Relationship between habitual physical activity and insulin area among individuals with impaired glucose tolerance. The San Luis Valley Diabetes Study.
OBJECTIVE
To determine whether higher levels of physical activity are associated with lower fasting insulin levels and lower insulin areas under the oral glucose tolerance curve in individuals with impaired glucose tolerance (IGT) in a community setting.


METHODS
Data from a cross-sectional study of a population consisting of 219 Hispanic and non-Hispanic white men and women with IGT (by World Health Organization criteria) in two rural Colorado counties were analyzed. Total physical activity was assessed by a 7-day physical activity recall, from which metabolic equivalents (METs) were estimated (expressed as MET h/week). Relationships of MET h/week with fasting insulin levels and insulin areas were assessed while considering obesity, age, and other risk factors known to influence fasting insulin level and insulin area.


RESULTS
Among all subjects, univariate analyses showed that higher physical activity levels were associated with lower mean insulin areas and fasting insulin levels (both P < 0.05). Multiple linear regression showed that higher levels of physical activity were significantly associated with lower values of of the insulin area (P < 0.001) but not with fasting insulin levels. The relationship between insulin area and habitual physical activity was independent of obesity, fat distribution, and age.


CONCLUSIONS
On the basis of cross-sectional data, we conclude that higher levels of habitual physical activity are associated with lower insulin areas in a population of individuals with IGT. Understanding the impact of physical activity on markers of insulin action in individuals with IGT is important because of the greatly enhanced risk of non-insulin-dependent diabetes mellitus and, hence, cardiovascular disease in this population.
D000328:Adult; D000367:Age Factors; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D003120:Colorado / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000208:ethnology; D005260:Female; D005951:Glucose Tolerance Test; D006630:Hispanic or Latino; D006801:Humans; D007328:Insulin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010809:Physical Fitness / Q000502:physiology*; D012044:Regression Analysis; D012307:Risk Factors; D012424:Rural Population; D011795:Surveys and Questionnaires; D044465:White People
D001786:Blood Glucose; D007328:Insulin