Habitual active transport, TV viewing and weight gain: A four year follow-up study

Abstract

ObjectivesTo examine the associations of TV viewing time and domain-specific physical activity with weight change; to determine whether domain-specific physical activity moderates the potential association of TV viewing time with weight change. MethodsWe used four-year longitudinal data (baseline: 2003–2004, follow-up: 2007–2008) on 969 adults from selected neighborhoods in Adelaide, Australia (Age: 48.6±10.6years, 61% females). Mixed models examined four-year weight change as the dependent variable, with TV viewing time, habitual transport and past week domain-specific physical activity at baseline as independent variables. ResultsOn average, participants gained 1.6kg over four years. TV viewing time at baseline was positively associated with weight gain at follow-up. Each additional hour of TV viewing was associated with 0.24–0.27kg of extra weight gain. This relationship was not moderated by recent recall of transport, leisure-time, and occupational physical activity, but was moderated by habitual transport: an additional hour of TV viewing time at baseline was significantly associated with an extra weight gain of 0.65kg at follow-up among those who were inactive in everyday transport; TV time was not significantly associated with weight change among those who were regularly active in transport. ConclusionHabitual active transport may protect adults against risk of weight gain associated with prolonged TV viewing time.