Health Effects of Chronic Intermittent Hypoxia at a High Altitude among Chilean Miners: Rationale, Design, and Baseline Results of a Longitudinal Study
Journal
Annals of Work Exposures and Health
ISSN
2398-7308
2398-7316
Date Issued
2021
Author(s)
Sergio Muñoz
Carolina Nazzal
Daniel Jimenez
Patricia Frenz
Patricia Flores
Diana Alcantara-Zapata
Nella Marchetti
Type
Resource Types::text::journal::journal article
Abstract
<jats:title>Abstract</jats:title>
<jats:sec>
<jats:title>Objectives</jats:title>
<jats:p>This study aims to assess the health effects on mining workers of exposure to chronic intermittent hypoxia (CIH) at high- and very high-altitude mining compared with similar work at lower altitudes in Chile, and it also aims to constitute the baseline of a 5-year follow-up study.</jats:p>
</jats:sec>
<jats:sec>
<jats:title>Methods</jats:title>
<jats:p>We designed a cross-sectional study to assess health conditions in 483 miners working at 2 levels of altitude exposure: 336 working at a very high or high altitude (HA; 247 above 3900–4400 m, and 89 at 3000–3900 m), and 147 below 2400 m. Subjects were randomly selected in two stages. First, a selection of mines from a census of mines in each altitude stratum was made. Secondly, workers with less than 2 years of employment at each of the selected mines were recruited. The main outcomes measured at the baseline were mountain sickness, sleep alterations, hypertension, body mass index, and neurocognitive functions.</jats:p>
</jats:sec>
<jats:sec>
<jats:title>Results</jats:title>
<jats:p>Prevalence of acute mountain sickness (AMS) was 28.4% in the very high-altitude stratum (P = 0.0001 compared with the low stratum), and 71.7% experienced sleep disturbance (P = 0.02). The adjusted odds ratio for AMS was 9.2 (95% confidence interval: 5.2–16.3) when compared with the very high- and low-altitude groups. Motor processing speed and spatial working memory score were lower for the high-altitude group. Hypertension was lower in the highest-altitude subjects, which may be attributed to preoccupational screening even though this was not statistically significant.</jats:p>
</jats:sec>
<jats:sec>
<jats:title>Conclusions</jats:title>
<jats:p>Despite longer periods of acclimatization to CIH, subjects continue to present AMS and sleep disturbance. Compromise of executive functions was detected, including working memory at HA. Further rigorous research is warranted to understand long-term health impacts of high-altitude mining, and to provide evidence-based policy recommendations.</jats:p>
</jats:sec>
<jats:sec>
<jats:title>Objectives</jats:title>
<jats:p>This study aims to assess the health effects on mining workers of exposure to chronic intermittent hypoxia (CIH) at high- and very high-altitude mining compared with similar work at lower altitudes in Chile, and it also aims to constitute the baseline of a 5-year follow-up study.</jats:p>
</jats:sec>
<jats:sec>
<jats:title>Methods</jats:title>
<jats:p>We designed a cross-sectional study to assess health conditions in 483 miners working at 2 levels of altitude exposure: 336 working at a very high or high altitude (HA; 247 above 3900–4400 m, and 89 at 3000–3900 m), and 147 below 2400 m. Subjects were randomly selected in two stages. First, a selection of mines from a census of mines in each altitude stratum was made. Secondly, workers with less than 2 years of employment at each of the selected mines were recruited. The main outcomes measured at the baseline were mountain sickness, sleep alterations, hypertension, body mass index, and neurocognitive functions.</jats:p>
</jats:sec>
<jats:sec>
<jats:title>Results</jats:title>
<jats:p>Prevalence of acute mountain sickness (AMS) was 28.4% in the very high-altitude stratum (P = 0.0001 compared with the low stratum), and 71.7% experienced sleep disturbance (P = 0.02). The adjusted odds ratio for AMS was 9.2 (95% confidence interval: 5.2–16.3) when compared with the very high- and low-altitude groups. Motor processing speed and spatial working memory score were lower for the high-altitude group. Hypertension was lower in the highest-altitude subjects, which may be attributed to preoccupational screening even though this was not statistically significant.</jats:p>
</jats:sec>
<jats:sec>
<jats:title>Conclusions</jats:title>
<jats:p>Despite longer periods of acclimatization to CIH, subjects continue to present AMS and sleep disturbance. Compromise of executive functions was detected, including working memory at HA. Further rigorous research is warranted to understand long-term health impacts of high-altitude mining, and to provide evidence-based policy recommendations.</jats:p>
</jats:sec>
Subjects
acute mountain sickness
;
chronic intermittent hypoxia
;
extreme environments
;
intermittent exposure to high altitude
;
mining
;
sleep disturbance
;
working in extreme conditions
;
altitude
;
altitude sickness
;
chile
;
cross-sectional studies
;
follow-up studies
;
humans
;
hypoxia
;
longitudinal studies
;
occupational exposure
;
diseases
;
landforms
;
sleep research
;
acute mountain sickness
;
chronic intermittent hypoxias
;
extreme conditions
;
extreme environment
;
health effects
;
intermittent exposure to high altitude
;
intermittent exposures
;
sleep disturbances
;
workers'
;
working in extreme condition
;
altitude
;
altitude disease
;
chile
;
cross-sectional study
;
follow up
;
human
;
hypoxia
;
longitudinal study
;
occupational exposure
;
miners