This Is MS Multiple Sclerosis Community: Knowledge & Support

Here is a new Pubmed abstract on a review of MS incidence rates.


Temporal trends in the incidence of multiple sclerosis: a systematic review

Neurology. 2008 Jul 8;71(2):129-35
Alonso A, Hernán MA.
Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, West Bank Office Building, 1300 S 2nd St, Suite 300, Minneapolis, MN 55454, USA. aalogut@alumni.unav.es

BACKGROUND: Multiple sclerosis (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 patients with MS has increased in the last decades. We have conducted a systematic review of incidence studies of MS to assess the overall incidence of MS and explore possible changes in the latitude gradient and the female-to-male ratio over time.

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. The female-to-male ratio in MS incidence increased over time, from an estimated 1.4 in 1955 to 2.3 in 2000.

CONCLUSION: The latitude gradient present in older incidence studies of multiple sclerosis (MS) is decreasing. The female-to-male MS ratio has increased in the last five decades.

Pubmed link

hmmmm.... thanks, dignan.
my California husband isn't really "special."
this confirms a hunch, from reading boards and talking to friends. MS is more prevalent today in the male community and sunny locales. Why?
AC

_________________
Husband dx RRMS 3/07
dx dual jugular vein stenosis (CCSVI) 4/09
dual stents placed 5/09
CCSVI in MS

a, more men are going to the doc? b, sunblock to protect us from the evil ball of flaming gas in the sky?

The female-to-male ratio is going the other way...



I also thought it was interesting that they find that the latitude effect is decreasing specifically because of higher MS incidence closer to the equator. Hmmm, more people in warm climates and more women with MS over the last 50 years...why? I guess a potential explanation for more MS closer to the equator could be that the countries closer to the equator are on average poorer and so maybe their ability to diagnose MS has increased at a faster rate over the last 50 years. Or it's related to a pathogen and globalisation has led to more of that pathogen closer to the equator. Or Bob's favorite, the hygiene hypothesis could be at play...or...