2013 Update:

A new story connecting altitude and white matter lesions:

High-altitude pilots in the Air Force have a poorly understood type of brain lesion three times as often and four times as large as those seen in the brains of other military personnel, according to a new study.

http://news.yahoo.com/flying-high-altitude-spy-planes-tied-brain-lesions-163110006.html

The pilots in the study had lesions called white matter hyperintensities, which appear as bright spots on brain scans and may be caused by reduced blood flow, similar to those seen with head trauma, McGuire said, though none had experienced such injuries.

The reconnaissance planes regularly fly at 64,000 feet and can go higher than 70,000 feet, where pilots can see the curvature of the Earth and the dividing line between night and day, while commercial flights typically cruise at about 40,000 feet. At high altitude, the spy planes maintain cabin pressure of 28,000 to 30,000 feet, compared to the average of 8,000 feet in a commercial flight.

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The Altitude Research Center at the University of Colorado at Denver has found that altitude has a definite impact on multiple sclerosis.  The mechanism of this association is being studied by combining existing medical databases with GIS methodology.

Multiple Sclerosis progression at altitude vs. sea level. Case control exploratory study to determine whether patients with multiple sclerosis experience more rapid progression of symptoms at altitude as compared to sea level using GIS mapping as a tool. The study will use the NARCOMS data base --a patient generated data base that has high correlation with clinical evaluations based on physical examination. In collaboration with several neurologists at UC Denver SOM.

http://www.altituderesearch.org/research/current-exploratory-research

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Those who've followed this page know that it was after a week at high altitude my husband came home with numbness, tingling and received an eventual MS diagnosis.  That's what got me going on vascular research.  I knew the two were connected.  Jeff always had a tough time whenever we'd go hiking at high altitude.   After we saw what his jugular veins looked like, it made more sense.

A compromised venous system and low oxygen due to high altitude is a bad mix.

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Here's the story of Nancy Davis, Founder of the Race to Erase MS, and Los Angeles resident.

It started with a tingle in her fingers after she finished a day skiing on the slopes in Aspen.  A lifelong skier, she chalked it up to a little strain from tearing up the moguls all day.  After all, she was only 32 years old and a young mother – a little too soon to be contemplating the proverbial rocking chair.  When her other hand started tingling the very next day, then her whole hand went numb and then a few days after that her eyesight started to go, a future in a rocking chair was about all the hope doctors were giving her as they told her she had multiple sclerosis (MS).

That was 21 years ago.  Since then Nancy Davis, daughter of the late billionaire oil tycoon and former owner of 20th Century Fox Marvin Davis and wife Barbara, has used her enduring inner-strength, her family and personal connections and her incredible ability to bring people together for a common goal to find a cure for the multiple sclerosis (MS) that has been her constant companion for the last two decades. 

Sadly, I haven't been able to meet with Ms. Davis--although we've tried to reach out to her, her neurological board does not want to discuss CCSVI research.

link

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Here is a study where mountain climbers showed white matter lesions on MRI --

PURPOSE: There are only anecdotal and small reports on brain systematic magnetic resonance imaging (MRI) studies in mountain climbers. The purpose of our work is to study the risk of brain lesions in mountain climbers by means of conventional MRI and magnetic resonance spectroscopy (MRS). 

METHODS: We recruited 35 climbers consecutively (12 were professional and 23 were amateur) in 4 expeditions without supplementary oxygen: 12 professionals and one amateur went up to Mt. Everest (8848 m), 8 amateurs to Mt. Aconcagua (6959 m), 7 amateurs to Mont Blanc (4810 m), and 7 amateurs to Mt. Kilimanjaro (5895 m). The mean age was 33.8 years (range: 22-46). All of them underwent general medical examination, standard blood tests, and MRI of the brain after the expeditions. MRI also was carried out in a control group of 20 healthy subjects. Single-voxel MR spectroscopy was carried out in 14 amateur subjects after the expeditions and in 10 healthy controls. As outcome measures, we evaluated changes in the hematocrit value, presence of cerebral lesions on MRI, as well as atrophy and dilatation of Virchow-Robin spaces, and differences in the metabolite ratios obtained from brain MRS in comparison with controls. 

RESULTS: Only 1 in 13 of the Everest climbers had a normal MRI; the amateur showed frontal subcortical lesions, and the remainder had cortical atrophy and enlargement of Virchow-Robin spaces but no lesions. Among the remaining amateurs, 13 showed symptoms of high-altitude illness, 5 had subcortical irreversible lesions, and 10 had innumerable widened Virchow-Robin spaces. Conversely, we did not see any lesion in the control group. We found no signi?cant differences in the metabolite ratios between climbers and controls. 

CONCLUSIONS: We conclude that there is enough evidence of brain damage after high altitude climbing; the amateur climbers seem to be at higher risk of suffering brain damage than professional climbers.

http://www.cns.nyu.edu/events/spf/SPF_papers/fayed2006evidence.pdf

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"There are potential impacts of high altitude exposure on persons with preexisting neurological conditions who normally reside at low altitude. These conditions include permanent and transient lack of oxygen to (portions of) the brain (e.g., stroke, transient ischemic attack [TIA, or stroke "warning"]), occlusive cerebral artery disease (e.g., atherosclerosis of the cerebral arteries), central venous thrombosis (clotted large veins in the brain), abnormal blood vessels within the skull (e.g., aneurysms), multiple sclerosis, space-occupying lesions within the skull (e.g., benign and malignant tumors), dementia, movement disorders, migraine and other headaches, and epilepsy (seizures)."

http://www.healthline.com/blogs/outdoor_health/2007/09/going-to-high-altitude-with-preexisting.html

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 I still do not know why the doctors haven't figured this one out.  Colorado has the highest number of MS patients per capita, and many people develop MS once they move there. 1 out of 580 people in Colorado has MS--and they live at high altitude.  I mean, how difficult is it to test for oxygen saturation in MS patients??

Here are the facts:  The highest point in Colorado, and in the Rocky Mountains, is Mt. Elbert at 14,440 feet above sea level. Colorado is home to more mountains 14,000 feet or higher than any other state. The lowest point in Colorado is the Arkansas River at 3,315 feet above sea level.  The Mean Elevation of the state of Colorado is 6,800 feet above sea level. This is the highest mean altitude of any of the 50 states.

High altitude's affect on MS is being studied in Colorado at the Altitude Research Center in Denver, Colorado--

According to ARC director Ben Honigman, M.D., the center has two main focuses. First is the study of integrative physiology, how hypoxia affects the whole person as well as at cellular and molecular levels. This includes the search for a prevention and cure for AMS — which could have implications both economic and military. Investigators are also identifying specific genes that can predict who will get sick and studying the responses of individuals who exercise vigorously in hypoxic environments to better understand physiology at altitude and minimize the risk of deadly edema.

The other focus is epidemiology, the effects of hypoxia on lifespan and progression of cancer, heart disease, obesity, lung diseases, and neurological diseases, including Alzheimer’s and multiple sclerosis. Projected studies will investigate multiple sclerosis progression, longevity, cardiovascular disease, and behavior of malaria at altitude. Medical applications for these studies are being realized in conjunction with sophisticated geographic information systems technology that tracks migrations of populations.

http://www.denvermagazine.com/May-2010/Changes-in-Altitude/

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Here's what happens at high altitude:

At the root of the problem is hypoxia. The absolute percentage of oxygen in the air is the same, regardless of altitude; however, as altitude increases, the number of molecules in any given volume of air decreases. This makes less oxygen available to diffuse across the alveolar membranes into the red cells' hemoglobin.

In a person at sea level, the arterial oxygen partial pressure is 90-95 mmHg; oxygen saturation is 97%. If that same individual travels to an altitude of 14,000 feet, the figures fall to 45 mmHg and 71% prior to acclimatization. With the increased tissue oxygen demands of exercise, blood oxygen saturation is accordingly lower.

As plasma and tissue hypoxia occur, the body reflexively begins to compensate. Minute ventilation increases, as does respiratory rate. Blood flow to the lungs also increases. In both the brain and lungs there is over perfusion of the microvasculature. Vessels then become leaky and fluid is exuded into the surrounding tissue spaces leading to edema.

http://findarticles.com/p/articles/mi_m0NHG/is_1_18/ai_n15887999/

Here's a woman who suffered from a cerebral venous infarction at high altitude:

http://smj.sma.org.sg/5008/5008cr11.pdf

Here's a woman who had an attack of aphasia at high altitude:

http://www.liebertonline.com/doi/abs/10.1089%2F15270290050144208

So, for those of you who live at high altitude, will your doctors discuss this with you?   Will someone at the Rocky Mountain MS Center in Colorado please talk about this??   Are there any doctors who are curious about the connection of hypoperfusion, low oxygen and high altitude? The possible implications of hypoperfusion/reperfusion injury?   link to information

And for our Canadian friends---Alberta has the highest MS rates in your country.  

http://www.direct-ms.org/sites/default/files/AlbertaDisadvantage.pdf  

The most populous city is Calgary at 3500 ft. above sea level, Red Deer is at 3000 ft., Edminton is at 2200, Banff at 4800 ft.

Any thoughts?

Joan