Abstract
Abstract: :
Purpose: To describe the changes in self–performed measures of physical function requiring different degrees of visual input. We describe changes in dialing speed and stair climbing over 6 years of follow–up in the SEE study, and examine how those changes are affected by vision and co–morbid conditions. Methods: The SEE project is a population–based study of 2520 older adults, between the ages of 65 and 84, living in Salisbury, MD; participants were recalled for 2 follow–up visits over a 6 year period. In two timed measures of function, participants were asked to dial a phone number from the phone book, and walk up a flight of 7 stairs. The association of dialing speed with best–corrected acuity and arthritis was explored, as well as the association of walking up 7 steps with contrast sensitivity and number of co–morbid conditions. We used linear models with random effects to estimate the extent of variation in individuals’ starting points and rates of decline. Models included "fixed" effects that estimated an average trajectory for the cohort, and accommodated correlation across visits within subjects. All models were adjusted for age at baseline, gender, race, and cognitive status. Results: Three rounds of data were available for 1280 participants; loss to follow–up was due mainly to refusal and death. Results for average decline in the cohort follow: time to dial took 7.2 seconds longer per year (p<0.0001). Those with worse acuity took more time to dial, but their decline was the same as those with good acuity; diagnosed arthritis was not significantly associated with speed. Time to climb the stairs took 8.1 seconds longer per year(p<0.0001); those with worse contrast took more time to climb, and their speed declined faster over time. Those with more co–morbid conditions were slower and their speed declined more quickly. There was appreciable variability in persons’ rates of speed change: we estimated a 6.9 seconds standard deviation of dialing time change rates and a 7.6 seconds standard deviation of time change for stair climb. Conclusions: In this older community dwelling population, changes in function over an 6–year period were modest: on average, dialing took 1 minute longer, as did climbing stairs. Loss of vision was in fact associated with slowing in performance of tasks. Co–morbid conditions independently contributed to slowing in mobility over time. Loss of vision among the elderly has a significant impact on IADL and mobility task performance.
Keywords: aging • clinical (human) or epidemiologic studies: natural history • vision and action