Effects on glucose tolerance, insulin secretion, insulin-like growth factor 1 and its binding protein, IGFBP-1, in a randomized controlled diet and exercise study in healthy, middle-aged men.
OBJECTIVE
To study the effects of advice on diet, exercise and their combination on oral glucose tolerance (OGTT), insulin secretion, insulin-like growth factor-1 (IGF-1) and its binding protein, IGFBP-1.


METHODS
A 6-month, randomized, controlled intervention study.


METHODS
Primary health care centres in Sollentuna, Stockholm and the Department of Medicine, Karolinska Hospital, Stockholm, Sweden.


METHODS
One hundred and fifty-seven normoglycaemic healthy men, mean age 46 years, range 35-60 years, with slightly to moderately raised cardiovascular risk factors.


METHODS
Advice on diet (D, n = 40), exercise (E, n = 39) a combination of both (DE, n = 39) and a control group (C, n = 39).


METHODS
An OGTT, insulin secretion, IGF-1 and its binding protein, IGFBP-1.


RESULTS
The number of pathological OGTTs in the intervention groups decreased from 42/118 to 33/118 whilst the number in the control group did not change. Fasting insulin levels decreased in groups E and DE from 8.8-7.4 mU L-1 (P < 0.01) and from 8.3-6.7 mU L-1 (P < 0.01), respectively. Accordingly, the insulin area under the curve decreased from 5278 to 4828 (P < 0.05) in group E, and from 5482 to 4809 (P < 0.01) in group DE. IGF-1 only increased in group D. The most prominent changes were noted for IGFBP-1, which increased in all three intervention groups and to the highest degree in group DE (from 33.7-42.6 micrograms L-1, P < 0.001).


CONCLUSIONS
A combination of increased exercise and improved diet, as well as increased exercise alone, favourably affect glucose and insulin homeostasis in middle-aged men with moderately elevated cardiovascular risk factors. The most marked changes were noted for IGFBP-1, possibly suggesting a decreased insulin secretion and an enhanced insulin sensitivity.
Hellénius
M L
ML
Department of Medicine, Karolinska Hospital, Stockholm, Sweden.
Brismar
K E
KE
Berglund
B H
BH
de Faire
U H
UH
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D002352:Carrier Proteins / Q000097:blood*; D004032:Diet; D015444:Exercise; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood*; D018970:Insulin-Like Growth Factor Binding Protein 1; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013548:Sweden; D013997:Time Factors
D001786:Blood Glucose; D002352:Carrier Proteins; D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D007334:Insulin-Like Growth Factor I