Table 2.
Stratified analysesa by genotypes of the PTPRD rs35331017 variant for the association between lifetime stress and spontaneous PTB in the mothers from the Boston Birth Cohort
| Maternal stress | Mothers carrying rs35331017 II genotype | Mothers carrying rs35331017-ID / DD genotype | Pint c | ||||||
|---|---|---|---|---|---|---|---|---|---|
|
|
|
||||||||
| sPTB | TB | OR (95% CI)b | Pb | sPTB | TB | OR (95% CI)b | Pb | ||
|
| |||||||||
| Maternal lifetime stress | |||||||||
| Low a | 116 | 368 | 1.0 | Ref | 28 | 26 | 1.0 | Ref | |
| Average | 226 | 473 | 1.46 (1.11–1.93) | 0.007 | 11 | 57 | 0.10 (0.03–0.27) | 1.1×10−5 | |
| High | 72 | 91 | 2.09 (1.40–3.11) | 0.0003 | 2 | 14 | 0.05 (0.01–0.32) | 0.0014 | 4.7×10−8 |
|
| |||||||||
| Maternal stress during pregnancy | |||||||||
| Low a | 123 | 352 | 1.0 | Ref | 23 | 30 | 1.0 | Ref | |
| Average | 186 | 415 | 1.25 (0.94–1.65) | 0.123 | 12 | 41 | 0.26 (0.10–0.68) | 0.006 | |
| High | 104 | 163 | 1.60 (1.14–2.26) | 0.007 | 4 | 23 | 0.11 (0.03–0.43) | 0.0014 | 1.2×10−5 |
CI: confidence interval. OR: odds ratio; sPTB: Spontaneous preterm birth; TB: Term birth.
a
The “low” category as the reference group in each genotype strata.
b
Adjusted for genotyping batch, maternal genetic ancestry, age at delivery, marital status, parity, social support from the baby’s father and newborn sex.
c
The interaction effect was analyzed in the total sample by adding lifetime stress, rs35331017 (under the additive genetic model) and their interaction term into the regression model, with adjustment of the same covariates as mentioned above.