Low vitamin B-12 but not folate is associated with incident depressive symptoms in community-dwelling older adults: a 4-year longitudinal study

This was a longitudinal study utilising the Irish Longitudinal Study on Ageing (n 3849 aged >= 50 years) and investigated the relationship between blood plasma folate and B-12 levels at baseline (wave 1) and incident depressive symptoms at 2 and 4 years (waves 2 and 3). A score >= 9 on the Center for Epidemiological Studies Depression Scale-8 at wave 2 or 3 was indicative of incident depressive symptoms. B-12 status profiles (pmol/l) were defined as < 185, deficient low; 185 to < 258, low normal; > 258-601, normal and > 601 high. Folate status profiles (nmol/l) were defined as <= 10 center dot 0, deficient low; > 10-23 center dot 0, low normal; > 23 center dot 0-45 center dot 0, normal; >45 center dot 0, high. Logistic regression models were used to analyse the longitudinal associations. Both B-12 and folate plasma concentrations were lower in the group with incident depressive symptoms v. non-depressed (folate: 21 center dot 4 v. 25 center dot 1 nmol/l; P = 0 center dot 0003; B-12:315 center dot 7 v. 335 center dot 9 pmol/l; P = 0 center dot 0148). Regression models demonstrated that participants with deficient-low B-12 status at baseline had a significantly higher likelihood of incident depression 4 years later (OR 1 center dot 51, 95 % CI 1 center dot 01, 2 center dot 27, P = 0 center dot 043). This finding remained robust after controlling for relevant covariates. No associations of folate status with incident depression were observed. Older adults with deficient-low B-12 status had a 51 % increased likelihood of developing depressive symptoms over 4 years. The findings highlight the need to further explore the low-cost benefits of optimising vitamin B-12 status for depression in older adults.

Automated summary

This longitudinal study used the Irish Longitudinal Study on Aging to investigate the relationship between blood plasma folate and B-12 levels and incident depressive symptoms in older adults. The results showed that individuals with lower blood plasma folate and B-12 concentrations had a higher likelihood of developing depressive symptoms. Further research is needed to explore the cost-effective benefits of optimizing vitamin B-12 status for depression in older adults.