213 stadiometer

BMI: Height and weight of all participating children were measured to establish BMI. Children were measured outside at the playground, wearing light clothes and no shoes. All measurements were conducted two times, with a third measurement if the difference between the first two was too large (pre-set limit; weight ≥ 0.2 kg, height ≥ 0.5 cm). Weight was measured to the nearest 0.1 kg (Weighing Scale 803, Seca, Hamburg, Germany), and height was measured to the nearest 0.1 cm (Stadiometer 213, Seca, Birmingham, UK).
Questionnaire: All participating children filled out a digital questionnaire, including questions regarding their diet and PA. At the end of the questionnaire, the HLS-Child-Q15 was included [29 (link)]. The questionnaire was filled out in class during class hours and took about 30 min to complete. During questionnaire administration, a minimum of one member of the research team was present in the classroom. Due to the digital questionnaire’s nature, participants could not skip questions, resulting in no true missings in the collected data. However, participants could select the “do not know” option when answering the HLS-Child-Q15, and no mean HL scores were calculated for respondents with >3 “do not know” responses (maximum missing rate of 20%).

Age, ethnicity, education attainment, household income and occupation of mothers were collected at recruitment. During the 6-year clinic visit, maternal total physical activity and BMI (kg/m²) was obtained via self-reported physical activity questionnaire and calculated from height (SECA stadiometer 213) and weight (SECA 803) measurements respectively. Child sex and birth order were obtained from delivery records, while birthweight and total skinfold were measured at birth.

During their clinic visit at age 6 years, children had their weight, height and skinfold thicknesses (triceps, biceps, subscapular and supra-iliac) measured using a standardised protocol, as detailed previously [42 (link)]. Weight and standing height, with the removal of shoes and inclusion of light clothing, were measured in duplicate using a weighing scale (SECA 803) and stadiometer (SECA stadiometer 213), respectively. The average of these measurements was then calculated. BMI (kg/m²) was converted into z-scores specific for age and sex in accordance to the World Health Organisation’s Child Growth Standards [43 ]. The cut-off for children who were overweight/obese was +1 SD above the reference distribution [43 ]. Skinfold thicknesses were measured in triplicates from the right side of the body using Holtain skinfold calipers (Holtain, Ltd., Crymych, UK), and the average of these measurements was calculated. Sum of skinfold thicknesses was calculated by taking the sum of the four averaged skinfold measurements.

Body height of the participants was measured using SECA Stadiometer 213 (Germany) to the nearest 0.1 cm. Body weight of the participants was measured to the nearest 0.1 kg using a calibrated digital electronic weighing scale (TANITA, HD 319) with light clothing, without accessories, socks, and shoes, by trained personnel. Body mass index (BMI) was calculated as weight in kilogram divided by the square of the height in meters. BMI was categorized as normal (BMI ≤ 18.5–24.99 kg/m²) and overweight/obese (≥BMI 25.00) [19 ].
Waist circumference (WC) was measured using the SECA measuring tape (SECureA 201, Germany). Abdominal obesity was classified as WC > 80 cm (women) and WC > 90 cm [20 ]. Blood pressure was measured using a digital automatic blood pressure monitor (Omron HEM-7221) to the nearest 0.1 units with appropriate cuff size. All measurements were done in duplicate, and mean readings were computed for data analysis.

In line with COVID-19-related restrictions applicable at the time, anthropometric measurements were performed in the schoolyard. Children were measured wearing light clothing and no shoes. All anthropometric measurements were performed twice, and a third measurement was conducted if the difference between the first two measurements exceeded a pre-set limit (weight ≥ 0.2 kg, height ≥ 0.5 cm, waist circumference ≥ 1.0 cm) [15 (link)]. Weight was measured to the nearest 0.1 kg (Weighing Scale 803, Seca, Hamburg, Germany) and height was measured to the nearest 0.1 cm (Stadiometer 213, Seca, Birmingham, UK) [15 (link)]. Waist circumference was measured with a measuring tape to the nearest 0.1 cm, following the World Health Organisation’s assessment protocol (model 201, Seca, Hamburg, Germany) [26 ].