Airplane stroke syndrome

Emerging Stroke Risk Factors: A Focus on Infectious and Environmental Determinants

This review focuses on emerging risk factors for stroke, including air pollution and climate change, gut microbiota, high altitude, and systemic infection. Up to 14% of all stroke-associated mortality is attributed to air pollution and is more pronounced in developing countries. Fine particulate matter and other air pollutants contribute to an increased stroke risk, and this risk appears to increase with higher levels and duration of exposure. Short term air pollution exposure has also been reported to increase the stroke risk. The gut microbiota is a complex ecosystem of bacteria and other microorganisms that reside in the digestive system and affect multiple body systems. Disruptions in the gut microbiota may contribute to stroke development, possibly by promoting inflammation and atherosclerosis. High altitudes have been associated with erythrocytosis and cerebrovascular sinus thrombosis, but several studies have reported an increased risk of thrombosis and ischemic stroke at high altitudes, typically above 3000 m. Systemic infection, particularly infections caused by viruses and bacteria, can also increase the risk of stroke. The risk seems to be greatest in the days to weeks following the infection, and the pathophysiology is complex. All these emerging risk factors are modifiable, and interventions to address them could potentially reduce stroke incidence.

Environmental Risk Factors for Stroke and Cardiovascular Disease

Besides the classical individual stroke risk factors a new class has appeared, the environmental risk factors. After a review of the evidences demonstrating that air pollution is a potent risk factor (Part 1), we propose an update of other physical, chemical, and biological factors, now considered as risk factors (Part 2). One of the challenges is to precise their specific roles as they can be combined in their noxious impacts (traffic air pollution + noise + weather + infections). This knowledge has practical consequences; From now on, medical advices cannot be limited to individual recommendations but must also deal with environmental public health issues.