Low birth weight does not increase the risk of nephropathy in Finnish type 1 diabetic patients

Background. Low birth weight (LBW) has been linked to renal disease both in animal models and human studies. However, the role of birth weight in the development of diabetic nephropathy is unclear. We, therefore, studied the impact of birth weight on the development of diabetic nephropathy and other related traits, such as diabetic retinopathy and macrovascular disease, in Caucasian type 1 diabetic patients. Methods. Data on size at birth were obtained from original birth certificates in 1543 Finnish patients with type 1 diabetes. The patients were divided into those with low (LBW; below the 10th percentile), normal (NBW; 11–90th percentile) and high birth weight (HBW; above the 90th percentile). Results. Diabetic nephropathy was equally common in the groups with various birth weight (LBW vs NBW vs HBW: 21 vs 20 vs 17%, P ¼ NS). End-stage renal disease (3 vs 5 vs 4%, P ¼ NS), laser-treated retinopathy (31 vs 31 vs 31%, P ¼ NS) and macrovascular disease (5 vs 5 vs 8%, P ¼ NS) were equally prevalent in the various birth weight groups. The time from the onset of diabetes to the onset of diabetic nephropathy was similar irrespective of birth weight (log-rank test; P ¼ NS). Conclusions. Based on our cross-sectional data, LBW does not have an impact on the development of diabetic nephropathy, laser-treated retinopathy or macrovascular disease later in life in Caucasians with type 1 diabetes.