Table 1

Summary of measures and biological samples collected in CheckPoint assessments

Construct and measureMainMiniHomeStationEquipment/instrument*Data/sample collection protocol in brief
ChPChPChP
Anthropometry
Height48 49 ●●●●●● Embedded Image 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 composition48 49 ●●●●●● Embedded Image 4-limb segmental (InBody230, Biospace, Seoul, Korea) or 2-limb (Tanita BC-351, Kewdale, Australia) body composition scalesWeight and body composition wearing light clothing without shoes or socks, measured once.
Waist circumference48 49 ●●●●●● Embedded Image 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●●● Embedded Image 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●●●●●● Embedded Image Embedded Image Study-designed questions about menstruationSelf-reported current menstruation (females only). Age of menstruation onset (girls only).
Acne●●● Embedded Image 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 density53 54 ●● Embedded Image 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 distensibility55 56 ●●●● Embedded Image Portable ultrasound (GE Healthcare Vivid i BT06 with 10 MHz linear array probe, Little Chalfont, UK) with ECGPerformed 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 ●●●●●● Embedded Image 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 ●● Embedded Image 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●●●●●● Embedded Image 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●●●● Embedded Image Recalling Sentences subtest, Pearson Clinical Evaluation of Language Fundamentals–fourth edition, Australian version,60 iPad (Apple, CA, USA) and headphonesParticipant recalls and repeats up to 32 recorded spoken sentences of varying length and syntactic complexity.
Receptive vocabulary●●●●●● Embedded Image National Institutes of Health Picture Vocabulary test61 (NIH Toolbox software with Cognition package), iPad and headphonesParticipant 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 threshold62 63 ●●●● Embedded Image Audiometer (Oscilla USB-330, V.3.3.4, Taastrup, Denmark) and Oscilla headphones. Data exported using V.4.0.0In 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 ●●●● Embedded Image 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●●●● Embedded Image Listening in Spatialised Noise–Sentences Test v1.10465 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●● Embedded Image 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 ●●●●●● Embedded Image Wrist-worn accelerometer (GENEActiv Original, Cambs, UK) and self-report activity logTriaxial 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●●● Embedded Image Multimedia Activity Recall for Children and Adults35 68 69 programmeActivities 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 ●●● Embedded Image 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 ● Embedded Image 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●●●● Embedded Image 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●●●● Embedded Image 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●● Embedded Image 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●●● Embedded Image 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●●● Embedded Image International Survey of Children’s Well-Being74 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●●● Embedded Image PedsQL 4.0 Generic Core Scale76 23-item measure of physical and psychosocial health, yielding total, physical and psychosocial summary scores.
●●● Embedded Image Assessment of Quality of Life 8D Scale77 35-item measure of health-related quality of life. Overall utility score and dimension scores calculated.
●●●●●● Embedded Image Embedded Image Child Health Utility 9D78 9-item measure of health-related quality of life. Overall utility score calculated.
Pain
Pain●●●●●● Embedded Image Embedded Image 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●●●●●● Embedded Image Embedded Image Adapted National Secondary Students’ Diet and Activity81 questions, supplemented with adapted International Study of Childhood Obesity, Lifestyle and Environment82 items26-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●●● Embedded Image Allergy and pet exposure questions from the HealthNuts study83 84; parent reportedBranched 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●●●●●● Embedded Image Questions adapted to self-report format from Paediatric Autoimmune Disease study85 colour chart; parent reported3-item measure of the natural skin, hair and eye colour of both the child and parent.
Medications and supplements
Current medications and supplements●●● Embedded Image Medications and supplement questions modified from LSAC28; parent reportedBranched questionnaire items about the child’s medication and supplement use.
Health, welfare and community services
Hospital admissions and health insurance●●● Embedded Image Child lifetime hospitalisations, healthcare card and insurance coverage questions modified from LSAC28; parent reportedBranched questionnaire items about child’s lifetime hospital admissions (including age, diagnosis), and concession card/private health insurance coverage.
Health service use●●● Embedded Image Use of service questions modified from LSAC28; parent reportedBranched questionnaire items about child’s health service use and parent time spent on service use.
Community participation●●● Embedded Image Community activity use questions modified from LSAC28; parent reportedBranched questionnaire on community activity participation (eg, team sports, music) in last year.
Biological samples
Venous blood●●●● Embedded Image 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, AustraliaApproximately 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●●●●●● Embedded Image Lancet (1.6 mm (No 85.1018) or 1.8 mm (No 85.1016) depth, Sarstedt Australia), Guthrie cardCard 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●●●●●● Embedded Image 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●●●● Embedded Image 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○●●
○		●●
○		 Embedded Image 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●●●● Embedded Image String, aluminium foil, envelope, scissorsTwo 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●●● Embedded Image Scissors, envelopeClean 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.