Environment/Climate Change
Environmental Metals and Depressive Symptoms among North American Pregnancy Planners: A Novel Application of Volumetric Absorptive Microsamplers (VAMS) for Epidemiologic Research Samantha Schildroth* Samantha Schildroth Schildroth Schildroth Schildroth Schildroth Schildroth Schildroth Schildroth Boston University School of Public Health
Background: Many metals and metalloids (hereafter, “metals”) are either neurotoxicants (e.g., heavy metals) or essential nutrients required for cellular processes. Exposure to metals can therefore affect health, often non-linearly or in opposing directions. However, less research has focused on psychosocial health outcomes, particularly among women. We assessed associations between capillary blood metal levels and depressive symptoms using volumetric absorptive microsamplers (VAMS) in a prospective preconception cohort.
Methods: We used cross-sectional data from 292 females participating in Pregnancy Study Online (PRESTO), a North American preconception cohort study. At baseline, we measured capillary whole blood concentrations of 22 metals collected in VAMs using a newly developed method and evaluated depressive symptoms using the Major Depression Index (MDI, range=0-50, higher scores reflected greater symptoms). We operationalized metals continuously (per 1-SD increase) or categorically (in tertiles, where there was evidence of non-linearity in splines). We used multivariable linear regression to estimate percent differences (β) in MDI scores with 95% CIs, adjusting for hypothesized confounders.
Results: Most metals were not strongly associated with depressive symptoms, though some heavy metals – e.g., lead, thallium – were weakly associated with higher MDI scores. Several nutrient metals were non-linearly associated with MDI scores: copper, for example, showed an inverted U-shaped association such that there were lower MDI scores for the first (β=-36.6%, 95% CI=-55.1%, -10.4%) and third (β=-27.7%, 95% CI=-48.6%, 1.8%) tertiles compared with the second tertile.
Conclusion: In this study of pregnancy planners, some metals were weakly associated with MDI scores, though the direction and magnitude of association varied by metal. This study represents one of the first to investigate metals and depressive symptoms among females during the sensitive preconception period.