. 2019 Jul 4;9(Suppl 3):3–22. doi: 10.1136/bmjopen-2017-020261

Table 1.

Summary of measures and biological samples collected in CheckPoint assessments

Construct and measure	Main		Mini		Home		Station	Equipment/instrument*	Data/sample collection protocol in brief
Construct and measure	Ch	P	Ch	P	Ch	P	Station	Equipment/instrument*	Data/sample collection protocol in brief
Anthropometry
Height^{48 49}	●	●	●	●	●	●		Portable rigid stadiometer (Invicta IP0955, Leicester, UK)	Standing height without shoes or socks, measured ×2, or ×3 if first two measures differed by ≥0.5 cm.
Weight and body composition^{48 49}	●	●	●	●	●	●		4-limb segmental (InBody230, Biospace, Seoul, Korea) or 2-limb (Tanita BC-351, Kewdale, Australia) body composition scales	Weight and body composition wearing light clothing without shoes or socks, measured once.
Waist circumference^{48 49}	●	●	●	●	●	●		Steel anthropometric measuring tape (Lufkin Executive Diameter W606PM, Maryland, USA)	Waist circumference at the narrowest point between the 10th rib and iliac crest, or midpoint between if no visible narrowing. Measured ×2, or ×3 if first two differed by ≥1 cm.
Pubertal status
Pubertal development	●		●		●			Sexual Maturity Scale⁵⁰ Pubertal Development Scale⁵¹	Sexual maturity assessed using three sets of images (1 male and 2 female) showing stages of puberty. Pubertal progress assessed using five sex-specific questions.
Menstruation	●	●	●	●	●	●		Study-designed questions about menstruation	Self-reported current menstruation (females only). Age of menstruation onset (girls only).
Acne	●		●		●			Modified Comprehensive Acne Severity Scale for the face⁵²	Current acne severity assessed using a sex-specific 5-point pictorial scale.
Bone and muscle measures
Bone and muscle morphology, bone density^{53 54}	●	●						Peripheral quantitative CT (pQCT, Stratec XCT 2000L scanner and XCT 2000 software, Birkenfeld, Germany)	Two pQCT scans of the non-dominant lower leg to image bone and muscle density and morphology. Scans taken at 4% (above ankle) and 66% (mid-calf) length of the tibia.
Cardiovascular measures
Carotid intima-media thickness and distensibility^{55 56}	●	●	●	●				Portable ultrasound (GE Healthcare Vivid i BT06 with 10 MHz linear array probe, Little Chalfont, UK) with ECG	Performed in supine position with head turned 45° to the left. Probe applied to right side of the neck to capture carotid artery wall images, with concurrent ECG trace.
Arterial stiffness and blood pressure⁵⁷	●	●	●	●	●	●		SphygmoCor XCEL (AtCor Medical, West Ryde, AUS)	Aortic-femoral pulse wave velocity measured ×3, supine, using a tonometer on the neck and blood pressure (BP) cuff on the thigh. Pulse wave analysis (including BP) measured ×3, 1 min apart, using a BP cuff on the arm.
Microvascular structure⁵⁸	●	●						Retinal camera (Canon CR-DGi, Tokyo, Japan), fitted with a digital SLR camera (Canon EOS 60D, Tokyo, Japan)	In a darkened room without mydriasis, two retinal photographs were taken per eye, one focused on the macula and one focused on the optic disc.
Respiratory measures
Lung function	●	●	●	●	●	●		Spirometer⁵⁹ (Vyntus, CA, USA) and Sentry Suite software (CA, USA) for collection (V.2.10) and download (V.2.17)	Children and parents perform 3–8 maximal exhalation manoeuvres. Children inhale 4 puffs of bronchodilator (Ventolin), wait 10 min and repeat test.
Language
Expressive and receptive language	●	●	●	●				Recalling Sentences subtest, Pearson Clinical Evaluation of Language Fundamentals–fourth edition, Australian version,⁶⁰ iPad (Apple, CA, USA) and headphones	Participant recalls and repeats up to 32 recorded spoken sentences of varying length and syntactic complexity.
Receptive vocabulary	●	●	●	●	●	●		National Institutes of Health Picture Vocabulary test⁶¹ (NIH Toolbox software with Cognition package), iPad and headphones	Participant hears word and selects picture best representing the word’s meaning. Adaptive test using computer-based algorithms to quickly approximate and then precisely pinpoint participant ability.
Hearing
Hearing threshold^{62 63}	●	●	●	●				Audiometer (Oscilla USB-330, V.3.3.4, Taastrup, Denmark) and Oscilla headphones. Data exported using V.4.0.0	In a soundproof booth with headphones, participant presses button on hearing sound. Adaptive test: sound presented at increasing and decreasing volume at 4 frequencies (1, 2, 4, 8 kHz). Each ear tested separately.
Middle ear function⁶⁴	●	●	●	●				Tympanometer (Oscilla TSM300) and AudioConsole software (V.3.3.4)	Tympanometer in ear canal varies air pressure, vibrating the tympanic membrane to measure canal volume, middle ear pressure and compliance.
Speech reception threshold	●	●	●	●				Listening in Spatialised Noise–Sentences Test v1.104^{65 66} (Phonak, NSW, Australia), laptop and headphones (Sennheiser HD215, Wedemark, Germany)	In a soundproof booth with headphones, participant repeats sentences at varying volume against fixed-volume background conversation. Adaptive test; computer algorithms pinpoint threshold.
Diet and food choices
Food choices	●	●						Digital weight scales accurate to 1 g (Breville, BSK500BSS)	Participant provided with a food box with prepacked snack food items to eat during a 15 min break. Boxes on different days randomised to differ by box size and food amount. Uneaten food weighed at end of session.
Physical activity and time use
Physical activity, sedentary behaviour, sleep⁶⁷	●	●	●	●	●	●		Wrist-worn accelerometer (GENEActiv Original, Cambs, UK) and self-report activity log	Triaxial accelerometer worn on non-dominant wrist for 8 days. Participant records type of day (school, non-school), sleep times and activities with device off.
Time use	●		●		●			Multimedia Activity Recall for Children and Adults^{35 68 69} programme	Activities recalled from the previous 24–48 hours, in increments of ≥5 min. 2–3 days recalled, including one school and one non-school day.
Strength and fitness
Eurofit broad jump⁷⁰	●		●		●			Gym mat and measuring tape (Lufkin L610CME, Maryland, USA)	Participant jumps horizontally from a standing start with double-leg take-off. After a practice jump, the distances of 3 jumps (measured in cm) are recorded.
PWC170 VO₂ max test⁷¹	●							Exercise bike (Monark 928G3, Manila, Philippines) and chest-worn heart rate monitor (Polar FT4, Smeaton Grange, Australia)	Warm up, then cycle at 60 RPM for 3×2 min bouts. Resistance increases as per heart rate at end of each bout. Aerobic work capacity (VO₂max) estimated.
Vision
Visual acuity	●	●	●	●				Computerised adaptive Freiburg Visual Acuity and Contrast Test⁷² with Landolt C optotypes (FrACT V.3.8.2, Breisgau, Germany)	Participant identifies optotypes (shapes) from 3 m. Right and left eyes tested separately, without glasses or contact lenses. Adaptive test; computer algorithms adjust size of optotypes presented to determine visual acuity. If visual acuity <1.0, test repeated with pinhole lens.
2D and 3D oral photography
2D and 3D oral photography	●	●	●	●				2D photography–Digital SLR camera (Canon 70D, Tokyo, Japan) 3D photography–3-pod 3D camera (3dMD Trio System, Georgia, USA)	2D photos of the dorsum of extruded tongue; then with lip retractors in place, teeth in occlusion and slightly apart with lower incisal edges visible. 3D photo of teeth in occlusion with lip retractors in place.
3D facial photography	●	●						3-pod 3D camera (3dMD Trio System)	3D photo of the face (neutral expression, hair pulled back in net to show hairline), ears and under chin.
Written story
Handwriting, written language	●		●		●			Pen, paper. Using protocol adapted from 1958 National Child Development Study (UK)⁷³	Child writes a short story about what they think their life will be like when they are 25 years old.
Well-being and quality of life
General well-being	●		●		●			International Survey of Children’s Well-Being^{74 75} Pediatric Quality of Life (PedsQL) 4.0 General Well-Being Scale⁷⁶	6-item measure of subjective well-being. 7-item measure of quality of life and general well-being.
Health-related quality of life	●		●		●			PedsQL 4.0 Generic Core Scale⁷⁶	23-item measure of physical and psychosocial health, yielding total, physical and psychosocial summary scores.
		●		●		●		Assessment of Quality of Life 8D Scale⁷⁷	35-item measure of health-related quality of life. Overall utility score and dimension scores calculated.
	●	●	●	●	●	●		Child Health Utility 9D⁷⁸	9-item measure of health-related quality of life. Overall utility score calculated.
Pain
Pain	●	●	●	●	●	●		Pain severity questions⁷⁹ with pain manikin adapted for online administration⁸⁰	Asked about pain >1 day in past month; if yes, when started, and (children only) which body regions.
Diet
Diet	●	●	●	●	●	●		Adapted National Secondary Students’ Diet and Activity⁸¹ questions, supplemented with adapted International Study of Childhood Obesity, Lifestyle and Environment⁸² items	26-item brief food frequency survey of usual intake of a range of different foods including fruits and vegetables.
Allergy and eczema
Family allergies and pet exposure		●		●		●		Allergy and pet exposure questions from the HealthNuts study^{83 84}; parent reported	Branched questionnaire items about child’s siblings and parent’s history of asthma, eczema, hay fever, latex/insect/food allergy and the family’s pets.
Colouring
Natural skin, hair and eye colouring	●	●	●	●	●	●		Questions adapted to self-report format from Paediatric Autoimmune Disease study⁸⁵ colour chart; parent reported	3-item measure of the natural skin, hair and eye colour of both the child and parent.
Medications and supplements
Current medications and supplements	●		●		●			Medications and supplement questions modified from LSAC²⁸; parent reported	Branched questionnaire items about the child’s medication and supplement use.
Health, welfare and community services
Hospital admissions and health insurance	●		●		●			Child lifetime hospitalisations, healthcare card and insurance coverage questions modified from LSAC²⁸; parent reported	Branched questionnaire items about child’s lifetime hospital admissions (including age, diagnosis), and concession card/private health insurance coverage.
Health service use	●		●		●			Use of service questions modified from LSAC²⁸; parent reported	Branched questionnaire items about child’s health service use and parent time spent on service use.
Community participation	●		●		●			Community activity use questions modified from LSAC²⁸; parent reported	Branched questionnaire on community activity participation (eg, team sports, music) in last year.
Biological samples
Venous blood	●	●	●	●				S-Monovette Vacutainer: 2.7 mL K3 EDTA (05.1167.001), 9 mL K3 EDTA (02.1066.001), 7.5 mL lithium heparin liquid (01.1608.001), 9 mL serum gel with clotting activator (02.1388.001), Sarstedt, Australia	Approximately 28 mL blood from non-dominant arm of semireclining (45°), semifasted participants, processed into 0.5 mL aliquots. Up to 6 EDTA plasma, 6 EDTA buffy coat, 6 LiH plasma, 6 LiH buffy coat (viable cells) and 6 sera per participant. In addition, either a whole blood clot or 3 whole blood aliquots and a dried blood spot (see next row). All serum, plasma and clot samples frozen directly at −80°C on site, while buffy coat aliquots were prepared in a freeze mix (10% fetal bovine serum+10% dimethyl sulfoxide+80% basal medium eagle) and placed within CoolCells (BioTools, Australia) prior to control the rate of freezing at −80°C to maximise cell viability.
Dried blood spot	●	●	●	●	●	●		Lancet (1.6 mm (No 85.1018) or 1.8 mm (No 85.1016) depth, Sarstedt Australia), Guthrie card	Card used for newborn screening is blotted with four drops of blood, collected via either a finger prick or pipetting a small amount of the venous whole blood sample. Stored at room temperature.
Urine	●	●	●	●	●	●		70 mL screw cap polypropylene sterile pot (No 75.9922.731, Sarstedt, Australia)	Participant collects random urine sample into sterile urine pot, pipetted into 12×0.7 mL aliquots. Stored at −80^○C on site.
Saliva	●	●	●	●				50 mL polypropylene sterile tube (FAL352070, Falcon, Corning, NY, USA)	5 min passive saliva drool into sterile tube. Sample weighed, then pipetted into 6×0.5 mL aliquots. Stored at −80°C on site.
Buccal swab		○	●	● ○	●	● ○		Buccal swab (Oracollect DNA OCR-100, The Hague, Netherlands. If not available, FloqSwab, COPAN Flock Technologies, Brescia, Italy was used).	Participant rubs swab over gums/inner cheeks. OCR-100: immerses swab in the preserving liquid, seals tube. Aliquoted into 2×0.5 mL aliquots. FloqSwab: seals swab in air-tight container. Stored at room temperature then −80°C.
Hair	●	●	●	●				String, aluminium foil, envelope, scissors	Two locks of hair (4 mm in diameter) tied with string and cut close to the scalp from the occipital area under the crown. Hair wrapped in aluminium foil (scalp end identified) and stored in a barcoded envelope at room temperature.
Toenails	●		●		●			Scissors, envelope	Clean toenails >3 mm trimmed from right big toe (if not available, left big toenail or fingernails) and stored at room temperature in barcoded envelope.

Questionnaire measures are self-reported, unless indicated they were parent reported.

*All questionnaire items administered by iPad or laptop, except the pain manikin, which was completed on paper at home visits. For brevity, iPad or laptop is not listed for every questionnaire item. Open circles indicate sample collected from non-attending parent.

2D, two dimensional; 3D, three dimensional; Ch, data/sample collected relates to child participant; FrACT, Freiburg Visual Acuity and Contrast Test; LiH, lithium heparin; LSAC, Longitudinal Study of Australian Children; NIH, National Institutes of Health; P, data/sample collected relates to parent participant; VO₂max, maximum volume of oxygen consumed.