Table 3.
Cross-sectional associations of body size and composition with brain size at term equivalent age (n=62).
| Mean (95% confidence interval) increase in brain size. | ||||||
|---|---|---|---|---|---|---|
| Bifrontal diameter (mm) | Biparietal diameter (mm) | Transverse cerebellar diameter (mm) | ||||
| Estimate | p | Estimate | p | Estimate | p | |
| Fat-free mass (per 100g) | 0.62 (0.24, 1.00) | 0.001 | 0.70 (0.27, 1.13) | 0.001 | 0.26 (0.003, 0.51) | 0.04 |
| Fat-free mass index (kg/m2) | 1.41 (0.56, 2.27) | 0.001 | 1.18 (0.13, 2.23) | 0.03 | 0.34 (−0.20, 0.88) | 0.22 |
| Fat-free mass Z-score | 1.39 (0.44, 2.35) | 0.004 | 1.40 (0.27, 2.54) | 0.02 | 0.53 (−0.10, 1.16) | 0.10 |
| Fat mass (per 100g) | 0.31 (−0.12, 0.76) | 0.17 | 0.50 (−0.16, 1.16) | 0.13 | 0.36 (−0.01, 0.73) | 0.06 |
| Fat mass index (kg/m2) | 0.62 (−0.32, 1.56) | 0.20 | 0.96 (−0.61, 2.54) | 0.23 | 0.81 (−0.06, 1.69) | 0.07 |
| Fat mass Z-score | 0.46 (−0.18, 1.11) | 0.16 | 0.62 (−0.38, 1.62) | 0.22 | 0.39 (−0.11, 0.89) | 0.13 |
| Body fat percent | 0.04 (−0.09, 0.16) | 0.59 | 0.10 (−0.12, 0.32) | 0.39 | 0.11 (−0.01, 0.23) | 0.07 |
| Body fat % Z-score | 0.13 (−0.37, 0.63) | 0.61 | 0.33 (−0.52, 1.19) | 0.45 | 0.39 (−0.07, 0.84) | 0.09 |
| Weight Z-score | 2.1 (0.60, 3.67) | 0.006 | 2.60 (0.90, 4.31) | 0.003 | 1.27 (0.32, 2.22) | 0.009 |
| Length Z-score | 1.13 (−0.48, 2.74) | 0.17 | 1.48 (−0.32, 3.27) | 0.11 | 0.91 (−0.05, 1.87) | 0.06 |
| BMI Z-score | 1.79 (0.69, 2.89) | 0.001 | 1.95 (0.45, 3.44) | 0.01 | 0.95 (0.11, 1.79) | 0.03 |
| Head circumference Z-score | 2.70 (1.74, 3.67) | <0.001 | 3.10 (2.04, 4.16) | <0.001 | 1.26 (0.48, 2.04) | 0.001 |
Estimates represent the difference in brain metric measurement associated with one unit difference in each growth or body composition parameter at term equivalent age, adjusted using generalized estimating equations for gestational age at birth, sex, birthweight Z-score, and postmenstrual age at time of brain MRI, and accounting for non-independence of infants born to the same mother.