Detrimental impact of solar and geomagnetic activity on plasma B-complex vitamins in the VA normative aging study cohort

It has been hypothesized that ultraviolet (UV) radiation can lead to depletion of plasma folate and B₁₂ vitamin, but few studies have investigated effects of other parameters of solar and geomagnetic activity (SGA). We investigated the association between four SGA parameters-interplanetary magnetic field (IMF), sunspot number (SSN), K_p index, and ground shortwave solar radiation (SWR)-and three plasma B-complex vitamins-folate, B₆, and B₁₂-in 910 participants from the Normative Aging Study (NAS) between 1998 and 2017. Mixed-effects regression models were used for 1- to 28-moving day averages of SGA exposure, adjusted for covariates. We compared the impact of SGA in individuals under higher and lower B-complex supplementation (> or < 50th quartile). Our findings show that increases in solar activity variables IMF and SSN were found to be significantly associated with decreases in B₁₂ vitamin. IMF and SSN were associated with decrease in folate levels, especially in individuals under higher levels of B-complex supplementation. No associations were found for SWR and K_p index. To our knowledge, this is the first study that demonstrated the detrimental impact of solar activity on plasma B₁₂ and folate in a large cohort. These findings have clinical implications during periods of high solar activity.