The world’s first study of more than 1200 people demonstrates how youth fitness and obesity affect cognition in middle life
Better physical test results are associated with better cognition later in life and may offer protection against dementia in later years, according to the world’s first study on the effects of childhood fitness and obesity on cognition in middle age, which followed over 1200 people born in 1985 for more than 30 years.
Importantly, these results are unaffected by academic ability, socioeconomic status in childhood, or cigarette and alcohol use in middle age.
The groundbreaking research, led by Dr. Jamie Tait and Associate Professor Michele Callisaya from Peninsula Health and Monash University in Melbourne, as well as researchers from the Childhood Determinants of Adult Health project from the Menzies Institute for Medical Research at the University of Tasmania, was recently published in the Journal of Science and Medicine in Sport.
It is well established that children who grow up participating in sports and other physical exercise have better health outcomes in the long run. A higher level of adult fitness is also linked to improved cognition and a lower risk of dementia in old age.
This is the first significant study to examine the relationship between obesity and objectively measured fitness in childhood and cognition in middle age, with the theory that early activity levels, fitness, and metabolic health may protect against dementia in our older years. Over 1200 participants were followed from 1985, when they were between the ages of 7 and 15, to 2017–19.
In 1985, 1244 participants aged 7–15 years from the Australian Childhood Determinants of Adult Health study were assessed for fitness (cardiorespiratory, muscular power, muscular endurance) and anthropometry (waist-to-hip ratio).
These participants were followed up between 2017 and 2019 (aged 39–50, average age 44) with respect to their cognitive function using a series of computerized tests.
According to Associate Professor Callisaya this is the first study demonstrating a relationship between phenotypic profiles of objectively measured fitness and obesity measures in childhood, with midlife cognition.
The researchers found that children with the highest levels of cardio-respiratory and muscular fitness and lower average waist-to-hip ratio had higher midlife scores in tests of processing speed and attention, as well as in global cognitive function.
Because a decline in cognitive performance can begin as early as middle age, and lower midlife cognition has been associated with a greater likelihood of developing mild cognitive impairment and dementia in older age, Associate Professor Callisaya states that it is important to identify factors in early life that may protect against cognitive decline during later life.
“Developing strategies that improve low fitness and decrease obesity levels in childhood are important because it could contribute to improvements in cognitive performance in midlife,” she said.
“Importantly the study also indicates that protective strategies against future cognitive decline may need to start as far back as early childhood so that the brain can develop sufficient reserve against developing conditions such as dementia in older life.”
Reference: “Longitudinal associations of childhood fitness and obesity profiles with midlife cognitive function: an Australian cohort study” by Jamie L. Tait, Taya A. Collyer, Seana L. Gall, Costan G. Magnussen, Alison J. Venn, Terence Dwyer, Brooklyn J. Fraser, Chris Moran, Velandai K. Srikanth and Michele L. Callisaya, 19 July 2022, Journal of Science and Medicine in Sport.
The study has been funded by the National Health and Medical Research Council and the Heart Foundation.