Dietary glycemic index and load in relation to risk of uterine leiomyomata in the Black Women's Health Study.
BACKGROUND
High dietary glycemic index (GI) and glycemic load (GL) may promote tumorigenesis by increasing endogenous concentrations of insulin-like growth factor I (IGF-I) or the bioavailability of estradiol. In vitro studies have shown that uterine leiomyoma (UL) cells proliferate in response to IGF-I and display increased IGF-I gene expression and protein synthesis. Previous epidemiologic studies suggest that a high GL is a risk factor for endometrial and ovarian cancers, which, like UL, are hormone-responsive tumors.


OBJECTIVE
We investigated the relation of dietary GI and GL with UL risk in the Black Women's Health Study.


METHODS
In this prospective cohort study, we followed 21,861 premenopausal women for incident UL from 1997 to 2007. Diet was assessed in 1995 and 2001 with food-frequency questionnaires. We used Cox regression to estimate incidence rate ratios (IRRs) and 95% CIs, controlled for potential confounders.


RESULTS
During 162,604 person-years of follow-up, there were 5800 cases of UL diagnosed by ultrasound or surgery. Dietary GI was weakly associated with UL risk overall (IRR for highest compared with lowest quintile: 1.09; 95% CI: 0.99, 1.19; P for trend = 0.04). Positive associations were observed between GL and UL in women aged <35 y (IRR for highest compared with lowest quintile: 1.18; 95% CI: 1.02, 1.37; P for trend = 0.15) and between GI and UL in college-educated women (IRR for highest compared with lowest quintile: 1.17; 95% CI: 1.03, 1.34; P for trend = 0.004).


CONCLUSIONS
Our results suggest that high dietary GI and GL may be associated with an increased UL risk in some women. The observed associations warrant investigation in future studies.
Radin
Rose G
RG
Slone Epidemiology Center, Boston University, Boston, MA 02215, USA. radin@bu.edu
Palmer
Julie R
JR
Rosenberg
Lynn
L
Kumanyika
Shiriki K
SK
Wise
Lauren A
LA
D000328:Adult; D044383:Black People / Q000706:statistics & numerical data*; D001786:Blood Glucose / Q000378:metabolism; D015331:Cohort Studies; D005260:Female; D038321:Glycemic Index; D006801:Humans; D007044:Hysterectomy; D015994:Incidence; D007889:Leiomyoma / Q000097:blood / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000601:surgery; D017697:Premenopause; D012306:Risk; D014463:Ultrasonography; D014594:Uterine Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000601:surgery
D001786:Blood Glucose