Associations between social isolation and diet quality among US adults with disability participating in the National Health and Nutrition Examination Survey, 2013–2018

•More than half of U.S. adults with disability have “poor” diet quality.•Healthy Eating Index (HEI) 2015 is a measure of diet quality based on U.S. guidelines.•Social isolation is associated with lower total HEI-2015 score in unadjusted results.•Social isolation is associated with lower vegetable, seafood and plant protein intake.•Associations were modest but underline areas for further research. Social isolation and disability are established risk factors for poor nutrition. We aimed to assess whether social isolation is associated with diet quality specifically among adults with disabilities. This cross-sectional analysis used data from the National Health and Nutrition Examination Survey, 2013–2018. Adults with a disability, who were not pregnant, breastfeeding, or missing dietary intake data were included (n = 5,167). Disability was defined as a physical functioning limitation based on difficulty with any activities of daily living, instrumental activities of daily living, lower extremity mobility activities, or general physical activities. The Healthy Eating Index (HEI)-2015 measured diet quality; higher scores correspond to higher diet quality. We computed a social isolation index by summing single status, living alone, and two social engagement difficulty measures (one point for each component met; maximum 4 points). Multivariable linear regression, controlling for demographic and health covariates, estimated differences in HEI scores for dietary intake data, by social isolation score. Over half of HEI scores were