Television Viewing and Low Leisure-Time Physical Activity in Adolescence Independently Predict the Metabolic Syndrome in Mid-Adulthood

OBJECTIVE

We investigated whether television (TV) viewing and low leisure-time physical activity in adolescence predict the metabolic syndrome in mid-adulthood.

RESEARCH DESIGN AND METHODS

TV viewing habits and participation in leisure-time physical activity at age 16 years were assessed by self-administered questionnaires in a population-based cohort in Northern Sweden. 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 criteria. Odds ratios (ORs) and CIs were calculated using logistic regression.

RESULTS

The overall prevalence of the metabolic syndrome at age 43 years was 26.9%. Adjusted OR for the metabolic syndrome at age 43 years was 2.14 (95% CI 1.24–3.71) for those who reported “watching several shows a day” versus “one show/week” or less and 2.31 (1.13–4.69) for leisure-time physical activity “several times/month” or less compared with “daily” leisure-time physical activity at age 16 years. TV viewing at age 16 years was associated with central obesity, low HDL cholesterol, and hypertension at age 43 years, whereas low leisure-time physical activity at age 16 years was associated with central obesity and triglycerides at age 43 years.

CONCLUSIONS

Both TV viewing and low leisure-time physical activity in adolescence independently predicted the metabolic syndrome and several of the metabolic syndrome components in mid-adulthood. These findings suggest that reduced TV viewing in adolescence, in addition to regular physical activity, may contribute to cardiometabolic health later in life.Current public health guidelines recommend moderate-intensity aerobic physical activity for a minimum of 30 min on 5 days each week or vigorous-intensity aerobic physical activity for a minimum of 20 min on 3 days each week to promote and maintain health (1). Aside from this, sedentary behavior such as prolonged sitting during commuting and in the workplace and the domestic environment has recently emerged as a distinct contributor to adverse health effects, particularly for cardiometabolic outcomes (2). On the physical activity continuum, sedentary behaviors do not simply exist at one end but, rather, are a class of behaviors that can coexist and compete with physical activity (3). Changes in television (TV)-viewing levels (a common leisure-time sedentary behavior) have been associated with concurrent changes in cardiometabolic biomarkers that are independent of the protective effects of regular moderate- to vigorous-intensity physical activity (4). Generally, evidence for a physical activity–independent link between TV viewing and cardiometabolic outcomes has been generated from cross-sectional analyses. Few longitudinal studies have been conducted, and a recently published review concluded that there is insufficient evidence to conclude that a definitive longitudinal relationship exists between sedentary behavior, markers of cardiometabolic health, and metabolic conditions (2). Moreover, there is a lack of prospective studies that have examined the relationship between sedentary behaviors during childhood or adolescence and adult cardiometabolic risk. One of the few longitudinal studies with a life course perspective showed that TV viewing in childhood was associated with raised cholesterol and overweight in adulthood (5). However, the individuals were not followed longer than up to age 26 years. Thus, although interventions to reduce TV viewing in children have shown promising short-term results (6), uncertainty remains as to whether preventive actions during childhood and adolescence may have an impact on cardiometabolic risk in adulthood.The aim of this study was to investigate whether TV viewing and low leisure-time physical activity in adolescence predict the metabolic syndrome in mid-adulthood. We also aimed to examine the extent to which leisure-time physical activity in mid-adulthood mediates the relationships of TV viewing and low leisure-time physical activity in adolescence with the metabolic syndrome in mid-adulthood.