Hyperglycemia, Obesity Relevant Risk Factors for Retinopathy in Type 1 Diabetes

Glycemic control represented the most influential risk factor for diabetic retinopathy in adults with type 1 diabetes (T1D), while overweight, obesity, and hypertension were also linked to an elevated likelihood, according to a new study in JAMA Ophthalmology.1

Overweight and obesity incidence continues to rise in global populations, yet its role in the risk of diabetic retinopathy is still mostly unknown—the link between hypertension and retinopathy is well-understood, aligning with these newly reported data.2

“Our study provides further insight into risk factors associated with DR using data from individuals with diabetes duration less than 5 years and 8 to 20 years of follow-up in a contemporary setting,” wrote the investigative team, led by Marcus Lind, MD, PhD, department of molecular and clinical medicine, institute of medicine, Sahlgrenska Academy, University of Gothenburg.1

Nearly 1 in 5 children and adolescents with T1D are affected by diabetic retinopathy, with intensive glucose control known to reduce its likelihood.3 According to Lind and colleagues, previous risk estimates could be unreliable as lifestyle habits, exposure to risk factors, and treatment advances evolve in this population.1

In this analysis, the investigative team sought to measure which risk factors, aside from glucose control, play a role in the development of retinopathy, and how these risk factors contribute compared with hemoglobin A1c levels (HbA1c) in T1D. A cohort of individuals with T1D for ≤5 years and ≥4 visits were recruited from the Swedish National Diabetes Register (NDR) from January 1998 to December 2017.

Lind and colleagues divided the follow-up duration into 8 to 9, 10 to 11, 12 to 13, 14 to 15, and 16 to 20 years after T1D diagnosis to account for nonproportional hazards over time. They also recorded the incidence of retinopathy by type (simplex, pre-proliferative, proliferative, or laser photocoagulation) during each follow-up period.

Approximately 9358 individuals (44% female) with T1D were included in the study, with mean HbA1c levels of 7.9% over a mean follow-up of 11 years. Notably, the mean age at first visit was 14 years and the mean duration of diabetes was 1.2 years.

Upon analysis, approximately one-third (33%) of the study population had any retinopathy, with risk increasing alongside the duration of diabetes. For those with any retinopathy, a 1-SD increase in mean HbA1c level was the strongest risk factor, followed by systolic blood pressure, diastolic blood pressure, body mass index (BMI), and smoking. This risk increased steadily with an elevated level of each factor.

Notably, Lind and colleagues found elevated high-density lipoprotein cholesterol (HDL-C) correlated with a reduced risk of retinopathy. For those with pre-proliferative retinopathy or worse, adjusted analyses revealed higher HbA1c levels as the only factor to achieve statistical significance, which remained in proliferative retinopathy and laser photocoagulation.

“In conclusion, this study confirms hyperglycemia as the dominant risk factor for retinopathy but also highlights that overweight, obesity, and hypertension need to be managed not only for cardiovascular diseases but also to potentially reduce the risk of retinopathy,” Lind and colleagues added.

References

1. Seyed Ahmadi S, Ludvigsson J, Imberg H, Nyström T, Lind M. Risk Factors for Retinopathy in Young Adults With Type 1 Diabetes. JAMA Ophthalmol. Published online December 12, 2024. doi:10.1001/jamaophthalmol.2024.5274
2. Fellinger P, Fuchs D, Wolf P, et al. Overweight and obesity in type 1 diabetes equal those of the general population. Wien Klin Wochenschr. 2019;131(3-4):55-60. doi:10.1007/s00508-018-1434-9
3. Allen DW, Liew G, Cho YH, et al. Thirty-Year Time Trends in Diabetic Retinopathy and Macular Edema in Youth With Type 1 Diabetes. Diabetes Care. 2022;45(10):2247-2254. doi:10.2337/dc21-1652