Associations of baroreflex sensitivity, heart rate variability, and initial orthostatic hypotension with prenatal and recent postnatal methylmercury exposure in the Seychelles Child Development Study at age 19 years

Autor: Daniel Périard, Bujar Beqiraj, Pascal Bovet, Daniel Hayoz, Bharathi Viswanathan, Gary J. Myers, Philip W. Davidson, Sally W. Thurston, Katie Evans
Rok vydání: 2014
Předmět:
Male
medicine.medical_specialty
mercury
Health
Toxicology and Mutagenesis
lcsh:Medicine
030204 cardiovascular system & hematology
Baroreflex
Seychelles
Article
03 medical and health sciences
Orthostatic vital signs
Hypotension
Orthostatic
Young Adult
0302 clinical medicine
Heart Rate
Pregnancy
Internal medicine
Heart rate
medicine
Heart rate variability
Humans
business.industry
lcsh:R
Public Health
Environmental and Occupational Health
heart rate variability
Environmental exposure
Environmental Exposure
Methylmercury Compounds
medicine.disease
baroreflex sensitivity
methyl mercury
Blood pressure
Anesthesia
Prenatal Exposure Delayed Effects
Cohort
Cardiology
Environmental Pollutants
Female
business
Baroreflex/drug effects
Environmental Exposure/adverse effects
Environmental Pollutants/toxicity
Heart Rate/drug effects
Hypotension
Orthostatic/chemically induced
Methylmercury Compounds/toxicity
Prenatal Exposure Delayed Effects/chemically induced
030217 neurology & neurosurgery
Zdroj: International Journal of Environmental Research and Public Health
International Journal of Environmental Research and Public Health, vol. 12, no. 3, pp. 3395-3405
Volume 12
Issue 3
Pages 3395-3405
International Journal of Environmental Research and Public Health, Vol 12, Iss 3, Pp 3395-3405 (2015)
ISSN: 1660-4601
Popis: Background: A few studies have suggested an association between prenatal exposure to methylmercury and decreased heart rate variability (HRV) related to autonomic heart function, but no study has examined this association using baroreflex sensitivity (BRS). In this study we assessed the distribution of BRS and immediate orthostatic hypotension (IOH) in young Seychellois adults and their associations with exposure to prenatal and recent postnatal methylmercury. Methods: Subjects in the Seychelles Child Development Study (SCDS) main cohort were evaluated at age 19 years. Non-invasive beat-to-beat blood pressure (BP) monitoring (Finapres, Ohmeda) was performed at rest and during active standing in 95 consecutive subjects. Recent postnatal mercury exposure was measured in subjects’ hair at the age of 19 years and prenatal exposure in maternal hair grown during pregnancy. BRS was estimated by sequence analysis to identify spontaneous ascending and descending BP ramps. HRV was estimated by the following markers: PNN50 (relative numbers of normal-to-normal intervals which are shorter by more than 50 ms than the immediately following normal-to-normal intervals)
rMSSD (root mean of the squared sum of successive interval differences)
LF/HF (low frequency/high frequency component ratio)
ratio of the mean expiratory/inspiratory RR intervals (EI ratio)
and the ratio between the longest RR interval 30 s after active standing and the shortest RR interval at 15 s (Max30/Min15). IOH was estimated by the deepest BP fall within the first 15 s after active standing up. Results: Prenatal MeHg exposures were similar in boys and girls (6.7 ± 4.3, 6.7 ± 3.8 ng/g) but recent postnatal mercury levels were higher in males than females (11.2 ± 5.8 vs 7.9 ± 4.3 ng/g, p = 0.003). Markers of autonomic heart rate control were within the normal range (BRS: 24.8 ± 7 ms/mm Hg, PNN50: 24.9 ± 6.8%, rMSSD: 68 ± 22, LF/HF: 0.61 ± 0.28) in both sexes. After standing, 51.4% of subjects had a transient systolic BP drop >
40 mm Hg, but only 5.3% reported dizziness or had syncope. Prenatal and recent postnatal MeHg levels, overall, were not associated with BRS, E/I ratio, PNN50, rMSSD, LF/HF ratio, Max30/Min15 ratio, and IOH. Conclusions: This study provides no support for the hypothesis that prenatal or recent postnatal MeHg exposure from fish consumption is associated with impaired autonomic heart rate control.
Databáze: OpenAIRE
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