Results from a recent study published in the journal SAGE Open revealed that the more hours young adults spend watching television each day, the greater the likelihood that they’ll have a higher body mass index and larger waist circumference.
The results are part of a 15-year analysis conducted by a team of researchers from the University of Pittsburgh Graduate School of Public Health.
The association did not hold in later years, demonstrating that young adulthood is an important time to intervene and promote less television viewing. “We were quite surprised to find that television viewing was associated with subsequent obesity for young adults, but not for the middle-aged,” said lead author Anthony Fabio, Ph.D., M.P.H., assistant professor of epidemiology at Pitt Public Health. “This suggests that middle-aged adults may differ from young adults in how they respond to the influence of TV viewing.”
In the study titled “Fifteen-Year Prospective Analysis of Television Viewing and Adiposity in African American and Caucasian Men and Women: The CARDIA Study,” the team of researchers examined the association between TV viewing and body mass index (BMI) and waist circumference (WST) over 15 years on 3,269 participants from the Coronary Artery Risk Development in Young Adults (CARDIA) study.
At year 5, mean age in the analysis sample was 29.9 ± 3.6 years. Younger people spent more time watching TV at baseline. People who watched more TV had lower diet scores and physical activity scores. Males were more likely to spend more time watching TV in comparison to females.
The results also showed that people from a Black background spent more time viewing TV compared to people from a White background (35.9% of Blacks versus. 8.6% of Whites in the ≥4 hour group).
People who had education beyond high school spent less time on TV viewing than those who had less education. People with an annual family income of ≥$50,000 were found to watch less TV compared to those with an annual family income of <$50,000. Smokers and alcohol drinkers ( ≥7 drinks/week) were more likely to engage in TV viewing in comparison to never smokers or alcohol drinkers.
The researchers used cross-lagged panel models at exam years 5, 10, 15, and 20 over 15 years to assess the association between TV viewing and obesity. Results revealed that the cross-lagged effects of TV viewing on anthropometry were significant from exam year 5 to year 10.
However, the cross-lagged effects of TV viewing at years 10 and 15 on obesity at years 15 and 20, respectively, were nonsignificant.
“Television viewing and obesity are both highly prevalent in many populations around the world,” said Dr. Fabio. “This means that even small reductions in television viewing could lead to vast public health improvements. Reducing sedentary time should be a healthy lifestyle guideline heavily promoted to the public. Our study indicates that the biggest bang for the buck would be in targeting young adults for interventions to reduce television viewing. Healthy lifestyle behaviors should start at early ages.”
According to the researchers, the study findings support the importance of reducing sedentary behaviors, especially TV viewing among young adults, for the prevention of obesity.