Gait speed at age 45 was a marker of cognitive and physical aging, a longitudinal cohort study showed.

Slow gait at age 45 was tied to accelerated biological aging across multiple organ systems and reduced brain volume and cortical thickness, according to Line J.H. Rasmussen, PhD, of Duke University in Durham, North Carolina, and co-authors.

Moreover, poor neurocognitive functioning as early as age 3 and deteriorating cognitive function from childhood to age 45 also were related to a slower midlife gait, the team reported in JAMA Network Open.

“Gait speed has been a routine test in geriatric medicine clinics, but it isn’t used anywhere else because the meaning and application of gait speed earlier in life has been unclear,” Rasmussen said.

Slow speed in this study was associated with “multiple indicators of accelerated aging and deteriorating organ function, much like in older adults, but already at the age of 45 years,” she told MedPage Today. “But the most remarkable thing was that we could predict how fast the participants walked at midlife by a childhood assessment of their cognitive functions at age 3: how well they did on an IQ test, how well they understood language, and how well they could master their emotions. Gait speed is not only an indicator of aging, but also an indicator of lifelong brain health.”

This work confirms that a subset of people in their 40s already are aging more quickly than their peers, observed Stephanie Studenski, MD, MPH, of the University of Pittsburgh School of Medicine, in an accompanying editorial. It suggests that unknown factors that had affected 3-year-old children may have influenced their function 40 years later, she added. “We should continue to learn more about how brains change across the life span, in terms of neural organization, connectivity, neurotransmitters, receptors, and subtle pathologic abnormalities,” she wrote.

“The human brain is dynamic; it is constantly reorganizing itself according to exposures and experience,” Studenski noted. “It is affected as an end organ by many other organ systems. Perhaps in this sense, brain health, reflected in brain structure, cognition, and gait speed, is not necessarily a first cause, but rather may be a consequence or mediator of lifelong opportunities and insults.”

In their analysis, Rasmussen and colleagues studied people from the Dunedin Longitudinal Study, who were born from April 1972 to March 1973 in New Zealand and who had been followed for 5 decades.

At age 45, participants had their gait speed measured under three conditions — normal walking, maximum walking speed, and dual-task speed (walking while reciting every other letter of the alphabet) — to calculate the primary measure of composite gait speed. Participants also took the Wechsler Adult Intelligence Scale-IVtest to assess their neurocognitive functioning, underwent brain MRIs, and had balance and strength tests at that age.

When participants were age 3, they had a 45-minute examination that included assessments by a pediatric neurologist, standardized tests of intelligence, receptive language, and motor skills, and examiner ratings of each child’s emotional and behavioral regulation. When the children were ages 7, 9, and 11, they took the Wechsler Intelligence Scale for Children–Revised.

At four points in the study — when participants were ages 26, 32, 38, and 45 — they had their physiological health assessed, including measurements of body mass index, waist-hip ratio, glycated hemoglobin, leptin, blood pressure, cardio-respiratory fitness, cholesterol, creatinine clearance, urea nitrogen, C-reactive protein, white blood cell count, and other markers. At age 45, a panel of raters also evaluated their facial aging.

Of the 904 participants who had their gait speed tested, 50.3% were male and 93% were white. Average gait speeds were 1.30 m/s for usual gait, 1.16 m/s for dual-task gait, and 1.99 for maximum gait.

Slow gait speed was related to accelerated biological aging across multiple organ systems (β −0.33; 95% CI −0.40 to −0.27; P <0.001), smaller brain volume (β 0.15; 95% CI 0.06 to 0.23; P< 0.001), more cortical thinning (β 0.09; 95% CI 0.02 to 0.16; P=0.01), smaller cortical surface area (β 0.13; 95% CI 0.04 to 0.21; P=0.003), and more white matter hyperintensities (β −0.09; 95% CI −0.15 to −0.02; P=0.01). Slow speed also was tied to poor balance and visual-motor coordination, weak strength, and older facial appearance.

People who had a lower IQ in midlife (β 0.38; 95% CI 0.32 to 0.44; P < 0.001) and participants who exhibited cognitive decline from childhood to adulthood (β 0.10; 95% CI 0.04 to 0.17; P < 0.001) had slower gait at age 45. People who had poor neurocognitive functioning at age 3 also had slower gait in midlife (β 0.26; 95% CI 0.20 to 0.32; P < 0.001).

This study had several limitations, the authors noted. Neither gait speeds nor brain imaging were assessed before age 45, and longitudinal changes in these measurements could not be seen. Unknown factors also may have influenced outcomes: “The markers of childhood brain health were all performance tests that might have been influenced by other important issues, such as sensory function, anxiety, familiarity with tasks, or how well a child felt on the day of testing,” Studenski noted.

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