October 15, 2019
Slow gait speed identified at age 45 correlates with accelerated physical and biological aging, according to data from a longitudinal study spanning five decades.
"How fast people are walking in midlife tells us a lot about how much the body and brain have aged over time," first author Line Jee Hartmann Rasmussen, PhD, Department of Psychology & Neuroscience, Duke University, Durham, North Carolina, told Medscape Medical News.
"But the most remarkable thing," she said, "was that we could predict how fast they walked at midlife by a childhood assessment of their cognitive function at age 3. Poor neurocognitive function as early as age 3 and deteriorating cognitive function from childhood to age 45 correlated with slower midlife gait."
The study was published online October 11 in JAMA Network Open.
The data come from 904 individuals from New Zealand who were followed for more than 40 years beginning at age 3 as part of the Dunedin Multidisciplinary Health and Development Study, a longitudinal investigation of health and behavior in a representative birth cohort.
At age 3, participants were assessed by a pediatric neurologist. They had standardized tests of intelligence, receptive language, and motor skills. In addition, each child's emotional and behavioral regulation was rated. At ages 7, 9, and 11, they took the Wechsler Intelligence Scale for Children–Revised.
At age 45, gait speed was measured under three conditions: usual walking, maximum walking speed, and dual-task speed. The Wechsler Adult Intelligence Scale-IV test and balance and strength tests were also administered and brain MRI was obtained. Facial aging was also rated at age 45.
Average gait speeds at age 45 were 1.30 meters per second for usual gait, 1.99 m/sec for maximum gait, and 1.16 m/sec for dual-task gait.
Slower gait speed measured at age 45 was significantly associated with multiple physical indicators of accelerated aging, including poor balance and visual-motor coordination, weak strength, and older facial appearance.
Slower gait speed was also associated with several biological indicators of accelerated aging, including compromised brain integrity (reduced brain volume and cortical thickness).
In addition, lower IQ in midlife and evidence of cognitive decline from childhood to adulthood was also significantly associated with slower gait at age 45. Importantly, the researchers also note that adults with poor neurocognitive functioning at age 3 also had slower gait in midlife.
These findings "call for rethinking gait speed, from a geriatric index of functional decline to an index of the role of lifelong neurocognitive functioning in processes of aging," the investigators write.
"Gait speed is something that has only been routinely used in geriatric medicine, so the notion of measuring walking speed in anyone under 65 is still highly unconventional, as the meaning and application in younger adults has been more unclear," Rasmussen told Medscape Medical News.
"But these findings suggests that gait speed could be a valuable indicator of health and aging in midlife, and it's possible that gait speed could be used as part of health check-ups, with slow gait speed being an indicator of potential health concerns," she said.
A Valuable Signal
Commenting on the study in an accompanying editorial, Stephanie Studenski, MD, MPH, Division of Geriatric Medicine, University of Pittsburgh School of Medicine in Pennsylvania, says gait speed appears to be a "valuable signal of potential health concerns in midlife adults."
Although the authors do not provide a clear-cut point for reduced gait speed, they do suggest that rates of aging, cognition, and brain health are most affected among persons in the lowest quintile of gait speed, Studenski notes.
For usual gait speed, using the authors' data, she suggests a cut point of roughly 1.1 meters per second. "Certainly, as the authors suggest, midlife adults with slow gait speed are a potential target for interventions to prevent late-life disability and dementia," she writes.
The implications for early childhood are less clear, Studenski says.
"We should not assume that poor results of cognitive testing in 3-year-old children in any way doom them to lifelong problems, but rather, look broadly at what might be contributing to poorer performance and explore strategies to ameliorate these contributors," she concludes.
The study was supported by grants from the National Institute on Aging and from the UK Medical Research Council. The authors have disclosed no relevant financial relationships. Studenski has received personal fees from Merck.