Latitude gradient decreasing, female/male ratio increasing in MS
Individual studies have recently reported on what seems to be a decrease of the MS "latitude gradient" (the lower incidence rate toward the equator) and an increase in the ratio of females to males with MS. To test the overall validity of these indications, two epidemiologists compiled and analyzed MS incidence data from 27 different studies conducted in Europe, the US, and Australia. These studies covered different time periods that ranged from 1950 to 2002.
The analysis confirmed that over these decades, MS rates have been increasing more rapidly in lower latitudes than in higher ones. Also confirmed was the increase in the female:male ratio, which grew from 1.4 in 1955 to 2.3 in 2000. The authors suggest possible explanations for these findings. For instance, changes in lifestyle and living conditions at lower latitudes may result in decreasing exposure to sunlight (and thus lower vitamin D levels) and decreasing exposure to infections at younger ages. The female:male ratio may have been affected by an increase among women in smoking, which has been associated with MS, or perhaps reproductive factors (although none of these have yet been associated with MS).
One of the limitations pointed out by the authors was that this was not truly a worldwide study due to the shortage of incidence figures from Africa, Asia, and Central/South America. It would be very interesting to study the gender ratio in these regions, for instance, to see whether the explanations put forth remain plausible and/or whether new ones emerge.
I have traveled to Hawaii
I have traveled to Hawaii several times in the last few years and on each trip experienced an exacerbation which lasted until I returned home. I decided on the last trip that it was not just coincidence but must be another factor. I mentioned this to my nuerologist and he related that he had other patients who noted the similar events. This would be the inverse of what this study is examining. Perhaps it is the change in latitude which we are sensitive to. I also have exacerbations when there is a big change in the weather. Anyone else?
Funny you should mention
Funny you should mention this. I had a dramatic increase in symptoms when I went to Hawaii too. But for me, I think it was the heat/humidity because they got much better when I got into the A/C.
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Art Mellor, Accelerated Cure Project for MS, art-msnews -at- acceleratedcure.com
Interesting. Jet lag and the
Interesting. Jet lag and the stress associated with long distance travel could cause problems. Does anyone experience the same thing when they travel elsewhere and cross time zones? Any clue as to what the MS rate is in Hawaii? I lived on Oahu for about 3 years as a young girl and developed MS in my late 30s.
I've traveled to Hawaii
I've traveled to Hawaii several times, all before I was diagnosed with MS. Each trip was a week or longer. Since my diagnosis, I've been to the Caribbean and Costa Rica several times for a week or longer. I definitely felt the effects of the heat, especially in more recent years, but I too found them to be only temporary and "cured" with a cool breeze and a pina colada!
I've been diagnosed for 7
I've been diagnosed for 7 years and in that time I've pretty much stopped asking the "If this then that" question as to causes and effects of symptoms I experience. Not that it isn't interesting to hypothesise - its just pretty frustrating, 'cause it seems I can have a great day at almost any time, or a bad day / hour without any real explanation that I can figure. And comparing notes with other MSers in my area I have found this cause and effect questioning is mostly an exercise in futility, at least for me.
That said - I am a frequent traveler to Hawaii. Annual 2 week trips - for the past 20 plus years. Yeah tropoical climate can be a consideration - but I find the predictibility of the weather to actually be a plus - always a high temp of about 85 and always a low temp of about 72, any month of the year. (And the ocean temp is almost aways about 84 degrees) The humidity is tropical but not oppressive, and the consistent trade winds are a bonus. I can work with that - and plan outside activities early and plan water activities for the afternoon. I also always stay where in accommodations with AC so I can recharge my system when I need to. A Mai Tai is also really nice!
Compare this to the midwest right now - highs in the 90's or worse, that start early in the day and can last late into the night, high humidity, no ocean neadby, etc. etc. I'll take Hawaii anyday.
And no I cannot say that I ever experienced an exacerbation during or immediately following a trip to the islands. Yes I have had exacerbations on the mainland at other times - and at times of the year that are cooler - and without as much activity as I typically undertake on vacation.
My thinking is that I have to live my life to the max of my abilities, to join in with family and friends as best I can and to stay connected to the world. I am fortunate to be in a situation that includes the ability to get away to Hawaii frequently, which I view as something of a break from the day to day stuff back at home. And as so many other things about Multiple Sclerosis - it is difficult to generalize about this disease and the way if affects anyone who suffers from it.