What month were you born in?
Did you know that month of birth is a risk factor for MS?
Why does the month you are born affect your risk of MS?
Did you know that month of birth is a risk factor for MS? In the Northern hemisphere, if you are born in May, you have a higher chance of developing MS than in November. This risk-ratio flips over in the Southern hemisphere.Â
This month-of-birth effect is usually attributed to the effect of low vitamin D levels in the womb. The low vitamin D affects how the immature immune system develops. In other words, if your mother was pregnant during winter, a time when she was more likely to be vitamin D deficient, your immune system was unable to develop correctly. It resulted in you being more susceptible to developing an autoimmune disease in later life. In support of the vitamin D hypothesis is the observation that the month-of-birth effect gets larger the further you are away from the equator, i.e. it is greater in Scotland than in England.Â
The month of birth effect is not unique to MS and has been observed in type 1 diabetes mellitus, rheumatoid arthritis, ulcerative colitis, systemic lupus erythematosus, and schizophrenia. Therefore a grand challenge in MS is to pin down the molecular and immunological mechanisms of the month of birth effect. This is very important as it will underpin prevention strategies, such as vitamin D supplementation in pregnancy. It will also provide potential markers to assess the future impact of MS preventative strategies. Any successful MS preventative strategy should correct the defect that is associated with the month of birth effect.
Based on this, I recommend that all my patients with MS, who are planning to fall pregnant, make sure they are vitamin-D replete before falling pregnant and whilst pregnant. However, a randomised international study of vitamin D supplementation during pregnancy is needed to see if it reduces autoimmune disease in later life.Â
What dose do I recommend?Â
In an ideal world, we would supplement your vD levels to a target, i.e. to keep your blood levels above 100nmol/L (20ng/mL) but less than 250nmol/L (100ng/mL). As the NHS and other healthcare systems limit vD level monitoring, I recommend supplementation at a fixed dose.Â
Less than two years of age 600U vD3 per day
2-10 years of age 2,000U vD3 per day
>10 years of age 4,000U vD3 per day
Pregnancy and breastfeeding 8,000U vD3 per day
Please note that these recommendations are based on much higher doses than the recommended daily allowance (RDA), between 400U and 800U vD3 per day. The latter level of supplementation is based on bone health and prevention of rickets, osteopaenia and osteoporosis and is not related to immune function. And yes, I take daily vD supplements and walk my talk.Â
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General Disclaimer: Please note that the opinions expressed here are those of Professor Giovannoni and do not necessarily reflect the positions of Barts and The London School of Medicine and Dentistry nor Barts Health NHS Trust. The advice is intended as general and should not be interpreted as personal clinical advice. If you have problems, please tell your healthcare professional, who will be able to help you.
May. 1957. Blackburn. Pre smokeless zones. Mum worked in factories. Doomed ;-}
I was born on my due date— October 3, 1998 in Colorado, USA but my mama grew up all over the world from Mexico, Italy to the US. I grew up between the US (Virginia and Colorado) and then Italy (Abruzzo and Emilia Romagna).