Do People with Lower Health Literacy Have Worse Diabetes Control? Insights from NHANES 2017–2020

Background: Glycemic control is necessary for reducing related complications in diabetic patients. However, disparities- often described as gaps in glycemic control- exist across all social and demographic groups. This study examines whether lower health literacy, proxied by educational attainment, is associated with low glycemic control among U.S. adults with diabetes. Methods: Data were extracted from the 2017-2020 National Health and Nutrition Examination Survey (NHANES). 1,423 adults aged 18 and older who self-reported a diabetes diagnosis were included. Glycemic control was measured using hemoglobin A1c (HbA1c) levels. The level of education was used as a proxy for health literacy. Descriptive statistics and one-way ANOVA were conducted to compare mean HbA1c values across education groups, with post hoc Tukey tests used to measure pairwise differences. Results: HbA1c levels is negatively associated with educational attainment. Participants with less a 9th-grade education had the highest mean HbA1c (7.78 %), while college graduates had the lowest (7.13%). ANOVA results showed a statistically significant difference between HbA1c across education levels F(4,1253) =3.59, p=0.006). The only significant pairwise difference was between those with less than a 9th-grade education and college graduates (p=0.003). Conclusion: Lower educational attainment, a proxy for limited health literacy, is associated with poorer glycemic control. These findings emphasize the need for diabetes education and management strategies designed for people with low literacy. This is needed to reduce disparities and improve health outcomes.