Risk factors for incident open-angle glaucoma: the Barbados Eye Studies.
OBJECTIVE
To evaluate risk factors for definite open-angle glaucoma (OAG), based on African-descent participants of the Barbados Eye Studies.


METHODS
Cohort study with 81% to 85% participation over 9 years' follow-up.


METHODS
We evaluated 3222 persons at risk, 40 to 84 years old, who did not have definite OAG at baseline.


METHODS
Participants had standardized study visits at baseline and after 4 and 9 years, with structured interviews, blood pressure (BP), and other measurements. The ophthalmic protocol included automated perimetry, applanation tonometry, fundus photography, and comprehensive ophthalmologic examinations for those referred. Central corneal thickness (CCT) was measured in a subset at the 9-year examination. Incidence was estimated by the product-limit approach; relative risk ratios (RRs) with 95% confidence intervals (CIs) were based on Cox regression models with discrete time.


METHODS
Nine-year incidence of definite OAG.


RESULTS
Over 9 years, 125 persons developed definite OAG (incidence, 4.4%; 95% CI, 3.7-5.2). Baseline factors influencing risk were age (RR, 1.04; 95% CI, 1.02-1.05 per year); family history of glaucoma (RR, 2.4; 95% CI, 1.3-4.6); higher intraocular pressure (IOP) (RR, 1.12; 95% CI, 1.08-1.16 per mmHg); lower systolic BP (RR, 0.91; 95% CI, 0.84-1.00 per 10 mmHg); and lower ocular systolic, diastolic, and mean perfusion pressures (RR, 0.66; 95% CI, 0.54-0.80 per 10 mmHg higher mean perfusion pressure) (RR, 2.6; 95% CI, 1.4-4.6 for low mean perfusion pressure [<40 mmHg]). Thinner CCT was also associated with OAG incidence (odds ratio, 1.41; 95% CI, 1.01-1.96 per 40 mum lower).


CONCLUSIONS
This is the first report of risk factors for long-term OAG incidence; it is also based on a sizable number of new cases. Incidence was high in this African-descent population, where the established factors of older age, higher IOP, and family history contributed to risk. Additional predictors were vascular factors, including lower systolic BP, and particularly lower ocular perfusion pressures, which more than doubled risk. Thinner CCT was also a factor. These findings indicate a multifactorial etiology of OAG and suggest that similar risk factors apply across populations. Results are relevant for understanding OAG causation and identifying groups at high risk.
Leske
M Cristina
MC
Department of Preventive Medicine, Stony Brook University School of Medicine, Stony Brook, New York 11794-8036, USA. cleske@notes.cc.sunysb.edu
Wu
Suh-Yuh
SY
Hennis
Anselm
A
Honkanen
Robert
R
Nemesure
Barbara
B
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001460:Barbados / Q000453:epidemiology; D044383:Black People / Q000208:ethnology*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000208:ethnology*; D006801:Humans; D015994:Incidence; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology; D009901:Optic Nerve Diseases / Q000208:ethnology*; D012307:Risk Factors; D014794:Visual Fields