Diet quality trends among adults with diabetes by socioeconomic status in the U.S.: 1999-2014

Background: The diet quality of adults living in the United States has improved overtime. We aim to determine whether diet quality among adults with diabetes mellitus has changed over time, and to examine trends in socioeconomic disparities in diet quality. Methods: Repeated cross-sectional analysis of eight National Health and Nutrition Examination Survey (NHANES) cycles (1999-2000 through 2013-2014). We included 5882 adult participants (age 20 or older) with diabetes mellitus (type 1 or 2) who completed 24-h dietary recalls. Diet quality was measured by the Healthy Eating Index 2010 (HEI) score (range 0-100, higher scores indicate better diet quality). We tested whether there were differences in diet quality across education, income, and food security categories, and whether any differences changed over time, using weighted linear regression models accounting for the complex survey design and adjusted for age, gender, and race/ethnicity. Results: Twenty nine percent of US adults with diabetes had less than a high school diploma, 17% had income < 100% of federal poverty level, and 15% reported food insecurity. Average adjusted HEI score increased from 49.4 to 52.4 over the study period (p for trend = 0.003). We observed differences in HEI between high and low education (4.1, 95% CI 3.0-5.3), high and low income (3.7, 95%CI 2.4-5.0) and food secure relative to food insecure (2.1, 95% CI 0.8-3.3). These differences did not improve over time for education (p = 0.56), income (p = 0.65) or food security (p = 0.39) categories. Conclusions: Diet quality for adults with diabetes in the U.S. has improved overall; however, substantial disparities exist and have not improved. A concerted effort to improve diet quality in vulnerable groups may be needed