Glycemic Index, Dietary Fiber, and Risk of Type 2 Diabetes in a Cohort of Older Australians
- Alan W. Barclay, BSC1,
- Victoria M. Flood, PHD23,
- Elena Rochtchina, MAPPSTAT2,
- Paul Mitchell, MD, PHD2 and
- Jennie C. Brand-Miller, PHD1
- 1Human Nutrition Unit, University of Sydney, Sydney, Australia
- 2Department of Ophthalmology, University of Sydney, Sydney, Australia
- 3NSW Centre for Public Health Nutrition, Human Nutrition Unit, University of Sydney, Sydney, Australia
- Address correspondence and reprint requests to Prof. Paul Mitchell, University of Sydney, Ophthalmology, Eye Clinic, Westmead Hospital, Westmead, NSW, Australia 2145. E-mail: paul_mitchell{at}wmi.usyd.edu.au
The role of glycemic index (GI) in the prevention of diabetes remains controversial. Some, but not all, prospective cohort studies have yielded positive relationships (1–8). A significant limitation of studies to date has been the fact that the food frequency questionnaires (FFQs) used were not validated for their ability to accurately assess GI. The purpose of this study was to assess the relationship of GI and fiber with incidence of type 2 diabetes in older Australians whose dietary intake was estimated by a fully validated FFQ.
RESEARCH DESIGN AND METHODS—
In 1991, 4,433 residents aged 49+ years were identified, of which 3,654 (82%) participated in detailed examinations during 1992–1994 (9,10). Of these, 2,335 (75% of survivors) returned for 5-year and 1,952 (76%) for 10-year examinations (2002–2004). Individuals were largely of Caucasian origin and broadly representative of the older Australian population (11).
Diagnostic criteria were either self-reported diabetes and current use of diabetes medications or fasting glucose concentration ≥126 mg/dl (12). Diabetes incidence was defined in participants without diabetes at baseline who were diagnosed with diabetes before or at the 5- or 10-year follow-up. In total, 2,564 individuals were followed from baseline. After excluding 163 participants with existing diabetes and 52 with missing data, 2,349 were considered at risk of incident diabetes. An additional 226 participants did not have fasting blood tests at either the 5- or …
