Sudden Sensorineural Hearing Loss Associated with Nutritional Anemia: A Nested Case–Control Study Using a National Health Screening Cohort

Previous studies have suggested an association of anemia with hearing loss. The aim of this study was to investigate the association of nutritional anemia with sudden sensorineural hearing loss (SSNHL), as previous studies in this aspect are lacking. We analyzed data from the Korean National Health Insurance Service-Health Screening Cohort 2002–2015. Patients with SSNHL (n = 9393) were paired with 37,572 age-, sex-, income-, and region of residence-matched controls. Both groups were assessed for a history of nutritional anemia. Conditional logistic regression analyses were performed to calculate the odds ratios (ORs) (95% confidence interval, CI) for a previous diagnosis of nutritional anemia and for the hemoglobin level in patients with SSNHL. Subgroup analyses were conducted for age and sex. Age, sex, income, and region of residence were stratified. Obesity, smoking, drinking alcohol, systolic/diastolic blood pressure, fasting blood glucose, total cholesterol, and the Charlson Comorbidity Index were considered in the regression models. Nutritional anemia was present in 4.8% (449/9393) of patients with SSNHL and 4.0% (1494/37,572) of controls (p < 0.001). The SSNHL group demonstrated 1.20-fold higher odds for nutritional anemia (95% CI = 1.08–1.34, p = 0.001). Hemoglobin levels were not associated with SSNHL. In subgroups <60 years old, there was a consistent positive association of nutritional anemia with SSNHL (adjusted OR = 1.55, 95% CI = 1.11–2.15, p = 0.010 for men <60 years old, and adjusted OR = 1.22, 95% CI = 1.02–1.45, p = 0.028 for women <60 years old). Nutritional anemia, but not hemoglobin level, was associated with an increased risk of SSNHL.