Table 1.
Characteristics of the sample.
| Combined Cohort (n=293) | I-GRAM Cohort (n=146) | Baby Peas Cohort (n=147) | Cohort difference (pvalue) | |
|---|---|---|---|---|
| Sample Characteristics at Birth | ||||
| Sex Male Female |
141 (48%) 152 (52%) |
68 (47%) 78 (53%) |
73 (50%) 74 (50%) |
p=0.60 |
| Ancestry European African- American Other |
(n=291) 95 (33%) 164 (56%) 32 (11%) |
0 (0%) 146 (100%) 0 (0%) |
95 (65%) 18 (12%) 32 (22%) |
p<0.001 |
| Gestational age (weeks) | 39.3 (1.1) (n=287) | 39.4 (1.1) | 39.3 (1.1) | p=0.53 |
| Birthweight (kg) | 3.3 (0.4) (n=287) | 3.2 (0.4) | 3.4 (0.4) (n=141) | p<0.001 |
| Birthweight Z-scorea | 0.21 (0.98) (n=286) | −0.11 (0.92) | 0.54 (0.93) (n=140) | p<0.001 |
| Birth length (cm) | 49.8 (2.5) (n=286) | 49.0 (0.02) | 50.6 (0.02) (n=140) | p<0.001 |
| Birth length Z-scorea | 0.41 (1.30) (n=286) | −0.04 (1.12) | 0.88 (1.31) (n=140) | p<0.001 |
| Sample Characteristics at Age 1 Month | ||||
| Age (days) | 30.1 (5.8) | 31.4 (3.3) | 28.7 (7.2) | p<0.001 |
| Weight (kg) | 4.3 (0.6) | 4.3 (0.5) | 4.3 (0.6) | p=0.98 |
| Length (cm) | 53.7 (2.3) | 53.3 (2.1) | 54.0 (2.4) | p=0.005 |
| BMI (kg/m2) | 14.7 (1.3) | 14.9 (1.2) | 14.5 (1.4) | p=0.006 |
| BMI-Z | 0.24 (0.9) | 0.33 (0.9) | 0.17 (1.0) | p=0.15 |
| WFL-Z | 0.1 (1.1) | 0.3 (1.0) | −0.2 (1.2) | p<0.001 |
| Body Composition at Age 1 Month | ||||
| Percent Fat (%) | 18.7 (4.4) | 19.3 (3.9) | 18.1 (4.8) | p=0.018 |
| Fat Mass (kg) | 0.80 (0.3) | 0.83 (0.2) | 0.78 (0.3) | p=0.085 |
| Fat Mass/Length2 (kg/m2) | 2.77 (0.8) | 2.91 (0.7) | 2.64 (0.9) | p=0.005 |
| Fat Mass/Length3 (kg/m3) | 5.17 (1.50) | 5.46 (1.31) | 4.88 (1.63) | p=0.001 |
| Fat-Free Mass (kg) | 3.44 (0.4) | 3.42 (0.4) | 3.46 (0.4) | p=0.386 |
| Fat-Free Mass/ Length2 | 11.94 (0.9) | 12.03 (0.8) | 11.84 (0.9) | p=0.068 |
Outcomes are summarized as mean (SD) for continuous variables or n (%) for categorical variables. P-value indicates difference between IGRAM and Baby Peas cohorts (2-sided t-test for continuous variables and chi-squared test for categorical variables). Birthweight and birth length Z-scores account for sex and gestational age. BMI Z-score accounts for age, sex, and gestational age. WFL Z-score accounts for age and sex. The number of participants with available measurement is as shown if different for the total number in the cohort.