Vitamin D supplementation during the first year of life and risk of schizophrenia: A Finnish birth cohort study

• Published in: Schizophrenia Research
• Main Authors: McGrath, John, Saari, Kaisa, Hakko, Helinä, Jokelainen, Jari, Jones, Peter, Järvelin, Marjo-Riitta, Chant, David, Isohanni, Matti
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2004
• Subjects: Epidemiology; Northern Finland
• Online Access: http://hdl.handle.net/10072/27172; https://doi.org/10.1016/j.schres.2003.08.005

Objective: Based on clues from epidemiology and animal experiments, low vitamin D during early life has been proposed as a risk factor for schizophrenia. The aim of this study was to explore the association between the use of vitamin D supplements during the first year of life and risk of developing schizophrenia. Method: Subjects were drawn from the Northern Finland 1966 Birth Cohort (n=9 114). During the first year of life, data were collected about the frequency and dose of vitamin D supplementation. Our primary outcome measures were schizophrenia, psychotic disorders other than schizophrenia, and nonpsychotic disorders as diagnosed by age 31 years. Males and females were examined separately. Results: In males, the use of either irregular or regular vitamin D supplements was associated with a reduced risk of schizophrenia (Risk ratio (RR)=0.08, 95% CI 0.01-0.95; RR=0.12, 95% CI 0.02-0.90, respectively) compared with no supplementation. In males, the use of at least 2000 IU of vitamin D was associated with a reduced risk of schizophrenia (RR=0.23, 95% CI 0.06-0.95) compared to those on lower doses. There were no significant associations between either the frequency or dose of vitamin D supplements and (a) schizophrenia in females, nor with (b) nonpsychotic disorder or psychotic disorders other than schizophrenia in either males or females. Conclusion: Vitamin D supplementation during the first year of life is associated with a reduced risk of schizophrenia in males. Preventing hypovitaminosis D during early life may reduce the incidence of schizophrenia. No Full Text