Impact Of Infant Exposure To Pyrethroid Pesticides On Their Neurodevelopment In Rural Areas

Objective(s):The study aimed to understand the infant pyrethroid pesticides(PYRs)exposure status and explore its correlation factors,and to explore the impact of infanthood exposure to PYRs on their neurodevelopment in rural areas.Methods:This study was based on the establishment of birth cohort study in Xuanwei of Yunnan.Recruiting infants when infants born and following up them until 1 year old.A questionnaire surveyed on sociodemographic characteristics,infant feeding and nurturing situation,baby’s life and living environment,etc.And urine samples of infants both at the age of half year and 1 year were collected.The PYRs metabolites 3-PBA,4-F-3-PBA and DBCA in urine samples were measured by High Performance Liquid Chromatography-Mass Spectrometry.Creatinine reagent was used to measure the creatinine value of the urine samples.Scales of Infant Development(3rd edition)was used to evaluate the neurodevelopmental status of 1-year-old infants.T test,one Way ANOVA,Correlation analysis,Multiple linear regression and Logistic regression analysis were used to explore the correlation factors of infant PYRs exposure and the impact of infanthood PYRs exposure on their neurodevelopment.Results:(1)A total of 230 babies were included in the study.53.91%were girls and 46.09%were boys,83.48%were Han nationality.The average maternal and paternal age were 25.45±5.29 years old and 28.83±5.23 years old,the total of 47.83%and 57.39%received middle school education,76.52%and 60.00%were farmers.The annual household income less than 10,000 RMB accounted for 23.48%.The average weight,length and gestational age of newborns were 3251.56±398.47g,50.09 ±1.22cm,39.34±1.30 weeks,and 21.74%were born abnormally.The total of 92.61%of infants were cared by their mothers.Infants fed with nutritional supplements accounted for 71.74%.(2)Among infants at the age of half year and 1 year,the median original concentrations of 3-PBA,4-F-3-PBA,DBCA were 0.099ng/ml,0.153ng/ml,<LOD and 0.374ng/ml,0.207ng/ml,<LOD,respectively.However,after urinary creatinine correction,the median concentrations of 3-PBA,4-F-3-PBA,DBCA were 0.301ug/g,0.626ug/g,<LOD and 0.850ug/g,0.668ug/g,<LOD,respectively.(3)Multiple linear regression analysis showed that the mother’s occupation of farming was positively correlated with the infant’s total PYRs exposure concentration(β=0.20,P=0.014,95%CI=0.04～0.36).The annual family income more than 2,5000 RMB was positively correlated with the infant’s total PYRs exposure concentration(β=0.20,P=0.025,95%CI=0.02～0.37).Frequent or every time carrying the infant to work in the field was positively correlated with the infant’s total PYRs exposure concentration(β=0.17,P=0.016,95%CI=0.03～0.31).(4)The scores of BSID-Ⅲ of infants were 98.98±17.20 for cognitive,97.76±15.25 for language,93.33±15.49 for motor,109.72±23.07 for social emotion and 89.66±16.81 for adaptive behavior.The developmental retardation rates of cognitive,language,motor,social emotion and adaptive behavior were 2.61%,5.65%,3.48%,1.30%,11.30%,respectively.(5)Multiple linear regression analysis showed that the DBCA concentration was positively correlated with the social emotion scores and adaptive behavior scores of infants at 1-year-old(β=3.56,95%CI=0.73～6.39,P=0.014.β=3.16,95%CI=0.85～5.47,P=0.008).Logistic regression analysis showed that infants’ 4-F-3-PBA high-exposure group language developmental retardation was 0.31 times of the low-exposure group,and the DBCA exposure group language and adaptive behavior developmental retardation were 0.38 times and 0.39 times of the unexposed group at 1-year-old(OR=0.31,95%CI=0.13～0.77,P=0.011.OR=0.38,95%CI=0.15～0.96,P=0.041.OR=0.39,95%CI=0.16～0.96,P=0.040),respectively.Conclusion(s):The majority of infants were exposured to low-level PYRs in rural areas.Mother occupation,annual household income,working in the filed with babies were important correlation factors to infants PYRs exposure.Moreover,It has not been found that low-level exposure to pyrethroid pesticides in rural infants’ daily life has a negative impact on their neurodevelopment.But considering the small sample size,further research is needed.Research suggests that caregivers should take personal protection and cleanliness when using pesticides.Meanwhile,extending the pesticides use safety interval,to reduce the exposure of infants to PYRs.We should continue to monitor the development of infants with a history of pesticides exposure to observe the long-term effects of pyrethroid pesticide exposure on the neurodevelopment of infants.