UCSF

Objective

Lower health literacy is associated with higher rates of mortality and chronic disease. It remains unclear whether health literacy is associated with diabetes and/or hyperglycemia in older adults, and if this relationship differs by sex.

Research design and methods

We performed a cross-sectional analysis of 2510 older adults in the Health, Aging and Body Composition (Health ABC) Study who had both a Rapid Estimate of Adult Literacy in Medicine (REALM) measurement and diabetes status available. Sex-stratified logistic regression models were used to analyze the relationship of health literacy categories (low, medium, and high) to diabetes status, adjusting for key covariates. Secondary analyses examined the relationship of health literacy to glycemic markers (A1C, fasting blood glucose).

Results

Among participants in the Health ABC cohort, 429 had diabetes. Mean age was 76years old and 45% were female. Men with diabetes more commonly had low health literacy levels than men without diabetes (10.1% versus 9.3%, p=0.02). Similar results were seen among women (14.7% versus 6.1%, p<0.01). In a model adjusting for age, race, income, education, BMI, smoking, and alcohol use, women with low versus high health literacy had a two-fold higher likelihood of diabetes (OR=2.2; 95% CI 1.1-4.3). No significant relationship was observed in men. Progressively lower categories of health literacy were associated with higher age-adjusted mean A1C and fasting blood glucose levels in women (both p for trend <0.01) but not men.

Conclusions

In this large, ethnically diverse sample of community-dwelling older adults, lower health literacy level is related to a greater likelihood of diabetes and higher A1C and fasting blood glucose levels in women-but not in men-after adjusting for age, race, and other demographic and lifestyle factors. Future studies are needed to assess mechanisms underlying this relationship and if interventions to improve health literacy are effective in reducing the burden of diabetes, particularly in women.