The 25-year incidence of visual impairment in type 1 diabetes mellitus the wisconsin epidemiologic study of diabetic retinopathy.
OBJECTIVE
To examine the 25-year cumulative incidence of visual impairment (VI) and its relation to various risk factors.


METHODS
Population-based study.


METHODS
Nine hundred fifty-five insulin-taking persons living in an 11-county area in southern Wisconsin with type 1 diabetes diagnosed before age 30 years who participated in a baseline (1980-1982) and at least 1 of 4 follow-up (4-, 10-, 14-, and 25-year) examinations or who died before the first follow-up examination (n = 64).


METHODS
Best-corrected visual acuity (VA) was measured using a modification of the Early Treatment Diabetic Retinopathy Study protocol. Visual impairment and severe VI were defined as best-corrected VA in the better eye of 20/40 or worse and 20/200 or worse, respectively.


METHODS
Incidence of VI.


RESULTS
The 25-year cumulative incidences of any VI and severe VI (accounting for competing risk of death) were 13% and 3%, respectively. Multivariate models showed increased risk of VI was associated (hazard ratio, 95% confidence interval, and P value) with more severe baseline retinopathy (1.14 per 1-step increase in retinopathy level; 1.03-1.27; P = 0.01), presence of cataract (2.49 versus absence; 1.53-4.04; P<0.001), higher glycosylated hemoglobin (1.28 per 1%; 1.16-1.42; P<0.001), presence of hypertension (1.72 versus absence; 1.05-2.83; P = 0.03), and currently smoking (vs. never smoked, 1.63; 1.01-2.61; P = 0.04), but not proteinuria.


CONCLUSIONS
These data show that the 25-year cumulative incidence of VI is related to modifiable risk factors and, therefore, that VI may be reduced by better glycemic and blood pressure control and avoidance of smoking.


BACKGROUND
Proprietary or commercial disclosure may be found after the references.
Klein
Ronald
R
Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI 53726-2336, USA. kleinr@epi.ophth.wisc.edu
Lee
Kristine E
KE
Gangnon
Ronald E
RE
Klein
Barbara E K
BE
D000328:Adult; D001794:Blood Pressure; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy / Q000453:epidemiology* / Q000503:physiopathology; D003930:Diabetic Retinopathy / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D015994:Incidence; D007328:Insulin / Q000627:therapeutic use; D008297:Male; D012307:Risk Factors; D013997:Time Factors; D014786:Vision Disorders / Q000453:epidemiology* / Q000503:physiopathology; D014792:Visual Acuity / Q000502:physiology; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*; D014922:Wisconsin / Q000453:epidemiology
D006442:Glycated Hemoglobin; D007328:Insulin; C517652:hemoglobin A1c protein, human