PMID- 33120227 OWN - NLM STAT- MEDLINE DCOM- 20210421 LR - 20210421 IS - 1873-6750 (Electronic) IS - 0160-4120 (Linking) VI - 146 DP - 2021 Jan TI - Heart rate variation and human body burdens of environmental mixtures in the Cree First Nation communities of Eeyou Istchee, Canada. PG - 106220 LID - S0160-4120(20)32175-9 [pii] LID - 10.1016/j.envint.2020.106220 [doi] AB - INTRODUCTION: Heart rate variability (HRV) is a measure of cardiac autonomic regulation that examines the variation in beat-to-beat fluctuations in heart rate. While many exposure-based studies have examined the effects of single or similar groups of contaminants on HRV parameters, none have examined the association between complex environmental mixtures, including organic and elemental contaminants, and HRV. METHODS: Using data collected from the Multi-Community Environment-and-Health Study in Eeyou Istchee (Quebec, Canada), we assessed HRV in two time domain measures: root mean square of successive differences (RMSSD) and standard deviation of the N-N (RR) intervals (SDNN); and in three frequency domains: high frequency (HF), low-frequency (LF), and very-low frequency (VLF) in 443 participants. We first examined mixture effects of nineteen organic and metal contaminants in blood using principal component analysis (PCA) and a multivariable general linear regression on HRV responses, adjusting for age, sex, body mass index, smoking status, and kidney disease covariates. We subsequently assessed HRV outcome response variables using Bayesian kernel machine regression (BKMR) to further examine individual contaminant contribution and overall mixture effects. RESULTS: In the PCA, a significant positive association was observed between RMSSD and principal component (PC) axis 2, which was highly positively-loaded for nickel and moderately negatively-loaded for mercury. A negative association between SDNN and PC-1, which was highly positively-loaded for all PCBs (polychlorinated biphenyls) and organochlorines and moderately positively-loaded for mercury, was observed. Additionally, a significant and positive association was observed between PC-2 and SDNN and a significant and negative association between PC-3 (negatively loaded for cadmium) and LF. Associations with contaminants were not observed for HF or VLF. BKMR results suggest that trans-nonachlor and cis-nonachlor are primarily responsible for reductions in HRV; however, their contributions to HRV deficits was non-significant when examined as a complete mixture. CONCLUSIONS: While PCA results suggested that organochlorines, mercury, nickel, and cadmium may all play a role in altering various HRV, subsequent BKMR analysis illustrated the individual components driving these effects may be trans- and cis-nonachlor and nickel and likely not mercury or cadmium. However, other contaminants appear to temper this effect when the entire mixture of chemicals is assessed as a whole. This study expands our knowledge of the effects of environmental contaminant mixtures on HRV, which is especially important in exposed populations such as those in the Eeyou Istchee territory, whilst utilizing novel statistical methods such as PCA and BKMR to examine co-exposures concurrently. CI - Copyright (c) 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved. FAU - Liberda, Eric N AU - Liberda EN AD - School of Occupational and Public Health, Ryerson University, Toronto, Ontario, Canada. Electronic address: eric.liberda@ryerson.ca. FAU - Zuk, Aleksandra M AU - Zuk AM AD - School of Nursing, Queen's University, Kingston, Ontario, Canada; Department of Physical and Environmental Sciences, University of Toronto, Toronto, Ontario, Canada. FAU - Tsuji, Leonard J S AU - Tsuji LJS AD - Department of Physical and Environmental Sciences, University of Toronto, Toronto, Ontario, Canada. LA - eng GR - 156396/CAPMC/CIHR/Canada PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20201026 PL - Netherlands TA - Environ Int JT - Environment international JID - 7807270 RN - 0 (Environmental Pollutants) SB - IM MH - Bayes Theorem MH - Body Burden MH - Canada MH - *Environmental Pollutants/analysis/toxicity MH - Heart Rate MH - Humans MH - Quebec OTO - NOTNLM OT - Contaminants OT - Exposure OT - First Nations OT - Heart rate variation OT - Indigenous EDAT- 2020/10/30 06:00 MHDA- 2021/04/22 06:00 CRDT- 2020/10/29 20:09 PHST- 2020/07/14 00:00 [received] PHST- 2020/09/25 00:00 [revised] PHST- 2020/10/14 00:00 [accepted] PHST- 2020/10/30 06:00 [pubmed] PHST- 2021/04/22 06:00 [medline] PHST- 2020/10/29 20:09 [entrez] AID - S0160-4120(20)32175-9 [pii] AID - 10.1016/j.envint.2020.106220 [doi] PST - ppublish SO - Environ Int. 2021 Jan;146:106220. doi: 10.1016/j.envint.2020.106220. Epub 2020 Oct 26.