Characteristics of extremely preterm and control participants
| Variables | Whole cohort | Controls | |
| N=315 | |||
| Perinatal variables | |||
| Male sex | % (n) | 49.2% (155) | 38.5% (25)* |
| Gestational age (weeks) | |||
| ≤23 | % (n) | 9.2% (29) | – |
| 24 | % (n) | 31.7% (100) | – |
| 25 | % (n) | 59.0% (186) | – |
| Multiple births | % (n/N) | 25.2% (79/314) | – |
| White ethnicity | % (n) | 76.5% (241) | – |
| Maternal age | Mean (SD) | 28.5 (5.9)(n=313) | – |
| Maternal smoking during pregnancy | % (n/N) | 32.9% (93/283) | – |
| Maternal education (A level or above)† | % (n/N) | 25.9% (68/263) | – |
| Higher SES† | % (n/N) | 31.0% (84/271) | – |
| Birth weight (kg) | Mean (SD) | 0.75 (0.11) (n=315) | – |
| Birth weight z-score | Mean (SD) | −0.18 (0.76) (n=312) | – |
| Early growth‡ | |||
| Weight gain from birth to term (kg) | Mean (SD) | 1.82 (0.49) (n=284) | – |
| Change in (∆) z-score from birth to term | Mean (SD) | −1.50 (1.05) (n=275) | – |
| Weight gain from term to 2.5y (kg) | Mean (SD) | 9.3 (1.7) (n=264) | – |
| ∆ z-score from term to 2.5 years | Mean (SD) | 0.07 (1.42) (n=258) | – |
| Weight gain from 2.5 to 6.0 years (kg) | Mean (SD) | 6.8 (2.7) (n=226) | – |
| ∆ z-score from 2.5 to 6.0 years | Mean (SD) | 0.37 (1.03) (n=226) | – |
| Weight gain from 6 to 11 years (kg) | Mean (SD) | 15.6 (6.2) (n=201) | 17.4 (7.5) (n=110) |
| ∆ z-score from 6 to 11 years | Mean (SD) | 0.84 (0.86) (n=201) | 0.25 (0.75) (n=110) |
| Continuous outcomes at 19 years | |||
| BMI (kg/m2) | Mean (SD) | 23.3 (4.4) (n=128) | 24.7 (5.7) (n=65) |
| Waist circumference (cm) | Mean (SD) | 82.7 (11.4 (n=103) | 82.3 (12.8) (n=52) |
| Waist:hip ratio | Mean (SD) | 85.3 (6.3) (n=103) | 81.3 (5.5) (n=52) |
| Seated brachial SBP (mm Hg) | Mean (SD) | 119.5 (10.1) (n=127) | 117.9 (9.8) (n=64) |
| Seated brachial DBP (mm Hg) | Mean (SD) | 73.2 (7.9) (n=127) | 71.6 (6.0) (n=64) |
| Supine brachial SBP (mm Hg) | Mean (SD) | 119.1 (10.0) (n=127) | 116.1 (10.0) (n=64) |
| Supine brachial DBP (mm Hg) | Mean (SD) | 69.4 (7.4) (n=127) | 65.9 (5.8) (n=64) |
| Central SBP (mm Hg) | Mean (SD) | 101.2 (8.0) (n=126) | 96.7 (7.8) (n=64) |
| Central DBP (mm Hg) | Mean (SD) | 70.6 (7.6) (n=126) | 66.9 (5.9) (n=64) |
| Aortic Augmentation Index (%) | Mean (SD) | 6.6 (9.0) (n=126) | 0.4 (8.2) (n=64) |
| Triglycerides (mmol/L) | Mean (SD) | 0.9 (0.5) (n=109) | 0.9 (0.4) (n=61) |
| HDL (mmol/L) | Mean (SD) | 1.5 (0.4) (n=109) | 1.6 (0.4) (n=61) |
| LDL (mmol/L) | Mean (SD) | 2.3 (0.8) (n=109) | 2.4 (0.7) (n=61) |
| Fasting glucose (mmol/L) | Mean (SD) | 4.9 (0.7) (n=111) | 4.9 (0.4) (n=60) |
| Metabolic syndrome at 19 years§ | % (n/N) | 8.7% (9/103) | 3.7% (2/54) |
| Central obesity§ | % (n/N) | 35.6% (37/104) | 35.2% (19/54) |
| Raised triglycerides§ (≥1.7 mmol/L) | % (n/N) | 9.2% (10/109) | 6.6% (4/61) |
| Raised HDL§ | % (n/N) | 17.4% (19/109) | 11.5% (7/61) |
| Raised blood pressure§ | % (n/N) | 18.1% (23/127) | 9.4% (6/64) |
| Raised glucose§ (≥5.6 mmol/L) | % (n/N) | 7.2% (8/111) | 3.3% (2/60) |
*Data reported for controls at 19 years.
†Maternal education and SES were collected using parent questionnaire at age 2.5 years; SES was based on using parent occupation: (1) higher: non-manual employment, (2) lower: including those in manual employment or unemployed.
‡Growth data at 2.5 years: uncorrected for prematurity.
§Metabolic syndrome was defined by the International Diabetes Federation as having central obesity measured by waist circumference or BMI, together with any two of the following components: (1) raised triglycerides, (2) reduced HDL cholesterol, (3) raised blood pressure and (4) raised fasting plasma glucose.
BMI, body mass index; DBP, diastolic blood pressure; HDL, high-density lipoprotein; LDL, low-density lipoprotein; SBP, systolic blood pressure; SES, socioeconomic status.