Abstract
Purpose :
There is a significant paucity of neuroprotective strategies to reduce the vulnerability to glaucoma-related cellular stressors. Recent work has suggested that patients with glaucoma have reduced plasma levels of nicotinamide adenine dinucleotide (NAD), a precursor for vitamin B3 (niacin). Additionally, mouse models have found a similar age-related decline in NAD with subsequent neuroprotection of retinal ganglion cells with very high-dose oral vitamin B3. We aimed to evaluate whether dietary vitamin B3 and 50 other vitamins, minerals and micronutrients explain variation in glaucoma-related endophenotypes in the general population.
Methods :
A population-based cross-sectional study was performed with 1,977 predominantly female participants from the TwinsUK registry. Energy adjusted intakes for 51 nutrients were estimated through a validated food frequency questionnaire. Endophenotypes evaluated included intraocular pressure (IOP), retinal nerve fibre layer (RNFL) thickness and vertical cup to disc ratio (VDCR) adjusted for disc area. Linear mixed models adjusted for age, sex and family structure were used to investigate the associations of individual nutrients and endophenotype. A backwards stepwise regression model was completed for each endophenotype, including all associated nutrients after stratifying intake into quartiles.
Results :
Within the study cohort, mean (SD) age was 60.1 (±14.6) years. Mean endophenotype values measured were IOP: 13.3mmhg (±2.81), VCDR: 0.4 (±0.12) and RNFL: 96.1µm (±10.10). Dietary vitamin B3 was not associated with any endophenotypes. Multivariate regression models evaluating lowest versus highest quartiles of dietary intake identified two nutrients associated with RNFL thickness, magnesium (β=-1.83, p=0.04) and thiamine (β=2.03, p=0.02); thiamine intake demonstrated a dose-related association with a thicker RNFL for each quartile. Flavonoids intake was associated with reduced IOP (β=-0.401, p= 0.05), and vitamin E (β=-0.017, p= 0.03) and selenium (β=0.019, p=0.04) were associated with VCDR.
Conclusions :
Dietary thiamine intake has a dose-response relationship to RNFL thickness, longitudinal studies are required to see if it protects against RNFL loss. In a healthy population dietary vitamin B3 did not appear to be protective for glaucoma-related endophenotypes. Dietary flavonoid intake appears to be associated with lower IOP.
This is a 2021 ARVO Annual Meeting abstract.