Moderate to Vigorous Physical Activity and Sedentary Time and Cardiometabolic Risk Factors in Children and Adolescents
Study Questions:
Do physical activity and sedentary time impact cardiometabolic factors in healthy children?
Methods:
This study used data pooled from the International Children’s Accelerometry Database. A total of 14 studies conducted between 1998 and 2009, with 20,871 children (ages 4-18 years), were included. Physical activity and sedentary time were measured through accelerometers. Primary outcomes of interest included waist circumference, systolic blood pressure, fasting triglycerides, high-density lipoprotein cholesterol, and insulin.
Results:
The number of minutes per day of sedentary time averaged 354 minutes, whereas the number of minutes per day of moderate to vigorous physical activity averaged 30 minutes. Time spent in performing moderate to vigorous activity was independently associated with several cardiometabolic outcomes after controlling for several variables including age, gender, and waist circumference. In contrast, time spent in sedentary activities was not associated with cardiometabolic factor after adjusting for moderate to vigorous physical activity. Mean differences in waist circumference between the bottom and top tertiles of moderate to vigorous physical activity were 5.6 cm (95% confidence interval [CI], 4.8-6.4 cm) for high sedentary time and 3.6 cm (95% CI, 2.8-4.3 cm) for low sedentary time. Mean differences in systolic blood pressure for high and low sedentary time were 0.7 mm Hg (95% CI, −0.07 to 1.6) and 2.5 mm Hg (95% CI, 1.7-3.3), and for high-density lipoprotein cholesterol, differences were −2.6 mg/dl (95% CI, −1.4 to −3.9) and −4.5 mg/dl (95% CI, −3.3 to −5.6), respectively. Differences for insulin and triglycerides demonstrated similar patterns. Those in the top tertile of moderate to vigorous physical activity accumulated more than 35 minutes per day in this intensity level compared with fewer than 18 minutes per day for those in the bottom tertile. In prospective analyses (n = 6,413 at 2.1-year follow-up), moderate to vigorous physical activity and sedentary time were not associated with waist circumference at follow-up, but a higher waist circumference at baseline was associated with higher amounts of sedentary time at follow-up.
Conclusions:
The investigators concluded that higher levels of moderate to vigorous physical activity time by children and adolescents was associated with better cardiometabolic risk factors regardless of the amount of sedentary time.
Perspective:
These data highlight the importance of regular physical activity. Given the popularity of sedentary pursuits (such as video games) among children and adolescents, finding time for moderate to vigorous activity, such as with regular gym classes, is of public health importance.
Keywords: Child, Cholesterol, Waist Circumference, Video Games, Insulin, Accelerometry, Cardiovascular Diseases, Lipoproteins, Blood Pressure, Triglycerides
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