Reference:
Perry JR, Ferrucci L, Bandinelli S, Guralnik J, Semba RD, Rice N, Melzer D; DIAGRAM Consortium, Saxena R, Scott LJ, McCarthy MI, Hattersley AT, Zeggini E, Weedon MN, Frayling TM. Circulating beta-carotene levels and type 2 diabetes-cause or effect? Diabetologia 2009;52(10): 2117-2121.