Television viewing habits and leisure-time physical activity at the age of 16 years independently predicts….
Television viewing habits and leisure-time physical activity at the age of 16 years independently predicts the metabolic syndrome at age 43, according to the first prospective study to examine this.
Patrik Wennberg, PhD, from Umeå University, Sweden, and colleagues in their article stated that, the work "supports previous findings" and, for TV viewing and subsequent metabolic risk, "provides new evidence that this association may stretch over a considerable proportion of the lifespan: from adolescence to mid-adulthood."
The researchers also believe that separate mechanisms may be at play here for TV-viewing and physical-activity habits, because these activities were linked to different metabolic-syndrome components.
Nevertheless, the findings "suggest that reduced TV viewing in adolescence, in addition to regular physical activity, may contribute to cardiometabolic health later in life," they state.
TV viewing habits and leisure-time physical activity at age 16 years were assessed by self-administered questionnaires in a population-based cohort. The presence of the metabolic syndrome at age 43 years was ascertained in 888 participants (82% of the baseline sample) using the International Diabetes Federation (IDF) criteria, defined as a waist circumference 80 cm or greater for women and 94 cm or greater for men and 2 or more of the following criteria:
- Increased triglycerides (1.7 mmol/L or greater) or specific treatment for that lipid abnormality.
- Reduced high-density lipoprotein (HDL) cholesterol (less than 1.29 mmol/L for women and less than 1.03 mmol/L for men) or specific treatment for that lipid abnormality.
- Increased blood pressure (systolic BP 130 mm Hg or greater or diastolic 85 mm Hg or greater) or treatment of hypertension.
- Increased fasting glucose (5.6 mmol/L or greater) or diagnosed type 2 diabetes.
Metabolic syndrome was identified in 26.9% of participants. Those who reported "watching several [TV] shows a day" at 16 were twice as likely to have the metabolic syndrome at age 43 than those who said they watched "1 show/week" or less (adjusted odds ratio [OR], 2.14). Similarly, those who noted leisure-time physical activity "several times per month" were more likely to have metabolic syndrome later in life than those who reported "daily" leisure-time physical activity in their teens (OR, 2.31).
Dr. Wennberg writes that, "Our results suggest a dose-response relationship for both TV viewing and leisure-time physical activity with subsequent cardiometabolic risk."
TV viewing at age 16 years was linked to central obesity, low HDL cholesterol, and hypertension at age 43 years. Low leisure-time physical activity in the teen years was associated with central obesity and raised triglycerides later in life. These observations suggest that associations between TV viewing/sedentary behavior and physical activity with subsequent metabolic risk may be mediated via different cardiometabolic pathways, the authors say.
This possibility means that "different strategies may need to be adopted" with regard to interventions targeting sedentary behavior, such as TV viewing, and those aiming to increase leisure-time physical activity, they note.
"Reduced TV viewing in adolescence, in addition to and independently of regular leisure-time physical activity in adolescence and adulthood, may contribute to cardiometabolic health later in life," the authors conclude.
Diabetes Care. Published online January 22, 2013. Abstract