Study links long-term air pollution exposure to postpartum depression risk

Study links long-term air pollution exposure to postpartum depression risk | Image Credit: © ttlsc – © ttlsc – stock.adobe.com.

Postpartum depression (PPD) risks are increased by long-term antepartum and postpartum air pollution exposure, according to a recent study published in JAMA Network Open.

PPD is one of the most frequent complications of childbirth, impacting approximately 10% to 20% of women worldwide. Symptoms associated with PPD include anxiety, depressed mood, and anhedonia, and infants of mothers with PPD are at increased risks of emotional, cognitive, and psychological impairments.

Data has indicated potential associations between air pollution exposure and various health concerns, including neuropsychological disorders leading to poor mental health. A link between air pollution and mental health disorders has been supported by increasing evidence. However, there is little data on the association between air pollution exposure and PPD.

To evaluate the associations between maternal air pollution exposure and PPD, investigators conducted a retrospective cohort study. Women with births from January 1, 2008, to December 31, 2016, were included in the analysis.

Exclusion criteria included not being a Kaiser Permanente Southern California (KPSC) member, giving birth at under 20 weeks’ or over 47 weeks’ gestation, having multiple births, not having a residential address, and having a stillbirth. Data on demographic characteristics, birth records, medical records, and individual lifestyles was obtained from KPSC electronic health records (EHRs).

The Edinburgh Postnatal Depression Scale (EPDS) was used to evaluate PPD. Scores of 10 or more were considered positive, with participants reaching this score referred to a clinical interview for additional evaluation and care. International Classification of Diseases, Ninth and 10th Revision diagnostic codes were used to confirm PPD diagnosis.

Exposures included particulate matter less than or equal to 2.5 μm (PM2.5), particulate matter less than or equal to 10 μm (PM10), nitrogen dioxide (NO2), and ozone (O3). Air pollution measurements of these exposures were obtained from the US Environmental Protection Agency’s monitoring stations.

KPSC EHRs were evaluated for residential data during pregnancy, with monthly air pollution estimates linked to participants based on geocoded residential history. Covariates included maternal age, race and ethnicity, educational level, smoking status during pregnancy, passive smoking exposure, season of conception, and year of infant birth.

There were 340,679 singleton births included in the analysis. PPD was reported in 7.54% of mothers at 6 months after delivery, 35.98% of which had both a PPD diagnosis and prescription medications, 24.5% were found only with diagnostic codes, and 39.52% were found through supplemental pharmacy records.

PPD was more common among participants who were older, Black, non-Hispanic White, had under 4 years of college education or more than a college education, living in low-income neighborhoods or rural areas, overweight, and smoked during pregnancy.

Exposures positively linked to PPD included PM2.5, PM10, and O3, with O3 having the strongest odds ratio (OR) per IQR increase of 1.09. This was followed by PM10 and PM2.5, both with an OR of 1.02. A significant association between NO2 and PPD was not found.

These results indicated long-term antepartum and postpartum air pollution exposure is associated with PPD. Study authors concluded, “identifying the modifiable environmental risk factors and developing interventions are important public health issues.”

Reference

Sun Y, Headon KS, Jiao A, et al. Association of antepartum and postpartum air pollution exposure with postpartum depression in southern California. JAMA Netw Open. 2023;6(10):e2338315. doi:10.1001/jamanetworkopen.2023.38315