Food environment associated with gestational diabetes

1. Women with gestational diabetes were more likely to live in neighborhoods with a greater prevalence of fast food establishments.

2. Fast food restaurant to supermarket ratio was associated with gestational diabetes and hemoglobin A1c (HbA1c) levels.

Evidence Rating Level: 3 (Average)       

Study Rundown: Gestational diabetes mellitus (GDM), or onset of diabetes during pregnancy, is an increasingly common condition affecting 6-7% of pregnancies in the U.S. Complications including preeclampsia, macrosomia, hydramnios, and neonatal morbidities have been associated with GDM. Screening for gestational diabetes is recommended between 24 and 28 weeks gestation so that affected women can be treated to reduce the risk of these adverse outcomes. Risk factors include personal history of impaired glucose tolerance, previous GDM, BMI ≥30 kg/m², and African American or Hispanic descent. In addition, modifiable risk factors such as exercise and diet have been linked to GDM. Previous studies suggested there is a relationship between food environment and development of diabetes, but this association has not been evaluated in the pregnant population. In the present work, the authors used geospatial analysis to assess whether proximity to healthy and unhealthy food options, specifically grocery stores and fast food establishments, was associated with GDM. They found that the presence of more fast food restaurants and a higher fast food to supermarket ratio was associated with GDM.

Strengths of the study included large population-based sample with assessment of food options by neighborhood rather than zip code. Weaknesses included case-control design, which limits inferences about causality and lack of data on food purchasing or consumption habits. Further prospective studies that measure dietary habits in more detail are needed to lend credence to the relationship identified in this study.

Click to read the study in AJOG

Relevant Reading: Effect of dietary and lifestyle factors on the risk of gestational diabetes: review of epidemiologic evidence

In-Depth [case-control study]: This study evaluated the impact of local food options on gestational diabetes incidence among women with singleton pregnancies who developed GDM (n = 1152) and who did not have GDM (n = 7442). Exposures of interest included density of fast food restaurants, supermarkets and convenience stores. Densities were determined by neighborhood, defined as a woman’s residential zip code plus the immediately surrounding zip codes.

Women who developed GDM were more likely to live in neighborhoods with fast food restaurant (OR 1.63, CI 1.21-2.19) density in the fourth quartile. Living in areas with high fast food to supermarket ratios was associated with GDM (OR 1.42, CI 1.25-1.69). HbA1c was positively correlated with fast food restaurant to supermarket ratio (r = 0.251, p = 0.025).

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