Obesity, vitamin D deficiency and progression to insulin use are the key modifiable risk factors associated with an elevated risk of diabetic retinopathy among patients with type 2 diabetes, an umbrella review confirms.

Conversely, intensive blood pressure targets and regular moderate-intensity physical activity are protective, UK researchers say after crunching data across 13 meta-analyses with a total 825,000 participants.

“To date, meta-analytic data regarding modifiable risk factors have not been aggregated according to the strength and credibility of the evidence,” the team, from the Vision and Eye Research Institute at Anglia Ruskin University, wrote.

Insulin use was strongly associated with both macular oedema and diabetic retinopathy, with those prescribed insulin having a more than fourfold and twofold increased risk of the complications, respectively.