Background: Dietary glycemic index (GI) and glycemic load (GL) have been related to the risk of selected cancers, but the issue remains open.
Patients and methods: Mailed questionnaires were completed between 1994 and 1997 in eight Canadian provinces for incident, histologically confirmed cases of the stomach (n=1182), colon (n=1727), rectum (n=1447), liver (n=309), pancreas (n=628), lung (n=3341), breast (n=2362), ovary (n=442), prostate (n=1799), testis (n=686), kidney (n=1345), bladder (n=1029), brain (n=1009), non-Hodgkin's lymphomas (NHL, n=1666), leukemias (n=1069), multiple myelomas (n=343), and 5039 population controls. Dietary information on eating habits 2 years before participants' enrollment in the study was obtained using a validated food frequency questionnaire (FFQ). Odds ratios (ORs) and 95% confidence intervals (CI) were derived by unconditional logistic regression including recognized confounding factors.
Results: Dietary GI was positively associated with the risk of prostate cancer (OR, 1.26 for the highest versus the lowest quartile). A higher dietary GL significantly increased the risk of colorectal (OR, 1.28), rectal (OR, 1.44) and pancreatic (OR, 1.41) cancers. No other significant associations were found.
Conclusions: Our findings suggest that a diet high in GI and GL is associated with increased risk of selected cancers.