Wave 12 collected a number of biomarkers throughout the survey to examine biomarker collection and determine the impact of mode of completion. Which biomarkers were collected and how was determined by mode of completion. (See the Section Mixed mode experiments: web and face-to-face on the allocation to nurse, interviewer or web survey in Wave 12.) The exception is self-collected blood pressure described above – all respondents regardless of web were asked to complete these measures in the same way.
The following outlines the biomarker data and samples collected by mode of data collection.
Face-to-Face (nurse, interviewer)
- Blood pressure. In the interview, both nurses and interviewers asked respondents for consent to take blood pressure readings. Blood pressure cuffs were provided to nurses and interviewers. For those consenting, three measures of blood pressure were taken. Feedback on the status of the blood pressure was given to respondents.
- Height and weight. In the interview, both nurses and interviewers asked respondents to consent to take actual height and weight measures using a stadiometer and scale.
Nurse
In addition to those reported above, nurses also asked respondents to give
- Whole blood sample. Drawn intravenously using several vials.
- Dried blood spots. While the nurse helped lance the finger and place the blood spots, respondents were asked to send back the dried blood spot sheet after the interview.
- Hair sample. The nurse cut and sent back a hair sample to test for hormones.
Interviewer
In addition to blood pressure, height and weight assessments, interviewers asked respondents to give
- Dried Blood Spots
- Hair Sample. Interviewers left a kit for respondents to take dried blood spot and a hair sample, both of which were to be sent back by the respondent after completion. The interviewer introduced the kits and provided explanations of the tests and the reasons for the requests, as well as pointing out instructions for completion.
Web
In addition to blood pressure, respondents were asked to collect
- Dried Blood Spots
- Hair Sample. For the dried blood sample and hair sample collection, web respondents were asked in interview if they were willing to receive these kits, with a short explanation of the tests and reasons for the request. For those accepting the request, the kits were shipped to their household, with instructions on how to complete and return the in-home sample.
Dried blood samples and Lab Closures
The closure of labs during the COVID-19 pandemic resulted in the dried blood samples being analysed at different times. The measurements that were made after the lab closure are impacted by that closure. To identify these the indicator variable late_lab_batches in l_indresp_ip shows whether the samples were processed before or after the lab closures. A value of 1 indicates they were analysed after the lab closures.
Analytes from hair samples:
- Cortisol (pg/mg)
- Cortisone (pg/mg)
- Testosterone (pg/mg)
- Progesterone (pg/mg)
- Dehydroandrosterone (pg/mg)
The following variables have a value of -8 or 1 (inapplicable or Yes). However respondents in the hair file do have lab results if consent was received.
- l_haircut take hair sample
- l_hrconsc explain hair consent
- l_hairwill hair sample consent
The variable l_haircut shows these inapplicable responses as a result of the hair being collected by the respondents themselves instead of a nurse.
Analytes from Blood samples:
These variables are derived from full blood samples
- l_fb_trig full blood triglycerides (unfasted) mmol/l
- l_fb_chol full blood cholesterol (total) mmol/l
- l_fb_hdl full blood high-density lipoprotein cholesterol mmol/l
- l_fb_hba1c full blood glycated hemoglobin (ifcc standardised) mmol/mol hb
- l_fb_hba1c_corrected full blood glycated hemoglobin (ifcc standardised) mmol/mol hb – corrected
These variables are derived from dried blood spot
- l_dbs_trig dried blood triglycerides (unfasted) mmol/l
- l_dbs_chol dried blood cholesterol (total) mmol/l
- l_dbs_hdl dried blood high-density lipoprotein cholesterol mmol/l
- l_dbs_hba1c dried blood glycated hemoglobin (ifcc standardised) mmol/mol hb
The variables used for this experiment are the following.
On record l_indresp_ip:
l_chbnd, l_bmcon, l_clota, l_clotb, l_fit, l_mastc, l_renald, l_dbswill, l_refbsc1, l_refbsc2, l_refbsc3, l_refbsc4, l_refbsc5, l_refbsc6, l_refbsc7, l_refbsc97, l_dbsconsc, l_dbssamptak, l_dbshand, l_dbsfingers1, l_dbsfingers2, l_dbsfingers3, l_dbsfingers4, l_dbsfingers5, l_dbstime, l_dbsvpalco, l_prick, l_attempts, l_dbsdifc1, l_dbsdifc2, l_dbsdifc3, l_dbsdifc4, l_dbsdifc5, l_dbsdifc6, l_dbsdifc97, l_nodbsm1, l_nodbsm2, l_nodbsm3, l_nodbsm4, l_nodbsm97, l_fullblwill, l_reffullbl1, l_reffullbl2, l_reffullbl3, l_reffullbl4, l_reffullbl5, l_reffullbl6, l_reffullbl7, l_reffullbl97, l_fbsconsc, l_sampf1, l_sampf2, l_sampf3, l_sampf4, l_sampf5, l_fbsamptak, l_faint1, l_samparm, l_samdifc1, l_samdifc2, l_samdifc3, l_samdifc4, l_samdifc5, l_samdifc6, l_samdifc97, l_nofbsm1, l_nofbsm2, l_nofbsm3, l_nofbsm97, l_vpsys, l_vpalco, l_vppress1, l_vppress2, l_vppress3, l_vpplaster, l_vpprob1, l_vpprob2, l_vpprob3, l_vpprob97, l_vpprob96, l_debslfbp, l_debbp, l_debbm, l_debhair, l_debdbs, l_debfb, l_webkit, l_webkitkid, l_kit1, l_drcons, l_bmnores_code, l_bpnores_code, l_dbsnores_code, l_fbnores_code, l_nodbsmoth_code, l_noslfbpoth_code, l_nxtendoth_code, l_othbdif_code, l_othdifbp_code, l_othfullbl_code, l_othnbp_code, l_othrefdbs_code, l_othreffbs_code, l_scrx_code, l_scux_code, l_selfbonores_code, l_slfbplocoth_code, l_slfbpprres_code, l_unreloth_code, l_unrelwgt_code, l_vpprobothr_code, l_bpcons, l_con30sb1, l_con30sb2, l_con30sb3, l_con30sb4, l_con30sb96, l_omronno, l_cufsize, l_airtemp, l_systolic1, l_diastolic1, l_pulse1, l_systolic2, l_diastolic2, l_pulse2, l_systolic3, l_diastolic3, l_pulse3, l_ynobp, l_respbp1, l_respbps, l_nattbpd1, l_nattbpd2, l_nattbpd3, l_nattbpd4, l_nattbpd5, l_nattbpd97, l_difbpc1, l_difbpc2, l_difbpc3, l_difbpc4, l_difbpc5, l_difbpc6, l_difbpc97, l_bpfeedc, l_bprisk, l_resphgt, l_stdhgt1, l_relhgt, l_unrelhgt1, l_unrelhgt2, l_unrelhgt3, l_unrelhgt4, l_unrelhgt5, l_unrelhgt97, l_hgtref1, l_hgtref2, l_hgtref3, l_hgtref4, l_hgtref5, l_hgtref6, l_hgtref97, l_nohgtob1, l_nohgtob2, l_nohgtob3, l_nohgtob4, l_nohgtob5, l_nohgtob97, l_rwgtob, l_respwgt, l_rwgt1, l_floorc, l_relwgt, l_reswtref1, l_reswtref2, l_reswtref3, l_reswtref4, l_reswtref5, l_reswtref6, l_reswtref97, l_nowtob1, l_nowtob2, l_nowtob3, l_nowtob4, l_nowtob5, l_nowtob6, l_nowtob7, l_nowtob8, l_nowtob97, l_fb_trig, l_fb_chol, l_fb_hdl, l_fb_hba1c, l_fb_hba1c_corrected, l_dbs_trig, l_dbs_chol, l_dbs_hdl, l_dbs_hba1c, l_dbsvalidconsent, l_fbvalidconsent, l_fb_sample_dv, l_dbs_sample_dv
On record l_hair_ip:
l_hairlen, l_headshk, l_hairwill, l_hrconsc, l_haircut, l_haircol, l_hairdye, l_dyetime, l_dyetype, l_orighair, l_hairtrea, l_hairtrea2, l_hairwet, l_hairstyle, l_stylefreq, l_hairnosa, l_haircloth_code, l_hairnores_code, l_hairtrea3_code, l_orighairoth_code, l_stylewhat, l_hairmass, l_hair_cortisol, l_hair_cortisone, l_hair_testosterone, l_hair_progesterone, l_dhea, l_hairsamplestatus_coded, l_hairsamplecomment_coded, l_hairvalidconsent, l_childpno, l_hairkid, l_hairkidcode, l_haircutkid, l_nohaircutkid, l_kitchild
On record l_experience_ip:
l_version, l_timespent, l_studyintrst, l_futstdylik, l_slfbpease, l_kitarr7d, l_kithowarr, l_kitcond, l_instrcteasy, l_taksmpeasy, l_samptoenvlp, l_clearsndbck, l_notprvdsamp, l_notconsent, l_bsease, l_bsretease, l_bsfutr, l_bsofffdbk, l_hairease, l_hairretease, l_hairfutr, l_hairnurse, l_bsnurse, l_kitself, l_moresample, l_discussfdbk, l_signature, l_contactnum
Questions asked in the main interview are in l_indresp. For each measure there are set of variables about why measures weren’t taken. They generally fall into these three groups, participant reasons, mechanical reasons and problems affecting the sample:
Blood pressure
- l_bpcons blood pressure consent
- l_ynobp reason no bp reading
- l_nattbpd1 problems with pc
- l_nattbpd2 respondent upset/anxious/nervous
- l_nattbpd3 error reading
- l_nattbpd4 problems with cuff fitting/painful
- l_nattbpd5 problems with equipment (not error reading)
- l_nattbpd97 other reason (please specify)
- l_difbpc1 no problems taking blood pressure
- l_difbpc2 reading taken on left arm because right arm not suitable
- l_difbpc3 respondent was upset/anxious/nervous
- l_difbpc4 problems with cuff fitting/painful
- l_difbpc5 problems with equipment (not error reading)
- l_difbpc6 error reading
- l_difbpc97 other problems or departures from protocol (please specify)
Height
- l_resphgt standing height intro
- l_hgtref1 cannot see point / height already known / doctor has measurement
- l_hgtref2 too busy / taken too long already / no time
- l_hgtref3 respondent too ill / frail / tired
- l_hgtref4 considered intrusive information
- l_hgtref5 respondent too anxious / nervous / shy / embarrassed
- l_hgtref6 refused (no other reason given)
- l_hgtref97 other, please specify
- l_nohgtob1 respondent is unsteady on feet
- l_nohgtob2 respondent cannot stand upright / too stooped
- l_nohgtob3 respondent unable to remove shoes
- l_nohgtob4 ill or in pain
- l_nohgtob5 stadiometer faulty or not available
- l_nohgtob97 other, please specify
Weight
- l_rwgtob respondent weight observation
- l_respwgt respondent weight intro
- l_reswtref1 cannot see point/weight already known/doctor has measurement
- l_reswtref2 too busy/taken long enough already/no time
- l_reswtref3 respondent too ill/frail/tired
- l_reswtref4 considered intrusive information
- l_reswtref5 respondent too anxious/nervous/shy/embarrassed
- l_reswtref6 refused (no other reason given)
- l_reswtref97 other, please specify
- l_nowtob1 respondent is unsteady on feet
- l_nowtob2 respondent cannot stand upright
- l_nowtob3 respondent is chairbound
- l_nowtob4 confined to bed
- l_nowtob5 respondent unable to remove shoes
- l_nowtob6 respondent weighs more than 198 kg
- l_nowtob7 ill or in pain
- l_nowtob8 scales not working
- l_nowtob97 other, please specify
Hair
- l_hairnosa no hair sample obtained
- l_nohaircutkid reason no child hair sample
Dried blood spot (DBS)
- l_clota clotting disorder
- l_clotb anticoagulants
- l_fit have a fit
- l_mastc mastectomy
- l_renald renal dialysis
- l_dbswill participant willing to have a dried blood spot sample taken by nurse
- l_refbsc1 dislike/fear of giving a blood sample
- l_refbsc2 respondent felt it would be unsafe
- l_refbsc3 respondent recently had blood test
- l_refbsc4 refused because of current illness
- l_refbsc5 worried about h.i.v. or aids
- l_refbsc6 not receiving feedback on results
- l_refbsc7 refusal – no other reason given
- l_refbsc97 other please specify
- l_dbsdifc1 no problems
- l_dbsdifc2 unable to obtain enough blood
- l_dbsdifc3 difficulty stopping bleeding
- l_dbsdifc4 respondent became light-headed/faint/nauseous
- l_dbsdifc5 respondent fainted
- l_dbsdifc6 equipment problems
- l_dbsdifc97 other (specify at next question)
- l_nodbsm1 no suitable finger or thumb
- l_nodbsm2 respondent was too anxious/nervous
- l_nodbsm3 respondent felt light-headed/faint/nauseous
- l_nodbsm4 respondent fainted
- l_nodbsm97 other (specify at next question)
Full blood
- l_fullblwill participant willing to have a full blood sample taken by nurse
- l_reffullbl1 previous difficulties with venepuncture
- l_reffullbl2 dislike/fear of needles
- l_reffullbl3 respondent recently had blood test/health check
- l_reffullbl4 refused because of current illness
- l_reffullbl5 worried about h.i.v. or aids
- l_reffullbl6 not receiving feedback on results
- l_reffullbl7 no information about what blood will be tested for
- l_reffullbl97 other (specify at next question)
- l_fbsconsc signed full blood consent obtained by nurse
- l_faint1 respondent feeling faint
- l_samdifc1 no problem
- l_samdifc2 incomplete sample
- l_samdifc3 collapsing/poor veins
- l_samdifc4 second attempt necessary
- l_samdifc5 some blood obtained but respondent felt faint/fainted
- l_samdifc6 unable to use tourniquet
- l_samdifc97 other (specify at next question)
- l_nofbsm1 no suitable or no palpable vein/collapsed veins
- l_nofbsm2 respondent was too anxious/nervous
- l_nofbsm3 respondent felt faint/fainted
- l_nofbsm97 other (specify at next question)
