Lipid and C-reactive protein levels as risk factors for hearing loss in older adults.

Abstract

To determine the role of cardiovascular disease (CVD) markers, lipids and C-reactive protein, in age-related hearing loss over time. Prospective cohort study. Research laboratories at an academic medical center. In total, 837 older adults (mean age 67.5 years) were included. Primary dependent variables were pure-tone thresholds (pure-tone average [PTA]), including "narrow" PTA (0.5, 1, 2, 4 kHz), "broad" PTA (0.5, 1, 2, 3, 4, 6, 8 kHz), low-frequency PTA (0.25, 0.5, 1 kHz), and high-frequency PTA (2, 3, 4, 6, 8 kHz). Repeated-measures mixed regression modeling was used to assess the relationship between C-reactive protein (CRP) and lipid levels with PTAs over time. In a cross-sectional sample of 837 subjects, modest associations were found between triglycerides and all PTAs. Weak associations were observed between the ratio of total cholesterol and high-density lipoprotein and narrow PTA, broad PTA, and high-frequency PTA. However, when assessing changes in hearing and lipids over time in a longitudinal analysis, no significant associations between hearing and lipids remained. PTAs and CRP were not statistically associated when controlling for age and sex. Associations between hearing and blood lipids have been the focus of scientific inquiry for more than 50 years. The current results suggest that the association is either spurious or too small to be of consequence in the assessment and treatment of hearing loss in older adults. Inquiry into other potential risk factors for age-related hearing loss and associations with CVD may prove more fruitful.