Zheng DD, et al. - In a population-based study of older US adults, researchers assessed the longitudinal relationships between visual impairment and cognitive function over time. The resulting data suggested an association of visual impairment measured at distance with declining cognitive function, both cross-sectionally and longitudinally over time, with worsening vision having a stronger correlation with declining cognition than the reverse. An adverse association of worsening vision in older adults with future cognitive functioning was seen. For mitigating age-related cognitive declines, maintaining good vision may be an important interventional strategy.

Methods

• Experts conducted this study of older adults in the greater Salisbury, MD area.
• They assessed overall 2,520 community-residing adults aged 65 to 84 years at baseline between September 1993 and August 1995 (round 1) and 2 (round 2), 6 (round 3), and 8 (round 4) years later.
• Using Early Treatment Diabetic Retinopathy Study charts, visual acuity (VA) was measured, and cognitive status was assessed using the Mini-Mental State Examination (MMSE).

Results

• Findings suggested that out of 2,520 individuals, the mean (SD) age was 73.5 (5.1) years, 1,458 (58%) were women, and 666 (26%) were black.
• As per data, in the second, third, and fourth round of study, there were 2,240 (89%), 1,504 (61%), and 1,250 (50%) participants, respectively, with more than half of the loss being due to death.
• Over time, both VA and MMSE scores worsened.
• Results demonstrated that 0.022 logMAR (approximately 1 line during 8 years; 95% CI, 0.018-0.026) was the mean biannual decline of VA, and the mean biannual worsening of MMSE score was -0.59 (95% CI, -0.64 to -0.54; both P < .001).
• They noted a correlation between worse baseline VA with worse baseline MMSE score (r=0.226; 95% CI, -0.291 to -0.16; P < .001).
• There was a correlation between the rate of worsening VA with the rate of declining MMSE score (r=-0.139; 95% CI, -0.261 to -0.017; P = .03).
• As per the cross-lagged models, VA in the previous round was correlated with MMSE score in the subsequent round (β=-0.995, P < .001), and MMSE score in the previous round was associated with VA in the following round (β=-0.003, P < .001).
• Nonetheless, relative to the reverse effect (β=-0.038; SE, 0.013; P < .001), the standardized effect size of VA on MMSE score (β=074; SE, 0.015; P .001) is larger, demonstrating VA is likely the driving force in these dynamic associations.