Research in Sweden suggests the risk of a relative of someone with MS also getting the condition is lower than previously thought.
Using health records dating back to the 1960s, researchers identified 28,396 people with multiple sclerosis and their parents, children, siblings and cousins. This was matched with information from people not affected by MS.
The results showed that the risk of the brother or sister of someone with MS also developing the condition was about seven times higher than in the general population. Previous studies suggested this risk was about nine times higher. The risk for children of someone with MS was five times higher, rather than the previously reported seven times.
Although the risk of developing MS is greater in people with a close relative with the condition, the overall risk of MS is low. For instance, of the 42,743 people in the study who had a parent with MS, only 515 (1.2%) had also been diagnosed with the condition.
The risk for the identical twin of someone with MS was found to be about one in four, which is consistent with previous studies.
The study also challenged the previous observation that relatives of women with MS had a higher risk than the relatives of men. In this study the risks were similar regardless of the gender of the relative with MS.
Westerlind H, et al.
Modest familial risks for multiple sclerosis: a registry-based study of the population of Sweden.
Brain 2014 Jan 17 [ePub ahead of print]