Diabetes Care, Vol 17, Issue 11 1311-1319, Copyright © 1994 by American Diabetes Association
Impaired glucose tolerance and NIDDM: does a lifestyle intervention program have an effect?
DM Bourn, JI Mann, BJ McSkimming, MA Waldron and JD Wishart
Department of Human Nutrition, University of Otago, Dunedin, New Zealand.
OBJECTIVE--To determine whether a 2-year lifestyle intervention program
improves glucose tolerance and lipid levels in people with persistent
impaired glucose tolerance (IGT) or non-insulin-dependent diabetes mellitus
(NIDDM). RESEARCH DESIGN AND METHODS--Screening for IGT and NIDDM was
carried out in 1,752 people. Subjects with persistent IGT or NIDDM
completed three 2-h oral glucose tolerance tests (OGTTs) before the start
of the study and after 2 years. A single OGTT was carried out every 3
months. A 4-day food diary and a 7-day exercise diary were completed, and
weight, blood pressure, glycated hemoglobin (HbA1), plasma lipids, and
fasting and 2-h serum insulin were measured at baseline and every 3 months.
Subjects were encouraged to make dietary changes and increase exercise.
RESULTS--Thirty-two subjects with persistent IGT and 20 subjects with NIDDM
were recruited. Women reported significant decreases in total and saturated
fat and an increase in carbohydrate, but few subjects reached the
recommended intakes. Men achieved smaller dietary changes. There were
significant decreases in body mass index, fasting and 2-h plasma glucose,
HbA1, total cholesterol, low-density lipoprotein cholesterol, and
triglyceride levels in both the IGT and NIDDM groups during the study.
CONCLUSIONS--Results suggest that a diet and exercise program can result in
significant improvements in a range of clinical and metabolic variables in
some people with IGT or NIDDM, although the absence of a control group
precludes firm conclusions. Screening for IGT in those at high risk for
developing NIDDM and offering those with persistent IGT a lifestyle
intervention program could help reduce the progression of IGT to NIDDM.