OBJECTIVE: To test the hypothesis that age-related demineralization of otoconia 
will result in an age-related increase in blood levels of otoconia matrix 
protein, otolin-1.
STUDY DESIGN: Cross-sectional observational clinical trial.
SETTING: Clinical research center.
PATIENTS: Seventy nine men and women ranging in age from 22 to 95 years old.
INTERVENTIONS: Diagnostic.
MAIN OUTCOME MEASURES: Blood levels of otolin-1 in relation to age.
RESULTS: Levels of otolin-1 of subjects divided into four age groups (1: 20-30 
[n = 20], 2: 50-65 [n = 20], 3: 66-80 [n = 20], 4: 81-95 [n = 19] years old) 
demonstrated an increasing trend with age. The difference between otolin levels 
of groups 2 and 3, as well as, (p = 0.04) and 2 and 4 (p = 0.031) were 
statistically significant, but there was no significant difference between the 
two oldest groups.
CONCLUSIONS: Otolin-1 blood levels are significantly higher in patients older 
than 65 years of age. This is consistent with previous scanning electron 
microscopy findings of age-related otoconia degeneration and increased 
prevalence of benign paroxysmal positional vertigo (BPPV) with age. Normative 
data provided here can serve as important reference values against which levels 
from BPPV patients can be compared with further evaluate otolin-1 as a 
circulatory biomarker for otoconia degeneration.