic Side Effects of Olanzapine in Patients With Psychotic Disorders in Oman: A Retrospective Cohort Study

We evaluated the impact of olanzapine on metabolic changes in patients with psychotic disorders. This was a retrospective cohort study involving patients prescribed olanzapine and attending Sultan Qaboos University Hospital (Muscat, Oman). Patients were followed up retrospectively from March 2006 until April 2021. Cardiovascular treatment targets were evaluated as per the 2019 European Society of Cardiology guidelines. We enrolled 253 patients (mean age: 40±17 years). Olanzapine monotherapy was associated with increased body weight (+8 kg; 95% confidence interval (CI): 6-9; P < .001), body mass index (+3 kg/m²; 95% CI: 2-4; P < .001), total cholesterol (+.4 mmol/L; 95% CI: .3-.5; P < .001), low-density lipoprotein cholesterol (LDL-C) (+.3 mmol/L; 95% CI: .1-.4; P < .001), fasting triglycerides (+.2 mmol/L; 95% CI: .1-.3; P<.001), fasting glucose (+.6 mmol/L; 95% CI: .4-.7; P< .001), HbA1c (+.3%; 95% CI: .2-.4; P < .001), systolic blood pressure (BP) (+9 mmHg; 95% CI: 6-12; P < .001) and diastolic BP (+4 mmHg; 95% CI: 2-6; P < .001) levels. Cardiovascular therapeutic goals were attained in 38% (n = 97), 61% (n = 154), 71% (n = 180), and 59% (n = 150) for LDL-C, non-high-density lipoprotein cholesterol, triglycerides, and BP, respectively. Olanzapine was associated with adverse metabolic changes. Therefore, many patients were not at their target cardiovascular treatment goals.