Symptoms reported by Canadians posted in Havana are linked with reduced white matter fibre density

2022 · Harm · Low evidence

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HarmLow evidencePaper 796

Study snapshot

Publicationmanual · 2022

Study typecohort

Reported directionHarm

Evidence ratingLow

Abstract

Symptoms reported by Canadians posted in Havana are linked with reduced white matter fibre density Guillermo Aristi, Lyna Kamintsky, Margaux Ross, Chris Bowen, Cynthia Calkin, Alon Friedman, Javeria A. Hashmi. Symptoms reported by Canadians posted in Havana are linked with reduced white matter fibre density, Brain Communications. 4:2, 2022, fcac053, doi: 10.1093/braincomms/fcac053. Abstract Diplomats representing the USA have reported with unusual neurologic symptoms and MRI changes after being posted in Havana, Cuba between late 2016 and 2018. Here, we examined white matter microstructure and network connectivity of individuals stationed in Havana, using diffusion-weighted MRI, fixel-based analysis and structural connectomics as implemented in MRtrix3. MRI data acquisition and clinical assessments were done in a total of 24 diplomats and their family members and 40 healthy controls. The diplomat data were grouped into an exposed cohort (n = 16) and an unexposed cohort (n = 10), and among these, two individuals were assessed before and after potential exposure. Fixel-based analysis revealed a reduction in fibre density in two specific regions: the fornix and the splenium, in exposed individuals, relative to unexposed individuals and healthy controls. Post hoc analyses showed the effect remained present (P < 0.05) in both regions when comparing exposed and unexposed diplomats; and reduced fibre density was correlated with longer time period stationed in Cuba after age correction. Reduction of fibre density was also found to be linked with clinical symptoms of persistent migraine, tinnitus, sound sensitivity and fatigue. Network statistical comparisons revealed decreased structural connectivity in two distinct networks, comprising subcortical and cortical systems in exposed individuals, relative to unexposed and normative data. While the cause for the differences between the groups remains unknown, our results reveal region-specific white matter injury, that is, significantly correlated with clinical symptoms. academic.oup.com

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typecohort

Effect directionharm

PopulationDiplomats and their family members stationed in Havana, Cuba; compared with healthy controls

Sample size64

ExposureLonger time period stationed in Cuba (Havana)

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

In exposed individuals (n=16) relative to unexposed diplomats (n=10) and healthy controls (n=40), fixel-based analysis found reduced fibre density in the fornix and splenium. Reduced fibre density correlated with longer time stationed in Cuba (after age correction) and was linked with reported symptoms (persistent migraine, tinnitus, sound sensitivity, fatigue). Structural connectivity was decreased in two networks in exposed individuals relative to unexposed and normative data.

Outcomes measured

White matter microstructure (fibre density) via diffusion-weighted MRI/fixel-based analysis
Structural brain network connectivity (structural connectomics)
Clinical symptoms (persistent migraine, tinnitus, sound sensitivity, fatigue)

Limitations

Cause of group differences stated as unknown in the abstract
Small sample size, including only two individuals assessed before and after potential exposure
Exposure type/agent not specified in the abstract

View raw extracted JSON

{
  "study_type": "cohort",
  "exposure": {
    "band": null,
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "Longer time period stationed in Cuba (Havana)"
  },
  "population": "Diplomats and their family members stationed in Havana, Cuba; compared with healthy controls",
  "sample_size": 64,
  "outcomes": [
    "White matter microstructure (fibre density) via diffusion-weighted MRI/fixel-based analysis",
    "Structural brain network connectivity (structural connectomics)",
    "Clinical symptoms (persistent migraine, tinnitus, sound sensitivity, fatigue)"
  ],
  "main_findings": "In exposed individuals (n=16) relative to unexposed diplomats (n=10) and healthy controls (n=40), fixel-based analysis found reduced fibre density in the fornix and splenium. Reduced fibre density correlated with longer time stationed in Cuba (after age correction) and was linked with reported symptoms (persistent migraine, tinnitus, sound sensitivity, fatigue). Structural connectivity was decreased in two networks in exposed individuals relative to unexposed and normative data.",
  "effect_direction": "harm",
  "limitations": [
    "Cause of group differences stated as unknown in the abstract",
    "Small sample size, including only two individuals assessed before and after potential exposure",
    "Exposure type/agent not specified in the abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "Havana",
    "diplomats",
    "diffusion-weighted MRI",
    "fixel-based analysis",
    "white matter",
    "fibre density",
    "fornix",
    "splenium",
    "structural connectivity",
    "migraine",
    "tinnitus",
    "sound sensitivity",
    "fatigue"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1093/braincomms/fcac053
PubMed: Not supplied

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