{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,14]],"date-time":"2025-11-14T17:19:17Z","timestamp":1763140757077,"version":"build-2065373602"},"reference-count":29,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2015,3,23]],"date-time":"2015-03-23T00:00:00Z","timestamp":1427068800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>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\u2019 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 \u00b1 4.3, 6.7 \u00b1 3.8 ng\/g) but recent postnatal mercury levels were higher in males than females (11.2 \u00b1 5.8 vs 7.9 \u00b1 4.3 ng\/g,  p = 0.003). Markers of autonomic heart rate control were within the normal range (BRS: 24.8 \u00b1 7 ms\/mm Hg, PNN50: 24.9 \u00b1 6.8%, rMSSD: 68 \u00b1 22, LF\/HF: 0.61 \u00b1 0.28) in both sexes. After standing, 51.4% of subjects had a transient systolic BP drop &gt;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.<\/jats:p>","DOI":"10.3390\/ijerph120303395","type":"journal-article","created":{"date-parts":[[2015,3,23]],"date-time":"2015-03-23T12:17:00Z","timestamp":1427113020000},"page":"3395-3405","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["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"],"prefix":"10.3390","volume":"12","author":[{"given":"Daniel","family":"P\u00e9riard","sequence":"first","affiliation":[{"name":"Service d'Angiologie, H\u00f4pital Cantonal, Fribourg 1700, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bujar","family":"Beqiraj","sequence":"additional","affiliation":[{"name":"Service d'Angiologie, H\u00f4pital Cantonal, Fribourg 1700, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniel","family":"Hayoz","sequence":"additional","affiliation":[{"name":"Service d'Angiologie, H\u00f4pital Cantonal, Fribourg 1700, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bharathi","family":"Viswanathan","sequence":"additional","affiliation":[{"name":"Section of Non Communicable Diseases, Ministry of Health, Victoria, Seychelles"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Katie","family":"Evans","sequence":"additional","affiliation":[{"name":"Department of Biostatistics, University of Rochester, Rochester, NY 14642, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sally","family":"Thurston","sequence":"additional","affiliation":[{"name":"Department of Biostatistics, University of Rochester, Rochester, NY 14642, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Philip","family":"Davidson","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, University of Rochester, Rochester, NY 14642, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4317-015X","authenticated-orcid":false,"given":"Gary","family":"Myers","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, University of Rochester, Rochester, NY 14642, USA"},{"name":"Institute of Social and Preventive Medicine, Lausanne University Hospital, CHUV, Lausanne 1010, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pascal","family":"Bovet","sequence":"additional","affiliation":[{"name":"Section of Non Communicable Diseases, Ministry of Health, Victoria, Seychelles"},{"name":"Institute of Social and Preventive Medicine, Lausanne University Hospital, CHUV, Lausanne 1010, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2015,3,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1106","DOI":"10.1016\/j.neuro.2006.03.024","article-title":"Prenatal methyl mercury exposure from fish consumption and child development: A review of evidence and perspectives from the Seychelles Child Development Study","volume":"27","author":"Davidson","year":"2006","journal-title":"Neurotoxicology"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1289\/ehp.11608","article-title":"Methylmercury exposure and adverse cardiovascular effects in Faroese whaling men","volume":"117","author":"Choi","year":"2009","journal-title":"Environ Health Perspect."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"924","DOI":"10.1016\/j.neuro.2007.06.002","article-title":"Does prenatal methylmercury exposure from fish consumption affect blood pressure in childhood?","volume":"28","author":"Thurston","year":"2007","journal-title":"Neurotoxicology"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"612","DOI":"10.1016\/j.amjhyper.2004.11.022","article-title":"Relationship between mercury in blood and 24-h ambulatory blood pressure in Greenlanders and Danes","volume":"18","author":"Pedersen","year":"2005","journal-title":"Am. 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