The Effect Of Different Size Particulate Matter Exposure Of Pregnant Women On Inflammatory Levels And Renal Function In Guangzhou:A Cohort Study

BackgroundThe regulation of inflammation is important for normal pregnancy,and the imbalance between pro-inflammatory and anti-inflammatory can lead to abnormal inflammation,which can lead to adverse pregnancy outcome.Exposure of pregnant women to airborne particulates can cause inflammatory reactions and kidney function injury in pregnant women,which may affect the health of pregnant women and fetuses.To understand the relationship between exposure to inflammatory levels of pregnant women and renal function injury with different particle sizes before and during pregnancy in Guangzhou,and to clarify their exposure sensitive window.MethodsSince January 2016,the birth cohort study on Prenatal Environments and Offspring Health（PEOH）has been established in Guangzhou.The study site was selected as Guangzhou Panyu Central Hospital,and the eligible pregnant women were recruited as the study subjects in the outpatient department of obstetrics.A total of 4928 cases were recruited in this study and followed up during their delivery in the hospital,of which 649 pregnant women were lost to follow-up due to relocation and other reasons.4279 cases were successfully followed up（follow-up rate 86.8%）.Participants lacking information on key variables were excluded,including those pregnant women who younger than16 years old or older than 50（3）,pregnant women with missing urine test information（267）,pregnant women with missing blood test information（193）,pregnant women with missing pre-pregnancy BMI（8）,pregnant women with lack of education（2）,Pregnant women with missing fetal sex（4）,pregnant women who failed to assess the exposure level of environmental pollutants due to missing key variables（49）.Finally,3753 pregnant women were included in the final analysis.A spatiotemporal land–use-regression model was used to estimate a pregnant woman’s weekly PM₁₀,PM_2.5exposure from 13 weeks before pregnancy to the sampling week in the third trimester,and the weekly PM₁exposure was estimated by the generalized additive model（GAM）.A distributed lag non-linear model incorporated with a Cox proportional hazard model was employed to assess the effect of weekly-specific maternal PM₁₀,PM_2.5and PM₁exposure on the risk of urinary leukocyte,urinary occult blood and urinary glucose positive and identify susceptible exposure windows;and a distributed lag non-linear model was applied to assess the exposure–lag-response associations between weekly PM₁₀,PM_2.5and PM₁exposure and neutrophils and white blood cell count and identify susceptible exposure windows,respectively.All analyses were performed in R 3.6.1（R Development Core Team 2017）.The statistical test is a two-sided test,and P<0.05 is considered statistically significant.ResultsThis study included 3753 pregnant women.There were 3556 pregnant women（94.8%）aged≥26 years old,and 3521 pregnant women gestational week（93.8%）>37 weeks.The weekly mean concentrations of PM₁₀PM_2.5and PM₁during the entire study period were 48.72±14.66μg/m³,32.06±10.24μg/m³and 27.92±9.50μg/m³,respectively.The average neutrophil count of pregnant women was 7.86±4.21×10⁹/L and the average white blood cell count of pregnant women was 10.31±3.07×10⁹/L;and there were1298（34.6%）people in the urinary leukocyte positive group,and the urinary glucose positive group had 160（4.5%）people,234（6.2%）people in the urinary occult blood positive group.The results showed that maternal exposure to PM₁₀,PM_2.5and PM₁during the 5th week before pregnancy to 8th gestational weeks,5th week before pregnancy to 6th gestational weeks and 6th week before pregnancy to6th gestational weeks were associated with white blood cell counts increasement,the strongest association was observed in 1st gestational week,zero gestational week,and the zero gestational week,during which each10μg/m³increment in PM₁₀,PM_2.5and PM₁was associated with a0.181%（95%CI:0.094%～0.267%）,0.227%（95%CI:0.988%～0.346%）and0.276%（95%CI:0.133%～0.419%）increase in white blood cell counts,respectively.The results showed that maternal exposure to PM10,PM2.5 and PM₁during the 5th week before pregnancy to 9th gestational weeks,3th week before pregnancy to 7th gestational weeks and 4th week before pregnancy to7th gestational weeks were associated with neutrophils counts increment,the strongest association was observed in the 1st gestational week,during which each 10μg/m³increment in PM₁₀,PM_2.5and PM₁was associated with a0.228%（95%CI:0.117%～0.338%）,0.284%（95%CI:0.124%～0.443%）and0.359%（95%CI:0.175%～0.542%）increase in neutrophils counts,respectively.The risk of urinary leukocyte was positively associated with PM₁₀,PM_2.5and PM₁exposure during the 23th to 26th gestational weeks,20th to 27th gestational weeks,and 20th to 27th gestational weeks,and the strongest association was observed in 24th gestational week,24th gestational week and25th gestational week,respectively,during which each 10μg/m³increment in PM₁₀,PM_2.5and PM₁were associated with the hazard risk（HR）were1.018（95%CI:1.002～1.034）、1.030（95%CI:1.001～1.054）and 1.032（95%CI:1.007～1.060）.The risk of urinary glucose was positively associated with PM₁₀,PM_2.5and PM₁exposure during the 20th to 26th gestational weeks,20th to28th gestational weeks,and 20th to 28th gestational weeks,and the strongest association was observed in 24th gestational week、25th gestational week and25th gestational week,respectively,during which each 10μg/m³increment in PM₁₀,PM_2.5and PM₁were associated with the hazard risk（HR）were1.018（95%CI:1.002～1.032）、1.035（95%CI:1.008～1.064）and 1.035（95%CI:1.008～1.062）.Conclusion（1）The susceptible exposure window of white blood cell counts might be the 5th week before pregnancy to 8th gestational weeks,5th week before pregnancy to 6th gestational weeks and 6th week before pregnancy to 6th gestational weeks.The susceptible exposure window of neutrophils counts might be the 5th week before pregnancy to 9th gestational weeks, 3th week before pregnancy to 7th gestational weeks and 4th week before pregnancy to 7th gestational weeks.（2）The susceptible exposure window of positive urinary leukocyte might be the 23th to 26th gestational weeks,20th to 27th gestational weeks,and 20th to 27th gestational weeks.The susceptible exposure window of positive urinary glucose might be the 20 th to 26 th gestational weeks,20th to 28th gestational weeks,and 20th to 28th gestational weeks.（3）Exposure of pregnant women to PM₁₀,PM_2.5and PM₁during pregnancy will increase the level of inflammation and cause renal function impairment,and the smaller the particle size,the greater the effect.