Lens opacities and mortality: The Barbados Eye Studies

doi:10.1016/S0161-6420(00)00542-X

Ophthalmology

Volume 108, Issue 3, March 2001, Pages 498-504

https://doi.org/10.1016/S0161-6420(00)00542-X Get rights and content

Abstract

Objective

To evaluate the association between cataract and mortality in a black population by type of opacity, which has not been documented previously.

Design

Population-based cohort study.

Participants

The Barbados Incidence Study of Eye Diseases reexamined the Barbados Eye Study cohort, identified through a simple random sample of predominantly black Barbadian-born citizens, aged 40 to 84 years. Of those eligible, 85% (3427 participants) had a 4-year follow-up visit.

Methods

Baseline and follow-up visits included an interview, blood pressure and other measurements, and a detailed ophthalmologic examination with slit-lamp lens gradings (Lens Opacities Classification System [LOCS] II protocol). Mortality at follow-up was verified from Ministry of Health records.

Main outcome measures

Lens opacities were defined by a LOCS II score of 2 or more. Opacity types were classified in two ways: (1) single (cortical-only, nuclear-only, and posterior subcapsular-only) and mixed opacities; and (2) any cortical, any nuclear, or any posterior subcapsular opacities. Information on dates and causes of death was obtained from death certificates.

Results

Cardiovascular disease was the principal cause of death in black participants (3.6%), followed by malignant neoplasms (1.4%). The cumulative 4-year mortality varied with lens types, increasing from 3.2% for those without cataract to 6.0% for cortical-only, 8.8% for nuclear-only, and 20.9% for mixed opacities. Persons with mixed opacities had a 1.6-fold increase in mortality, while controlling for other factors (age, male gender, diabetes, hypertension, obesity, cigarette smoking, cardiovascular disease, and family history of diabetes) in Cox proportional-hazards regression analyses. Persons with any nuclear opacities also had increased mortality (death rate ratio, 1.5). The death rate ratios increased with age, but peaked at age 60 to 69 years. Coexisting diabetes further increased mortality: people with mixed opacities and diabetes had a 2.7-fold increased risk of death. A trend toward increased mortality from neoplasms was observed for individuals with mixed opacities or with any nuclear opacities.

Conclusions

Participants with mixed opacities or any nuclear opacities had increased 4-year mortality rates, with diabetes acting as an effect modifier. This study is the first to identify a relationship between type of cataract and mortality in an African-descent population.

Section snippets

Methods

The Barbados Eye Study (BES; 1988–1992) measured prevalence and evaluated risk factors for the major causes of visual loss among 4709 persons who were identified by a simple random sample of Barbadian-born citizens, 40 to 84 years of age. Participation was 84%, and the demographic composition of BES participants closely resembled the census population.15 Four years later, the surviving members of the cohort were reexamined in the Barbados Incidence Study of Eye Diseases (BISED), which involved

Results

Of the 4314 black participants in the cohort, 306 had died before the BISED follow-up visit (mean interval, 4 years; standard deviation, 5 months). The remaining participants were considered as survivors, after excluding 19 persons who could not be located. Table 1 presents demographic and clinical characteristics by 4-year survivorship. The deceased participants were older than those surviving (median age, 73 years at baseline vs. 57 years), as expected; they were also more likely to be male.

Discussion

This study found associations between lens opacities and mortality in a black population. Cardiovascular disease was the principal cause of death, followed by malignant neoplasms (Table 2). The cumulative 4-year mortality in this cohort increased from 3.2% among those without cataract to 6.0%, 8.8%, and 20.9% for cortical-only, nuclear-only, and mixed opacities, respectively (Table 3). Cox proportional hazards analyses demonstrated an independent association between mixed opacities and 4-year

Conclusions

High prevalences of cataract are consistently reported in black populations.10, 11, 12 As far as we are aware, the present report documents an association between different types of lens opacities and mortality in an African-descent population for the first time. Mixed opacities were independently associated with mortality and diabetes acted as an effect modifier, increasing mortality risk. Consistent with data from white populations, nuclear opacities in the BES were associated with increased

The Barbados Eye Studies Group

Principal Investigator: M. Cristina Leske, MD, MPH.

Coordinating Center: University at Stony Brook, Stony Brook, NY; M. C. Leske, MD, MPH; Barbara Nemesure, PhD; Suh-Yuh Wu, MA; Leslie Hyman, PhD; Xiaowei Li, PhD; Shu-Hong Xie, MS; Lixin Jiang, MS; Koumudi Manthani.

Data Collection Center: Ministry of Health, Bridgetown, Barbados, West Indies; Anthea M. S. Connell, FRCS, FRCOphth; Anselm Hennis, MRCP(UK), PhD; Ann Bannister, MB, BS, DO; Muthu A. Thangaraj, MB, BS, DO; Coreen Barrow; Patricia

Acknowledgements

The authors thank the Barbados Eye Studies participants and the Ministry of Health, Barbados, West Indies, for their role in the study.

References (35)

D.A. Street et al.
National five-year mortality after inpatient cataract extraction
Am J Ophthalmol
(1992)
M.C. Leske et al.
Diabetes, hypertension, and central obesity as cataract risk factors in a Black population. The Barbados Eye Study
Ophthalmology
(1999)
M.C. Leske et al.
Incidence and progression of lens opacities in the Barbados Eye Studies
Ophthalmology
(2000)
E. Rogot et al.
Survivorship and causes of death among the blind
J Chronic Dis
(1966)
W.H. Benson et al.
Increased mortality rates after cataract surgery. A statistical analysis
Ophthalmology
(1988)
M.J. Podgor et al.
Lens changes and the incidence of cardiovascular events among persons with diabetes
Am Heart J
(1989)
M.C. Leske et al.
Antioxidant vitamins and nuclear opacitiesthe longitudinal study of cataract
Ophthalmology
(1998)
B. Thylefors et al.
Global data on blindness
Bull World Health Organ
(1995)
D.C. Minassian et al.
Mortality and cataractfindings from a population-based longitudinal study
Bull World Health Organ
(1992)
M.J. Podgor et al.
Lens changes and survival in a population-based study
N Engl J Med
(1985)

R. Klein et al.

Age-related eye disease and survival. The Beaver Dam Eye Study

Arch Ophthalmol

(1995)

J.R. Thompson et al.

Cataract and survival in an elderly nondiabetic population

Arch Ophthalmol

(1993)

S.K. West et al.

Mixed lens opacities and subsequent mortality

Arch Ophthalmol

(2000)

B.E.K. Klein et al.

Cataracts and macular degeneration in older Americans

Arch Ophthalmol

(1982)

R. Hiller et al.

Epidemiologic associations with cataract in the 1971–1972 National Health and Nutrition Examination Survey

Am J Epidemiol

(1983)

M.C. Leske et al.

The Lens Opacities Case-Control Study. Risk factors for cataract

Arch Ophthalmol

(1991)

M.C. Leske et al.

Prevalence of lens opacities in the Barbados Eye Study

Arch Ophthalmol

(1997)

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^☆: Supported by the National Eye Institute, Bethesda, Maryland (grant nos.: EYO7625 and EYO7617).

¹: The authors have no proprietary interest in the products or devices mentioned herein.

View full text

Lens opacities and mortality: The Barbados Eye Studies1☆,

Abstract

Objective

Design

Participants

Methods

Main outcome measures

Results

Conclusions

Section snippets

Methods

Results

Discussion

Conclusions

The Barbados Eye Studies Group

Acknowledgements

Am J Ophthalmol

Ophthalmology

Ophthalmology

J Chronic Dis

Ophthalmology

Am Heart J

Ophthalmology

Global data on blindness

Bull World Health Organ

Mortality and cataractfindings from a population-based longitudinal study

Bull World Health Organ

Lens changes and survival in a population-based study

N Engl J Med

Age-related eye disease and survival. The Beaver Dam Eye Study

Arch Ophthalmol

Cataract and survival in an elderly nondiabetic population

Arch Ophthalmol

Mixed lens opacities and subsequent mortality

Arch Ophthalmol

Cataracts and macular degeneration in older Americans

Arch Ophthalmol

Epidemiologic associations with cataract in the 1971–1972 National Health and Nutrition Examination Survey

Am J Epidemiol

The Lens Opacities Case-Control Study. Risk factors for cataract

Arch Ophthalmol

Prevalence of lens opacities in the Barbados Eye Study

Arch Ophthalmol

Lens opacities and mortality: The Barbados Eye Studies¹ ☆,