Common genetic variants that are associated with risk of type 2 diabetes and blood glucose levels are reported in 2 studies online this week in Nature Genetics. Together, the reports shed light on the genetic variants that influence circulating glucose levels in the body, many of which also influence risk of type 2 diabetes.
More than 220 million people have diabetes worldwide, and 90% of those affected have type 2 diabetes (T2D). Clinically, T2D is defined by a chronic state of elevated blood sugar levels, when measured during fasting or 2 hours after an oral glucose challenge. The oral glucose challenge test is commonly performed to measure the body's ability to use a defined amount of sugar. Typically, the patient is asked to ingest a sweet liquid containing glucose and blood samples are taken prior and after drinking the glucose. In T2D, the body does not produce enough insulin or the body's cells cannot utilize insulin to properly manage blood sugar levels.
The MAGIC (Meta-Analyses of Glucose and Insulin-related traits Consortium) investigators led by Jose Florez performed a meta-analysis of fasting glucose levels in approximately 50,000 individuals, with replication in an additional 76,558 people and identified nine new genetic variants that influence fasting glucose levels. The investigators also found that several of these variants are also associated with increased risk of T2D. In a separate report, the MAGIC investigators led by Richard Watanabe studied blood sugar levels 2 hours after an oral glucose challenge. The authors found three new genetic variants that influence certain glucose levels, with one variant overlapping those variants found to be associated with T2D in the first study.