摘要：Objectives . We analyzed factors associated with improvement in walking ability among respondents to the nationally representative Health and Retirement Study. Methods . We analyzed data from 6574 respondents aged 53 years or older who reported difficulty walking several blocks, 1 block, or across the room in 2000 or 2002. We examined associations between improvement (versus no change, deterioration, or death) and baseline health status, chronic conditions, baseline walking difficulty, demographic characteristics, socioeconomic status, and behavioral risk factors. Results . Among the 25% of the study population with baseline walking limitations, 29% experienced improved walking ability, 40% experienced no change in walking ability, and 31% experienced deteriorated walking ability or died. In a multivariate analysis, we found positive associations between walking improvement and more recent onset and more severe walking difficulty, being overweight, and engaging in vigorous physical activity. A history of diabetes, having any difficulty with activities of daily living, and being a current smoker were all negatively associated with improvement in walking ability. After we controlled for baseline health, improvement in walking ability was equally likely among racial and ethnic minorities and those with lower socioeconomic status. Conclusions . Interventions to reduce smoking and to increase physical activity may help improve walking ability in older Americans. In the past 2 decades, older Americans have experienced accelerating gains in disability-free life expectancy. 1 – 4 This phenomenon is in part related to primary prevention of chronic illness, the so-called compression of morbidity. 5 – 7 However, chronic conditions are increasingly prevalent among older Americans, and key factors in the reduction of disability are earlier detection and better management, including innovative therapeutics and rehabilitation strategies. 3 , 8 Among many examples of how older Americans limit the disabling effects of chronic illness are improved pain medication; better control of hyperlipidemia, heart disease, diabetes, and hypertension; and increased use of cataract surgery and of canes and walkers. 1 The rapid increase in numbers of total joint replacement surgeries may in itself account for half a percentage point of the recent 2% to 3% annual decreases in disability rates. 9 Modification of behavioral risk factors, particularly smoking cessation and increased physical activity, also affect both primary prevention and maintenance of function among Americans with chronic conditions. 6 , 9 , 10 Although there is disease-specific literature on recovery after acute episodes of illness, population-based disability research has focused almost exclusively on correlates of declining functional status. However, several recent panel studies of functional and health status transitions (i.e., changes from 1 level of function to another), which used different methods, found that improvement in function was common. 11 – 15 One study of several hundred adults aged 70 years and older with new-onset disabilities involving activities of daily living (ADL) found that more than 80% recovered at some point over the next year. 14 Analyses of improvement rates found that many of the demographic, socioeconomic, and behavioral risk factors that predicted functional decline and mortality did not necessarily predict functional improvement. 12 , 15 – 17 We analyzed functional improvement in walking difficulty among a nationally representative sample of Americans 53 years or older in 2000 who reported difficulty in walking in 1 of 2 biennial waves (1998–2004) of the Health and Retirement Study (HRS). We examined the likelihood of walking improvement among respondents who reported specific chronic conditions and behavioral risk factors, important targets for public health interventions. We also examined the range of improvement in walking ability reported across age groups and among those with more recent onset of walking limitations. Finally, to evaluate the role of demographic characteristics, baseline health status, socioeconomic status, and behavioral risk factors as predictors of improvement in walking ability, we assessed correlations of improvement with these variables. We hypothesized that walking improvement would differ significantly across baseline levels of limitation, with the greatest likelihood of improvement occurring among those whose only baseline difficulty was walking several blocks and those with the most recent onset of a walking limitation. 13
