Diet quality is prospectively associated with incident impaired fasting glucose in older adults

Dietary modifications may play an important role in the prevention of diabetes. We aimed to assess the temporal association between diet quality and both impaired fasting glucose and Type 2 diabetes among older adults.

A total of 2564 participants aged 49+ years at baseline were examined between 1992 and 1994 and 2002-2004 and had their fasting blood glucose measured. Dietary data were collected using a semi-quantitative food frequency questionnaire. A modified version of the Healthy Eating Index for Australians was developed to determine Total Diet Score. Incident diabetes (or impaired fasting glucose) was defined in participants at risk who were newly diagnosed by a physician during the follow-up or found to have a fasting blood glucose level ≥ 7.0 mmol/l (or 6.1-6.9 mmol/l).

After adjusting for age, sex, current smoking, body mass index, hypertension and serum triglycerides, comparing highest with lowest tertile of total diet score, a significant 75% decrease in risk of incident impaired fasting glucose was observed in men (P(trend) = 0.02). Also, in men, each two-point increase in Total Diet Score was associated with a 52% reduction in the 10-year incidence of impaired fasting glucose, (OR 0.48, 95% CI 0.33-0.69). No significant associations were observed among women or with the 10-year incidence of diabetes.

Greater compliance with published dietary guidelines (better diet quality) was associated with a reduced risk of pre-diabetes in men, but not women.