Association of glucose metabolism and retinopathy signs in non-diabetic individuals in midlife-The Northern Finland Birth Cohort 1966 study

Abstract

Diabetic retinopathy is a microvascular complication of hyperglycaemia. Little is known about the association of glucose metabolism and retinopathy signs in the non-diabetic middle-aged population. We studied prevalence of retinopathy in a subsample of Northern Finland Birth Cohort study (NFBC1966) of 1809 subjects, at 47 years of age, without previously diagnosed type 2 diabetes and/or blood pressure-lowering medication. All participants underwent clinical evaluations including an oral glucose tolerance test (glucose and insulin values measured at 0, 30, 60 and 120 min) and HbA1c. The retinopathy signs were diagnosed by fundus photographs and classified according to the Eurodiab classification scheme. The overall prevalence of newly diagnosed retinopathy was 1.4%. The retinopathy signs were significantly associated with increased 30 min, 1-h and 2-h glucose levels and 2-h insulin level in an OGTT. After adjustment with systolic blood pressure, only 30 min glucose, 1-h glucose and 2-h insulin levels were associated with retinopathy signs. Our findings show the potential role of 30 min and 1-h post-load glucose and 2-h insulin levels as risk factors for retinopathy lesions among the participants without previously diagnosed diabetes or hypertensive medication.

Fig 1. Flowchart of the Northern Finland Birth Cohort 1966 study.

Fig 2. Example of mild non-proliferative retinopathy.

Fig 3. Change in plasma glucose level (mmol/l) during the oral glucose tolerance test (OGTT) of two study groups; no retinopathy and retinopathy.

Fig 4. Retinopathy prevalence (%) of 1-h glucose and 2-h glucose concentrations by glucose quantiles.

Retinopathy prevalence is based on fundus photographs. The lowest glucose values of each quintiles are presented in the figure.