Research has long since uncovered the link between type 1 diabetes (T1D) and celiac disease, but few research studies have examined whether a diagnosis of celiac disease influences the risk of a T1D specific complication such as diabetic retinopathy (DRP). In a recent Swedish study, researchers delved into this unchartered research territory to examine the risk of developing DRP in people living with both T1D and celiac in order to determine the need for additional routine screening in T1D patients.

DRP is a condition caused by damage to the blood vessels in the retina, the back portion of the inner eye. In severe cases, it can lead to blindness. To determine the prevalence and increased risk of DRP in people with T1D and celiac, researchers looked at data from the Swedish National Patient Register (NPR). In looking at data from the NPR, researchers found 947 patients with T1D and biopsy-proven celiac who were under the age of 30. The diagnosis data used was based on biopsies performed in Sweden between 1969 and 2008. Using an adjusted hazard ratio (aHR), an analysis scale referred to as the Cox regression analysis, researchers compared the prevalence of DRP in patients with T1D and celiac disease to patients with only T1D.

The study results showed a strong correlation between the time since celiac diagnosis and the development of DRP. When compared to people living with only T1D, those with a celiac diagnosis of less than five years were at a decreased risk of developing DRP, while those diagnosed for five to 10 years had a neutral risk factor. Those with a celiac diagnosis of more than 10 years had the highest risk of developing DRP. Age, sex or calendar period at the time of a celiac diagnosis did not impact the risk of developing DRP over time.

The findings from this study are consistent with results from a similar study completed in the UK, which showed that advanced DRP occurred in 58.3% of patients with T1D and celiac versus 25% of people who were diagnosed with T1D only. The researchers believe this increase in DRP risk over time could be due to higher adherence to the gluten-free diet immediately after diagnosis as opposed to years after the diagnosis. In addition, the Swedish study suggested that a constant, low-grade inflammation of the intestines due to celiac may also contribute to the increased risk of DRP. Low-grade inflammation with few symptoms may make a person less likely to adhere to a strict gluten-free diet, which could potentially lead to a higher risk of DRP in the future.

While this study is important in stressing the need for DRP screening in people with celiac and T1D, especially over 10 years after the diagnosis, there are a few limitations to point out from the findings:

• Adherence to a gluten-free diet was not taken into account.
• There was no data available on metabolic control, which includes factors such as BMI and insulin dosage.
• The people with celiac in the study were not screened specifically for this research, so this information may vary among other people with celiac.

To view the full study results, visit the US National Library of Medicine.