{
  "abstract": "Objectives To investigate the response to an invitation to participate in a blended mobile Health intervention among adults living in deprived areas.Design Secondary analysis of recruitment data from a randomised controlled trial.Setting A primary care population from disadvantaged geographies in the UK.Participants Individuals in mid-to-late life at increased risk of developing dementia based on their risk profile.Interventions Invitation by letter from GP, followed by a text reminder by phone.Main outcome measures (1) Response rate to the invitation. (2) Association of response with GP practice size, area-level deprivation and COVID-19 restrictions. (3) Reasons for non-participation.Univariate linear regression analyses were performed to assess the association between practice size and area deprivation (Index of Multiple Deprivation), with positive response rates per GP practice. The impact of COVID-19 isolation policies was assessed visually by comparing positive response rates across different restriction phases.Results Of the 13 814 invited participants, 12 816 (93%) did not respond. Of the 998 (7%) who responded, 690 (69%) were willing to participate (positive response), while 308 (31%) declined (negative response). Of the 308 negative responders, 209 provided a reason for not being willing or able to participate. The most frequently cited reason was the requirement to use a smartphone (40%), with 33% reporting they did not have a smartphone or internet access and 7% stating that they were unable or willing to use one. There was no association between response rate and COVID-19 restrictions on public life.Conclusions In deprived areas, most people invited to participate in a dementia prevention study via their GP practice did not respond. Smartphone use emerged as a barrier to participation in this population. Our results suggest that major efforts are needed to reduce participation bias, increase generalisability of study results and address health inequalities in preventive interventions.Trial registration number ISRCTN15986016.",
  "authors": [
    {
      "affiliations": [
        "Department of Psychiatry, University of Cambridge, Cambridge, UK"
      ],
      "name": "Rachael Brooks"
    },
    {
      "affiliations": [
        "Department of Public and Occupational Health, Amsterdam Public Health Research Institute, Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, The Netherlands"
      ],
      "name": "Marieke P Hoevenaar-Blom"
    },
    {
      "affiliations": [
        "Aging team, Center for Epidemiology and Research in Population Health (CERPOP), University of Toulouse-INSERM UMR1295, Toulouse, France",
        "Department of Epidemiology and Public Health, Toulouse University Hospital, Toulouse, France",
        "IHU HealthAge, Toulouse, France"
      ],
      "name": "Nicola Coley"
    },
    {
      "affiliations": [
        "Department of Public and Occupational Health, Amsterdam Public Health Research Institute, Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, The Netherlands",
        "Department of General Practice, Amsterdam Public Health Research Institute, Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, The Netherlands"
      ],
      "name": "Eric P Moll van Charante"
    },
    {
      "affiliations": [
        "Department of Psychiatry, University of Cambridge, Cambridge, UK"
      ],
      "name": "Linda Barnes"
    },
    {
      "affiliations": [
        "Department of General Practice, Amsterdam Public Health Research Institute, Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, The Netherlands",
        "Department of Neurology, Radboud University Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands"
      ],
      "name": "Edo Richard"
    },
    {
      "affiliations": [
        "Department of Psychiatry, University of Cambridge, Cambridge, UK"
      ],
      "name": "Carol Brayne"
    },
    {
      "affiliations": [
        "Department of Psychiatry, University of Cambridge, Cambridge, UK",
        "Department of Public and Occupational Health, Amsterdam Public Health Research Institute, Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, The Netherlands",
        "Aging team, Center for Epidemiology and Research in Population Health (CERPOP), University of Toulouse-INSERM UMR1295, Toulouse, France",
        "Department of Epidemiology and Public Health, Toulouse University Hospital, Toulouse, France",
        "IHU HealthAge, Toulouse, France",
        "Department of General Practice, Amsterdam Public Health Research Institute, Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, The Netherlands",
        "Department of Neurology, Radboud University Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands"
      ],
      "name": "on behalf of the PRODEMOS consortium"
    },
    {
      "affiliations": [],
      "name": "The PRODEMOS consortium"
    }
  ],
  "title": "Smartphone barrier: uncovering the digital divide in mHealth prevention among disadvantaged middle-aged and older-aged UK communities",
  "uid": "a1e8f2af-4285-54dd-bb41-21b34bfc495f"
}