Original Articles
The epidemiology of cataract in Australia

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Abstract

PURPOSE:

To describe the prevalence and risk factors for cataract in an Australian population aged 40 years and older.

METHODS:

Participants were recruited by a household census and stratified, random cluster sampling to represent residents of Victoria, Australia, aged 40 years and older. The following information was collected: initial visual acuity and best-corrected visual acuity, demographic details, health history, dietary intake of antioxidants, lifetime ocular ultraviolet B exposure, and clinical eye examination, including lens photography. Cortical opacities were measured in sixteenths. Cortical cataract was defined as opacity greater than or equal to 4/16 of pupil circumference. Nuclear opacities were graded according to the Wilmer cataract grading scheme, and cataract was defined as greater than or equal to nuclear standard 2.0 of four standards. The height and width of any posterior subcapsular opacity was measured and recorded. Posterior subcapsular cataract was defined as posterior subcapsular opacity greater than or equal to 1 mm2. The worse eye was selected for analysis. Backward stepwise logistic regression was used to quantify independent risk factors for cataract.

RESULTS:

A total of 3,271 (83% of eligible) of the urban residents, 403 (90% of eligible) nursing home residents, and 1,473 (92% of eligible) rural residents participated. The urban residents ranged in age from 40 to 98 years (mean, 59 years), and 1,511 (46%) were men. The nursing home residents ranged in age from 46 to 101 years (mean, 82 years), and 85 (21%) were men. The rural residents ranged in age from 40 to 103 years (mean, 60 years), and 701 (47.5%) were men. The overall weighted rate of cortical cataract was 11.3% (95% confidence limits, 9.68%, 13.0%) excluding cataract surgery and 12.1% (95% confidence limits, 10.5%, 13.8%) including cataract surgery. The risk factors for cortical cataract that remained in the multivariate logistic regression model were age, female gender, diabetes duration greater than 5 years, gout duration greater than 10 years, arthritis diagnosis, myopia, use of oral beta-blockers, and increased average annual ocular ultraviolet B exposure. Overall, 12.6% (95% confidence limits, 9.61%, 15.7%) of Victorians aged 40 years and older had nuclear cataract including previous cataract surgery, and 11.6% (95% confidence limits, 8.61%, 14.7%) had nuclear cataract excluding previous cataract surgery. In the urban and rural cohorts, age, female gender, rural residence, brown irides, diabetes diagnosed 5 or more years earlier, myopia, age-related maculopathy, having smoked for greater than 30 years, and an interaction between ocular ultraviolet B exposure and vitamin E were all risk factors for nuclear cataract. The rate of posterior subcapsular cataract excluding previous cataract surgery was 4.08% (95% confidence limits, 3.01%, 5.14%), whereas the overall rate of posterior subcapsular cataract including previous cataract surgery was 4.93% (95% confidence limits, 3.68%, 6.17%). The independent risk factors for posterior subcapsular cataract in the urban and rural cohorts that remained were age in years, rural location, use of thiazide diuretics, vitamin E intake, and myopia.

CONCLUSIONS:

The expected increase in the prevalence of cataract with the aging of the population highlights the need to plan appropriate medical services and public health interventions for primary and secondary prevention. Many of the identified risk factors for cataract in the population have the potential for being modified through public health interventions.

Section snippets

Methods

Details about the study methodology for the Visual Impairment Project have been published.37 Briefly, cluster sampling within three strata was used to recruit subjects aged 40 years and older to participate. Within the Melbourne Statistical Division, nine pairs of census collector districts were randomly selected. Fourteen nursing homes within a 5-km radius of these nine test sites were randomly chosen to recruit nursing home residents. Finally, four pairs of census collector districts in four

Results

A total of 3,271 (83% of eligible) of the urban residents, 403 (90% of eligible) nursing home residents, and 1,473 (92% of eligible) rural residents participated. Nonparticipants differed from participants only in language spoken at home; they were more likely to speak a language other than English at home.46 The participation rate for people who spoke Greek at home was 76% compared with 85% participation for people who spoke English at home. The study population is representative of Victoria

Discussion

This study differs from previous reports of cataract epidemiology in that the study population truly represents the general population. Victoria represents approximately one quarter of the entire Australian population, and the demographics of the study population have been shown to represent Australia.46 Therefore, these data can be used to estimate the increasing need for medical services in Australia for cataract and to plan public health interventions to target the modifiable risk factors

References (52)

  • J.E Keeffe et al.

    Cataract surgery in Australia 1985–94

    Aust N Z J Ophthalmol

    (1996)
  • G Guiffrè et al.

    Casteldaccia eye studyprevalence of cataract in the adult and elderly population of a Mediterranean town

    Int Ophthalmol

    (1995)
  • R Hiller et al.

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

    Am J Epidemiol

    (1983)
  • R Hiller et al.

    Epidemiologic associations with nuclear, cortical, and posterior subcapsular cataracts

    Am J Epidemiol

    (1986)
  • M.C Leske et al.

    The Lens Opacities Case-Control Studyrisk factors for cataract

    Arch Ophthalmol

    (1991)
  • Risk factors for age-related cortical, nuclear, and posterior subcapsular cataracts

    Am J Epidemiol

    (1991)
  • S Miglior et al.

    Risk factors for cortical, nuclear, posterior subcapsular and mixed cataracta case control study

    Ophthalmic Epidemiol

    (1994)
  • B.E.K Klein et al.

    Older-onset diabetes and lens opacitiesthe Beaver Dam Eye Study

    Ophthalmic Epidemiol

    (1995)
  • I.M Heiba et al.

    Evidence for a major gene for cortical cataract

    Invest Ophthalmol Vis Sci

    (1995)
  • Familial aggregation of lens opacitiesthe Framingham Eye Study and the Framingham Offspring Eye Study

    Am J Epidemiol

    (1994)
  • R.G Cumming et al.

    Alcohol, smoking, and cataractsthe Blue Mountains Eye Study

    Arch Ophthalmol

    (1997)
  • R.G Cumming et al.

    Use of inhaled corticosteroids and the risk of cataract

    N Engl J Med

    (1997)
  • B.E.K Klein et al.

    Is there evidence of an estrogen effect on age-related lens opacities? The Beaver Dam Eye Study

    Arch Ophthalmol

    (1994)
  • R.G Cumming et al.

    Hormone replacement therapy, reproductive factors, and cataractthe Blue Mountains Eye Study

    Am J Epidemiol

    (1997)
  • S.K West et al.

    Lack of evidence for aspirin use and prevention of cataracts

    Arch Ophthalmol

    (1987)
  • J.J Harding et al.

    Drugs, including alcohol, that act as risk factors for cataract, and possible protection against cataract by aspirin-like analgesics and cyclopenthiazide

    Br J Ophthalmol

    (1988)
  • Cited by (0)

    The Visual Impairment Project was funded in part by grants from the Victorian Health Promotion Foundation, Melbourne, Victoria, the National Health and Medical Research Council, Woden, Connecticut, the Ansell Ophthalmology Foundation, Melbourne, Victoria, the Dorothy Edols Estate, Melbourne, Victoria, the Jack Brockhoff Foundation, Melbourne, Victoria, and the Ophthalmic Research Institute of Australia, Sydney, NSW. Dr McCarty is the recipient of the Wagstaff Research Fellowship in Ophthalmology from the Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria.

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