title: Effects of a Web-Based Personalized Intervention on Physical Activity in European Adults: A Randomized Controlled Trial.
abstract: BACKGROUND
  The high prevalence of physical inactivity worldwide calls for innovative and more effective ways to promote physical activity (PA). There are limited objective data on the effectiveness of Web-based personalized feedback on increasing PA in adults.
  
  
  OBJECTIVE
  It is hypothesized that providing personalized advice based on PA measured objectively alongside diet, phenotype, or genotype information would lead to larger and more sustained changes in PA, compared with nonpersonalized advice.
  
  
  METHODS
  A total of 1607 adults in seven European countries were randomized to either a control group (nonpersonalized advice, Level 0, L0) or to one of three personalized groups receiving personalized advice via the Internet based on current PA plus diet (Level 1, L1), PA plus diet and phenotype (Level 2, L2), or PA plus diet, phenotype, and genotype (Level 3, L3). PA was measured for 6 months using triaxial accelerometers, and self-reported using the Baecke questionnaire. Outcomes were objective and self-reported PA after 3 and 6 months.
  
  
  RESULTS
  While 1270 participants (85.81% of 1480 actual starters) completed the 6-month trial, 1233 (83.31%) self-reported PA at both baseline and month 6, but only 730 (49.32%) had sufficient objective PA data at both time points. For the total cohort after 6 months, a greater improvement in self-reported total PA (P=.02) and PA during leisure (nonsport) (P=.03) was observed in personalized groups compared with the control group. For individuals advised to increase PA, we also observed greater improvements in those two self-reported indices (P=.006 and P=.008, respectively) with increased personalization of the advice (L2 and L3 vs L1). However, there were no significant differences in accelerometer results between personalized and control groups, and no significant effect of adding phenotypic or genotypic information to the tailored feedback at month 3 or 6. After 6 months, there were small but significant improvements in the objectively measured physical activity level (P<.05), moderate PA (P<.01), and sedentary time (P<.001) for individuals advised to increase PA, but these changes were similar across all groups.
  
  
  CONCLUSIONS
  Different levels of personalization produced similar small changes in objective PA. We found no evidence that personalized advice is more effective than conventional "one size fits all" guidelines to promote changes in PA in our Web-based intervention when PA was measured objectively. Based on self-reports, PA increased to a greater extent with more personalized advice. Thus, it is crucial to measure PA objectively in any PA intervention study.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT01530139; http://clinicaltrials.gov/show/NCT01530139 (Archived by WebCite at: http://www.webcitation.org/6XII1QwHz).
authors.affiliation: Department of Human Biology, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre + (MUMC+), Maastricht, Netherlands. c.marsaux@maastrichtuniversity.nl.
authors.forename: Cyril Fm
authors.identifier: http://orcid.org/0000-0002-4725-6359
authors.initials: CF
authors.lastname: Marsaux
authors.forename: Carlos
authors.identifier: http://orcid.org/0000-0003-2612-3917
authors.initials: C
authors.lastname: Celis-Morales
authors.forename: Rosalind
authors.identifier: http://orcid.org/0000-0003-3734-6489
authors.initials: R
authors.lastname: Fallaize
authors.forename: Anna L
authors.identifier: http://orcid.org/0000-0003-0368-9336
authors.initials: AL
authors.lastname: Macready
authors.forename: Silvia
authors.identifier: http://orcid.org/0000-0002-8360-797X
authors.initials: S
authors.lastname: Kolossa
authors.forename: Clara
authors.identifier: http://orcid.org/0000-0001-6323-0012
authors.initials: C
authors.lastname: Woolhead
authors.forename: Clare B
authors.identifier: http://orcid.org/0000-0003-3367-6173
authors.initials: CB
authors.lastname: O'Donovan
authors.forename: Hannah
authors.identifier: http://orcid.org/0000-0001-5944-8027
authors.initials: H
authors.lastname: Forster
authors.forename: Santiago
authors.identifier: http://orcid.org/0000-0002-5163-2230
authors.initials: S
authors.lastname: Navas-Carretero
authors.forename: Rodrigo
authors.identifier: http://orcid.org/0000-0001-8054-6553
authors.initials: R
authors.lastname: San-Cristobal
authors.forename: Christina-Paulina
authors.identifier: http://orcid.org/0000-0001-8065-989X
authors.initials: CP
authors.lastname: Lambrinou
authors.forename: George
authors.identifier: http://orcid.org/0000-0003-3009-6675
authors.initials: G
authors.lastname: Moschonis
authors.forename: Agnieszka
authors.identifier: http://orcid.org/0000-0003-2189-9249
authors.initials: A
authors.lastname: Surwillo
authors.forename: Magdalena
authors.identifier: http://orcid.org/0000-0002-1891-7859
authors.initials: M
authors.lastname: Godlewska
authors.forename: Annelies
authors.identifier: http://orcid.org/0000-0002-4115-5186
authors.initials: A
authors.lastname: Goris
authors.forename: Jettie
authors.identifier: http://orcid.org/0000-0003-2442-4361
authors.initials: J
authors.lastname: Hoonhout
authors.forename: Christian A
authors.identifier: http://orcid.org/0000-0002-7216-2784
authors.initials: CA
authors.lastname: Drevon
authors.forename: Yannis
authors.identifier: http://orcid.org/0000-0001-6486-114X
authors.initials: Y
authors.lastname: Manios
authors.forename: Iwona
authors.identifier: http://orcid.org/0000-0002-0483-7778
authors.initials: I
authors.lastname: Traczyk
authors.forename: Marianne C
authors.identifier: http://orcid.org/0000-0002-6651-2434
authors.initials: MC
authors.lastname: Walsh
authors.forename: Eileen R
authors.identifier: http://orcid.org/0000-0001-9465-052X
authors.initials: ER
authors.lastname: Gibney
authors.forename: Lorraine
authors.identifier: http://orcid.org/0000-0002-7711-7499
authors.initials: L
authors.lastname: Brennan
authors.forename: J Alfredo
authors.identifier: http://orcid.org/0000-0001-5218-6941
authors.initials: JA
authors.lastname: Martinez
authors.forename: Julie A
authors.identifier: http://orcid.org/0000-0001-7633-9455
authors.initials: JA
authors.lastname: Lovegrove
authors.forename: Michael J
authors.identifier: http://orcid.org/0000-0001-5250-361X
authors.initials: MJ
authors.lastname: Gibney
authors.forename: Hannelore
authors.identifier: http://orcid.org/0000-0003-3937-9719
authors.initials: H
authors.lastname: Daniel
authors.forename: John C
authors.identifier: http://orcid.org/0000-0003-3406-3002
authors.initials: JC
authors.lastname: Mathers
authors.forename: Wim Hm
authors.identifier: http://orcid.org/0000-0003-0985-0047
authors.initials: WH
authors.lastname: Saris
mesh_terms: D000328:Adult; D000368:Aged; D005060:Europe; D005260:Female; D005838:Genotype; D006801:Humans; D020407:Internet / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D010641:Phenotype; D057285:Precision Medicine; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
keywords: Internet; eHealth; genotype; personalized nutrition; phenotype; physical activity; randomized controlled trial