Why is the incidence of MS increasing amongst woman?
To prove that MS is caused by a single factor or the interaction of several factors it has to explain everything we know about the epidemiology of the disease.
Epidemiology = the branch of medicine involved with the study of disease in the population; epidemiology deals with the study of the causes, distribution, and control of disease in populations.
One observation that is being noticed across several populations, but not all, is the increasing incidence of MS in woman. Why is this occurring? Some of it may be due to the changing in smoking prevalence amongst woman, which has been increasing relative to males. Another is cultural factors, for example the addition of UV blockers in cosmetics over the last 15 years. Other have suggested the use of oral contraceptive pill (OCP) or change in work environment. However, the change in sex ratio appears to go back to the beginning of the 20th century so it predates the change in work environment associated with World War 2 or the introduction of the OCP in the '60s.
Other posts of interest:
Research: the MS diagnosis just got better in the Netherlands, 26 July 2012; "The increasing incidence amongst woman can be seen with a change in the sex ratio. Why this is occurring is not clear. Some of the increasing incidence can be explained by changes in the rate of smoking amongst woman ...
Research: Sex Ratio with MS increasing in Women, 24 May 2012; METHODS: Since environmental risk factors seem to act early in life, we calculated sex ratios by birth year in 27 074 Canadian patients with multiple sclerosis identified as part of a longitudinal population-based dataset.
Research: More women than men have MS in Sweden, 22 Jun 2012; Methods:Data from the Swedish MS Register and data from the Swedish National Statistics Office were used to estimate sex ratio by year of birth and year of onset. Results:In the analysis of sex ratio by year of birth there were ...
Article of interest (1): change in sex ratio of MS - Multiple Sclerosis ..., 11 Jun 2011; 2006 Nov;5(11):932-6. This study showed that the female to male sex ratio by year of birth has been increasing for at least 50 years and now exceeds 3.2:1 in Canada. "The incidence of MS is increasing; particularly in woman.
Multiple Sclerosis Research: Research:MS in Women , 23 May 2012; At the turn of the 1900's Canadian data indicate that the sex ratio of female to males was around is 1 to 1 it is now nearer to 3 to 1. In Iran the ratio is 6:1. MS is increasing in women and staying constant in men. Why is this the ...
Labels: Grand Challenges, sex Ratio