Effects of PM 2.5 exposure on metabolic dysfunction during pregnancy via personalized measurement of pollutant concentration in South Korea: A multicenter prospective cohort, air pollution on pregnancy outcome (APPO) study

Background: Ambient particulate matter (PM) is a trigger factor for metabolic dysfunction. This study aimed to evaluate the associations between PM exposure and metabolic dysfunction in pregnancy. Methods This prospective, multicentre, observational, cohort study was conducted from January 2021 to June 2022. A total of 333 women with singleton pregnancies were recruited. For individual measurement of PM 2.5 levels, an AirguardK ® was installed inside the participants’ houses. Time-activity logs were recorded to predict each participant’s personal exposure to PM 2.5 . The participants were divided into groups according to the concentration of PM 2.5 calculated by a time-weighted average model. We used the Student t-test and chi-squared test (or Fisher’s exact test) to evaluate changes in metabolic compound levels, blood pressure (BP), glucose intolerance, and lipid profiles, including serum triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) ratios. Logistic and linear regression models were used to analyse the association between PM 2.5 exposure and metabolic dysfunction, using odds ratios (ORs) and 95% confidence intervals (CIs). Results PM 2.5 exposure during pregnancy worsened metabolic dysfunction. Third trimester BP was elevated in those participants exposed to higher levels of PM 2.5 (p <0.05). The incidence of gestational diabetes mellitus (GDM) was constantly higher in those exposed to more PM 2.5 , regardless of the PM 2.5 cut-off level (PM 2.5 ≥10 µg/m 3 , 7.91 % vs. 16.09 %, p <0.05; PM 2.5 ≥25 µg/m 3 , 7.91 % vs. 26.67 %, p <0.05). The proportion with a TG/HDL-C ratio ≥3.0 was significantly higher when PM 2.5 was ≥10 µg/m 3 (75.3 % vs. 83.0 %, p <0.05). Triglyceride levels were significantly higher in the PM 2.5 ≥25 µg/m 3 group (p=0.0171). We found an increased risk of elevated BP (adjusted OR [aOR]: 2.228, 95% CI: 1.115–4.449) and GDM (aOR 2.263, 95% CI 1.106–5.039) in the third trimester after adjusting for confounders. Conclusion Exposure to PM 2.5 worsens metabolic dysfunction in pregnancy. Further studies are required to investigate the mechanisms by which ambient PM affects metabolic dysfunction in pregnancy.