Dietary Fiber, Glycemic Index, and Glycemic Load in Relation to Breast Cancer in Iran

Background: habitual consumption of diets with a high glycemic index (gi) and a high glycemic load (gl) may influence breast cancer, but consistent evidence is lacking in this regard. objectives: in this hospital-based case-control study, we evaluated the contribution of gi, gl and dietary fiber to the risk of breast cancer in iran, 2011-2012. patients and methods: data on lifestyle, diet and family history were collected from the 87 newly diagnosed breast cancer premenopausal patients and 198 five-year agematched controls. usual dietary intake was assessed by means of a 168-item semi-quantitative food frequency questionnaire (ffq), which was interviewer-administered. dietary average gi and gl were calculated by gi of iranian food table and international tables of gi and gl values: 2008. multivariate odds ratios (ors) and 95% confidence intervals (cis) for gi and gl intake were adjusted for age and major relevant covariates based on the review of literature. results: mean } sd gi was 59 } 17 among control patients and 70 } 16 among breast cancer cases; the corresponding numbers for gl were 159 } 45 and 189 } 44, respectively. the multivariate adjusted comparing the highest tertile of dietary gi and gl with the lowest tertile were 2.11 (95% ci 1.33-3.57; p-test for trend = 0.027) and 2.84 (95% ci 2.93-4.11; p-test for trend = 0.037) respectively with a significant trend. fiber intake was suggestively inversely associated with breast cancer (or = 0.79; 95% ci 0.34-0.88; p-test for trend = 0.015). conclusions: our results suggest that high dietary levels of gi and gl and low fiber intake may have unfavorable effects on breast cancer.