(P18-052-23) Interactions Between Gestational Dairy Consumption and Exposure to Secondhand Smoke on the Risk of Antenatal Depression: A Cross-Sectional Study in 10 Cities of China

Objectives: Exposure to secondhand smoke (SHS) during pregnancy may increase the risk for antenatal depressive (AD) symptoms, but few studies have investigated the joint effects of exposure to SHS and dairy consumption. This study aimed to explore whether gestational dairy consumption modified the association between SHS and AD.

Methods: In this cross-sectional study, a total of 907 nonsmoking pregnant women from 10 cities in China were included. The Edinburgh Postnatal Depression Scale (EPDS) was used to screen for AD, and those with scores ≥ 9 were considered to have depression. SHS exposure and dairy consumption during pregnancy were measured using a self-report questionnaire. Logistic regression was used to examine the individual and joint effects of gestational SHS exposure and dairy consumption on AD, followed by strata-specific analyses.

Results: The prevalence of antenatal depression in China was 33.0%. The rate of low dairy consumption in the AD group was significantly higher than that in the non-AD group (81.3% vs 76.2%, P = 0.081), as was the exposure rate of SHS (28.4% vs 18.8%, P < 0.001). SHS was independently associated with a 70% increased risk of AD [adjusted odds ratio (aOR) = 1.70, 95% confidence interval (CI): 1.22, 2.37], while no significant association was observed between dairy consumption and AD. However, we observed that exposure to SHS with low dairy consumption had a significantly higher likelihood of AD than non-SHS exposed people with high dairy consumption among nonsmoking Chinese pregnant women (OR = 2.31, 95% CI: 1.42, 3.76, P_interaction = 0.001), indicating a potential combined effect of SHS and dairy consumption on AD. This synergistic effect was more obvious when stratified by BMI (in obese pregnant women, aOR, 95% CI =4.96, 1.48-16.65 for interaction vs 2.82, 1.27-6.27 for SHS only) and pregnancy period (in third-trimester gestation, aOR, 95% CI =3.74, 1.71-8.20 for interaction vs 2.96, 1.67-5.28 for SHS only).

Conclusions: Antenatal depressive prevention strategies aimed at reducing SHS exposure and improving dairy consumption during pregnancy may exceed the expected benefits based on targeting either risk factor alone, with more significant effects in pregnant women who were obese or in the third trimester.

Funding Sources: The study was supported by the Applied Technology Research and Development Fund of Inner Mongolia (No. 2019YL0416).