No seasonal/sun variation to disease activity

[calcal]

From AAN looking at variations in MS activity throughout the seasons:

P08.184] Does Disease Activity as Measured by Contrast Enhancing Lesions in Multiple Sclerosis Reflect a Seasonal Variation?

Joan M. Ohayon, Sungyoung Auh, Henry McFarland, Gaithersburg, MD, Fredric Cantor, Bethesda, MD

OBJECTIVE: To determine if there is a seasonal variation in disease activity as measured by contrast-enhancing lesions (CELs) in patients with multiple sclerosis (MS).

BACKGROUND: Studies reporting to detect seasonal variations in MS activity have differing and contradictory conclusions. Some conclude summer to be worse; others conclude winter to be worse. Various causes including sunlight and its relation to vitamin D and viral exposure have been proposed. Most studies evaluated relapses; fewer evaluated MRI changes.

DESIGN/METHODS: Since CELs are thought to represent a marker of acute disease activity, we retrospectively reviewed MRI scans done at approximately monthly intervals from relapsing remitting (n=67), secondary progressive (n=11), and primary progressive (n=2) MS patients followed for at least one year. Three month seasonal data was evaluated in two different paradigms: seasons defined by average daily temperature and seasons defined by amount of sunlight, as determined by the National Oceanic and Atmospheric Administration and the United States Naval Observatory, respectively. Each patients mean number of CELs per season (based on mean CELs per scan) was compared to the yearly mean to determine best and worst seasons for the group. Additionally, a second analysis was performed examining each patients best and worst season.

RESULTS: CELs occurred in 73 patients. Repeated measures of ANOVA showed no significant seasonal effect by temperature: F(3,216)=0.89 with p=0.4447 or by sunlight exposure: F(3,216)=1.15 with p-value=0.3067. Evaluation of best and worst seasons for each patient also showed no seasonal effect. Seven patients had no CELs and, therefore, no seasonal variation.

CONCLUSIONS/RELEVANCE: We found no significant seasonal variation in the mean number of contrast enhancing lesions in seasons defined by temperature or by amount of sunlight. Supported by: The Intramural Program of the National Institutes of Neurological Disorders and Stroke, NIH.
Category - MS and Related Diseases
SubCategory - Clinical Science

[Ted Hutchinson]

Bethesda, MD at latitude 38 is hardly in the North.

It would have been better if vitamin D status had been measured so seasonal changes in Vitamin D status, had they occurred, been included.
If you stay indoors all the time then it doesn't matter what happens seasonally your vitamin D status will remain insufficient.

[lady_express_44]

Bethesda, MD at latitude 38 is hardly in the North.

Here we go with that "moving target" again. :rolleyes:

According to Nick:

Everyone who resides further than 32 degrees from the equator is vulnerable to a vitamin D winter. The "winter" being a time of year when an individual can not receive intense enough sunshine to generate vitamin D.

http://brain.hastypastry.net/forums/showthread.php?t=26878&page=4

Cherie

[BBS1951]

Savannah Georgia is at latitude 32 degrees. So, most of the USA is north of 32 degrees.

[lady_express_44]

Also from the upcoming AAN:

[P06.142] Temporal Trends in the Incidence of Multiple Sclerosis: A Systematic Review

Alvaro Alonso, Minneapolis, MN, Miguel A. Hernan, Boston, MA

OBJECTIVE: To conduct a systematic review of incidence studies of multiple sclerosis (MS) and to explore possible changes in the latitude gradient and the female to male ratio over time.

BACKGROUND: MS has been traditionally considered to be more frequent in women and in regions more distant from the equator. However, recent reports suggest that the latitude gradient could be disappearing and that the female to male ratio among MS patients has increased in the last decades.

DESIGN/METHODS: Systematic review of incidence studies of MS published in Medline between 1966 and February 2007. Age- and sex-specific incidence rates were collected from eligible publications. We computed age-adjusted rates using the world population as standard, and assessed differences in rates according to latitude and period of case ascertainment. Additionally, we evaluated the association between period of case ascertainment and the female to male ratio.

RESULTS: The overall incidence rate of MS was 3.6 cases per 100,000 person-years (95% CI 3.0, 4.2) in women and 2.0 (95% CI 1.5, 2.4) in men. Higher latitude was associated with higher MS incidence, though this latitude gradient was attenuated after 1980, apparently due to increased incidence of MS in lower latitudes. Female to male ratio in MS incidence increased over time, from an estimated 1.4 in 1955 to 2.3 in 2000.

CONCLUSIONS/RELEVANCE: The latitude gradient present in older incidence studies of MS seems to be disappearing. The female to male MS ratio has increased in the last five decades.

Category - MS and Related Diseases
SubCategory - Clinical Science

Thursday, April 17, 2008 7:00 AM

Poster Sessions VI: Multiple Sclerosis and Related Diseases: Genetics and Epidemiology (7:00 AM-10:00 AM)

http://www.abstracts2view.com/aan2008chicago/view.php?nu=AAN08L_P06.142

Cherie