Does insulin-like growth factor I predict incidence and progression of diabetic retinopathy?
We evaluated the relationship of insulin-like growth factor (IGF)-I to incidence and progression of diabetic retinopathy over a 6-year interval in a large population-based study of diabetes in southern Wisconsin. Participants included people with younger-onset diabetes (n = 66 adolescents, n = 661 adults > or = 18 years of age) and older-onset diabetes (n = 285 for those using insulin, n = 248 for those not using insulin). Fundus photographs were graded in a masked fashion using standardized protocols to determine the severity of retinopathy in each eye. Serum IGF-I levels were measured during 1984-1986 using a double-antibody radioimmunoassay. Mean IGF-I was highest in adolescents (499.1 micrograms/l), lower in younger-onset adult (280.1 micrograms/l), and lowest in the older-onset group (205.7 and 221.2 micrograms/l for older-onset group using insulin and not using insulin, respectively). The incidence of retinopathy was not significantly higher in people with higher IGF-I levels in any group. The odds of developing diabetic retinopathy in 6 years for each 10 micrograms/l increase in IGF-I after controlling for age, glycosylated hemoglobin, and duration of diabetes at baseline was 1.21 (95% confidence interval [CI] 0.95-1.54) for adolescents; 1.00 (95% CI 0.93-1.08) for younger-onset adults; 0.93 (95% CI 0.85-1.02) for the older-onset group using insulin; and 0.99 (95% CI 0.95-1.04) for the older-onset group not using insulin. In summary, IGF-I was not associated with 6-year incidence or progression of diabetic retinopathy in any of the groups.
Department of Ophthalmology and Visual Sciences, University of Wisconsin Medical School, Madison.
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Wang
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Dills
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Klein
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Klein
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Moss
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000097:blood; D015992:Body Mass Index; D003920:Diabetes Mellitus / Q000097:blood* / Q000188:drug therapy; D003930:Diabetic Retinopathy / Q000097:blood* / Q000453:epidemiology; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000627:therapeutic use; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008875:Middle Aged
D006442:Glycated Hemoglobin; D007328:Insulin; D007334:Insulin-Like Growth Factor I