Wei-Jen Chen, Alison M. Rector, Monica Guxens, Carmen Iniguez, Michael D. Swartz, Elaine Symanski, Jesús Ibarluzea, Albert Ambros, Marisa Estarlich, Aitana Lertxundi, Isolina Riano-Galán, Jordi Sunyer, Ana Fernandez-Somoano, Suneet P. Chauhan, Jennifer Ish, Kristina W. Whitworth, and Child and Adolescent Psychiatry / Psychology
While prior studies report associations between fine particulate matter (PM2.5) exposure and fetal growth, few have explored temporally refined susceptible windows of exposure. We included 2328 women from the Spanish INMA Project from 2003 to 2008. Longitudinal growth curves were constructed for each fetus using ultrasounds from 12, 20, and 34 gestational weeks. Z-scores representing growth trajectories of biparietal diameter, femur length, abdominal circumference (AC), and estimated fetal weight (EFW) during early (0-12 weeks), mid- (12-20 weeks), and late (20-34 weeks) pregnancy were calculated. A spatio-temporal random forest model with back-extrapolation provided weekly PM2.5 exposure estimates for each woman during her pregnancy. Distributed lag non-linear models were implemented within the Bayesian hierarchical framework to identify susceptible windows of exposure for each outcome and cumulative effects [βcum, 95% credible interval (CrI)] were aggregated across adjacent weeks. For comparison, general linear models evaluated associations between PM2.5 averaged across multi-week periods (i.e., weeks 1-11, 12-19, and 20-33) and fetal growth, mutually adjusted for exposure during each period. Results are presented as %change in z-scores per 5 μg/m3 in PM2.5, adjusted for covariates. Weeks 1-6 [βcum = -0.77%, 95%CrI (-1.07%, -0.47%)] were identified as a susceptible window of exposure for reduced late pregnancy EFW while weeks 29-33 were positively associated with this outcome [βcum = 0.42%, 95%CrI (0.20%, 0.64%)]. A similar pattern was observed for AC in late pregnancy. In linear regression models, PM2.5 exposure averaged across weeks 1-11 was associated with reduced late pregnancy EFW and AC; but, positive associations between PM2.5 and EFW or AC trajectories in late pregnancy were not observed. PM2.5 exposures during specific weeks may affect fetal growth differentially across pregnancy and such associations may be missed by averaging exposure across multi-week periods, highlighting the importance of temporally refined exposure estimates when studying the associations of air pollution with fetal growth. This work was supported by grant R01ES028842 from the National Institutes of Health / National Institute of Environmental Health Sciences (NIH/ NIEHS); grants Red INMA G03/176, CB06/02/004; ISCIII-FEDER: PI03/1615, PI04/1509, PI04/1112, PI04/1931, PI04/2018, PI05/1079, PI05/1052, PI06/0867, PI06/1213, PI07/0314, PI09/02311, PI09/02647, PI11/01007, PI11/02591, PI11/02038, PI13/1944, PI13/2032, PI13/02429, PI14/00891, PI14/01687, PI16/1288, PI16/00118, PI17/00663, PI18/00909, PI18/01142, PI18/01237; Miguel Servet-FEDER CP11/00178, CP15/00025, CPII16/00051, CPII18/00018, and CP16/00128 from Instituto de Salud Carlos III, grant 1999SGR 00241 from Generalitat de Catalunya- CIRIT, grant FP7-ENV-2011 cod 282957 and HEALTH. 2010.2.4.5–1 from the EU Commission, Assistance Award No. R-82811201 from the Health Effects Institute, grant UGP 15-230, UGP-15-244, and UGP-15-249 from Generalitat Valenciana: FISABIO, grant 2005111093 from Alicia Koplowitz Foundation (2017), Department of Health of the Basque Government, grant DFG06/002 from the Provincial Government of Gipuzkoa, and annual agreements with the municipalities of the study area (Zumarraga, Urretxu, Legazpi, Azkoitia y Azpeitia y Beasain), Obra Social Cajastur/Fundación Liberbank, and Universidad de Oviedo. We also acknowledge support from the Spanish Ministry of Science and Innovation and the State Research Agency through the “Centro de Excelencia Severo Ochoa 2019–2023” Program (CEX2018-000806-S), and support from the Generalitat de Catalunya through the CERCA Program. KWW and ES were partially supported by the P30 Environmental Health Sciences Core Center grant P30ES030285 from the NIH/NIEHS and by funding from the NIH/National Institute on Minority Health and Health Disparities (NIMHD) under Award Number P50MD015496. JI was supported by the Intramural Research Program of the NIH, National Institute of Environmental Health Sciences.