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.

Correlation between vitamin D and serum brain derived neurotropic factor levels in type 2 diabetes mellitus patients

Diabetes Mellitus (DM) currently ranks as the most common endocrine disorder worldwide. Current opinion views DM as a group of heterogeneous metabolic diseases characterized by hyperglycemia triggered by defects in the ability of the body to produce or use insulin in type 1 and 2 DM, respectively. Brain-derived neurotrophic factor (BDNF), one of the neurotrophin family of growth factors, has been linked to the pathogenesis of DM and insulin resistance. Moreover, vitamin D has been associated with insulin resistance and DM. Recently, the interactions between vitamin D and BDNF have been investigated in diabetic rats. However, this correlation has never been investigated in humans. Thus, the aim of the present study was to assess the alterations in serum BDNF and vitamin D levels in T2DM patients in Jordan, prior to and following vitamin D supplementation. A combination of non-experimental case-control and experimental designed studies were utilized to assess the relationship between serum BDNF and vitamin D levels in T2DM patients. The levels of BDNF and vitamin D were measured using commercially available ELISA kits, and fasting blood glucose (FBG) and HbA1c levels were measured in medical labs. The results showed that diabetic patients had lower levels of serum vitamin D and higher levels of BDNF compared with the healthy controls. Moreover, linear regression analysis indicated that BDNF levels were inversely correlated with serum vitamin D levels. Furthermore, vitamin D supplementation significantly increased vitamin D serum levels and decreased BDNF serum levels in diabetic patients. Intriguingly, FBG and HbA1c levels were significantly improved post vitamin D supplementation. These data demonstrate a positive effect of vitamin D supplementation in diabetic patients suggesting the implementation of vitamin D as part of future T2DM treatment plans. However, additional studies are needed to investigate the direct link between vitamin D, BDNF, and T2DM.

The prevalence and clinical correlates of metabolic syndrome and cardiometabolic alterations in 430 drug-naive patients in their first episode of schizophrenia

RATIONALE

Although metabolic abnormalities and metabolic syndrome (MetS) have been extensively investigated in schizophrenia, few studies have examined them in first-episode drug-naive (FEDN) patients.

OBJECTIVES

This study aimed to investigate the prevalence and clinical correlates of metabolic abnormalities in FEDN schizophrenia patients.

METHODS

A total of 430 FEDN schizophrenia patients and 453 controls were recruited. Various parameters were measured including BMI, waist circumference, blood pressure, lipid profiles, blood glucose, glycosylated hemoglobin (HbA1c), insulin, and homeostatic model assessment for insulin resistance (HOMA-IR).

RESULTS

Patients had a higher prevalence of MetS, hypertension, hypertriglyceridemia, hypo-HDL-C, elevated HAb1c, and elevated insulin than controls (19.1% vs. 6.6%, OR = 2.52; 33.3% vs. 12.1%, OR = 3.05; 30.5% vs. 16.1%, OR = 2.25; 43.1% vs. 24.0%, OR = 2.21; 25.6% vs. 10.8%, OR = 2.62; 9.1% vs. 0.9%, OR = 10.29; all p_Bonferroni < 0.001). Waist circumference was associated with PANSS general psychopathology and total score (correlation coefficient r = 0.17, p_Bonferroni < 0.001; correlation coefficient r = 0.16, p_Bonferroni = 0.004). Fasting glucose was associated with PANSS negative, general psychopathology, and total score (correlation coefficient r = 0.13, p_Bonferroni = 0.03; correlation coefficient r = 0.19, p_Bonferroni < 0.001; correlation coefficient r = 0.20, p_Bonferroni < 0.001). BMI (OR = 1.37), smoking (OR = 3.39), and HOMA-IR (OR = 5.60) were associated with MetS in FEDN schizophrenia (all p < 0.001).

CONCLUSIONS

Our results demonstrate that MetS and metabolic abnormalities co-existed in the early stages of schizophrenia without antipsychotics. Waist circumference and glucose were associated with psychopathological symptoms, while BMI, smoking, and HOMA-IR were associated with MetS in FEDN schizophrenia.

Vitamin D deficiency and Schizophrenia in Adults: A Systematic Review and Meta-analysis of Observational Studies

Schizophrenia is a heterogeneous disorder in which there is an interaction between genetic and environmental factors. Accumulating data show that there may be an association between vitamin D deficiency and schizophrenia. We conducted an updated meta-analysis to investigate the relationship between schizophrenia and blood vitamin D level. All published observational articles have been searched from five databases until September 2019. In total, 36 articles with a total of 12528 participants were included in this study. Patients with schizophrenia have significantly lower levels of vitamin D than controls. The subgroup analyses based on study design, hospitalization status, quality score, type of biomarker [25-hydroxyvitamin D or 25-hydroxyvitamin D₃], and the country did not explain between-study heterogeneity; however, meta-regression on match factors indicted that match of BMI could account for some degree of heterogeneity. No significant differences in publication bias were observed. Also, subjects with schizophrenia were more likely to have vitamin D deficiency or insufficiency compared to controls. In conclusion, our analyses are consistent with the hypothesis that vitamin D deficiency is associated with schizophrenia. More well-designed randomized control trials are needed to determine whether this association is causal.