Study of serum copper and zinc in diabetic retinopathy and its correlation with glycemic status

Diabetes Mellitus (DM) is a global public health problem. It is associated with increased level of free radicals which lead to oxidative stress and dangerous complications like retinopathy. Trace elements have specific role in progress to complications of DM.

The study was designed to estimate and compare the levels of serum copper and zinc among type-2 DM with and without retinopathy and to compare them with matched healthy controls. A correlation of serum copper and zinc was done with glycosylated haemoglobin (HbA1c) in patients of type 2 DM with retinopathy.

It was a case control study. The investigation included 50 cases of type 2 DM with retinopathy and 50 cases of type 2 DM without retinopathy and 50 matched healthy controls. Venous blood sample was analysed for fasting blood sugar(FBS), post prandial blood sugar (PPBS), serum copper, serum zinc and glycosylated haemoglobin(HbA1c) in both cases and controls. Statistical analysis was done using student ‘t’ test. Pearson's correlation was performed to establish the relationship between study variables.

There was statistically highly significant increase in serum copper levels in cases of retinopathy compared to controls(p<0001) and significantly decreased levels of serum zinc in cases of DM with retinopathy(p<0.001). There was significant positive correlation between serum copper with HbA1c and highly significant negative correlation between serum zinc with HbA1c in cases of retinopathy.

Diabetic retinopathy is influenced by various factors such as glycemic status, trace elements such as copper, zinc which correlated well with HbA1c. Hence these parameter can be used as a supportive diagnostic tool.