Successful Aging and Frailty: Opposite Sides of the Same Coin?

OBJECTIVES: Operational definitions of successful aging place a strong emphasis on functional capacity, and strategies for successful aging include many factors common to frailty research. We explore the hypothesis that frailty and successful aging are two sides of the same coin and that walking speed may be an objective indicator of successful aging.

DESIGN: Observational study of two Chinese cohorts using one to define "fast walkers" and applying this criteria to another cohort to examine associated factors.

SETTING: Community survey in cities in China.

PARTICIPANTS: A total of 1929 men and women aged 25 to 89 years of age in four cities in China and 4000 men and women 65 years old in Hong Kong SAR China.

MEASUREMENTS: The top 25th percentile of walking speed for the whole cohort of 1929 men was determined, and the cutoff value was used to define "fast walkers." This value was applied to the Hong Kong Chinese population to examine factors associated with fast walking speed. These factors include age, gender, socioeconomic and lifestyle factors, medical history, quality of life, cognitive function, depressive symptoms, body mass index, body composition, and telomere length.

RESULTS: Fast walkers had better self-rated health, lower prevalence of stroke, hypertension, cataracts, osteoporosis, and impaired cognitive function. They were more likely to be current alcohol users, more physically active, consumed more vegetables, had better physical component of health-related quality of life, and received more education. They also had lower body mass index, percentage whole body fat as well as appendicular fat, and higher appendicular muscle mass index. In multivariate analysis, the significant contributing variables were age, gender, current alcohol use, physical activity level, vegetable intake, quality of life, and appendicular fat. The area under the curve value on receiver-operating characteristic analysis was 0.77 for these seven variables.

CONCLUSIONS: Frailty and successful aging may be considered two sides of the same entity, and fast walking speed may be used as an objective indicator of successful aging.