Maternal occupational exposure to carbonaceous nanoscale particles and neurodevelopmental outcomes in early childhood: Analysis of the French Longitudinal Study of Children - Elfe study

OBJECTIVE

To investigate the association between occupational exposures to carbonaceous unintentionally emitted nanoscale particles (UNPs) during pregnancy and the child's language development and behaviour at two years old.

METHODS

Using data from the French Longitudinal Study of Childhood - ELFE, we selected mothers who worked during pregnancy and their children. Exposure to carbonaceous UNPs was assessed by the MatPUF (job-exposure matrix for ultrafine particles). Children's lexical development was analysed using 'the Mac Arthur - Bates communicative development inventories-words and sentences-short form' (MB-CDI) in a multivariate binary logistic regression. Their risk for autism spectrum disorders was studied using 'the Modified-CHecklist for Autism in Toddler' (M-CHAT) according to the recommended thresholds (low risk = 0-2; intermediate risk = 3-6 and high risk = 7-23) in unordered multinomial logistic regression models.

RESULTS

Maternal occupational exposure to carbonaceous UNPs was associated with delayed child language development (ORadj: 1.34; 95 % CI: 1.00, 1.80) but not with behavioural disorders (autism spectrum disorders) at two years old.

CONCLUSION

This is the first epidemiological study to show a significant association between maternal occupational exposure to carbonaceous nanoscale particles and child language development at 2 years old.

Maternal occupational exposure to carbonaceous nanoscale particles and small for gestational age and the evolution of head circumference in the French Longitudinal Study of Children - Elfe study

OBJECTIVES

To investigate the association between exposure to unintentionally emitted carbonaceous nanoscale particles (NPs) and small for gestational age (SGA), as well as head circumference (HC) at birth and at two years of age.

METHODS

Mothers from the French Longitudinal Study of Children (Elfe cohort) who worked during pregnancy were selected for our study. Data collected at birth and during follow-up (up to two years) were used. The probability and frequency of maternal occupational exposure to unintentionally emitted carbonaceous NPs was estimated using a job exposure matrix (MatPUF). Multivariate logistic regression, linear regression, and mixed models were applied to estimate any associations. Analyses were carried out depending on whether mothers stopped working during the first, second, or third trimester of pregnancy.

RESULTS

Maternal occupational exposure to unintentionally emitted carbonaceous NPs was associated with SGA in the overall study population by multivariate analysis (ORa = 1.80, 95% CI: 1.29, 2.46), as well as in sub-groups of mothers who stopped working during the second (ORa = 1.84, 95% CI: 1.13, 3.02) or third (ORa = 1.80, 95% CI: 1.10, 2.95) trimesters. There were no significant associations with HC at birth or two years of age.

CONCLUSIONS

We found a significant association between occupational exposure to carbonaceous NPs and SGA, with the effect depending on the period of exposure during pregnancy. These results should encourage further studies concerning the adverse effects of exposure to carbonaceous NPs on the development of offspring.