title: Physical activity and sedentary behaviour at different life stages and adult blood pressure in the 1958 British cohort.
abstract: OBJECTIVE
  To investigate whether physical activity or sedentary behaviour at different life stages is associated with blood pressure (BP) in mid-adulthood; activity levels have accumulative associations with BP; and adult body mass index (BMI) mediates associations.
  
  
  METHODS
  Information on activity and television-viewing was available at several ages (23, 33, 42, 45 years) and BP at 45 years for the 1958 British birth cohort (n = 9927). Associations were examined with and without adjustment for covariates.
  
  
  RESULTS
  Active adults, generally, had lower mean systolic and diastolic BP and risk of hypertension than nonactive, although varying by age. After adjustment for covariates, systolic and diastolic BP for active men at 23 years or at 45 years were 1-2 mmHg lower; similar associations were seen for women active at 33 years. Some but not all associations attenuated with further adjustment for BMI: odds ratio (OR) for hypertension associated with 23 years activity changed from 0.82 [95% confidence interval (CI) 0.74, 0.91] to 0.79 (0.70, 0.90) after BMI adjustment. Independent associations of activity at more than one age were found, such that prevalence of hypertension was higher in men active at 23 years but not at 45 years, than men sustaining activity (39 vs. 31%). Sitting at work was unrelated to BP, but there was a trend of higher BP with greater television-viewing: for example risk of hypertension was higher by 10-12% per h/day television-viewing at 45 years after adjustment for covariates, attenuating after allowance for BMI.
  
  
  CONCLUSIONS
  Our study suggests that there are benefits to BP of becoming and sustaining active lifestyles and minimizing television-viewing over many years of adulthood, with a mediating role for BMI.
authors.affiliation: MRC Centre of Epidemiology for Child Health, Centre for Paediatric Epidemiology and Biostatistics, UCL Institute of Child Health, UK.
authors.forename: Theodora
authors.initials: T
authors.lastname: Pouliou
authors.forename: Myung
authors.initials: M
authors.lastname: Ki
authors.forename: Catherine
authors.initials: C
authors.lastname: Law
authors.forename: Leah
authors.initials: L
authors.lastname: Li
authors.forename: Chris
authors.initials: C
authors.lastname: Power
mesh_terms: D000328:Adult; D001794:Blood Pressure; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity; D057185:Sedentary Behavior; D006113:United Kingdom