The Pregnancy Exposome: Multiple Environmental Exposures in the INMA-Sabadell Birth Cohort

The
“exposome” is defined as “the totality
of human environmental exposures from conception onward, complementing
the genome” and its holistic approach may advance understanding
of disease etiology. We aimed to describe the correlation structure
of the exposome during pregnancy to better understand the relationships
between and within families of exposure and to develop analytical
tools appropriate to exposome data. Estimates on 81 environmental
exposures of current health concern were obtained for 728 women enrolled
in The INMA (INfancia y Medio Ambiente) birth cohort, in Sabadell,
Spain, using biomonitoring, geospatial modeling, remote sensors, and
questionnaires. Pair-wise Pearson’s and polychoric correlations
were calculated and principal components were derived. The median
absolute correlation across all exposures was 0.06 (5th–95th
centiles, 0.01–0.54). There were strong levels of correlation
within families of exposure (median = 0.45, 5th–95th centiles,
0.07–0.85). Nine exposures (11%) had a correlation higher than
0.5 with at least one exposure outside their exposure family. Effectively
all the variance in the data set (99.5%) was explained by 40 principal
components. Future exposome studies should interpret exposure effects
in light of their correlations to other exposures. The weak to moderate
correlation observed between exposure families will permit adjustment
for confounding in future exposome studies.