BOSTON—Results from a study at Boston University suggest high dietary glycemic index (GI) and glycemic load (GL) may be associated with an increased risk of uterine leiomyoma (UL), benign tumors on the uterus, in some women (Am J Clin Nutr. 2010;91(5):1281-1288). High dietary GI and GL may promote tumor growth by increasing endogenous concentrations of insulin-like growth factor I (IGF-I) or the bioavailability of estradiol, a hormone present in the ovaries. And, in vitro studies have shown UL cells multiply in response to IGF-I and display increased IGF-I gene expression and protein synthesis.
In this prospective cohort study, researchers followed 21,861 premenopausal women for incident UL from 1997 to 2007. Diet was assessed in 1995 and 2001 with food-frequency questionnaires. During 162,604 person-years of follow-up, there were 5,800 cases of UL diagnosed by ultrasound or surgery. Dietary GI was weakly associated with UL risk overall. Positive associations were observed between GL and UL in women aged younger than35 years and between GI and UL in college-educated women.