TV habits in childhood may impact metabolic health in mid-adulthood

Children and teens who watch a lot of television often grow to be adults with metabolic syndrome, obesity, or poor fitness, according to a study.

“This association is independent of adult viewing, indicating that childhood television viewing has long-term adverse effects on metabolic health,” the investigators said.

Mean television viewing time between ages 5 and 15 years was positively associated with metabolic syndrome at 45 years of age in a model adjusted for sex, socioeconomic status, and body mass index (BMI) at age 5 (odds ratio [OR], 1.30, 95 percent confidence interval [CI], 1.08–1.58; p=0.006) and in a model further adjusted for adult television viewing (OR, 1.26, 95 percent CI, 1.03–1.54; p=0.026). [Pediatrics 2023;152:e2022060768]

Greater hours of television viewing between ages 5 and 15 years were also associated with lower cardiorespiratory fitness (p=0.007) and higher BMI (p=0.16) at 45 years of age.

The analysis included 879 participants, with their TV viewing time averaging just over 2 hours per weekday.

“Our findings … lend support to the idea of a sensitive period during childhood and adolescence, during which sedentary behaviours, such as television viewing, may have a greater influence on adult health than adult behaviours,” the investigators noted.

Mechanisms

How longer television viewing times could lead to poorer long-term health has several plausible explanations.

For the most part, “television viewing has low energy expenditure and could displace physical activity and reduce sleep quality,” said principal investigator Prof Bob Hancox of the Dunedin School of Medicine, University of Otago in Dunedin, New Zealand.

“Screentime may also promote higher energy intake, with children consuming more sugar-sweetened beverages and high-fat dietary products with fewer fruit and vegetables. These habits may persist into adulthood,” Hancox added.

Ideal screen time

Recent World Health Organization (WHO) guidelines recommend that children keep the amount of time being sedentary to a minimum, especially recreational screen time. However, WHO concluded that there was insufficient evidence for a dose-response association and did not specify a time limit. [https://apps.who.int/iris/handle/10665/336657]

“[O]ur cohort had few screen time options when they were growing up, limiting their exposure. [On the other hand], children today have access to many more screen-based media, greatly increasing the potential for sedentary behaviour,” with recent data indicating that children have higher screen times, Hancox pointed out. [Adolescent Health 2016;58:417-425; J Phys Act Health 2015;12:1102-1111; Prev Med Rep 2018;12:271-283]

Hancox and colleagues called for interventions to reduce the time that children and young people spend in screen-based activities and assess whether these interventions may have substantial long-lasting benefits for health.