Developmental exposure to vitamin D deficiency and subsequent risk of schizophrenia.
Level 5 - mechanism / opinion, no new human data
Narrative review of epidemiological and genetic studies without systematic review methodology
PubMed 34247885 · doi:10.1016/j.schres.2021.06.004
What was done
This narrative review synthesized epidemiological and genetic evidence examining whether early-life exposure to vitamin D deficiency increases the risk of schizophrenia. The authors reviewed ecological associations (season of birth, migrant status), findings from two Danish neonatal dried blood spot case-control studies, and recent genetic data.
What was found
Two case-control studies based on Danish neonatal dried blood spots showed that neonatal vitamin D deficiency was associated with an increased risk of schizophrenia. However, recent genetic analyses indicated that common variants linked to schizophrenia may also lead to lower vitamin D concentrations (possibly mediated via reduced outdoor activity). No specific numerical effect sizes or risk estimates were provided in the abstract.
Why it matters
Early-life vitamin D status is a potentially modifiable exposure, but current findings remain inconclusive and cannot yet justify targeted public health supplementation policies for schizophrenia prevention.
Limits
The underlying evidence relies heavily on observational case-control designs and ecological proxies subject to confounding. Genetic findings suggest plausible reverse causality, and no randomized controlled trial data exist to establish a causal preventive effect.
Cited by
- supports There is a scientific hypothesis proposing that individuals with ancestry from equatorial climates are more susceptible to schizophrenia when living in colder climates due to the activation of genetic risk factors.