Cardiovascular risk and obesity in miner workers exposed to intermittent hypobaric hypoxia in the Peruvian Andes

TL;DR

Workers exposed to high-altitude hypoxia in Peru show higher obesity rates but no increased cardiovascular risk compared to low-altitude workers.

Contribution

This study identifies a link between intermittent high-altitude hypoxia and obesity without adverse cardiovascular effects in miners.

Findings

CIHH-exposed workers had higher obesity prevalence (80%) compared to controls (20%).

Hematocrit levels were higher in CIHH workers, indicating mild erythropoietic adaptation.

Cardiovascular and metabolic biomarkers remained comparable between groups.

Abstract

Occupational activities such as mining and interprovincial transportation expose Peruvian workers to large altitude fluctuations, generating repeated cycles of chronic intermittent hypobaric hypoxia (CIHH). In this study, we aimed to evaluate the effect of CIHH exposure on cardiovascular risk, obesity, sleep quality, and physical activity among male workers performing rotational shifts at high altitude.

A cross-sectional study was conducted with 96 male participants aged 20–60 years, who were divided into two groups: those exposed to CIHH (n = 53; ≥3,000 m, alternating with <2,500 m) and controls working permanently at low altitude (<2,500 m; n = 43). Anthropometric and body composition parameters were assessed by bioelectrical impedance, and cardiovascular risk was estimated using the Reynolds Risk Score (RRS) and Framingham Risk Score (FRS). Sleep apnea risk and physical activity were evaluated using the STOP-Bang Questionnaire and the International Physical Activity Questionnaire—Short Form (IPAQ-SF), respectively. Biochemical and hematological profiles were also analyzed.

Obesity prevalence was significantly higher in the CIHH group (80%) than in controls (20%) (p = 0.036; PR = 1.58, 95% CI: 1.12–2.24). Despite this, body fat (56.8% vs. 43.2%, p = 0.5), skeletal muscle (55.2% vs. 44.8%, p = 0.9), and visceral fat (57.8% vs. 51.0%, p = 0.5) did not differ significantly. Hematocrit levels were higher in CIHH workers (median 52.3%) than in controls (50.7%) (p = 0.03), indicating mild erythropoietic adaptation. No significant between-group differences were observed in lipid profile, glucose, insulin, high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), physical activity, or obstructive sleep apnea (OSA) risk (all p > 0.05). Estimated cardiovascular risk remained low and comparable between groups.

CIHH exposure was associated with higher hematocrit levels and a significantly greater prevalence of obesity but no adverse alterations in cardiovascular or metabolic biomarkers. These findings suggest a dual physiological response to intermittent hypoxia—erythropoietic adaptation coexisting with metabolic vulnerability—highlighting the need for preventive strategies in high-altitude occupational health.

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