[1] Vrije Univ Amsterdam, Ctr Diabet, Dept Endocrinol, Med Ctr, POB 7057, NL-1007 MB Amsterdam, Netherlands
[2] Isala Clin, Dept Clin Chem, Zwolle, Netherlands
[3] Maastricht Univ, Med Ctr, Sch Nutr Toxicol & Metab NUTRIM, Dept Human Biol, Maastricht, Netherlands
[4] Vrije Univ Amsterdam, Med Ctr, Dept Phys & Med Technol, Amsterdam, Netherlands