Biomarker Measurements in the LISS Panel. Mauricio Avendano Arie Kapteyn Johan Mackenbach Annette Scherpenzeel Stephanie Stam

Transcription

1 Biomarker Measurements in the LISS Panel Mauricio Avendano Arie Kapteyn Johan Mackenbach Annette Scherpenzeel Stephanie Stam

2 LISS panel (part of the MESS project) Online panel of 5000 households For scientific use, at no cost Questionnaires every month Seven year longitudinal study Probability sample including households without internet access London, April

3 Two experiments The first experiment followed strict medical protocols and involved both invasive and noninvasive measurements: Blood cholesterol levels Diurnal salivary cortisol Waist circumference The second experiment only involved waist circumference and varies the protocol and incentives London, April

4 Experiment 1 Can biomarkers be collected in an Internet survey?

5 Pilot study by Mackenbach & Avendano, Erasmus MC Overview most commonly collected biomarkers in surveys Evaluation with respect to: Respondent burden and invasiveness Health risk Ease of sample collection (protocol, costs) London, April

6 Choice of biomarkers for pretest Blood cholesterol levels Diurnal salivary cortisol Waist circumference London, April

7 Protocol cholesterol and waist Participation request Eligibility Brochure and consent form Home kit and video Measurement Report outcome 5 euro Questionnaire about test Feedback London, April

8 Protocol salivary cortisol Participation request Eligibility Brochure and consent form Home kit and video Measurement Report times of testing Return samples London, April

9 Self-test 1 Easy Home Test Cholesterol HVZR TM Puncture finger with lancet Drop of blood on test device Level of total cholesterol and HDL cholesterol London, April

10 Self-test 2 Salivettes with cotton roll Chew 45 seconds on cotton roll Five points of a single day Return salivettes by mail: laboratory London, April

11 Self-test 3 Measuring tape (cm and inches) Designed by Centre for Obesity Research and Education, Queen s University in Canada London, April

12 All three tests Video instruction, especially developed for all three tests After login on respondent s LISS panel startpage London, April

13 London, April

14 Analysis Response and participation rates Range and distributions of outcome values Relation with demographics London, April

15 Response cholesterol test Baseline sample N=200 N=192 8 (4%) not eligible N=139 (70%) 61 (30%) did not respond to first invitation N=82 (41%) 49 (24%) did not agree to participate N=38 Response rate=19% 44 (22%) did not report result or return consent form N=31 7 (4%) had invalid values Final sample=16% London, April

16 Response cortisol and waist circumference test Cortisol: similar to cholesterol test Response rate=15.0% Final sample N=30 Waist: higher final response Response rate=26.5% Final sample N=53 Nonresponse and refusal similar to cholesterol/cortisol, but more consent and completed tests results London, April

17 Experiment 2: The Waist Circumference Experiment Purpose of the experiment is to investigate which procedures yield high response rates for simple non-invasive self-administered biomarker measurements Waist Circumference as an example Treatments vary on a number of dimensions: heavy or light procedures; written or electronic consent; The number of steps involved Incentive levels Promised feedback or not London, April

18 The most involved procedure Announcement in panel and mention of incentive ( 5, 15, 30) Electronic ( ) request to participate. If the respondent agrees, a consent form is mailed. Respondent returns consent form Tape measure mailed to respondent Measurement entered on-line by respondent London, April

19 Slightly less involved Announcement in panel and mention of incentive ( 5, 15, or 30). Consent form mailed to respondent (half of these with 5 enclosed) Consent returned by respondent Tape measure mailed to respondent Measurement entered on-line by respondent London, April

20 A lighter procedure Announcement in panel and mention of incentive ( 5, 15, or 30). Electronic ( ) announcement. Electronic ( ) request. Consent by clicking a button Tape measure mailed to respondent Measurement entered on-line by respondent London, April

21 The lightest procedure Announcement in panel and mention of incentive ( 5, 15, or 30). Electronic invitation to participate. Consent by clicking a button Tape measure mailed to respondent Measurement entered on-line by respondent London, April

22 Flow chart of various treatments (feedback choices, prepaid incentives, video or not, and conditional incentives not shown) London, April

23 ANNOUNCEMENT AGREEMENT AGREEMENT ANNOUNCEMENT INITIAL INVITATION Written consent Electronic consent (66%) Saw initial invitation 124(89%) 355(66%) 160(67%) Consented 313(88%) 145(91%) 164(68%) Saw initial invitation 124(89%) 304(96%) 303(97%) Written consent returned 218(69%) 243(78%) 140(85%) Consented 124(89%) 199(92%) 226(93%) 117(81%) 106(85%) Measured waist-circumference with tape measure 41.5% 41.9% 48.8% 44.2% London, April

24 Impressions If respondents are asked for their agreement electronically, about 2/3 respond (either positively or negatively). Note that about 25% of the sample has not responded to any questionnaire during the last three months (the sleepers ) Requiring a written consent leads to serious loss of respondents The more steps the fewer respondents (but not linearly Conditional on a non-missing response to the agreement question, the compliance rate in the most favorable treatment is 117/160=73% Comparable # in 1 st experiment: 39% London, April

25 Other findings Across the whole sample, respondents who are offered a video showing are more than three times more likely to comply than those who only receive written instructions Promising feedback has no effect Financial incentives have a relatively minor effect on compliance London, April

26 Multivariate Analysis Probit of treatment effects Waist measured Written consent-announcement-5euro (0.91) Written consent-announcement-no incentive (0.73) Written consent-agreement-5euro (1.43) Electronic consent-announcement (1.58) Electronic consent-agreement (2.85)** Controlled for education, income, incentives, feedback, gender. None of these are significant London, April

27 Probability of compliance by treatment (conditional on having been contacted) Treatment effects 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% w cons-ann w cons-ann5 w cons-agr w cons-agr5 econs-ann econs-agr Total Not measured Measured London, April

28 Elderly are more likely to measure their waist Compliance probabilities in the optimal treatment 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Total Not measured Measured London, April