Vitamin D Deficiency Is Not Good for You

Abstract

In this issue of Diabetes Care , Joergensen et al. (1) demonstrate a strong association between severe vitamin D deficiency and increased mortality in patients with type 1 diabetes. This observation confirms previous findings in the general population and in subgroups at high cardiovascular risk such as patients with type 2 diabetes or renal impaired patients (2–4). The data by Joergensen et al. complete the picture while carefully avoiding possible criticisms that have made the vitamin D field so hazardous to tread in recent years. Indeed, rather than hard science, it is hype and media statements that crowd the scene. This article brings with it a breath of fresh air. Many studies are conducted retrospectively or measure vitamin D levels when patients are already sick. Thanks to the excellent registries present in several Northern European countries—and here in particular thanks to the database and tissue bank of the reputed Steno Diabetes Center—this study is able to assess levels of vitamin D measured within 3 years after diagnosis and during up to 25 years of clinical follow-up. This way of working avoids justified criticisms on studies where vitamin D levels were measured at the time of severe diseases. Obviously, patients with congestive heart failure or cancer are less likely to go out and about in the sun or eat fatty fish. Only prospective studies will help to understand the relationship between vitamin D levels and disease. Because vitamin D deficiency in rodents in the early stages of life is predictive of future disease, it would be of great interest to evaluate vitamin D levels in neonates. We have previously demonstrated a twofold risk for the development of diabetes in NOD mice that had been vitamin D deficient in the first 100 days of their lives (5). As vitamin D …