Diabetic Retinopathy in Oklahoma Indians With NIDDM: Incidence and risk factors
- Elisa T Lee, PHD,
- Vivian S Lee, MD, DPHIL,
- Ronald M Kingsley, MD,
- Min Lu, MB, MM,
- Dana Russell, MPH,
- Nabih R Asal, PHD,
- C P Wilkinson, MD and
- Reagan H Bradford Jr, MD
- Center for Epidemiologic Research and the Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center Oklahoma City; The Dean A. McGee Eye Institute Oklahoma City, Oklahoma; and the Department of Surgery, Duke University Medical Center Durham, North Carolina
- Address Correspondence and reprint requests to Elisa T. Lee, PHD, Center for Epidemiologic Research, College of Public Health, University of Oklahoma Health Sciences Center, PO Box 26901, Oklahoma City, OK 73190.
Abstract
OBJECTIVE To determine the incidence rates and risk factors for development of diabetic retinopathy in Oklahoma Indians.
RESEARCH DESIGN AND METHODS Cohort follow-up study with baseline examination between 1972 and 1980 and follow-up examination between 1987 and 1991. Mean ± SD follow-up time was 12.8 ± 1.7 yr. Eleven Indian Health Service facilities (clinics and hospitals) in Oklahoma participated in the study. Study participants were a quasirandom sample of 1012 American Indians (379 men, 633 women) in Oklahoma with NIDDM, 927 of whom received a detailed eye examination at baseline. The mean age of participants was 52 yr with a duration of diabetes of 6.9 yr at baseline. The average quantum of Indian blood was 92% (77% full blood). At follow-up, 515 (55.6%) were alive, 408 (44.0%) were deceased, and 4 (0.4%) could not be traced. Of the living participants, 380 (73.8%) underwent an ophthalmoscopic examination.
RESULTS The incidence of retinopathy among the participants who were free of disease at baseline and who survived the follow-up interval was 72.3%. By multivariate analysis, significant independent predictors of retinopathy recorded at baseline were FPG level, therapeutic regimen, systolic blood pressure, and duration of diabetes. FPG levels ≥ 11.1 mM (200 mg/dl) increased the risk of retinopathy 1.7 times that for levels < 7.8 mM (140 mg/dl). Insulin use was associated with a 20% greater incidence. Hypertension was a particularly significant risk factor for those with lower FPG levels.
CONCLUSIONS Given that NIDDM is reaching epidemic proportions in Oklahoma Indians and that most may be afflicted with retinopathy, frequent ophthalmological examinations are clearly indicated for this high-risk population. The role of intervention, namely glycemic and hypertensive control, deserves further study.
- Received June 3, 1991.
- Revision received April 14, 1992.
- Accepted April 14, 1992.
- Copyright © 1992 by the American Diabetes Association
