Are my children or family members more likely to get MS?
Children and other relatives of people with MS are at risk of developing the disease (see Genetic Factors). Offspring are about 30-40 times more likely to develop MS than the rest of the population − even more if they are female and smoke.
Risk of developing MS in family
General population risk: 1 in 330 (this varies greatly from region to region; the quoted figures are around the highest in the world, for places like Scandinavia and Canada, while many other countries are around 1 in 1000 or less).
But lifestyle adjustments, chiefly sun exposure, vitamin D supplements and quitting smoking can reduce that risk. In the US Nurses Health Study, those that took even a low dose of vitamin D had around half the risk of MS, and there are similar data for quitting smoking. OMS believes doctors must advise people with MS of these important avenues to protect children and other relatives.
We recommend that close adult relatives of people with MS take 5,000IU of vitamin D a day in winter (and in summer when sun exposure is limited), suitably reduced for children. For more information, including dosage and frequency, see Sunlight & Vitamin D.
Vitamin D supplementation should be routine in pregnancy, as folic acid is. Children are never too young to begin vitamin D supplements; ideally, they should start in the womb.
The diet question
The evidence on whether dietary changes help is not so clear-cut. We strongly advise people with MS to follow a plant-based wholefood diet that is very low in saturated fat, but it is not clear that putting family members on the same diet will reduce their risk.
But here is one compelling set of data: In The Multiple Sclerosis Diet Book, Professor Roy Swank writes that he placed all family members of people with MS on the same diet, regardless of their own MS status. He tracked more than 3,500 people with MS, and not one of their relatives on the diet developed the disease, to his knowledge.
This is extraordinary, given the risk statistics of relatives (see above). Given the risk data above, in the 3,500 families Swank treated, we would expect to see many hundreds of new cases of MS.
The following moderate lifestyle adjustments (discussed in depth elsewhere on this site) are likely to help protect relatives who do not show signs of MS:
For more information on all these topics, please see the MS Encyclopedia.