title: Physical activity, sedentary time and gain in overall and central body fat: 7-year follow-up of the ProActive trial cohort.
abstract: OBJECTIVE
  The objective of this study is to examine the independent associations of time spent in moderate-to-vigorous physical activity (MVPA) and sedentary (SED-time), with total and abdominal body fat (BF), and the bidirectionality of these associations in adults at high risk of type 2 diabetes.
  
  
  METHODS
  We measured MVPA (min per day) and SED-time (h per day) by accelerometry, and indices of total (body weight, fat mass (FM), BF% and FM index) and abdominal BF (waist circumference (WC)) using standard procedures in 231 adults (41.3 ± 6.4 years) with parental history of type 2 diabetes (ProActive UK) at baseline, 1-year and 7-year follow-up. Mixed effects models were used to quantify the independent associations (expressed as standardised β-coefficients (95% confidence interval (CI))) of MVPA and SED-time with fat indices, using data from all three time points. All models were adjusted for age, sex, intervention arm, monitor wear time, follow-up time, smoking status, socioeconomic status and MVPA/SED-time.
  
  
  RESULTS
  MVPA was inversely and independently associated with all indices of total BF (for example, 1 s.d. higher MVPA was associated with a reduction in FM, β = -0.09 (95% CI: -0.14, -0.04) s.d.) and abdominal BF (for example, WC: β = -0.07 (-0.12, -0.02)). Similarly, higher fat indices were independently associated with a reduction in MVPA (for example, WC: β = -0.25 (-0.36, -0.15); FM: β = -0.27 (-0.36, -0.18)). SED-time was positively and independently associated with most fat indices (for example, WC: β = 0.03 (-0.04, 0.09); FM: β = 0.10 (0.03, 0.17)). Higher values of all fat indices independently predicted longer SED-time (for example, WC: β = 0.10 (0.02, 0.18), FM: β = 0.15 (0.07, 0.22)).
  
  
  CONCLUSIONS
  The associations of MVPA and SED-time with total and abdominal BF are bidirectional and independent among individuals at high risk for type 2 diabetes. The association between BF and MVPA is stronger than the reciprocal association, highlighting the importance of considering BF as a determinant of decreasing activity and a potential consequence. Promoting more MVPA and less SED-time may reduce total and abdominal BF.
authors.affiliation: Medical Research Council Epidemiology Unit, University of Cambridge School of Clinical Medicine, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: R
authors.initials: R
authors.lastname: Golubic
authors.affiliation: Medical Research Council Epidemiology Unit, University of Cambridge School of Clinical Medicine, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: K
authors.initials: K
authors.lastname: Wijndaele
authors.affiliation: Medical Research Council Epidemiology Unit, University of Cambridge School of Clinical Medicine, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: S J
authors.initials: SJ
authors.lastname: Sharp
authors.affiliation: Medical Research Council Epidemiology Unit, University of Cambridge School of Clinical Medicine, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: R K
authors.initials: RK
authors.lastname: Simmons
authors.affiliation: Medical Research Council Epidemiology Unit, University of Cambridge School of Clinical Medicine, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: S J
authors.initials: SJ
authors.lastname: Griffin
authors.affiliation: Medical Research Council Epidemiology Unit, University of Cambridge School of Clinical Medicine, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: N J
authors.initials: NJ
authors.lastname: Wareham
authors.affiliation: 1] Medical Research Council Epidemiology Unit, University of Cambridge School of Clinical Medicine, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK [2] Department of Sport Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors.forename: U
authors.initials: U
authors.lastname: Ekelund
authors.affiliation: Medical Research Council Epidemiology Unit, University of Cambridge School of Clinical Medicine, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: S
authors.initials: S
authors.lastname: Brage
mesh_terms: D061725:Accelerometry; D050154:Adiposity; D000328:Adult; D002318:Cardiovascular Diseases / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D019317:Evidence-Based Medicine; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D007722:Health Knowledge, Attitudes, Practice; D006293:Health Promotion; D006801:Humans; D008297:Male; D009765:Obesity / Q000150:complications / Q000378:metabolism / Q000517:prevention & control*; D012307:Risk Factors; D057185:Sedentary Behavior; D013997:Time Factors; D055105:Waist Circumference; D015430:Weight Gain
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