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Posted on May 30, 2012, 6 a.m.
Levels of Insulin-like growth factor (IGF) axis proteins associate with a greatly reduced risk for developing type-2 diabetes up to a decade or more later.
The IGF axis was originally named for insulin-like growth factor-1, (IGF-1), so called because it has biological effects similar to those of insulin (the hormone that regulates blood glucose levels) but has a greater effect on cell growth than insulin. The IGF axis includes binding proteins (IGFBPs), namely IGFBP-1, IGFBP-2, and IGFBP-3, that may exert biological effects independent of IGF-1. Researchers have previously hypothesized that the IGF axis may influence risk for developing diabetes – an idea supported by laboratory and mouse studies, and a few initial studies in humans. Howard Strickler, from Albert Einstein College of Medicine (New York, USA), and colleagues have completed a large, prospective investigation of several components of the IGF-axis and the risk for developing diabetes. The team analyzed levels of IGF-1, IGFBP-1, IGFBP-2, and IGFBP-3 in blood taken from 742 women enrolled in the Nurses' Health Study who years later developed type 2 diabetes, as well as a similar number of women in the study who did not develop diabetes. None of the women had any signs or symptoms of the disease at the time their blood samples were taken. The median time between the taking of blood samples and diabetes onset was nine years. Each component of the IGF axis (IGF-1 and IGFBP-1, -2, and -3) had a significant independent association with diabetes risk – most notably IGFBP-1 and -2. Compared with women in the bottom 20% with respect to their levels of IGFBP-1, having high levels of IGFBP-1 (top 20%) was associated with a three-fold reduction in risk for diabetes, while high levels of IGFBP-2 were associated with a more than five-fold reduction in diabetes risk. The study authors conclude that: “this prospective study found strong associations of incident diabetes with baseline levels of three [insulin growth factor binding proteins] and free [insulin-like growth factor-1], consistent with hypotheses that the [insulin-like growth factor] axis might influence diabetes risk.”
Rajpathak SN, He M, Sun Q, Kaplan RC, Muzumdar R, Strickler HD, et al. “Insulin-Like Growth Factor Axis and Risk of Type 2 Diabetes in Women.” Diabetes. May 3, 2012.
