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Too much TV in young adulthood leads to poorer midlife cognitive function

High television viewing and low physical activity in early adulthood was associated with poorer executive function and processing speed in midlife, according to recent findings.

“Over the life course, levels of physical activity tend to peak in childhood with large declines occurring during early adulthood in conjunction with major life transitions, such as entrance into the workforce and parenthood,” Tina D. Hoang, MSPH, of Northern California Institute for Research and Education, San Francisco, and colleagues wrote. “Coupled with the increasing prevalence of sedentary or screen-based activities, such as watching television, these trends are of particular concern for upcoming generations of young people. In middle-aged and older adults, low levels of physical activity and high sedentary behavior are associated with cognitive impairment and dementia, but the long-term risks associated with these lifestyle behaviors require further investigation.”

To assess associations between 25-year patterns of television viewing, physical activity and midlife cognition, researchers prospectively analyzed data for 3,247 adults enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA). The study included black and white participants aged 18 to 30 years. Television viewing was assessed at least three times over 25 years via questionnaire. Cognitive function was assessed at year 25 via the Digit Symbol Substitution Test (DSST), Stroop test, and Rey Auditory Verbal Learning Test. Study participants had a mean age of 25.1 years at baseline.

A 25-year pattern of high television viewing was defined as watching TV for more than 3 hours per day for more than two-thirds of assessments. A 25-year pattern of low physical activity was defined as activity levels below the lower, sex-specific baseline quartile for more than two-thirds of assessments.

Participants with high TV viewing were more likely to have poor cognitive performance on the DSST (adjusted OR = 1.64; 95% CI, 1.21-2.23) and Stroop test (aOR = 1.56; 95% CI, 1.13-2.14), but not the Rey Auditory Verbal Learning Test, compared with those with low TV viewing.

Low physical activity was significantly associated with poor performance on the DSST (OR = 1.47; 95% CI, 1.14-1.9).

Odds of poor performance were almost two times higher for adults with both high TV viewing and low physical activity on the DSST (OR = 1.95; 95% CI, 1.19-3.22) and the Stroop test (OR = 2.2; 95% CI, 1.36-3.56), compared with adults low TV viewing and high physical activity.

“Our results indicate that the lifestyle behaviors in early adulthood that were evaluated in this study could have an effect on the risk of cognitive impairment in midlife and support a potential role for both physical activity and sedentary behavior as modifiable risk factors for prevention. Individuals with both low physical activity and high sedentary behavior may represent a critical target group,” the researchers concluded. – by Amanda Oldt

Disclosure: Hoang reports no relevant financial disclosures. Please see the full study for a list of all authors’ relevant financial disclosures.