Through the Eye: Retinal Changes of Prenatal Mercury Exposure

Overview

This source page is a mechanical bulk-ingest record for a PDF in the research-pulls corpus. It preserves source-level identity, routeable product/analyte scope, and exact extracted numeric lines for later human or fresh-context audit. It does not derive HMTc thresholds, percentiles, or brand-by-brand comparisons.

Key numbers

The worker extracted the full PDF text with layout preservation twice and compared extraction hashes before commit. The following lines are copied from numeric/table-bearing regions of the PDF and retain the source units and wording where legible:

• blood Hg concentrations ≥ 5.8 µg/L were more likely to present bilateral abnormal retinal
• thinning (OR = 3.51; (95% CI: 1.06–11.53)). These findings suggest that, in this Indigenous
• 95% of the Hg content in fish (2,3). In 1968, Hg concentrations in walleye downriver of the
• showed that MeHg made up over 75% of total Hg (10,11). The evolution of Hg concentra-
• transported across the placenta and constitutes 95% of umbilical cord blood Hg (20–24).
• year of birth and sex (12). Although cord blood MeHg accounts for at least 95% of total
• 284 subjects (mean age 46.5 years; 19–84 years) and the macula protocol database contains
• 282 subjects (mean age 46.6 years; 19–84 years). Refractive errors of the database are limited
• range includes the thickest values (>95th percentile), coded white, while green represents
• the existing database. A total of 91 community members fitted the criteria and 62 (65.9%)
• The present analyses included 59 individuals (54% women, 46% men); the mean age
• was 40.5 years (SD = 4.8) and the median age was 41 years (IQR 38–45), ranging from
• current smokers and 23 (46.9%) consumed alcoholic beverages less than a few times a
• month over the past year. Thirty-seven (75.5%) were working at the time of the study.
• Umbilical cord blood Hg concentrations for the 59 participants ranged from 1.1 µg/L to
• of 6.9 µg/L (IQR 3.1–13.7). In total, 33 persons (55.9%) had umbilical cord blood Hg
• 5.8 µ/L (69) and 25 measurements (42.4%) were above the Health Canada recommendation
• Table 1 shows the visual characteristics for all eyes (N = 116). The median distance
• visual acuity was 0.1 logMAR (Snellen equivalent 20/25) and the median refractive error
• Table 1. Visual characteristics of all eyes (N = 116).
• Table 2 shows the distribution of retinal thicknesses for the optic disc cube scan,
• Average RNFL thickness was in the abnormal range (yellow and red code) for 17% of eyes.
• code) for almost 30% of eyes. No significant differences in thickness were observed between
• RNFL and GC-IPL quadrants (Wilcoxon Kruskal–Wallis; p > 0.10) (Tables A1 and A2).
• Table 2. Distribution of retinal layer thicknesses measured by optical coherence tomography (OCT).
• Nasal 71 (64–80) 104 (98.1%)
• Temporal 55 (50–61) 89 (84%)
• Superior nasal 83 (77–86) 86 (78.9%)
• Inferior nasal 80 (74–85) 87 (79.8%)
• Inferior temporal 79 (73–83) 80 (73.4%)
• Superior temporal 79 (74–83) 80 (73.3%)
• models and were retained for the subsequent analyses when p < 0.2. Table 3 presents the
• Table 3. Linear mixed effects model estimates for umbilical cord Hg for measures of retinal ganglion
• OCT Measures (y Variable) N 95% CI p-Value
• eye that showed significant retinal thinning with higher cord blood Hg (Tables A3 and A4).
• thickness maps (Figure 2b) reveal advanced temporal RNFL loss with notable symmetry
• Qualitative clinical assessments showed that 20 participants (33.9%) presented either
• advanced temporal RNFL loss, or bilateral partial temporal RNFL loss. Table 4 describes
• among individuals with umbilical cord blood Hg concentrations ≥ 5.8 µg/L was more than
• Table 4. Retinal thinning distribution and general characteristics with abnormal qualitative clinical
• Bilateral partial GC-IPL circular loss 8 8 (40.0%)
• Bilateral advanced GC-IPL circular loss 12 12 (60.0%)

Methods (brief)

• 59 participants (116 eyes) with umbilical cord Hg measurements, sampled between 1971
• and hair samples, analyzed for the composition of the inorganic and organic components,
• tions in human samples paralleled those observed in fish, with the highest concentrations
• Between 1970 and 1992, a government biomonitoring program collected umbilical
• with the authors. All samples were analyzed for total Hg (11,55); Hg concentrations for
• OCT measurements were collected using the Cirrus HD-OCT (Carl Zeiss, Meditec Inc.,
• also provided blood samples as part of the Niibin study. This subgroup served to test the
• 2022, respectively. Karen Percy, phlebotomist, took the blood samples. Joannie Richer coordinated
• flameless atomic absorption, and of methylmercury by gas chromatography. Clin. Chem. 1974, 20, 222–229. (CrossRef)
• 35. Goodman, C.V.; Green, R.; DaCosta, A.; Flora, D.; Lanphear, B.; Till, C. Sex difference of pre- and post-natal exposure to
• 55. Farant, J.P.; Brissette, D.; Moncion, L.; Bigras, L.; Chartrand, A. Improved cold-vapor atomic absorption technique for the
• microdetermination of total and inorganic mercury in biological samples. J. Anal. Toxicol. 1981, 5, 47–51. (CrossRef) (PubMed)

Implications

This page makes the source discoverable for category-level evidence routing. Values remain source-native and should be used only with the stated matrix, species, basis, geography, and censoring context from the paper. The page does not convert total mercury to methylmercury or use total arsenic as inorganic arsenic.

Wiki pages this source may touch

• Fish — marine, non-predatory (sardines, anchovies, salmon, cod)
• Seaweed/kelp foods (nori, wakame, kombu, dulse — as food products)
• Mercury
• Mercury

Verification notes

• Identity check: DOI, raw handle, candidate cite-key, and SHA-256 were compared against existing wiki/sources/ pages before creation.
• Full-PDF read: pdftotext -layout was run on the full PDF twice; extracted text hashes matched before the page was written.
• Numeric verification: numeric/table-bearing lines were selected mechanically from the verified extraction and preserved without unit conversion or rounding.
• Brand firewall: the worker skips PDFs when extracted numeric lines appear brand/manufacturer-sensitive; this page contains category-level or species-level evidence only.
• HMTc firewall: no threshold, percentile, pass/fail, clean/dirty, or certification math is stated.

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.