title: Prospective study of sedentary behavior, risk of depression, and cognitive impairment.
abstract: BACKGROUND
  Modern-day lifestyles are characterized by large amounts of prolonged sedentary activities, which may pose a risk to health in its own right, although little is known about their effects on mental health. We examined the association between several types of common sedentary behaviors (TV viewing, Internet use, reading) and different aspects of mental health.
  
  
  METHODS
  We conducted a 2-yr follow-up of 6359 (age 64.9 ± 9.1 yr) men and women from the English Longitudinal Study of Ageing, a cohort of community-dwelling older adults. Self-reported TV viewing time, reading, and use of the Internet was assessed at baseline. Mental health was assessed using the eight-item Centre of Epidemiological Studies Depression scale to measure depressive symptoms and neuropsychological tests of memory and verbal fluency to assess cognitive function.
  
  
  RESULTS
  At baseline, TV viewing time (≥ 6 vs. <2 h · d(-1)) was associated with higher depressive symptoms (coefficient = 0.49, 95% confidence interval [CI] = 0.63 to 0.35) and poorer global cognitive function (coefficient = -1.16, 95% CI = -1.00 to -1.31). Conversely, participants using the Internet reported lower depressive symptoms (coefficient = -0.58, 95% CI = -0.50 to -0.66) and higher global cognitive function (coefficient = 1.27, 95% CI = 1.37 to 1.18). There was no association between any sedentary behaviors at baseline and change in mental health measures over follow-up, suggesting that the difference in scores persisted but did not increase over time.
  
  
  CONCLUSIONS
  Some, but not all sedentary behaviors, are linked to adverse mental health. It is likely that these associations are being driven by the contrasting environmental and social contexts in which they occur.
authors.affiliation: 1Population Health Domain Physical Activity Research Group, Department of Epidemiology and Public Health, University College London, London, UNITED KINGDOM; 2School for Physiology, Nutrition and Consumer Sciences, North-West University, Potchefstroom, SOUTH AFRICA; and 3Prevention Research Collaboration, School of Public Health, University of Sydney, Sydney, AUSTRALIA.
authors.forename: Mark
authors.initials: M
authors.lastname: Hamer
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Stamatakis
mesh_terms: D000368:Aged; D003072:Cognition Disorders / Q000523:psychology*; D003863:Depression / Q000523:psychology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020407:Internet; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011932:Reading; D012307:Risk Factors; D057185:Sedentary Behavior; D013690:Television