Accelerometer-assessed physical activity and diabetic retinopathy in the United States.

Accelerometer-Assessed Physical Activity and Diabetic Retinopathy in theUnited States Hemoglobin A1c (HbA1c) and blood pressure currently represent the only reversible risk factors associated with diabetic retinopathy.1 Physical activity (PA) is another potential modifiable risk factor for preventing diabetic ocular complications, although studies investigating this association have produced conflicting results.2 These studies have relied exclusively on self-report to quantify PA, which is prone to considerable error. Herein, we assess whether accelerometer-defined PA is associated with more advanced retinopathy independent of HbA1c level and blood pressure in a nationally representative sample of patients with diabetes mellitus. Methods |Data fromthe2005to2006NationalHealthandNutritionExaminationSurveywereused.All studyprocedureswere approvedbytheNationalCenterforHealthStatisticsreviewboard, and all participants providedwritten informed consent. Diabetes was defined by self-report of a previous diabetes diagnosis, use of insulin or diabetesmedications, anHbA1c level of 6.5% of total hemoglobin or higher (to convert to proportionof total hemoglobin,multiplyby0.01), or a fastingglucose level of 126mg/dL or higher (to convert tomillimoles per liter, multiply by 0.0555). Retinal imagingwasperformedusing theCanonNonmydriatic Retinal Camera CR6-45NM, with details reported elsewhere.3 Thepresence and severityofnonproliferativediabetic retinopathy (NPDR) (none,mild, ormoderate to severe) wasdeterminedusing theEarlyTreatmentDiabeticRetinopathy Study grading criteria.4