Table 2

Factors related to the presence of metabolic syndrome at 19 years in young adults born extremely preterm*

Metabolic syndrome†
No Yes Yes versus no p value
Mean (SD) Mean (SD) Difference in means (95% CI)
Maternal age (years)29.58 (5.18)(n=92)27.89 (5.25)(n=9)−1.69 (-5.28 to 1.91)0.354
Gestational age (years)24.95 (0.78)(n=94)24.76 (1.21)(n=9)−0.19 (-0.76 to 0.37)0.500
Birthweight z-score−0.15 (0.77)(n=92)−0.70 (0.55)(n=8)−0.55 (-1.10 to 0.01)0.053
Change in (∆) weight z-score from birth to term−1.59 (1.05)(n=88)−1.51 (1.28)(n=6)0.08 (-0.81 to 0.97)0.853
∆ weight z-score from term to 2.5 years‡0.11 (1.50)(n=86)1.11 (1.48)(n=7)1.00 (-0.17 to 2.17)0.094
∆ weight z-score from 2.5 to 6.0 years‡0.38 (1.06)(n=87)0.70 (1.25)(n=9)0.32 (-0.43 to 1.06)0.403
∆ weight z-score from 6 to 11 years0.72 (0.82)(n=88)0.90 (0.68)(n=8)0.17 (-0.42 to 0.77)0.561
Metabolic syndrome
No Yes
% (n/N) % (n/N) p value
Sex
 Female92.7% (51/55)7.3% (4/55)0.573
 Male89.6% (43/48)10.4% (5/48)
Gestational age (weeks)
 ≤2383.3% (10/12)16.7% (2/12)0.325
 2496.8% (30/31)3.2% (1/31)
 2590.0% (54/60)10.0% (6/60)
Multiple births
 Yes88.2% (30/34)11.8% (4/34)0.459
 No92.6% (63/68)7.4% (5/68)
White ethnicity
 Yes92.9% (79/85)7.1% (6/85)0.190
 No83.3% (15/18)16.7% (3/18)
Maternal smoking during pregnancy
 Yes78.6% (22/28)21.4% (6/28)0.005§
 No96.0% (72/75)4.0% (3/75)
Higher SES¶
 Yes95.5% (42/44)4.5% (2/44)0.227
 No88.7% (47/53)11.3% (6/53)
Maternal education (A level or above)¶
 Yes96.2% (25/26)3.8% (1/26)0.340
 No90.1% (64/71)9.9% (7/71)
  • *p values were calculated using two-sample t-tests or χ2 tests.

  • †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.

  • ‡Growth data at 2.5 years: uncorrected for prematurity.

  • §Correction for multiple comparisons was applied using the Benjamini-Hochberg procedure, and a false discovery rate of 0.05 was chosen. Adjusted p value: 0.070 for maternal smoking during pregnancy.

  • ¶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.

  • BMI, body mass index; HDL, high-density lipoprotein; SES, socioeconomic status.