Assessing the Alterations in Brain Morphological Characteristics and White Matter Hyperintensity Burdens in Professionals with High-Altitude Occupations: A Systematic Review and Meta-Analysis
Mohamed I. Mohamed1, Yomna E. Dean1, Shree Rath2, Atta Ur Rehman3, Muhammad Ali Aleem3, Adham Hamza1, Nasser A Abdelall4
1Alexandria University, Faculty of Medicine, Alexandria, Egypt, 2All India Institute of Medical Sciences, Bhubaneswar, India, 3Gujranwala Medical College, University of Health Sciences Lahore, 4Department of Neurology, Louisiana State University School of Medicine, New Orleans, LA
Objective:
To systematically review and meta-analyze morphological brain changes, specifically white matter hyperintensities (WMH), in high-altitude careers and spaceflights.
Background:
Occupational exposure to hypobaric, hypoxic, and microgravity environments, such as in high-altitude careers and spaceflights, poses significant neurological risks. White matter hyperintensities, detected via MRI, are abnormal lesions associated with cognitive decline, cardiovascular diseases, and neurocognitive impairments. Despite their prevalence, there is limited understanding of the incidence and causes of WMHs in these professions. This study aims to explore the relationship between occupational high-altitude exposure and WMHs.
Design/Methods:
This systematic review and meta-analysis was registered on Prospero (CRD42023487668) and followed PRISMA guidelines. A comprehensive search of PubMed, Scopus, Web of Science, and Cochrane was conducted to identify relevant studies. Studies were screened independently by two reviewers, and data were extracted and analyzed using R software. Mean differences (MD) with 95% confidence intervals (CI) were used for statistical analyses, with significance defined as p<0.05.
Results:
A total of 1,565 articles were identified, with 5 studies meeting the inclusion criteria after screening. The meta-analysis included 441 individuals (264 pilots, 177 controls). The pooled burden of WMHs was 6.97 per pilot. Our single-armed analysis revealed a pooled WMH volume of 0.27 cm³. Pilots had a significantly higher number of WMHs compared to controls (MD: 3.57, 95% CI: 1.71–5.43, p=0.0002) and greater WMH volume (MD: 0.09 cm³, 95% CI: 0.04–0.14, p=0.0001). No heterogeneity was observed (I² = 0%).
Conclusions:
The results suggest that occupational exposure to high altitudes is associated with an increased burden of WMHs. Given the potential cognitive and health implications, periodic neurological screening is recommended for individuals in high-altitude and spaceflight professions. Further research is needed to explore the etiopathogenesis and long-term effects of WMHs in these populations.
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