RIVERSIDE, Calif. - University of California, Riverside psychologist Chandra A. Reynolds has been awarded a $7 million, five-year grant by the National Institute on Aging to study how early childhood influences versus recent influences affect cognitive and physical health by middle age.
Reynolds is the contact principal investigator on the multi-PI project, with co-principal investigator Sally J. Wadsworth from the University of Colorado-Boulder (UCB), and co-investigator Robert Plomin from King's College in London, as well as seven other co-investigators at UCB.
Little is known about the cumulative effect of genetic and environmental factors and their interaction, on cognition in middle age, which some researchers suggest could begin at conception, Reynolds said.
"We will look at how early influences impact how people function cognitively as they approach mid-life," she explained. "There are studies that suggest that how you do cognitively and physically in mid-life predicts how you will function in old age. If there is a relation between cognitive function and physical health in later life, we should start to see evidence of that earlier in mid-life as well as connections with childhood, adolescence and early adulthood."
The research has important personal and public health implications, she said.
"One of the biggest fears people report when asked about aging is loss of memory and cognitive functioning," Reynolds said. "It's a stronger fear than loss of physical function."
The study is called the "Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging" (CATSLife). The research team will analyze data compiled from two ongoing, internationally recognized studies of behavioral development -- the Colorado Adoption Project (CAP), which was originated by John C. DeFries and Robert Plomin in the 1970s, and which Wadsworth currently directs, and the Colorado Longitudinal Twin Study, originated by DeFries and others in the 1980s, and now directed by John K. Hewitt. Participants in these longitudinal studies have been tracked since infancy and now range in age from about 30 to 40 years of age. New data will be collected as part of CATSLife. Moreover, Plomin's team in London will compare findings from the CATSLife samples to his Twins Early Development Study (TEDS).
Reynolds said the team will assess patterns of early cognitive development, such as memory, knowledge, and how quickly children process information, and how it relates to midlife functioning, and will look for patterns of environmental and genetic influences among more than 1,600 adoptees and their siblings as well as twins.
"This unparalleled combined adoption/twin study of birth to the cusp of mid-adulthood will contribute to a greater understanding of how cognitive abilities and physical health in early life might promote cognitive functioning by midlife," Reynolds explained. "An improved understanding of genetic and environmental influences, and how they interact with early-life factors to affect adult outcomes may contribute to improved cognitive and physical functioning and well-being, as well as to better health education and services."
One genetic factor, among many the team will explore, is the APOE (apolipoprotein E) gene, a transporter of cholesterol in the brain. The presence of one form of the gene (ε4) has been linked to a higher risk for developing late-onset Alzheimer disease, said Reynolds, whose previous research has considered cholesterol, inflammatory, and related gene pathways that may influence cognitive change and decline.
"Could some form of this gene influence cognition earlier in life?" Reynolds asked. "Although there are known links of APOE with later life cognitive dysfunction and dementia it is unclear whether APOE has an early or emerging role in cognition (and health) in the first half of the lifespan. We have the opportunity in CATSLife to evaluate APOE from a long-term longitudinal perspective. Cholesterol is a key component in the brain and vital to its functioning. One of the things we will look at is multiple genes in the cholesterol/lipid pathway that might be relevant to aspects of how neurons are altered when memories are being formed in the hippocampus, for example, and hence impact longitudinal cognitive performance."
The team also will examine the impact of choosing activities and environments that are mentally or physically stimulating, or socially engaging, all of which may influence cognitive and physical health and well-being.
"There is a connection between engagement in activities and cognitive function," Reynolds said. "If you like to read or play games, that might provide more cognitive stimulation, which could create more of a reserve as you age to maintain cognitive function later in life."