Sex-specific impact of vitamin D and B9 concentrations on neuroticism: a polygenic score-based study

Neuroticism is a personality domain with prognostic value for physical and mental health. To properly inform public health policy, it is crucial to uncover the mechanisms underlying high neuroticism. Many internal and external factors that affect brain development and functioning and therefore might contribute to the variability of neuroticism remain understudied. Among them, the impact of vitamin sufficiency is of great interest, as it is a modifiable factor. This study aimed to evaluate the associations of neuroticism with vitamin D (VD) and vitamin B9 (VB9) using polygenic scores (PGS) in a nonclinical cohort.

We analyzed data from 348 healthy unrelated individuals, including neuroticism scores on the Eysenck Personality Inventory, VD-PGS, VB9-PGS and PGS for neuroticism-related traits.

The analysis controlling for demographic and genetic confounders revealed a negative association between VB9-PGS and neuroticism scores in women and a positive association between VD-PGS and neuroticism scores in men. The highest values of the VD-PGS were observed in men, who scored high on both neuroticism and extraversion. In men, unlike women, neuroticism scores were not correlated with PGS for neuroticism but were associated with PGS for bipolar disorder type 1 and alcohol use disorders.

The results suggest that the effects on neuroticism of genetic propensity for suboptimal vitamin D and B9 concentrations might differ across the two sexes. The findings are consistent with the idea of the importance of vitamin B9 for emotional stability in women and indicate the involvement of genetic factors predisposing to higher vitamin D levels in excitability-related components of neuroticism in men.