PROJECT SUMMARY Hearing loss is highly prevalent among older individuals, and affects approximately half of all adults over the age of 60 years in the United States (U.S.) Notably, given the current aging trends in the country, the number of older adults with hearing loss is projected to double by the year 2060. Previously considered as an inconsequential aspect of aging, recent research has implicated hearing loss as an independent predictor of age-related declines in physical and cognitive functioning, incident dementia, disability, and institutionalization. There is, therefore, an urgent need for the identification of effective strategies in delaying the onset and preventing aging-associated hearing loss. Dietary factors are considered to influence hearing status by mediating vulnerability of the inner ear to noise insult and to detrimental age-related changes. And while several nutrients and overall diet quality have been studied, a significant limitation of the literature to date has been either cross-sectional design or use of self-report for measuring hearing status, which has low sensitivity compared to objectively measured hearing loss or limited generalizability due to inclusion of only one sex, predominantly one race/ethnicity and short follow-up period. Dietary patterns now form the basis of nutrition research and policy; and there is accumulating evidence on the benefits of following a Mediterranean-style diet in the prevention of chronic diseases and age-related declines in physical and cognitive functioning. However, there are no investigations that have examined its associations in a carefully designed study with objectively measured hearing loss. We therefore propose to address this gap in research, by conducting a study to: (a) characterize adherence to a Mediterranean-style dietary pattern in middle aged and older adults living in the U.S. using three indices, one based the traditional Mediterranean diet, another based on the federal guidelines and the third based on a hybrid of Mediterranean and the Dietary Approaches to Stop Hypertension patterns, (b) examine whether adherence to a Mediterranean-style diet, assessed using these indices, is associated with and is a predictor of age-related hearing loss, and lastly, (c) determine the associations between a Mediterranean-style dietary pattern on high and low frequency hearing loss. This study will be conducted in the NIA-supported Baltimore Longitudinal Study of Aging (BLSA). The BLSA provides us the opportunity for prospective analyses and includes dietary data collected using valid methods, hearing loss which has been objectively assessed using audiometry examinations, and a wealth of data on potential covariates and confounders has also been collected.