TILDA Biomeasures

Biomarkers in Social Science Research Workshop

Hilary Cronin

April 30th 2010

OUTLINE OF TALK

1. Brief description TILDA

2. Biomeasures Wave 1

3. Blood collection & proposed core set of biomarkers for TILDA

Wave 1

4. Discussion

BACKGROUND

The Irish LongituDinal Study on Ageing (TILDA) is the most comprehensive longitudinal study of ageing conducted in Ireland

The study is led by Trinity College Dublin* and guided by a cross-institutional, multi-disciplinary team of experts

The multidisciplinary approach promises to bring unique and exciting insights to the whole area of ageing research, both nationally and internationally

Strong emphasis on biomarkers

Focus in this talk on Health component Extensive economic and social data

*Lead PI Professor RoseAnne Kenny,

Research Director Prof Brendan Whelan

*Funded by Irish Life, Atlantic

Philanthropies & the Irish Government

*For more information visit

www.tilda.ie

Economic

Social

Health

DESCRIPTION OF STUDY

CAPI

SCQ

Health Assessment

n = 8000

n = 6800

(RR 85%)

640639

638637636

635634 633632631

630629 628

627626625624

623

622 621620619

618

617616615614

613612 611

610609

608607606605604603602601

600599598597

596595

594

593

592591590589

588587

586585

584 583582581580

579578577

576 575574573572

571570569568

567566565564 563

562

561

560559

558

557

556555554

553552

551550549

548

547

546545544543542541540539538537536535534533532531530529528527526

525

524523 522

521520519518

517516

515514513

512511510509508507

506505

504503502501

500 499

498497

496495

494493

492 491490

489488487486

485484483482481480479478477476475474473

472

471 470469468467 466465

464463

462 461460

459458

457

456455

454

453452

451450449448

447446445

444443

442 441440439438

437

436435

434 433 432431430

429428427

426425424423422421

420419418417416415414413412411410409408407406405404403402401400399398397396395394393392391390389388387386385384383382381380379378377376375374373372371370369368367366365364363362361360359358357356355354353352351350349348347346345344343342341340

339 338337336335334333332331330329328327326325324323322321320319318317316315314313312311310309308307306305304303302301300299298297296295294293292291290289288287286285284283282281280279278277276275274273272271270269

268267266265264263262261

260259258

257256

255254253

252 251250249248

247246245244243

242241240239238237

236235

234

233 232

231230229228227

226225224223

222221 220

219

218217

216

215

214

213212

211210

209208 207206

205204203202201

200 199 198

197196

195 194

193192

191

190 189

188187 186

185 184

183182181

180179

178177

176175174 173

172171

170169168167166165164163

162161

160 159158157

156

155154153152151150149 148

147 146145144143142

141

140139138

137136135134

133132131130

129128127126125

124 123122

121120119118117

116

115 114

113112111110109108107 106105

104

103 102

1011009998

97

9695

94 93929190

89

88

87

8685

848382

81

80

7978

7776

75

7473

7271

70

69

68 67

66

6564

636261

6059

585756

55 5453

52

51

50494847

4645

44

434241

40

3938

3736353433

32

3130

2928

2726

25

24

23222120

19 1817

16 1514

1312

1110

98

76

54

321

0

50000

100000

150000

200000

250000

300000

350000

400000

450000

500000

0 50000 100000 150000 200000 250000 300000 350000

CAPI & SCQ

Physical

Health

Cognitive

Health

Psychological

Health

Behavioural

Health

Health Care

Utilisation

SR health

Chronic illness

Functional ability

Falls, Fear of falling

Pain

Sensory Decline

Incontinence

Medical screening

Medications

SR Memory

Forgetfulness

Orientation

Memory

•Immediate &

delayed recall

•Prospective

Executive

function

•Verbal fluency

SR Mental Health

Depression

•CES-D 20 item

•Suicide

Anxiety & Worry*

•HADS – A

•PSWQ 8 item

Loneliness*

•UCLA Loneliness

QOL*

•CASP-19

Life satisfaction

Ageing

Perceptions*

Exercise

•IPAQ short form

Alcohol*

•Patterns of drinking

•CAGE

Smoking

Sleep

Quality of

healthcare

Access to

healthcare

‘Met need’ versus

‘unmet need’

*SCQ

MAIN AREAS OF INTEREST IN THE

HEALTH ASSESSMENT

Neuro cardiovascular

Instability

Gait & Balance

Vision

HEALTH ASSESSMENT

Cognition

Gait & Balance

Cardiovascular

Eye

Global

cognition

Sustained

attention

Height &

Weight

Balance*Dual tasks*GAITRite*

BP Phasic BP*

TUG

HRV*

MemoryExecutive

function

CRT

Acuity* Contrast

sensitivity*

Retinal

photo*

Macular

pigment*

Grip

strength

PWV*

Heel U/S*

GeneralWHR

Health centre assessment takes approx 3 hours and the home

assessment 1.5 hours

*HAC only

Decision on model for

blood collection

GENERAL APPROACH

1. To collect samples that would facilitate the analyses of measures currently known to be of interest for describing and studying ageing

2. To allow the widest possible range of assays that could plausibly be envisaged for the future

3. To avoid collection, processing or storage approaches that would inherently preclude such assays - “future proofing” the collection as far as possible given current knowledge and available resources

CRITICAL CONSIDERATIONS

The inclusion of both centre and home based health assessments was

considered essential to minimise selection bias in the biological

sampling component of TILDA

High priority was given to ensure that identical processes were

undertaken in the home and centre

640639

638637636

635634 633632631

630629 628

627626625624

623

622 621620619

618

617616615614

613612 611

610609

608607606605604603602601

600599598597

596595

594

593

592591590589

588587

586585

584 583582581580

579578577

576 575574573572

571570569568

567566565564 563

562

561

560559

558

557

556555554

553552

551550549

548

547

546545544543542541540539538537536535534533532531530529528527526

525

524523 522

521520519518

517516

515514513

512511510509508507

506505

504503502501

500 499

498497

496495

494493

492 491490

489488487486

485484483482481480479478477476475474473

472

471 470469468467 466465

464463

462 461460

459458

457

456455

454

453452

451450449448

447446445

444443

442 441440439438

437

436435

434 433 432431430

429428427

426425424423422421

420419418417416415414413412411410409408407406405404403402401400399398397396395394393392391390389388387386385384383382381380379378377376375374373372371370369368367366365364363362361360359358357356355354353352351350349348347346345344343342341340

339 338337336335334333332331330329328327326325324323322321320319318317316315314313312311310309308307306305304303302301300299298297296295294293292291290289288287286285284283282281280279278277276275274273272271270269

268267266265264263262261

260259258

257256

255254253

252 251250249248

247246245244243

242241240239238237

236235

234

233 232

231230229228227

226225224223

222221 220

219

218217

216

215

214

213212

211210

209208 207206

205204203202201

200 199 198

197196

195 194

193192

191

190 189

188187 186

185 184

183182181

180179

178177

176175174 173

172171

170169168167166165164163

162161

160 159158157

156

155154153152151150149 148

147 146145144143142

141

140139138

137136135134

133132131130

129128127126125

124 123122

121120119118117

116

115 114

113112111110109108107 106105

104

103 102

1011009998

97

9695

94 93929190

89

88

87

8685

848382

81

80

7978

7776

75

7473

7271

70

69

68 67

66

6564

636261

6059

585756

55 5453

52

51

50494847

4645

44

434241

40

3938

3736353433

32

3130

2928

2726

25

24

23222120

19 1817

16 1514

1312

1110

98

76

54

321

0

50000

100000

150000

200000

250000

300000

350000

400000

450000

500000

0 50000 100000 150000 200000 250000 300000 350000

Centre 1

Centre 2

DECISION ON MODEL

Decision made to 1. Collect blood samples in the health centres and in the home

2. Minimum local processing (inversion of tubes)

3. Transport the samples to a central laboratory for processing and separation

This approach precluded the collection of serum samples as these require immediate processing (within 2 hours)

Model moved away from immediate analysis of “lots of biomarkers”, towards ensuring correct processing & storage would allow batch analysis at end of wave of a set of biomarkers

ensuring longevity of samples for future waves

Procedure for blood

collection

SAMPLE LABELLING & TRACKING

Blood taken from

respondent

Central Lab

Long term storage

CourierFULL

TRACEABILITY

TILDA Barcode labels (linear)

Message sent electronically to

lab to expect samples

Barcode label scanned along

with courier label

Can locate aliquotted samples

down to an individual tube

within a box within a freezer

(2D labels)

SAMPLE INTEGRITY

Short term storage & transport to lab

Decision made to transport all samples

between 2 – 80 C to maintain integrity of

the sample

Specialist Packaging Biotherm 5*

Recycled

*All packaging conforms to UN3373 regulations

Long term storage

Cryovials

COURIER

Dublin & Cork centres have daily

pick up at 6pm (Mon - Sat)

Home nurses have 38 drop off

points located geographically

around the country

Option for Saturday collection

for home assessments (if

required)

DX drop off point

FLOW SHEET FOR TILDA BLOOD COLLECTION

COURIER

Set pick up time in

each HAC

PA

CK

AG

ING

(1

) S

ampl

es k

ept

2-8

C

(2)

Re-

usab

le

COURIER

Operating via host

exchanges/drop off

points

CO

UR

IER

(1

) C

onve

nien

t lo

cati

ons

(2)

Sec

ure

(3)

Mon

day

- S

atur

day

ST

OR

AG

E

(1)

Sam

ple

trac

king

(2)

Cap

acit

y

TILDA Participants (Health Assessment Centres & Home Assessments)

25 mL venous blood drawn

5 ml Lithium Heparin

CENTRAL

LAB

Aliquots for long term storage

in -80C freezers (+/- liquid

nitrogen) +/- analysis (TBC)

At end of Wave 1

10 ml EDTA 10 ml EDTA (covered)

Immediate analysis

Lipid profile*

1ml LiH

Plasma

3 x 1ml

EDTA

plasma

5 aliquots frozen at -80C **

FREEZER #1

1ml

buffy

coat

1ml

buffy

coat

3 x 1ml

EDTA

plasma

5 aliquots frozen at -80C

**

FREEZER #2

Within

48 hrs

1ml FROZEN plasma

sample batched to WIT for

carotenoids (cryovial

protected from the light)

1ml EDTA

plasma

covered†

LA

B

(1)

Goo

d IT

/lab

elli

ng &

sam

ple

trac

king

(2)

Cap

acit

y

(3)

Wee

kend

s

Dublin HAC Cork HAC Home nurses

*We will feed the lipid result back to the participant

†Sample for carotenoids must be protected from the light once taken

** Samples may be stored at -20C for short period (days) until transfer to -80C freezer

Proposed Core Biomarkers for

Wave 1 TILDA

CONSIDERATIONS WHEN CHOOSING

BIOMARKERS

Should complement and add to the data collected in CAPI and the

health assessment

Should be feasible

Must consider

Logistics

Cost of collecting, transporting, processing and storing

We anticipate ~ 7000 participants agreeing to a health assessment, either

in a centre or in their own home

PROPOSED LIST FOR WAVE 1 ANALYSIS

1. Lipids

2. HbA1c

3. Fibrinogen

4. hsCRP

5. Ferritin

6. Carotenoids

7. Renal function

8. Genetic preparation

Neuro cardiovascular

Instability

Gait & Balance

Vision

Discussion

Additional Information

Neuro-cardiovascular Instability

1. Lipid profile

Associated with CVS disease – heart disease, stroke, kidney dx, dementia….

Of interest, TC is related to other behaviours and conditions in addition to cardiovascular disease, including depression and suicide, Alzheimer’s disease and stress-related conditions

Improve response rate to the health assessment - test most frequently requested by participants in pilot 1 & 2

Robust and easy to measure

This is the only biomarker that has been pre-determined as we

feed the results back to the respondent +/- GP

2. HbA1c Blood sugar binds to RBC hemoglobin in

predictable ways; and the amount of binding is related to the “integrated” level of blood glucose over time

Glycosylated hemoglobin is a measure of blood glucose over a long period of time (120 days: the average lifespan of RBC)

Neuro-cardiovascular Instability

HbA1c is most commonly used to monitor the level of control in diabetics, but it has used profitably in other ways: as a risk factor for diabetes-related conditions such as cardiovascular disease & as a method of screening for diabetes in persons whose status is unknown

Inflammatory markers Implicated in cardiovascular and neurological

disease as well as social isolation & loneliness

3. Fibrinogen is a soluble plasma glycoprotein that is synthesised in the liver. It is involved in the coagulation cascade

Neuro-cardiovascular Instability

Too much – excessive activation of the coagulation

cascade leading to thrombosis (clotting)

Too little - predisposes to haemorrhage

4. hsCRP and 5. Ferritin

acute phase proteins - levels rise dramatically during inflammatory processes occurring in the body

Ferritin important for dx Haemochromatosis

6. Carotenoids

Fat soluble vitamins which play an important potential role in human

health by acting as biological antioxidants, protecting cells and tissues

from the damaging effects of free radicals and singlet oxygen

Particularly important for macular nutrition

Vision

Normal healthy macula Macular degeneration

8. Genetics

Pre-preparatory stage

Buffy coats extracted from EDTA

plasma & frozen at -80C

Buffy coat

Extract DNA

Lysis of red & white cells

Next stage……

Nutritional markers

B12, Folate

Hormones

Cortisol

PTH

Sex hormones

Vitamin D

Cytokines

OTHER BIOMARKERS CONSIDERED

STANDARD GUIDELINES

Standard guidelines for blood sampling handling state that

plasma or serum should be separated from cells as soon as

possible and certainly within 2 hours

This requirement results in a need for either immediate local

separation of blood samples of their rapid chilled transfer to a

central laboratory increased complexity & cost

Blood serum is blood plasma without fibrinogen or the other clotting factors (i.e. whole blood minus both the cells and the clotting factors)

Blood plasma is the yellow

liquid component of blood in

which the blood cells in whole

blood would normally be

suspended

• Venous blood

• Capillary blood

• Dried Blood SpotsBlood

• Difficulty of collection

• Limited additional benefit

• Additional cost of storageUrine

• Limited additional information (e.g. indicators of periodontal disease and oral cancer)

• Extra cost of storageSaliva

• Limited additional information

• Complicating effects of cosmetic products

• Inconsistency of sample collection

• Possible impact on recruitment of clipping nails

Nails

The collection of biological samples other than blood

was ultimately excluded for Wave 1 as it was decided that

these methods did not provide sufficient additional

information to justify the additional cost or complexity

required

BIOLOGICAL SAMPLES CONSIDERED