Table 1.
Maternal and infant characteristics by altitude and study cohort.
| STATEWIDE COHORT | LONGITUDINAL COHORT | |||||
|---|---|---|---|---|---|---|
| Low altitude (n=608,422)1 | High altitude (n=9,536)1 | p | Low altitude (n=227) | High altitude (n=227) | p | |
| Maternal background factors | ||||||
| Altitude of residence (m) | 1688±202 | 2752±180 | <.001 | 1651±89 | 2847±126 | <.001 |
| Age (years) | 28.3 ±6.0 | 30.2 ±6.0 | <.001 | 30.7±5.0 | 30.4±5.7 | .452 |
| Race (% Caucasian) | 86.8% | 95.7% | <.001 | 66.8% | 95.3% | <.001 |
| Ethnicity (% Hispanic) | 29.8% | 18.8% | <.001 | 20.3% | 25.3% | .200 |
| WIC and/or Medicaid | 30.5% | 20.8% | <.001 | 19.4% | 44.7% | <.001 |
| Primiparity | 33.1% | 36.7% | <.001 | 40.0% | 41.6% | .731 |
| Pre-preg BMI (kg/m2) | 25.6 ± 5.8 | 24.2 ± 4.8 | <.001 | 25.0±5.8 | 24.4±5.2 | .305 |
| Preg weight gain (kg) | 13.4±6.4 | 13.7±5.8 | <.001 | 12.9±4.8 | 12.7±2.4 | .686 |
| Too much wt gain | - | - | - | 36.1% | 0% | <.001 |
| Prenatal visits (#) | 10.2±3.6 | 9.8±3.6 | <.001 | 11.0±2.3 | 12.6±3.5 | <.001 |
| Preg tobacco use | 7.6% | 6.1% | <.001 | 6.6% | 8.9% | .648 |
| GDM | 3.8% | 3.1% | .001 | 8.4% | 4.6% | .103 |
| Maternal Hypertensive characteristics | ||||||
| Gest HTN/preeclampsia | 3.9% | 4.9% | <.001 | 11.5% | 18.5% | .035 |
| Eclampsia | 0.4% | 0.6% | .006 | - | - | - |
| HELLP | 0.3% | 0.4% | .031 | - | - | - |
| 2nd trimester HTN | - | - | - | 1.8% | 9.3% | <.001 |
| 3rd trimester HTN | - | - | - | 9.3% | 14.5% | .082 |
| Maximum systolic BP | - | - | - | 126±10 | 126±11 | .967 |
| Maximum diastolic BP | - | - | - | 78±8 | 81±9 | .002 |
| Maximum MAP | - | - | - | 92±8 | 94±8 | .007 |
| Infant Outcomes | ||||||
| Birth wt (gm) | 3232±526 | 3115±498 | <.001 | 3264±426 | 3109±406 | <.001 |
| LBW (<2500 gm) | 6.8% | 9.4% | <.001 | 4.0% | 10.4% | .009 |
| GA (wk) | 38.8±1.9 | 38.8±1.9 | .385 | 39.1±2.2 | 39.1±1.2 | .928 |
| Preterm birth (<37 wk) | 7.0% | 7.5% | .058 | 3.5% | 5.4% | .334 |
| 5 min Apgar score <7 | 2.4% | 3.7% | <.001 | 1.8% | 1.0% | .448 |
| NICU admission | 6.8% | 7.4% | .036 | - | - | - |
Data are expressed as means ± standard deviations or percent.
1
sample sizes (n) are cases with complete data. Hyphens (−) indicate data that were not available. Abbreviations: BMI = body mass index, BP = blood pressure, GA = gestational age, GDM = gestational diabetes, HELLP = hemolysis, elevated liver enzymes & low platelets syndrome, HTN = hypertension, LBW = low birth weight, MAP = mean arterial blood pressure, # = number, NICU = neonatal intensive care unit, Preg = pregnancy, WIC = eligible for the assistance from the supplemental nutrition program for low-income women, wt = weight. Bolded values are statistically significant.