Familial link to diabetes affects risk for diabetic retinopathy, DME differently
The presence of a family member with diabetes affects the risk for developing proliferative diabetic retinopathy and diabetic macular edema differently, according to a study.
“Clustering of vision threatening diabetic retinopathy within specific families can be the result of similarities in lifestyle but may also be due to a common genetic background,” Toke Bek, DMSci, MBA, of the department of ophthalmology at Aarhus University Hospital in Denmark, wrote in Current Eye Research. “An evaluation of the role of heredity for the development of diabetic retinopathy may help [in] adjusting control intervals in screening programs to each patient’s individual risk profile.”
The study used survival analysis of data originating from examinations of 18,216 Danish patients from 1994 to 2019, which included assessment of visual acuity, fundus photography and previous ocular treatment, cataract surgeries and family diabetes history. The final study group included 12,281 participants (41% women, 59% men), of whom 3,660 had type 1 diabetes, and 8,921 had type 2 diabetes.
According to the study, among participants with some knowledge of diabetic heredity, 974 were treated for proliferative diabetic retinopathy (PDR), and 1,225 were treated for DME as their first treatment during the follow-up period of up to 25 years after the onset of diabetes.
Statistical analysis included a pseudo-values method with linear modeling to calculate the contribution of covariates including age at onset of diabetes, sex, history of cataract surgery, HbA1c exposure, BMI, blood pressure and time in years after the onset of diabetes. Four models were created based on presence of relative with diabetes, sex of diabetic relative and the type of diabetes.
Bek reported that the presence of male relatives with type 2 diabetes showed no significant contribution to the risk for developing PDR as the first vision-threatening complication after the onset of diabetes.
However, the risk was significantly reduced 4 to 10 years after onset if the participant had knowledge of a relative with diabetes, 3 to 10 years if the participant had female relatives with diabetes and 1 to 10 years if the relative had type 1 diabetes. Based on these findings, Bek determined the presence of female relatives with type 1 diabetes was the heredity risk parameter for developing PDR.
Study results also revealed that after 10 years of known diabetes duration, a history of cataract surgery counteracted the risk reduction from the presence of a female relative with type 1 diabetes.
The presence of relatives with type 2 diabetes was reported to be the heredity risk parameter for developing DME: The risk significantly increased 4 to 24 years after the onset of diabetes in participants with relatives with type 2 diabetes, while the presence of relatives with type 1 diabetes and the sex of relatives with diabetes were not significant contributors to the risk for developing DME.
Further, after 10 years of known diabetes duration, a history of cataract surgery, cumulative exposure to systolic blood pressure, BMI, age of onset of diabetes and increasing year of onset of diabetes further exacerbated the risk from the presence of male relative with diabetes.
“These parameters may contribute to an individualization of control intervals during screening for diabetic retinopathy,” Bek wrote. “The study underlines the need for considering PDR and DME as separate end points in [a] screening program for diabetic retinopathy.”
Perspective
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There are known factors that influence the onset and progression of diabetic retinopathy. Many are lifestyle-related and modifiable. They are often stressed during the eye care consult — glycemic control, blood pressure, cholesterol, smoking and obesity. But there are two factors that patients have no control over — duration since the onset of diabetes and genetic susceptibility.
In this manuscript, the author analyzed the clinical data from a single medical center in Denmark to investigate the association between family history and the development of vision-threatening conditions, such as proliferative diabetic retinopathy (PDR) and diabetic macular edema. The study relied on the patient’s report of familial diabetes history, which might have impacted the accuracy. Nevertheless, they were able to obtain more than 12,000 data over 16 years.
The results show a statistically significant impact of familial history on the development of PDR and DME. The study reconfirms the previous understanding of familial susceptibility to vision-threatening diabetic complications. For this, optometrists should be extra diligent in investigating family history when weighing retinopathy risks. Optometrists may modify their follow-up plans based on the patient’s family history once they show signs of diabetic retinopathy.
Lastly, this study’s results imply how (much more) impactful the duration of diabetes is on our patient’s risk for developing sight-threatening diabetes complications.
Editor’s note: This perspective was updated November 15, 2022.
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