A normal but high circulating levels of total prolactin was associated with a lower risk of type 2 diabetes within 9-10 years of follow-up, according to a study published October 11, 2018 in Diabetologia. The inverse association of total prolactin with type 2 diabetes was significant during the first 9 years after blood draw but waned linearly with time, whereas for bioactive prolactin, the inverse relationship persisted for a longer follow-up time after blood draw.