The short version
- Researchers at Edith Cowan University in Australia compared hearing tests with routine blood counts in 7,920 American adults from a national health survey.
- Five of six inflammation scores built from white-cell and platelet counts were linked to hearing loss, four running higher and one lower, each by about 7% to 14%.
- The study took one snapshot in time, so it cannot say whether inflammation damages hearing, and the scores are not a test for hearing loss.
A team at Edith Cowan University’s Centre for Precision Health in Western Australia, with hospital co-authors in China, looked for a link between chronic inflammation and hearing. Writing in Immunity, Inflammation and Disease on October 29, they used the US National Health and Nutrition Examination Survey from 1999 to 2020: 7,920 adults aged 40 to 85 who had both a hearing test and a routine blood count. Using a cutoff of an average of 20 dB or worse across four test tones from 500 to 4,000 Hz in the better ear, 2,262 of them, 28.6%, had hearing loss.
The researchers turned each blood count into six standard inflammation scores, ratios of neutrophils, lymphocytes, monocytes and platelets. After adjusting for age, sex, ethnicity, education, income, blood pressure, diabetes, weight and cholesterol, five of the six were linked to hearing loss: four ran higher and the lymphocyte-to-monocyte ratio ran lower. The strongest, the systemic inflammation response index, carried a prevalence ratio of 1.14 per unit on a log scale. The platelet-to-lymphocyte ratio showed no link.
The associations are modest and come from one point in time. The survey lacks consistent records of ear-damaging drugs, heart disease and infections, and Hearing Health & Technology Matters notes that the scores are not validated for diagnosing or predicting hearing problems.
