Vitamin D and white matter abnormalities in older adults: a cross‐sectional neuroimaging study

Background and purposeMorphological brain changes related to hypovitaminosis D have been poorly studied. In particular, the age‐related decrease in vitamin D concentrations may explain the onset of white matter abnormalities (WMA) in older adults. Our objectives were (i) to investigate whether there was an association between serum 25‐hydroxyvitamin D (25OHD) concentration and the grade of WMA in older adults and (ii) to determine whether the location of WMA was associated with 25OHD concentration.MethodsOne hundred and thirty‐three Caucasian older community‐dwellers with no clinical hydrocephalus (mean 71.6 ± 5.6 years; 43.6% female) received a blood test and a magnetic resonance imaging scan of the brain. The grades of total, periventricular and deep WMA were scored using semiquantitative visual rating scales from T2‐weighted fluid‐attenuated inversion recovery images. The association of WMA with as‐measured and deseasonalized 25OHD concentrations was evaluated with the following covariates: age, gender, body mass index, use of anti‐vascular drugs, number of comorbidities, impaired mobility, education level, Mini‐Mental State Examination score, medial temporal lobe atrophy, serum concentrations of calcium, thyroid‐stimulating hormone and vitamin B12, and estimated glomerular filtration rate.ResultsBoth as‐measured and deseasonalized serum 25OHD concentrations were found to be inversely associated with the grade of total WMA (adjusted β = −0.32, P = 0.027), specifically with periventricular WMA (adjusted β = −0.15, P = 0.009) but not with deep WMA (adjusted β = −0.12, P = 0.090). Similarly, participants with 25OHD concentration <75 nM had on average a 33% higher grade of periventricular WMA than those with 25OHD ≥75 nM (P = 0.024). No difference in average grade was found for deep WMA (P = 0.949).ConclusionsLower serum 25OHD concentration was associated with higher grade of WMA, particularly periventricular WMA. These findings provide a scientific basis for vitamin D replacement trials.