Study
PLCO
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Project ID
2008-0058
Initial CDAS Request Approval
Feb 5, 2009
Title
Dietary Glycemic Load, Glycemic Index, and Carbohydrate and Risk of Breast Cancer in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial
Summary
Breast cancer remains a major public health problem in the US despite significant advances in treatment and decades of research into its etiology and prevention. More than 182,000 incident cases of breast cancer and more than 40,000 deaths from breast cancer are projected for 2008, ranking this cancer as the leading incident cancer and number two cause of cancer mortality in women (1). Many dietary factors have been speculated as influencing breast cancer risk, including total energy, total and saturated fat, meat, dairy products, fruits and vegetables, and fiber (2). Although most studies of diet and breast cancer have focused on dietary fat, dietary carbohydrate may play a role in the etiology of this cancer. Carbohydrates elicit a wide spectrum of blood glucose and insulin responses, influenced by both their quality and quantity. Glycemic index (GI) is a ranking of carbohydrate-containing foods based on their postprandial blood glucose responses and is a measure of carbohydrate quality (3). Generally, the lower the GI, the lower the rate of absorption of the carbohydrate and the smaller the rise in postprandial glucose and insulin concentrations (4). Glycemic load (GL) is a measure that incorporates both the quality and quantity of dietary carbohydrates and is determined by multiplying the carbohydrate content of a serving of the food by the food's GI value. GL is probably the most relevant exposure as far as carbohydrate intake and disease risk is concerned (5). High dietary GI and GL have been associated with an increased risk of cancer at multiple sites, possibly by increasing insulin levels, which influence the insulin-like growth factor axis (6). We propose to study the association between dietary GI and GL (estimated from the DQx) and breast cancer in PLCO subjects.
Aims
Primary Aims 1. We will investigate the association of dietary GI (estimated from the DQx) with incident breast cancer during follow-up in PLCO participants assigned to the screening arm. We hypothesize that dietary GI will be positively associated with breast cancer risk. 2. We will investigate the association of dietary GL (estimated from the DQx) with incident breast cancer during follow-up in PLCO participants assigned to the screening arm. We hypothesize that dietary GL will be positively associated with breast cancer risk. Secondary Aims 1. We will investigate the association of dietary carbohydrate (estimated from the DQx) with incident breast cancer during follow-up in PLCO participants assigned to the screening arm. We hypothesize that dietary carbohydrate will be positively associated with breast cancer risk. 2. Investigate the associations between GL, GI, and carbohydrate and circulating insulin and glucose concentrations and glycosylated hemoglobin
Collaborators
Regina Ziegler (EBP/DCEG/NCI)
