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Family health: Can you help prevent MS?

Family members of people with MS may have a slightly higher risk of developing the condition. Explore the lifestyle factors that may help reduce risk and support overall health.

Do family members have a greater risk of developing MS

MS is influenced by both genetic and environmental factors, which means that children, siblings and other relatives of people with MS have a higher risk of developing the condition [1].

The general global population has around a 1 in 1000 chance of developing MS, although this figure varies significantly between regions. 

  • If you have an identical twin with MS, you have a 25%-33% chance of developing it too [2].
  • If you have a sibling with MS, your chance of developing it is around seven times higher than the general population (7 in 1000).
  • If you are the child of someone with MS, your chance of developing it is about five times higher than the general population (5 in 1000).

While the risk is higher for close relatives, it is still relatively low overall. Lifestyle choices may also play a role in supporting long-term health and reducing risk.

Lifestyle habits that may help reduce MS risk

While no lifestyle change can guarantee that MS will be prevented, research suggests that certain habits may help reduce risk and support overall health.

These are the same healthy lifestyle approaches recommended in the Overcoming MS Program:

  • Avoid smoking, which is a known risk factor for MS
  • Take vitamin D supplements when sunlight exposure is limited
  • Eat a healthy diet low in saturated fat, rich in whole plant foods
  • Include sources of omega-3 fatty acids, such as flaxseed or oily fish
  • Support emotional wellbeing and manage stress, for example through meditation or mindfulness

These habits are beneficial for everyone in the family, not just people with MS. They are also known to reduce the risk of many other chronic conditions, including heart disease and type 2 diabetes.

Research exploring partners of people with MS who undertake lifestyle modification has found positive effects on partners’ wellbeing, including increased hope, empowerment and stronger relationship connection [3].

How does smoking affect my family’s risk of MS?

Smoking is one of the clearest risk factors linked to multiple sclerosis.

Research has shown that exposure to cigarette smoke in childhood may increase the risk of developing MS later in life. In one population-based study, children exposed to parental smoking at home had around twice the risk of developing MS compared with children who were not exposed [4].

Other research has also found that exposure to second-hand smoke is associated with an increased risk of MS, even among people who have never smoked themselves [5].

Because relatives of people with MS already have a slightly higher genetic susceptibility, reducing exposure to cigarette smoke in the home may be one practical way families can support long-term health.

If you or someone in your household smokes, stopping can benefit everyone in the family.

To find out more about the effects of smoking on personal and family health, read more here:

Smoking and MS

Vitamin D for family members

Vitamin D plays an important role in MS, and research continues to highlight its impact on disease progression and overall health. 

Adult relatives – We recommend that close adult relatives of people with MS take 4,000 IU of vitamin D3 a day in winter (and in summer when sun exposure is limited).

During pregnancy – In the UK the NHS recommend all pregnant and breastfeeding mothers take a daily vitamin D supplement of 10 micrograms (mcg) / 400 units (IU). If you or your child are at a higher risk of MS and considering taking a higher dose, a randomised controlled trial found that vitamin D3 supplementation of up to 4,000 IU per day during pregnancy was safe. In the study, supplementation began between 12 and 16 weeks of pregnancy [6].

Children at higher risk Vitamin D supplementation in children may reduce the future risk of developing MS. While definitive prevention trials are not feasible, higher vitamin D exposure in the womb, and during childhood and adolescence, has consistently been associated with a lower risk of developing MS later in life.  

For children at a higher risk of MS (such as the children of people with MS), we therefore recommend daily vitamin D supplementation of 400 IU daily for infants under 12 months of age and 1,000 IU daily for children and adolescents aged 1–18 years. 

These recommendations are based on the current best available evidence [7-10]. These recommended doses are below the established safe upper limits, though higher than routine supplementation recommended for the general population, reflecting their use for MS risk reduction rather than routine bone health alone. Families should be advised that vitamin D supplementation is a risk-reduction strategy, not a guarantee of prevention, and should be used alongside routine paediatric care.  

Diet for family members

While the evidence around whether dietary changes reduce the risk of family members developing MS is limited, it may make sense to strongly consider a healthier diet.

Following a healthier diet with more fruits, vegetables and whole foods and less animal products, processed foods and saturated fat is important in preventing many chronic health issues such as heart disease and type 2 diabetes. 

Sharing healthy meals as a family can also make lifestyle changes easier to maintain. Cooking and eating together can help create supportive routines, reduce the feeling that one person is eating differently, and encourage everyone to develop healthier habits over time.

Even if not every family member follows every aspect of the Overcoming MS recommendations all the time, small shared changes can make a positive difference.

To discover what foods to eat and avoid, check out the full guide to the Overcoming MS diet.

A guide to family health

A Guide to Family Health

If you want a quick guide to understanding the Family Health pillar on the Overcoming MS Program you can download this one. It delves into the key components, benefits and practical tips that can guide you on your way to making the lifestyle changes that will help you to Live Well with MS.

Overcoming MS background logo

Ready to learn about the other Program pillars to support your wellbeing?

References

[1] Westerlind H, Ramanujam R, Uvehag D, et al. (2014). Modest familial risks for multiple sclerosis: a registry-based study of the population of Sweden. Brain. 137(3): 770–778. https://pubmed.ncbi.nlm.nih.gov/24441172/

[2] Compston A, Coles A. (2008). Multiple sclerosis. Lancet. 372(9648): 1502–1517.

https://pubmed.ncbi.nlm.nih.gov/18970977/

[3] Neate SL, Taylor KL, Jelinek GA, De Livera AM, Brown CR, Weiland TJ. (2018). Psychological shift in partners of people with multiple sclerosis who undertake lifestyle modification: an interpretive phenomenological study. Frontiers in Psychology. 9:15.

Frontiers | Psychological Shift in Partners of People with Multiple Sclerosis Who Undertake Lifestyle Modification: An Interpretive Phenomenological Study

[4] Mikaeloff Y, Caridade G, Tardieu M, Suissa S. (2007). Parental smoking at home and the risk of childhood-onset multiple sclerosis. Brain. 130(10): 2589–2595.

https://pubmed.ncbi.nlm.nih.gov/17827175/

[5] Hedström AK, Bäärnhielm M, Olsson T, Alfredsson L. (2011). Exposure to environmental tobacco smoke is associated with increased risk for multiple sclerosis. Multiple Sclerosis Journal. 17(7): 788–793. https://pubmed.ncbi.nlm.nih.gov/21372120/

[6] Palacios C, Trak‐Fellermeier MA, Martinez RX, Lopez‐Perez L, Lips P, Salisi JA, John JC, Peña‐Rosas JP. (2019). Regimens of vitamin D supplementation for women during pregnancy. Cochrane Database of Systematic Reviews. 2019(10): CD013446. DOI: 10.1002/14651858.CD013446

[7] Great Ormond Street Hospital for Children (2025). Multiple Sclerosis and Vitamin D. Available at: https://www.gosh.nhs.uk/conditions-and-treatments/conditions-we-treat/multiple-sclerosis/multiple-sclerosis-and-vitamin-d/ (Accessed 6th March 2026)  

[8] National Institutes of Health (2025). Vitamin D fact sheet for health professionals. Available at: https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/ (Accessed 11th March 2026)  

[9] Institute of Medicine (2011). Dietary reference intakes for Calcium and vitamin D, Institute of Medicine. Available at: https://www.nationalacademies.org/projects/FNBX-H-08-08-A/publication/13050 (Accessed 6th March 2026)  

[10] European Food Safety Authority (2012). Statement on vitamin D Exposure Levels in Formula Fed Infants and Children: Tolerable upper limits for vitamin D. Available at: https://cot.food.gov.uk/Tolerable%20upper%20limits%20for%20vitamin%20D%3A (Accessed 6th March 2026)  

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