A Relationship Between Blood Levels of Otolin-1 and Vitamin D

Abstract

Objective: Low vitamin D levels have been associated with and could play a role in the pathogenesis of idiopathic benign paroxysmal positional vertigo (iBPPV). Since otoconia degeneration contributes to iBPPV and a lack of vitamin D may impact otoconia structure and integrity, we proposed a negative association between vitamin D levels and levels of a proposed circulatory biomarker for otolithic degeneration, otolin-1.

Study design: Cross-sectional clinical study.

Setting: Clinical research center.

Patients: Seventy-nine men and women ranging in age from 22 to 95 years old without known vertigo.

Interventions: Diagnostic.

Main outcome measures: Blood levels of 25-OH vitamin D and otolin-1.

Results: Previously, we had reported higher otolin-1 levels in older age groups. The majority of the subjects (83%) had vitamin D levels that were below 40 ng/ml. Vitamin D level was lowest in the young and increased with age before declining in subjects 70 years of age and older (p = 0.005). There was a negative correlation between vitamin D and otolin-1 levels of subjects over 70 (r = -0.36, p = 0.036).

Conclusion: Our results demonstrate a relationship between vitamin D and otolin-1. The majority of our subjects had abnormally low vitamin D levels, but only those over 70 years of age showed a negative correlation with high otolin-1 levels. We postulate that a seasonal drop in vitamin D may not be sufficient for otoconia fragmentation and ultimately iBPPV, rather, chronically low vitamin D maybe required to induce otoconia degeneration.

Figures

Figure 1

Mean vitamin D levels for the four age groups after removal of outliers. The number of subjects in each group was: young (20–30 years) = 20, middle aged (50–65 years) = 20, old (66–80 years) = 20 and oldest old (81–95 years) = 19. Error bars represent standard error of the mean (SEM).

Figure 2

Scatter plot of vitamin D levels as a function of age. A second degree regression line demonstrates the age-related trends.

Figure 3

Scatter plot of the relationship between vitamin D and otolin-1 levels in subjects 70 years of age and older. A linear trendline demonstrates graphically illustrates the relationship between the two variables. Subjects with otolin-1 levels > 350 ng/ml were determined to be statistical outliers are not represented in this figure.