Hearing loss is a major sensory impairment linked to oxidative stress and inflammation. Flavonoids possess antioxidant and anti-inflammatory properties, but their longitudinal association with incident hearing loss is unclear. We examined the association between a Flavonoid Diet Score (FDS) and incident hearing loss in the UK Biobank, and explored potential mediation by systemic inflammation.

We included 55,859 participants without baseline hearing loss who completed 24-h dietary recalls. FDS was calculated from flavonoid-rich food intake and categorized into quartiles. Incident hearing loss was identified using ICD-10 codes (H90, H91) from linked hospital and death records. Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs). Mediation analyses assessed whether inflammatory biomarkers (C-reactive protein [CRP], glycoprotein acetyls, neutrophil count/percentage, and leukocyte count) explained the association.

During 613,590 person-years of follow-up, 1,681 incident cases of hearing loss occurred. After adjusting for demographic, lifestyle, and cardiometabolic factors, higher FDS was associated with a reduced risk of hearing loss (HR for Q4 vs. Q1 = 0.84, 95% CI: 0.73–0.96; P for trend = 0.021). Among the evaluated biomarkers, CRP significantly mediated this association (average causal mediation effect = −0.0079, P = 0.010), accounting for 4.8% of the total effect. Other inflammatory markers were not significant mediators.

Higher adherence to a flavonoid-rich diet was independently associated with a lower risk of incident hearing loss, an effect partially mediated by reduced systemic inflammation (CRP). Promoting dietary flavonoids may serve as a beneficial nutritional strategy to preserve auditory aging.