Background
Methods
Study design
Outcomes
Potential risk factors
Statistical analyses
Regression analyses
Subgroup analyses
Results
Variable | Frequency n = 7587 | |
---|---|---|
Age | ||
Mean (SD) | 30.3 (5.06) | |
Race a (missing/unknown N = 415, 5.5%) | ||
African | 152 | (2.12%) |
Middle eastern | 224 | (3.12%) |
Asian | 422 | (5.88%) |
Caucasian | 6250 | (87.1%) |
Other | 124 | (1.73%) |
BMI (missing N = 136, 1.8%) | ||
Mean (SD) | 24.9 (5.5) | |
Range | 14.7–61.3 | |
Participant education (missing N = 7, 0.09%) | ||
Grade school | 153 | (2.02%) |
High school | 962 | (12.7%) |
College/University not completed | 754 | (10.0%) |
College/University completed | 5711 | (75.3%) |
Paternal/partner education (missing N = 95, 1.25%) | ||
Grade school | 137 | (1.83%) |
High school | 1519 | (20.3%) |
College/University not completed | 590 | (7.88%) |
College/University completed | 5246 | (70.0%) |
Household income (missing N = 485, 6.4%) | ||
< 25 k | 415 | (5.84%) |
25 k - < 50 k | 1188 | (16.7%) |
50 k - < 80 k | 2077 | (29.2%) |
> =80 k | 3422 | (48.2%) |
MTHFR genotype b | ||
CC (wild type) | 1768 | (44.1%) |
CT (heterozygous) | 1760 | (43.9%) |
TT (mutant) | 478 | (11.9%) |
Effect of homocysteine
Variable | Odds ratio (95% CI) | p-value c | |
---|---|---|---|
Homocysteine (linear) | 0.0007 | ||
5 μmol/L increase | 1.629 | (1.227, 2.161) | |
Age (restricted cubic spline, three knots) | 0.0031 | ||
34 versus 27 years | 1.187 | (1.063, 1.325) | |
Race | 0.0002 | ||
Caucasian versus others | 0.644 | (0.509, 0.814) | |
Education | 0.0056 | ||
College/University completed versus less than completed | 0.763 | (0.630, 0.924) | |
Nulliparous | < 0.0001 | ||
Yes versus no | 1.941 | (1.636, 2.303) | |
Smoking | < 0.0001 | ||
No | Reference | ||
Second-hand | 0705 | (0.392, 1.268) | |
Med/light smoker (< 10 cigarettes per day) | 1.631 | (1.228, 2.166) | |
Heavy smoker (> 10 cigarettes per day) | 1.921 | (1.348, 2.737) | |
Diabetes | 0.0336 | ||
Yes versus no | 1.687 | (1.041, 2.733) | |
BMI (restricted cubic spline, four knots) | 0.0499 | ||
27.3 versus 21.1 kg/m2 | 1.057 | (0.883, 1.265) | |
Hormonal birth control prior to conception | 0.3692 | ||
No | Reference | ||
Oral | 0.927 | (0.784, 1.096) | |
Injection or IUD | 0.732 | (0.436, 1.227) | |
Chronic hypertension | < 0.0001 | ||
Yes versus no | 2.750 | (1.687, 4.483) | |
History of PMC (Preeclampsia, placental abruption, IUGR, stillbirth, loss) | 0.0110 | ||
Yes versus no | 1.359 | (1.073, 1.722) | |
Folic acid supplementation | 0.7328 | ||
Yes versus no supplementation | 0.943 | (0.674, 1.320) | |
Serum folate (linear) | 0.5326 | ||
45.1 versus 30.6 nmol/L | 1.025 | (0.949, 1.106) | |
Gestational age at blood work (restricted cubic spline, four knots) | 0.0004 | ||
13.7 versus 12.4 weeks | 0.939 | (0.804, 1.095) |
Outcome variable | Odds ratio (95% CI) b | p-value c | |
---|---|---|---|
Any placenta-mediated complication (759 events d) | |||
Homocysteine (linear) | 0.0007 | ||
5 μmol/L increase | 1.629 | (1.227, 2.161) | |
SGA (512 events d) | |||
Homocysteine (linear) | 0.0010 | ||
5 μmol/L increase | 1.756 | (1.254, 2.458) | |
SGA < 5th percentile (221 events d) | |||
Homocysteine (linear) | 0.0012 | ||
5 μmol/L increase | 2.022 | (1.322, 3.092) | |
Preeclampsia (227 events) | |||
Homocysteine (linear) | 0.0736 | ||
5 μmol/L increase | 1.546 | (0.959, 2.491) | |
Severe preeclampsia (43 events) | |||
Homocysteine (linear) | 0.0595 | ||
5 μmol/L increase | 1.762 | (0.978, 3.177) | |
Placental abruption (68 events) | |||
Homocysteine (linear) | 0.9851 | ||
5 μmol/L increase | 1.005 | (0.590, 1.711) | |
Pregnancy loss (85 events) | |||
Homocysteine (linear) | 0.1586 | ||
5 μmol/L increase | 1.392 | (0.879, 2.206) |
Subgroup analyses
Outcome variable | Odds ratio (95% CI) for 5 μmol/L increase b | p-value c | |
---|---|---|---|
TT | CC/CT | ||
Any placenta-mediated complication (395 events d) | 0.712 (0.243, 2.083) | 1.778 (1.159, 2.729) | 0.1172 |
SGA (277 events d) | 0.639 (0.161, 2.536) | 2.430 (1.450, 4.073) | 0.0714 |
Preeclampsia (109 events) | 1.174 (0.523, 2.633) | 1.258 (0.682, 2.322) | 0.8439 |
Outcome variable | Odds ratio (95% CI) for 5 μmol/L increase b | p-value c | |
---|---|---|---|
High-risk | Low-risk | ||
Any placenta-mediated complication (759 events d) | 2.368 (1.239, 4.525) | 1.595 (1.176, 2.163) | 0.2714 |
SGA (512 events d) | 2.474 (1.050, 5.828) | 1.821 (1.276, 2.597) | 0.5081 |
Preeclampsia (227 events) | 2.839 (1.187, 6.792) | 1.308 (0.743, 2.302) | 0.1351 |