Generational Differences in the 10-year Incidence of Impaired Contrast Sensitivity

ABSTRACT

Purpose

To determine if incidence of contrast sensitivity (CS) impairment differs by generation and identify factors to explain these differences.

Methods

The Beaver Dam Eye Study (BDES) and Beaver Dam Offspring Study (BOSS) are cohort studies of aging adults in Beaver Dam, Wisconsin. Baseline examinations occurred from 1993 to 1995 (BDES) and 2005–2008 (BOSS). Follow-up examinations occurred in five-year intervals. CS testing was conducted with Pelli-Robson letter sensitivity charts; Incident impairment was a log CS score <1.55 in either eye at follow-up. Associations of incidence with generation were investigated using estimated hazard ratios (HR) with 95% confidence intervals (CI).

Results

Participants (N = 3185) had a mean age of 51.9 years at baseline (standard deviation = 9.9) and 51.9% were female. Ten-year cumulative incidence of CS impairment was 40.1%, was higher among women (41.7%) than men (38.8%), and increased by age group. The risk of incident CS impairment decreased by 39% per generation. In multivariable models, the Baby Boom Generation (HR = 0.42, 95%CI = 0.31, 0.58) and Generation X (HR = 0.56, 95%CI = 0.34, 0.91) had a significantly decreased risk of CS impairment compared to the Greatest Generation. Results were similar in sensitivity analyses excluding those with cataract, age-related macular degeneration, or visual acuity impairment.

Conclusion

The risk of incident CS impairment decreased by birth cohort, with the greatest reduction in the Baby Boom Generation. The difference in risk suggests that there are unknown modifiable risk factors that may help to further explain the etiology of CS impairment and provide potential pathways for prevention in the future.

KEYWORDS:

• Epidemiology
• Birth Cohort Effect
• Contrast Sensitivity
• Visual Function
• Aging

Disclosure of interest

The authors report no conflict of interest. The funding organizations had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. The content is solely the responsibility of the authors and does not necessarily reflect the official views of the National Institute on Aging, the National Eye Institute, the National Institutes of Health, or Research to Prevent Blindness.

The authors warrant that this article is original, is not simultaneously under consideration by another journal, and has not been previously published. This manuscript was previously submitted to JAMA Ophthalmology, and despite a favorable review, was not accepted. The authors used the feedback from this review to clarify the sample selection in the current version of the manuscript. We conducted additional analyses to address concerns of overlap of age ranges among the birth cohorts.

Additional information

Funding

This work was supported by the National Institute on Aging and the National Eye Institute under Grant R01AG021917 (Dr. Cruickshanks); the National Institute on Aging under Grant R37AG011099 (Dr. Cruickshanks); the National Eye Institute under Grant U10EY06594 (Drs. B.E.K. Klein and R. Klein); Research to Prevent Blindness under an unrestricted grant to the Department of Ophthalmology and Visual Sciences at the University of Wisconsin School of Medicine and Public Health