Table 2 shows the results of the modified Poisson regression analysis in
the overall population. We did not observe significant associations
between prenatal depression and childhood respiratory outcomes.
Postpartum depression was significantly associated with increased risk
of current wheeze (RR: 1.88, 95% CI: 1.21, 2.92) and asthma (RR: 2.79,
95% CI: 1.13, 6.87) at 48 months. We observed an association between
postpartum depression and any current wheeze (RR: 1.59, 95% CI: 1.03,
2.46) and ever asthma (RR: 2.15, 95% CI: 1.06, 4.39). Lastly, a
statistically significant association was observed between postpartum
depression and ever wheeze at 72 months (RR: 1.54, 95% CI: 1.02, 2.32).
Maternal recurrent depression was associated with an increased risk of
ever wheeze at 48 months (RR: 1.48, 95% CI: 1.07, 2.03) and 72 months
(RR: 1.76, 95% CI: 1.12, 2.77). It was also associated with increased
risks of current wheeze (RR: 2.39, 95% CI: 1.52, 3.78) and asthma at 48
months (RR: 3.14, 95% CI: 1.26, 7.84). Additionally, we found that
recurrent depression was associated with increased risks of any ever
wheeze (RR: 1.53, 95% CI: 1.15, 2.03), any current wheeze (RR: 2.08,
95% CI: 1.32, 3.28), and ever asthma (RR: 2.46, 95% CI: 1.16, 5.21).
In two-way interaction models, we found evidence for effect modification
by sex for postpartum (pinteraction= 0.06) and recurrent
depression (pinteraction= 0.06) on current wheeze at 48
months. As shown in figure 1, postpartum depression were associated with
higher risk of current wheeze at 48 months in females (RR: 3.04, 95%
CI: 1.47, 6.27) when compared to males (RR: 1.53, 95% CI: 0.87, 2.68).
We observed a similar pattern for recurrent depression, with females
having a higher risk of current wheeze (RR: 3.95, 95% CI: 1.86, 8.36)
when compared to males (RR: 1.92, 95% CI: 1.06, 3.46). We also found
interactions between child sex and postpartum depression
(pinteraction= 0.05) on current wheeze at 72 months
(figure 2). Sensitivity analyses including additional adjustment for
average PM2.5 in the first 2 postnatal years,
breastfeeding, and SES showed similar results (results not shown).