Dietary glycemic index and glycemic load, and breast cancer risk: a case-control study.
BACKGROUND
Certain types of carbohydrates increase glucose and insulin levels to a greater extent than others. In turn, insulin may raise levels of insulin-like growth factors, which may influence breast cancer risk. We analyzed the effect of type and amount of carbohydrates on breast cancer risk, using the glycemic index and the glycemic load measures in a large case-control study conducted in Italy.


METHODS
Cases were 2,569 women with incident, histologically-confirmed breast cancer interviewed between 1991 and 1994. Controls were 2588 women admitted to the same hospital network for a variety of acute, non-neoplastic conditions. Average daily glycemic index and glycemic load were calculated from a validated 78-item food frequency questionnaire.


RESULTS
Direct associations with breast cancer risk emerged for glycemic index (odds ratio, OR for highest vs. lowest quintile = 1.4; P for trend <0.01) and glycemic load (OR = 1.3; P < 0.01). High glycemic index foods, such as white bread, increased the risk of breast cancer (OR = 1.3) while the intake of pasta, a medium glycemic index food, seemed to have no influence (OR = 1.0). Findings were consistent across different strata of menopausal status, alcohol intake, and physical activity level.


CONCLUSIONS
This study supports the hypothesis of moderate, direct associations between glycemic index or glycemic load and breast cancer risk and, consequently, a possible role of hyperinsulinemia/insulin resistance in breast cancer development.
Augustin
L S
LS
Servizio di Epidemiologia, Centro di Riferimento Oncologico, Istituto Nazionale Tumori, Aviano, Italy.
Dal Maso
L
L
La Vecchia
C
C
Parpinel
M
M
Negri
E
E
Vaccarella
S
S
Kendall
C W
CW
Jenkins
D J
DJ
Francesch
S
S
D000328:Adult; D000368:Aged; D000428:Alcohol Drinking; D001786:Blood Glucose / Q000378:metabolism*; D001943:Breast Neoplasms / Q000097:blood / Q000209:etiology*; D016022:Case-Control Studies; D004040:Dietary Carbohydrates / Q000009:adverse effects*; D004493:Education; D015444:Exercise; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D006946:Hyperinsulinism / Q000209:etiology*; D007328:Insulin / Q000097:blood; D007558:Italy / Q000453:epidemiology; D008593:Menopause; D008875:Middle Aged; D016017:Odds Ratio; D010298:Parity; D012307:Risk Factors
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D007328:Insulin