Abstract
Vitamin D has many immunomodulatory, anti-inflammatory, and neuroprotective functions, and previous studies have demonstrated an association between vitamin D deficiency and neuropsychiatric disease. The aim of our study was to analyze the prevalence of vitamin D deficiency in a 1-year cohort of adult inpatients with schizophreniform and autism spectrum syndromes in a naturalistic inpatient setting in Germany. Our study was comprised of 60 adult schizophreniform and 23 adult high-functioning autism spectrum patients who were hospitalized between January and December of 2015. We compared our findings with a historical German reference cohort of 3,917 adults using Pearson's two-sided chi-squared test. The laboratory measurements of 25-hydroxyvitamin D2/3 [25(OH)vitamin D] were obtained using a chemiluminescence immunoassay. In the schizophreniform group, we found decreased (<20 ng/ml) 25(OH)vitamin D levels in 48/60 (80.0%) of the patients. In the autism spectrum group, decreased levels were detected in 18/23 (78.3%) of the patients. 25(OH)vitamin D deficiencies were found in 57.3% of the historical control group. Particularly, severe deficiencies (<10 ng/ml) occurred much more frequently in the schizophreniform (38.3%) and autism spectrum groups (52.2%), when compared to the control group (16.3%). The recommended 25(OH)vitamin D values of >30 ng/ml were observed in only 5% of the schizophreniform patients, 8.7% of the autism spectrum patients, and 21.9% of the healthy controls. We found very high rates of 25(OH)vitamin D deficiencies in both patient groups and have discussed whether our findings might be related to alterations in the immunological mechanisms. Irrespective of the possible pathophysiological links between vitamin D deficiency and schizophrenia or autism spectrum disorders, a more frequent measurement of vitamin D levels seems to be justified in these patient groups. Further prospective, controlled, blinded, and randomized research should be conducted to analyze the effectiveness of vitamin D supplementation on the improvement of psychiatric symptoms.
Highlights
The role of vitamin D levels in skeletal health is well known; for example, vitamin D deficiency can cause or exacerbate osteoporosis, lead to muscle weakness, and increase the risk of bone fractures [1]
For the schizophrenia spectrum group, we found decreased 25(OH)vitamin D levels in 80% of the patients, and relative insufficiency in 15%; the preferred 25(OH)vitamin D range was observed in only 5% of the cases
When looking at dimensional associations in the correlation analyses of the autism spectrum disorder group, we found a significant dimensional association between the 25(OH)vitamin D and energy levels, as well as with the circadian rhythms, in that higher 25(OH)vitamin D levels were associated with a higher severity of symptoms
Summary
The role of vitamin D levels in skeletal health is well known; for example, vitamin D deficiency can cause or exacerbate osteoporosis, lead to muscle weakness, and increase the risk of bone fractures [1]. The associations between vitamin D deficiency and multiple sclerosis (MS), Parkinson’s disease, schizophreniform disorder, autism spectrum disorders, and Alzheimer’s disease have recently been described [4,5,6]. Earlier studies have shown clear indications of an association between vitamin D deficiency and schizophreniform disorder. A recent meta-analysis found vitamin D deficiencies in 65.3% of these patients [9]. In another meta-analysis, statistically significantly lower vitamin D levels were found in autistic patients compared to healthy controls. Most of these studies were performed in children [10]. An adult deficiency may be associated with diverse immunological alterations, as well as neurochemical changes [6, 10]
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