The prevalence of coeliac disease in adult Danish patients with type 1 diabetes with and without nephropathy

To the Editor: Coeliac disease causes malabsorption due to small bowel villous atrophy, which normalises when gluten, which is found in wheat, rye and barley, is withdrawn from the diet. Coeliac patients should be treated with a gluten-free diet that corrects the intestinal malabsorption and protects against the development of osteoporosis and intestinal lymphoma. As shown in several studies (review [1]), type 1 diabetes is associated with a high prevalence (2–10%) of coeliac disease. This has, in part, been explained by genetic factors, in particular by increased frequencies of HLA-DR3 and HLA-DQ2 [2]. Coeliac symptoms are often absent or atypical in type 1 diabetic patients and the diagnosis is therefore often delayed. Diabetic nephropathy is the leading cause of end-stage renal disease and develops in approximately one-third of type 1 diabetic patients within the first 20 years of diabetes. The pathogenesis of diabetic nephropathy is only partially understood. In addition to genetic factors, haemodynamic, metabolic and growth factors are generally accepted to contribute [3]. As in diabetic nephropathy [4], reduced final height is a significant clinical manifestation of coeliac disease. In this study we investigated the prevalence of coeliac disease in adult Danish type 1 diabetes patients, with the specific aim of studying whether undiagnosed coeliac disease is more prevalent in type 1 diabetic patients with diabetic nephropathy than in type 1 diabetic patients without nephropathy. We studied 967 type 1 diabetic patients [5]. The patient population comprised a group of 462 patients with overt diabetic nephropathy (defined as persistent macroalbuminuria [>300 mg/24 h], retinopathy and no signs of other kidney or urinary tract disease; 284 men, median age 41 [range: 17–78] years, median serum creatinine 103 [range: 52–706] μmol/l) and a group of 505 patients with longstanding (23 [range: 10–63] years) type 1 diabetes and persistent normoalbuminuria (275 men, age 46 [range: 20– 81] years). Median age at onset of diabetes was 12 (range: 0–47) and 18 (range: 0–64) years in the nephropathy and normoalbuminuric groups respectively (p