Food Insecurity, Food "Deserts," and Glycemic Control in Patients With Diabetes: A Longitudinal Analysis

Abstract

Objective: Both food insecurity (limited food access owing to cost) and living in areas with low physical access to nutritious foods are public health concerns, but their relative contribution to diabetes management is poorly understood.

Research design and methods: This was a prospective cohort study. A random sample of patients with diabetes in a primary care network completed food insecurity assessment in 2013. Low physical food access at the census tract level was defined as no supermarket within 1 mile in urban areas and 10 miles in rural areas. HbA_1c measurements were obtained from electronic health records through November 2016. The relationship among food insecurity, low physical food access, and glycemic control (as defined by HbA_1c) was analyzed using hierarchical linear mixed models.

Results: Three hundred and ninety-one participants were followed for a mean of 37 months. Twenty percent of respondents reported food insecurity, and 31% resided in an area of low physical food access. In adjusted models, food insecurity was associated with higher HbA_1c (difference of 0.6% [6.6 mmol/mol], 95% CI 0.4-0.8 [4.4-8.7], P < 0.0001), which did not improve over time (P = 0.50). Living in an area with low physical food access was not associated with a difference in HbA_1c (difference 0.2% [2.2 mmol/mol], 95% CI -0.2 to 0.5 [-2.2 to 5.6], P = 0.33) or with change over time (P = 0.07).

Conclusions: Food insecurity is associated with higher HbA_1c, but living in an area with low physical food access is not. Food insecurity screening and interventions may help improve glycemic control for vulnerable patients.

Figure 1

Proportional Venn diagram showing overlap between those with food insecurity and those living in a census tract with low physical food access (1 mile in urban area and 10 miles in rural area definition). Seventy-eight (20%) participants were food insecure, 120 (10%) lived in an area of low physical food access, and 12 (3%) were both food insecure and lived in an area of low physical food access.

Figure 2

Predicted mean HbA_1c values with SE bars from the models described in Supplementary Table 2 (left) and Supplementary Table 3 (right), by 6-month increments, comparing those who reported food insecurity and those who are food secure (left) and those who lived in neighborhoods with adequate and poor food access (right). In addition to the exposures of interest, models were adjusted for age, age squared, sex, race/ethnicity, education, insurance, health literacy, language, age at diabetes diagnosis, baseline Charlson comorbidity score, insulin use, statin use, number of outpatient care visits, census tract median family income, census tract poverty rate, and census tract vehicle access.