Bone Remodeling and Metals Exposure during Pregnancy: Results from Progress Cohort

Abstract

Background: Environmental exposure to metals has been associated with decreased bone density and higher risk of fracture mainly among premenopausal women and older adults. Metals such as lead (Pb) and cadmium (Cd) interfere with calcium incorporation into the bone cells leading to low bone density. However, little is known about the effects of metals exposure on bone remodeling during pregnancy, a window of susceptibility to the toxic effects of metals.Objective: The aim of this study was to assess concurrent exposure to metals [Pb, Cd, chromium (Cr) and arsenic (As)] and bone remodeling at radius during second and third trimester of pregnancy.Methods: We studied 1,054 mothers from PROGRESS cohort (Programming Research in Obesity, Growth, Environment and Social Stress). We measured BMD at radius by ultrasound and metals exposure by inductively coupled plasma during second and third trimesters of pregnancy. We generated linear mixed models to assess associations between metals exposure and z-scores at radius during second and third trimesters of pregnancy. Additionally, at each trimester of pregnancy, we assessed associations between metals exposures and z-scores using simple linear regression models.Results: At third trimester of pregnancy, Pb and Cr were associated with lower z-score at radius [for Pb (estimate: -0.89; 95% CI: -1.54, -0.24) and for Cr (estimate:-0.70; 95% CI: -1.37, -0.34)] in adjusted models. Similarly, we observed a decreasing trend in z-score at radius associated with Pb and Cr exposure during pregnancy, although it was not statistically significant. Overall, we did not observe associations between Cd or As and z-scores during pregnancy.Conclusions: Lead and chromium exposure during the third trimester of pregnancy might decrease bone remodeling at radius. Further studies should be conducted to assess bone remodeling at different anatomic sites in relation to metals exposure during pregnancy.