Metabolic syndrome (MetS) is an increasingly common condition, with about 3% and 5% of children and adolescents, respectively, diagnosed with the condition in recent years. A new study published in the journal BMC Public Health examines the impact of a sedentary lifestyle and increased screen time on MetS among young Chinese individuals.
Study: Association between sedentary behavior, screen time and metabolic syndrome among Chinese children and adolescents. Image Credit: Pressmaster / Shutterstock.com
What is MetS?
MetS refers to a cluster of abnormal metabolic parameters, including abdominal obesity, hypertension, high triglyceride (TG) levels, low high-density lipoprotein cholesterol (HDL-C) levels, and insulin resistance with impaired glucose tolerance or type 2 diabetes mellitus. MetS is also associated with an increased risk of cardiovascular disease (CVD).
The rising prevalence of MetS among children and adolescents has increased concern among public health professionals. Childhood is a crucial intervention period for long-term health; therefore, identifying potentially modifiable risk factors for MetS, such as sedentary behavior and screen time, is vital.
A sedentary lifestyle is one in which the individual expends 1.5 metabolic equivalent tasks or less. A recent survey revealed that 25% of boys and girls sit for over three hours daily, in addition to time spent sitting while completing schoolwork and homework. Moreover, the World Health Organization (WHO) estimates that over 80% of teenagers worldwide do not participate in sufficient physical activity.
Screen time is associated with higher rates of chronic disease, insomnia, and mental health disorders. Almost all American teenagers own or can access a smartphone, while up to 70% of European children between 11 and 15 years of age watch television. Computer gaming for two or more hours daily is reported in up to 66% of young European boys, depending on the country, compared to 11-47% of girls.
About the study
The current study investigates how sedentary behavior and screen time are associated with MetS among young Chinese people between seven and 17. Data were obtained from the survey conducted as part of the China National Nutrition and Health Surveillance of Children and Lactating Mothers between 2016 and 2017.
What did the study show?
Among the 58,712 children included in the current study, 5.5% were diagnosed with MetS, whereas 15.6%, 15.9%, 11.3%, 1.6%, and 38.1% were diagnosed with abdominal obesity, high TG, low HDL-C, hyperglycemia, or high blood pressure, respectively.
Residing in urban areas, being of an older age, and higher levels of sedentary time and screen time were associated with a greater risk of MetS. Moreover, higher sedentary time was associated with a greater prevalence of abdominal obesity, high TG, low HDL-C, and MetS in boys. Increased screen time was also associated with a greater risk of abdominal obesity, low HDL-C, and MetS in boys, whereas abdominal obesity and MetS were more likely to occur in girls who reported three or more hours of screen time daily.
After compensating for confounding factors, those who were sedentary most of the time had a 40% increased risk of abdominal obesity compared to less sedentary children. The likelihood of high TG and low HDL-C levels also increased by 16% and 12% among more sedentary children. With three or more hours of screen time daily, the risk of abdominal obesity and MetS increased by approximately 15%.
Conclusions
The current study is the first national-level study to identify connections between sedentary habits, screen time, and MetS among students. To this end, a 5.5% prevalence of MetS was reported in children between the ages of seven and 17, compared to 2.4% of children diagnosed with MetS in Beijing and Guangzhou. These differences may be due to different ages, MetS criteria, and geographic locations between studies.
The current findings align with most previous studies, except one that reported a lack of an association between abdominal obesity and sedentary behaviors. The observed association in the present study is biologically plausible, as abdominal obesity is the most common sign of MetS.
In order to avoid MetS, students, parents and schools should work together to develop a healthy lifestyle to reduce sedentary behavior and screen time.”
Additional studies should incorporate objective measures through the use of inclinometers and accelerometers, in addition to self-reported measures. These tools are associated with limitations, such as imprecise cutoff values and low compliance, thus necessitating a combination approach. Future studies should also distinguish between sedentary time spent in front of a screen and other sedentary time.
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