Vitamin D and white matter abnormalities in older adults: a quantitative volumetric analysis of brain MRI

Background: Vitamin D insufficiency is associated with brain changes. Our objective was to investigate whether vitamin D insufficiency was associated with a greater volume in mm(3) of white matter abnormalities (WMA) in older adults.

Methods: Seventy-five Caucasian older community-dwellers (mean, 70.9 ± 5.0 years; 48%female) received a blood test and brain MRI. The volumes of total white matter (WM) and WMA were measured from T1-weighted MR images using automatic, accurate and reproducible segmentation of the brain provided by FreeSurfer. Vitamin D insufficiency was defined a priori as serum 25-hydroxyvitamin D<50 nmol/L. Age, gender, body mass index, mean arterial pressure, use of anti-vascular drugs, education level, Mini-Mental State Examination score, Instrumental Activities of Daily Living score, serum calcium concentration, estimated glomerular filtration rate, and season of evaluation were used as potential confounders.

Results: Participants with vitamin D insufficiency (n = 29) had a greater volume of WMA than the others (4233 ± 4359 mm(3) versus 2658 ± 1544 mm(3), P = 0.028), even after normalization for WM volume (P = 0.031). Vitamin D insufficiency was cross-sectionally associated with an increased ratio of WMA volume to WM volume (fully adjusted β = 0.35, P = 0.047).

Conclusions: Vitamin D insufficiency was associated with increased WMA volume in the studied sample of older adults. These findings may provide insight into the pathophysiology of cognitive and mobility declines in older adults with vitamin D insufficiency.