title: Combined effect of physical activity and leisure time sitting on long-term risk of incident obesity and metabolic risk factor clustering.
abstract: OBJECTIVE
  Our study aimed to investigate the combined effects of moderate-to-vigorous physical activity and leisure time sitting on the long-term risk of obesity and clustering of metabolic risk factors.
  
  
  METHODS
  The duration of moderate and vigorous physical activity and of leisure time sitting was assessed by questionnaire between 1997 and 1999 among 3,670 participants from the Whitehall II cohort study (73% male; mean age 56 years). Multivariable-adjusted logistic regression models examined associations of physical activity and leisure time sitting tertiles with odds of incident obesity (BMI ≥ 30 kg/m(2)) and incident metabolic risk factor clustering (two or more of the following: low HDL-cholesterol, high triacylglycerol, hypertension, hyperglycaemia, insulin resistance) at 5 and 10 year follow-ups.
  
  
  RESULTS
  Physical activity, but not leisure time sitting, was associated with incident obesity. The lowest odds of incident obesity after 5 years were observed for individuals reporting both high physical activity and low leisure time sitting (OR = 0.26; 95% CI 0.11, 0.64), with weaker effects after 10 years. Compared with individuals in the low physical activity/high leisure time sitting group, those with intermediate levels of both physical activity and leisure time sitting had lower odds of incident metabolic risk factor clustering after 5 years (OR 0.53; 95% CI 0.36, 0.78), with similar odds after 10 years.
  
  
  CONCLUSIONS
  Both high levels of physical activity and low levels of leisure time sitting may be required to substantially reduce the risk of obesity. Associations with developing metabolic risk factor clustering were less clear.
authors: Department of Epidemiology and Public Health, University College London, 1-19 Torrington Place, London, WC1E 6BT, UK, joshua.bell.11@ucl.ac.uk.
authors: Joshua A
authors: JA
authors: Bell
authors: Mark
authors: M
authors: Hamer
authors: G David
authors: GD
authors: Batty
authors: Archana
authors: A
authors: Singh-Manoux
authors: Séverine
authors: S
authors: Sabia
authors: Mika
authors: M
authors: Kivimaki
mesh_terms: D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007899:Leisure Activities; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology*; D012307:Risk Factors; D057185:Sedentary Behavior; D011795:Surveys and Questionnaires