Individual Variations of Taste and Smell Perception in Alcohol Use Disorder (AUD)

Overview

Background: Alcohol use disorder (AUD) is the most common substance use disorder in the world. Long-term AUD can affect a person s sense of taste and smell. This natural history study will compare alcohol drinking behaviors and measures of taste and smell in people with and without AUD. Objective: To understand how alcohol use changes the senses of taste and smell. Eligibility: People aged 18 to 65 years with or without AUD. Design: Participants will be screened. They will have several tests to assess their smell and taste functions. They will answer questions about their eating, alcohol use, and smoking or vaping habits. Participants will have 2 study visits. They will give samples of blood, nasal mucous, saliva, stool, and urine. Their bodies will be measured. They will undergo a type of scan that uses X-rays to measure their body composition. They will complete taste measurements. They will taste liquids by swishing them in their mouth, without swallowing. Then, they will be asked what they can detect and which flavors they preferred. They will also complete smell measurements. They will be asked if they can identify strong odors on a metal wand. They will be asked to rate the intensity and pleasantness of odors. Their brain activity in the frontal regions will be measured while they smell various odors. For this, we will use a brain imaging tool called functional near infrared spectroscopy. They will have sensory testing. Sensations such as pressure, pinpricks, heat, or vibrations will be applied to their skin. Then, they will be asked what they felt. They will keep diaries. They will write down what they eat (for 3 days), the alcohol they drink (3 days), and how much they sleep (14 days). They will wear a wristwatch-like device that records their activity for 14 days.

Study Description: This study involves comparison of taste and smell measures between individuals with and without AUD. AUD has been associated with alterations in taste and smell. These alterations are inherently concerning, regardless of whether they have any bearing on the course of other aspects of AUD. Therefore, in the proposed study we intend to assess the taste and smell differences between individuals with and without AUD. Also, we would explore the extent of taste and smell alteration in individuals with AUD and identify the biological correlates of these alterations in taste and smell. Objectives: AUD is a major public health concern in America. Overconsumption of alcohol is a recognized risk factor for the development of future alcohol problems. Public health efforts to modify drinking behaviors have had limited success. Not only does alcohol overuse contribute to AUD, albeit it can lead to changes in gut microbiota, as well as salivary and metabolic hormones that likely result in inflammation. Taste and smell perceptions, which can influence alcohol consumption, may differ between individuals with AUD and those without. Currently, little is known about the biomarkers related to variations in taste and smell systems in individuals with AUD. We plan to perform a series of analysis designed to investigate how individuals' variations in taste and smell perception affect alcohol consumption. We will conduct deep phenotype for taste and smell and collect blood, saliva, and nasal samples to assess the biomarkers. Findings from this study can be used to provide evidence for future mechanistic studies to identify targets and strategies for countermeasures in preventing or improving AUD and its comorbidities. Moreover, outcomes will foster new lines of investigation for reducing risk of alcohol-related concurrent taste and smell alterations. The proposed research is aligned with the overall mission of the National Institutes of Health to promote health and disease prevention. Lastly, approaches included in this study are innovative and highly applicable to other complex health phenomena in which biological variations in inflammation and taste and smell perception impact an individual's health. This is a hypothesis-generating protocol which plays an important role at the initial stages of clinical research. We expect that the findings of the present proposed study would add some clarification to the existing contradictory reports on the chemosensory changes associated with AUD. Most importantly, this protocol is likely to help identify the differential impact of alcohol consumption on chemosensation in individuals with and without AUD. Endpoints: Primary Endpoint: The primary dependent measures for this study are taste and olfaction measures. Secondary Endpoints: Secondary measures include inflammatory markers, genotypes, microbiota, salivary and metabolic hormones, biological measures, and personal factors.