Objective: To examine the longitudinal association between sedentary behaviors and risk of development of depressive symptoms.
Patients and methods: The study population consisted of 4802 participants in the Aerobics Center Longitudinal Study (1012 women and 3790 men) aged 18 to 80 years who did not report depressive moods when they completed a health survey during 1982 in which they reported their time spent watching television (TV) and riding in a car each week. All participants completed a follow-up health survey when they responded to the 10-item Center for Epidemiologic Studies Depression Scale. Those who scored 8 or more on the Center for Epidemiologic Studies Depression Scale were considered to have depressive symptoms.
Results: Among the 4802 participants, 568 reported depressive symptoms during a mean follow-up of 9.3 years. After multivariate adjustment including moderate- and vigorous-intensity physical activity, time riding in a car, time watching TV, and combined time spent in the 2 sedentary behaviors were positively associated with depressive symptoms (each P<.05 for trend). Individuals who reported 9 h/wk or more riding in a car, more than 10 h/wk watching TV, or 19 h/wk or more of combined sedentary behavior had 28%, 52%, and 74% greater risk of development of depressive symptoms than those who reported less than 5 h/wk, less than 5 h/wk, or less than 12 h/wk, respectively, after adjusting for baseline covariates and moderate- and vigorous-intensity physical activity. The positive association between time riding in a car or time watching TV and depressive symptoms was only observed among individuals who did not meet the current physical activity guidelines.
Conclusion: More time reported in these 2 sedentary behaviors was positively associated with depressive symptoms. However, the direct associations between time spent in car riding and TV viewing and depressive symptoms were only significant among those who did not meet the current physical activity recommendations.
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