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Factors affecting Factors affecting the attrition of the attrition of older people in older people in longitudinal (health longitudinal (health research) studies research) studies Anthea Tinker and Gill Mein on behalf of the team: Anthea Tinker, Gill Mein, Suneeta Bhamra, Richard Ashcroft, Clive Seale (and the late Janet Askham) Presentation of the findings of the research to the NatCen conference 23.3.09

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Factors affecting the Factors affecting the attrition of older people in attrition of older people in

longitudinal (health longitudinal (health research) studiesresearch) studies

Anthea Tinker and Gill Mein on behalf of the team:Anthea Tinker, Gill Mein, Suneeta Bhamra,

Richard Ashcroft, Clive Seale (and the late Janet Askham)

Presentation of the findings of the research to the NatCen conference 23.3.09

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The projectThe project Funded by Atlantic PhilanthropiesFunded by Atlantic Philanthropies For 9 months from 1For 9 months from 1stst March 2008 March 2008

(extended until 30.12.08)(extended until 30.12.08) Investigators from multidisciplinary Investigators from multidisciplinary

backgrounds (disciplines include social backgrounds (disciplines include social policy, sociology, philosophy, nursing, policy, sociology, philosophy, nursing, social sciences, biomedical ethics) social sciences, biomedical ethics)

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Rationale and research questionRationale and research question

The research question was:The research question was:

““What factors encourage older people to What factors encourage older people to remain as participants, or discourages remain as participants, or discourages them from continuing to participate in them from continuing to participate in

health related longitudinal or panel health related longitudinal or panel studies?”studies?”

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Aims Aims

The main aim of the research was to The main aim of the research was to provide guidance to research teams provide guidance to research teams planning or carrying out surveys about planning or carrying out surveys about ways of increasing retention of older ways of increasing retention of older participants and reducing drop out ratesparticipants and reducing drop out rates

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Some early issuesSome early issues What is a longitudinal study?What is a longitudinal study? How far back should the study go? We took current How far back should the study go? We took current

and completed studies within 20 yearsand completed studies within 20 years What ages should be taken into account? We have What ages should be taken into account? We have

taken 55+taken 55+ We have included only those that cover both men and We have included only those that cover both men and

womenwomen The use of proxies – some studies allow this and we The use of proxies – some studies allow this and we

have included studies where someone answered the have included studies where someone answered the questions on behalf of the respondent but not where questions on behalf of the respondent but not where the respondent was replaced by someone else. the respondent was replaced by someone else.

We included studies from the UK, Europe, North We included studies from the UK, Europe, North America and AustralasiaAmerica and Australasia

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MethodsMethods

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1. Literature Review1. Literature Review A review of existing qualitative and quantitative literature A review of existing qualitative and quantitative literature

on the retention of older people in longitudinal studies on the retention of older people in longitudinal studies that have met our criteriathat have met our criteria

Factors where there is relatively clear evidence of the Factors where there is relatively clear evidence of the association with attrition association with attrition

Factors where there is no clear evidence about the Factors where there is no clear evidence about the relationship with attritionrelationship with attrition

Reasons for drop-out in these studiesReasons for drop-out in these studies

How other longitudinal studies have tried to reduce drop-How other longitudinal studies have tried to reduce drop-out and retain older participantsout and retain older participants

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Literature review - Literature review - FindingsFindings

We found a larger number of studies than We found a larger number of studies than anticipated (45)anticipated (45)

Few studies mention attrition in publications.Few studies mention attrition in publications. A meta analysis of attrition based on 12 studies of A meta analysis of attrition based on 12 studies of

people aged 65 and over showed attrition was people aged 65 and over showed attrition was associated with being older, having poor functioning associated with being older, having poor functioning and cognitive impairment, living alone and not being and cognitive impairment, living alone and not being married (Chatfield et al, 2005)married (Chatfield et al, 2005)However this study did not examine all the variables However this study did not examine all the variables that we have and was limited to only 12 studiesthat we have and was limited to only 12 studies

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Literature review - FindingsLiterature review - FindingsThe following factors indicate that people are more likely to drop out of The following factors indicate that people are more likely to drop out of

longitudinal studies if:longitudinal studies if: They are olderThey are older They are cognitively impairedThey are cognitively impaired They are from a lower socio-economic statusThey are from a lower socio-economic status They have fewer years of educationThey have fewer years of education They do not have childrenThey do not have children They are not retiredThey are not retired They are less socially active e.g. clubsThey are less socially active e.g. clubsThe relationship of the following with attrition is unclear:The relationship of the following with attrition is unclear: GenderGender Marital statusMarital status Being in poor healthBeing in poor health Home ownershipHome ownership

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Literature review Literature review - findings- findings

Main reasons for drop-out:Main reasons for drop-out: Too time consuming - contact is too frequent Too time consuming - contact is too frequent Questionnaires - difficult, intrusive, humiliatingQuestionnaires - difficult, intrusive, humiliating Medical Exams - tiring, dislike of blood samples and Medical Exams - tiring, dislike of blood samples and

cognitive testscognitive testsDrop-out can be reduced by: Drop-out can be reduced by: Personal gestures – b’day cards, letters from PIPersonal gestures – b’day cards, letters from PI Feedback - on study progress and medical results Feedback - on study progress and medical results Emphasising importance of study – media coverageEmphasising importance of study – media coverage Incentives? - small gifts, monetaryIncentives? - small gifts, monetary Practical issues - home visits, transport to medicalsPractical issues - home visits, transport to medicals

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Questionnaires to researchers of Questionnaires to researchers of other longitudinal studiesother longitudinal studies

Questionnaires were sent to 38 studies which Questionnaires were sent to 38 studies which

included both men and women together, identified included both men and women together, identified from the literature review. 20 studies responded.from the literature review. 20 studies responded.

Researchers were asked about identifying Researchers were asked about identifying attrition, measuring attrition, and efforts to reduce attrition, measuring attrition, and efforts to reduce attrition. attrition.

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Questionnaires to researchers on Questionnaires to researchers on studies of older people studies of older people - findings- findings

Studies differed. Across country, locality based, Studies differed. Across country, locality based, organisation based. All were aware of attrition. organisation based. All were aware of attrition.

Very few had collected reasons for dropout. Few had Very few had collected reasons for dropout. Few had published details. published details.

Attrition was measured in a variety of ways Attrition was measured in a variety of ways comparison with baseline, between waves, annually.comparison with baseline, between waves, annually.

Participation was described differently in most studies Participation was described differently in most studies and terms used were: full, partially active, partially and terms used were: full, partially active, partially withdrawn, withdrawn, active, temporary refusal, and withdrawn, withdrawn, active, temporary refusal, and dead.dead.

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Methods used by other studies to Methods used by other studies to reduce attritionreduce attrition

Information:Information: newsletters, personal response to newsletters, personal response to queries, meetings, results feedback, queries, meetings, results feedback, study study websitewebsite

Incentives:Incentives: fridge magnets, pens, money, fridge magnets, pens, money, calendarscalendars

Contact:Contact: newsletters, information meetings, newsletters, information meetings, birthday cards, reminder telephone callsbirthday cards, reminder telephone calls

Efforts to reduce attrition: Efforts to reduce attrition: tracing lost participants, completing questionnaires tracing lost participants, completing questionnaires

online and a study website. Having local medical online and a study website. Having local medical examinations.examinations. Use close relatives/proxiesUse close relatives/proxies

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2. Secondary analysis of existing 2. Secondary analysis of existing datadata

The Whitehall II study (the Stress and Health Study) The Whitehall II study (the Stress and Health Study) of civil servants recruited from 20 London based of civil servants recruited from 20 London based departments in 1985, when participants were aged departments in 1985, when participants were aged between 35-55 years between 35-55 years

The original group =10,308 people (a response rate The original group =10,308 people (a response rate of 73%) of 73%)

Participants self complete questionnaires (every two Participants self complete questionnaires (every two years) and medical examinations (every 5 years) years) and medical examinations (every 5 years)

There have been other sub studies e.g. an MRI There have been other sub studies e.g. an MRI scan, vascular sub study etc.scan, vascular sub study etc.

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Secondary analysis of existing Secondary analysis of existing data data – Whitehall II Study– Whitehall II Study

The Whitehall II study was originally set up The Whitehall II study was originally set up to investigate the social gradient in health. to investigate the social gradient in health. It has particularly looked at the It has particularly looked at the relationship between stress, health and relationship between stress, health and occupational gradesoccupational grades

PI is Professor Sir Michael Marmot at PI is Professor Sir Michael Marmot at UCL. The Study uses newsletters to UCL. The Study uses newsletters to maintain contact and participationmaintain contact and participation

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The Whitehall study: Ethical The Whitehall study: Ethical issuesissues

All the active participants in the Whitehall II All the active participants in the Whitehall II study have given consent to being followed up. study have given consent to being followed up. The process for contacting them, interviews The process for contacting them, interviews etc have been approved by the UCL research etc have been approved by the UCL research ethics committeeethics committee

The PI is a participant in the Whitehall II study, The PI is a participant in the Whitehall II study, she will not have access to the data of her she will not have access to the data of her fellow participants except in an anonymised fellow participants except in an anonymised manner (this has been declared to the relevant manner (this has been declared to the relevant ethics committees)ethics committees)

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Secondary analysis of existing Secondary analysis of existing quantitative dataquantitative data

Quantitative Analysis Quantitative Analysis To see if we can determine what drop-out is related to To see if we can determine what drop-out is related to

and establish predictors of attrition (e.g. characteristics and establish predictors of attrition (e.g. characteristics of respondents) of respondents)

The choice of variables was guided by the literature The choice of variables was guided by the literature review and the variables available in the Whitehall II review and the variables available in the Whitehall II study data setstudy data set

We examined: age, gender, marital status, We examined: age, gender, marital status, accommodation type, education level, employment accommodation type, education level, employment grade, and longstanding illness (at baseline)grade, and longstanding illness (at baseline)

A comparison of those who have stated they doA comparison of those who have stated they donot wish to take any further part in the study (excluding not wish to take any further part in the study (excluding people who withdrew for other reasons e.g. death) with people who withdrew for other reasons e.g. death) with those who have continued to fully participatethose who have continued to fully participate

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Summary of statistical findingsSummary of statistical findings

Using Logistic regression we found attrition in the Whitehall II study is Using Logistic regression we found attrition in the Whitehall II study is associated with:associated with:

Having a lower occupational gradeHaving a lower occupational grade Being olderBeing older Being femaleBeing female Being unmarried at baselineBeing unmarried at baseline Engaging in fewer social activities at phase 5Engaging in fewer social activities at phase 5 Renting house from council or privately - unfurnished Renting house from council or privately - unfurnished

(rather than owning house or renting privately -furnished)(rather than owning house or renting privately -furnished) Being less educatedBeing less educated

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Secondary analysis of Secondary analysis of existing dataexisting data

Qualitative AnalysisQualitative Analysis An analysis of the Whitehall II data base of An analysis of the Whitehall II data base of comments from the views of participants comments from the views of participants who have dropped out of the study and who have dropped out of the study and their reasons for doing sotheir reasons for doing so

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Qualitative Analysis of existing Qualitative Analysis of existing Whitehall II Data - resultsWhitehall II Data - results

For those who withdrew from the study and left For those who withdrew from the study and left comments, the most frequent reasons for dropping comments, the most frequent reasons for dropping out were:out were:

Too busy/study takes up too much timeToo busy/study takes up too much time Journey is too long/difficultJourney is too long/difficult Chronic ill healthChronic ill health Being seen elsewhere e.g. GPBeing seen elsewhere e.g. GP No longer interested in study No longer interested in study RetirementRetirement Relocation or travellingRelocation or travelling

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3. The collection of new data3. The collection of new data

Using the Whitehall II study participants, a Using the Whitehall II study participants, a small qualitative study to gather data small qualitative study to gather data about people’s experiences of, and views about people’s experiences of, and views about, participating in longitudinal about, participating in longitudinal research.research.

Data was collected through 3 focus groups Data was collected through 3 focus groups and telephone interviews. and telephone interviews.

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Recruitment to focus groupsRecruitment to focus groups 100 invitations given to participants 100 invitations given to participants

attending the medical examinationattending the medical examination 35 responded 35 responded 5 refused5 refused 30 agreed to take part in focus group or 30 agreed to take part in focus group or

telephone interviewstelephone interviews 19 attended focus groups /or were 19 attended focus groups /or were

interviewed on the telephoneinterviewed on the telephone

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Focus groups - Focus groups - resultsresults

The transcriptions from the focus groups were The transcriptions from the focus groups were coded and themes were identified and were put coded and themes were identified and were put into categories of:into categories of:

Good and bad Good and bad experiences of the study experiences of the study (medical and questionnaire)(medical and questionnaire)

Motivating factors Motivating factors for continuing in the studyfor continuing in the study

Suggestions to make future participation Suggestions to make future participation easiereasier

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Focus group resultsFocus group results – – good thingsgood things

Liked having a medical examinationLiked having a medical examination Liked explanation of some of the testsLiked explanation of some of the tests Impressed with the offer of home visitsImpressed with the offer of home visits Liked flexible appt systemLiked flexible appt system Enjoyed meeting ex-colleaguesEnjoyed meeting ex-colleagues Appreciates use of headphones for people Appreciates use of headphones for people

who cannot hearwho cannot hear

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Focus group results Focus group results - bad things- bad things

The memory questions in the medical The memory questions in the medical examination made participants feel “stupid” examination made participants feel “stupid” “humiliated”“humiliated”

Lack of understanding of reasons for Lack of understanding of reasons for doing measuresdoing measures

Really disliked the questionnaire Really disliked the questionnaire Found the questions repetitive, did not like Found the questions repetitive, did not like

having to chose between boxes to answerhaving to chose between boxes to answer Lack of information about studyLack of information about study

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Focus group results Focus group results – – Motivation for continuing with the studyMotivation for continuing with the study

The most important factor was having a The most important factor was having a medical examinationmedical examination

Loved the prestige of being recognised as Loved the prestige of being recognised as part of the study, publicity, mediapart of the study, publicity, media

“ “Giving something back”Giving something back”

Enjoyed talking to friends/old colleagues Enjoyed talking to friends/old colleagues after medical examination – boosted after medical examination – boosted

confidence as all the sameconfidence as all the same

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Suggestions for the future from focus groups and Suggestions for the future from focus groups and telephone interviews (1).telephone interviews (1).

More information about themselves, in relation to More information about themselves, in relation to previous previous phases, the average, the population, the phases, the average, the population, the study in general study in general

Information about the study. How the study benefits Information about the study. How the study benefits others. Public presentation from PI others. Public presentation from PI

Increase the medical examination with popular tests Increase the medical examination with popular tests e.g. e.g. PSA, eye checks, hearing testsPSA, eye checks, hearing tests

Complete questionnaire onlineComplete questionnaire online

Have an online resource to answer participants Have an online resource to answer participants queries queries

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Suggestions for the future from focus groups Suggestions for the future from focus groups and telephone interviews (2)and telephone interviews (2)

Would like to be sent a set of memory test Would like to be sent a set of memory test questions to prepare beforehand!questions to prepare beforehand!

Would like questions to reflect retirement Would like questions to reflect retirement

Reduce the length of the questionnaireReduce the length of the questionnaire

Addressing travel and access to medical Addressing travel and access to medical examinationsexaminations

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Recommendations from the Recommendations from the Whitehall studyWhitehall study

Foster loyalty to the studyFoster loyalty to the study Invite people by departmentsInvite people by departments Introduce popular tests e.g. PSA, hearing, eyesIntroduce popular tests e.g. PSA, hearing, eyes Give more information, individual, comparisons Give more information, individual, comparisons

to average, to population. Pitch information to average, to population. Pitch information between lay and scientific. Presentation by PI.between lay and scientific. Presentation by PI.

Continue with, good refreshments, comfortable Continue with, good refreshments, comfortable examination surroundings and continue to offer examination surroundings and continue to offer home visitshome visits

Exit interview to record reasons for withdrawalExit interview to record reasons for withdrawal

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Recommendations contd.Recommendations contd. Continue to be flexible about support of Continue to be flexible about support of

travel needstravel needs Examine ways of shortening the Examine ways of shortening the

questionnairesquestionnaires Ask participants what would help them Ask participants what would help them

continue participating- more involvement continue participating- more involvement in questionnaires/medical testsin questionnaires/medical tests

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ConclusionConclusion Our major conclusion is that longitudinal studies Our major conclusion is that longitudinal studies

are facing serious problems of drop out and are are facing serious problems of drop out and are anxious to find ways of avoiding thisanxious to find ways of avoiding this

Our contacts with other studies, including the Our contacts with other studies, including the Whitehall II study indicate their willingness to Whitehall II study indicate their willingness to consider ways of retaining participants. We will consider ways of retaining participants. We will be producing a short summary to be widely be producing a short summary to be widely distributed of ways in which this might be distributed of ways in which this might be achievedachieved

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Further informationFurther informationArticle reporting the literature review Quality in Article reporting the literature review Quality in

Ageing (Vol 9 issue 4 Dec 2008)Ageing (Vol 9 issue 4 Dec 2008) [email protected]@kcl.ac.uk [email protected]@natcen.ac.uk [email protected]@sgul.kingston.ac.uk [email protected]@qmul.ac.uk [email protected]@qmul.ac.uk