RT Journal Article
SR Electronic
T1 Decreased serum pyridoxal levels in schizophrenia: meta-analysis and Mendelian randomization analysis
JF Journal of Psychiatry and Neuroscience
JO J Psychiatry Neurosci
FD Canadian Medical Association
SP 194
OP 200
DO 10.1503/jpn.170053
VO 43
IS 3
A1 Tomioka, Yukiko
A1 Numata, Shusuke
A1 Kinoshita, Makoto
A1 Umehara, Hidehiro
A1 Watanabe, Shin-ya
A1 Nakataki, Masahito
A1 Iwayama, Yoshimi
A1 Toyota, Tomoko
A1 Ikeda, Masashi
A1 Yamamori, Hidenaga
A1 Shimodera, Shinji
A1 Tajima, Atsushi
A1 Hashimoto, Ryota
A1 Iwata, Nakao
A1 Yoshikawa, Takeo
A1 Ohmori, Tetsuro
YR 2018
UL http://jpn.ca/content/43/3/194.abstract
AB Background: Alterations in one-carbon metabolism have been associated with schizophrenia, and vitamin B6 is one of the key components in this pathway.Methods: We first conducted a case–control study of serum pyridoxal levels and schizophrenia in a large Japanese cohort (n = 1276). Subsequently, we conducted a meta-analysis of association studies (n = 2125). Second, we investigated whether rs4654748, which was identified in a genome-wide association study as a vitamin B6-related single nucleotide polymorphism, was genetically implicated in patients with schizophrenia in the Japanese population (n = 10 689). Finally, we assessed the effect of serum pyridoxal levels on schizophrenia risk using a Mendelian randomization (MR) approach.Results: Serum pyridoxal levels were significantly lower in patients with schizophrenia than in controls, not only in our cohort, but also in the pooled data set of the meta-analysis of association studies (standardized mean difference −0.48, 95% confidence interval [CI] −0.57 to −0.39, p = 9.8 × 10−24). We failed to find a significant association between rs4654748 and schizophrenia. Furthermore, an MR analysis failed to find a causal relationship between pyridoxal levels and schizophrenia risk (odds ratio 0.99, 95% CI 0.65–1.51, p = 0.96).Limitations: Food consumption and medications may have affected serum pyridoxal levels in our cross-sectional study. Sample size, number of instrumental variables and substantial heterogeneity among patients with schizophrenia are limitations of an MR analysis.Conclusion: We found decreased serum pyridoxal levels in patients with schizophrenia in this observational study. However, we failed to obtain data supporting a causal relationship between pyridoxal levels and schizophrenia risk using the MR approach.