Stroke-Related Mortality at Different Altitudes: A 17-Year Nationwide Population-Based Analysis From Ecuador

Ortíz-Prado, Esteban; Espinosa, Patricio; Borrero, Alfredo; Cordovez, Simone; Vásconez, Eduardo; Barreto-Grimales, Alejandra; Coral-Almeida, Marco; Henriquez-Trujillo, Aquiles R.; Simbaña-Rivera, Katherine; Gómez-Barreno, Lenin; Viscor, Ginés; Roderick, Paul

doi:10.3389/fphys.2021.733928

Cited by 22 publications

(24 citation statements)

References 76 publications

(94 reference statements)

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“…An altitude of residence ≥ 2500 masl was negatively and significantly associated with decreased Framingham 10-year risk scores. This finding is in agreement with that reported in studies conducted in high-altitude regions of Switzerland [ 30 ], Austria [ 31 ], Greece [ 32 ], the United States [ 33 ], and Ecuador [ 34 ], in which it was found that living in a high-altitude region has a protective effect on cardiovascular mortality and the incidence of cardiovascular events, especially coronary heart disease and stroke. From animal models, it is postulated that altitude has a cardioprotective effect due to biological mechanisms associated with hypobaric hypoxia.…”

Section: Discussionsupporting

confidence: 92%

Association between Altitude and the Framingham Risk Score: A Cross-Sectional Study in the Peruvian Adult Population

Hernández-Vasquéz

Vargas-Fernández

Chacón-Díaz

2022

IJERPH

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To determine the association between altitude and the Framingham risk score in the Peruvian population, we performed a cross-sectional analytical study of data collected by the 2017–2018 Food and Nutrition Surveillance by Life Stages survey. The outcome of this study was the Framingham 10-year cardiovascular disease event risk prediction, which is composed of six modifiable and non-modifiable coronary risk factors. A generalized linear model (GLM) of the gamma family and log link function was used to report the crude and adjusted β coefficients. Several sensitivity analyses were performed to assess the association of interest. Data from a total of 833 surveyed participants were included. After adjusting for educational level, poverty level, alcohol consumption, physical activity level, the presence of any limitation, obesity, and area of residence, it was observed that altitude ≥ 2500 m above sea level (β = −0.42 [95% CI: −0.69 to −0.16]) was negatively and significantly associated with a decrease in the Framingham 10-year risk score. High altitude was significantly and negatively associated with Framingham 10-year risk scores. Our results will allow prevention strategies considering modifiable risk factors to avoid the development of cardiovascular diseases, especially in people living at low altitudes.

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Section: Discussionsupporting

confidence: 92%

Association between Altitude and the Framingham Risk Score: A Cross-Sectional Study in the Peruvian Adult Population

Hernández-Vasquéz

Vargas-Fernández

Chacón-Díaz

2022

IJERPH

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“…Study 14: An ecological analysis of all stroke hospital admissions, mortality rates and disability-adjusted life-years in Ecuador published by Ortiz-Prado et al in 2021 demonstrated that high-altitude populations had lower stroke mortality in men (OR 0.91, 95% CI 0.88 to 0.95) and women (OR 0.83, 95% CI 0.79 to 0.86) and had a significant lower risk of getting admitted to the hospital when compared with the low-altitude group in men (OR 0.55, 95% CI 0.54 to 0.56) and women (OR 0.65, 95% CI 0.64 to 0.66). 35 …”

Section: Resultsmentioning

confidence: 99%

“…Several anecdotal case reports and case series of people suffering from stroke-related disorders at high altitude have been published since the late 1800s 25. Despite this apparent relationship, very few well-conducted epidemiological studies have been conducted worldwide, and we have only included those studies that fulfilled our inclusion and exclusion criteria 14 15 20 21 26–36…”

Section: Resultsmentioning

confidence: 99%

Chronic high-altitude exposure and the epidemiology of ischaemic stroke: a systematic review

et al. 2022

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IntroductionAbout 5.7% of the world population resides above 1500 m. It has been hypothesised that acute exposure to high-altitude locations can increase stroke risk, while chronic hypoxia can reduce stroke-related mortality.ObjectiveThis review aims to provide an overview of the available evidence on the association between long-term high-altitude exposure and ischaemic stroke.DesignA systematic review was performed from 1 January 1960 to 1 December 2021 to assess the possible link between high-altitude exposure and ischaemic stroke. The AMED, EMBASE, Cochrane Library, PubMed, MEDLINE, the Europe PubMed Central and the Latin-American bibliographic database Scielo were accessed using the University of Southampton library tool Delphis. In this review, we included population and individual-based observational studies, including cross-sectional and longitudinal studies except for those merely descriptive individual-based case reports. Studies were limited to humans living or visiting high-altitude locations for at least 28 days as a cut-off point for chronic exposure.ResultsWe reviewed a total of 1890 abstracts retrieved during the first step of the literature review process. The authors acquired in full text as potentially relevant 204 studies. Only 17 documents met the inclusion criteria and were finally included. Ten studies clearly suggest that living at high altitudes may be associated with an increased risk of stroke; however, five studies suggest that altitude may act as a protective factor for the development of stroke, while two studies report ambiguous results.ConclusionsThis review suggests that the most robust studies are more likely to find that prolonged living at higher altitudes reduces the risk of developing stroke or dying from it. Increased irrigation due to angiogenesis and increased vascular perfusion might be the reason behind improved survival profiles among those living within this altitude range. In contrast, residing above 3500 m seems to be associated with an apparent increased risk of developing stroke, probably linked to the presence of polycythaemia and other associated factors such as increased blood viscosity.

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“…It is believed that at high-altitudes there is a lower expression of ACE-2 receptors, which are precisely the gateway to our cells for the SARS-CoV-2 virus [ 8 ]. A more plausible explanation goes along with the fact that high-altitude inhabitants express genes responsible for producing more erythrocytes (increasing oxygen transport) and creating new blood vessels (greater oxygen supply) [ 10 , 46 , 47 ]. On top of this, we must add certain anatomical and morphological characteristics among high-altitude dwellers, such as larger and bigger thoraxes as well as greater ventilatory capacities, that might play a role in reducing hypoxia found during severe ARDS due to COVID-19 [ 23 , 48 – 50 ].…”

Section: Discussionmentioning

confidence: 99%

High-altitude is associated with better short-term survival in critically ill COVID-19 patients admitted to the ICU

Simbaña-Rivera

Jaramillo²,

Silva

et al. 2022

PLoS ONE

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Background Multiple studies have attempted to elucidate the relationship between chronic hypoxia and SARS-CoV-2 infection. It seems that high-altitude is associated with lower COVID-19 related mortality and incidence rates; nevertheless, all the data came from observational studies, being this the first one looking into prospectively collected clinical data from severely ill patients residing at two significantly different altitudes. Methods A prospective cohort, a two-center study among COVID-19 confirmed adult patients admitted to a low (sea level) and high-altitude (2,850 m) ICU unit in Ecuador was conducted. Two hundred and thirty confirmed patients were enrolled from March 15th to July 15th, 2020. Results From 230 patients, 149 were men (64.8%) and 81 women (35.2%). The median age of all the patients was 60 years, and at least 105 (45.7%) of patients had at least one underlying comorbidity, including hypertension (33.5%), diabetes (16.5%), and chronic kidney failure (5.7%). The APACHE II scale (Score that estimates ICU mortality) at 72 hours was especially higher in the low altitude group with a median of 18 points (IQR: 9.5–24.0), compared to 9 points (IQR: 5.0–22.0) obtained in the high-altitude group. There is evidence of a difference in survival in favor of the high-altitude group (p = 0.006), the median survival being 39 days, compared to 21 days in the low altitude group. Conclusion There has been a substantial improvement in survival amongst people admitted to the high-altitude ICU. Residing at high-altitudes was associated with improved survival, especially among patients with no comorbidities. COVID-19 patients admitted to the high-altitude ICU unit have improved severity-of-disease classification system scores at 72 hours.

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Stroke-Related Mortality at Different Altitudes: A 17-Year Nationwide Population-Based Analysis From Ecuador

Cited by 22 publications

References 76 publications

Association between Altitude and the Framingham Risk Score: A Cross-Sectional Study in the Peruvian Adult Population

Association between Altitude and the Framingham Risk Score: A Cross-Sectional Study in the Peruvian Adult Population

Chronic high-altitude exposure and the epidemiology of ischaemic stroke: a systematic review

High-altitude is associated with better short-term survival in critically ill COVID-19 patients admitted to the ICU

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