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Immune system development in newborn babies has been proven to vary based on birth month and vitamin D levels, according to new research.

Scientists from Queen Mary, University of London and University of Oxford have teamed up to indentify a potential biological basis explaining why an individual's risk of developing multiple sclerosis (MS) is influenced by the month of their birth.

Approximately 100,000 people in the UK have MS, a neurological condition which affects the central nervous system. The body damages its own immune system and interferes with the transmission of messages between the brain and other parts of the body. This affects vision, muscle control, hearing and even memory.

The development of MS is believed to be a result of a complex interaction between genes and the environment. Researchers also recently found infants' vitamin D levels may also play a role in development.

Several studies have suggested that birth month can influence the risk of developing MS. This is especially prevalent in England where the risk of developing MS is high for individuals born in May and significantly lowers for those delivered in November. Researchers believe Vitamin D is linked to the "month of birth" effect because Vitamin D forms when skin is exposed to the sun, meaning there could be a prenatal role for Vitamin D and the risk of MS.

Scientists studied samples of cord blood from 50 babies born in November and 50 babies born in May between 2009 and 2010. The study extracted blood from the newborn babies' umbilical cords and analyzed levels of vitamin D and levels of autoreactive T-cells. While T-cells serve to identify and destroy infectious agents in the body such as viruses, a T-cell which is autoreactive will attack the body's own cells. This can cause an autoimmune disease which should eliminated by the immune system during its development.

The study showed that the babies born in May had lower levels of vitamin D (by about 20 percent), and also had approximately double the amount of autoreactive T-cells when compared to the babies born in November.

"By showing that month of birth has a measurable impact on in utero immune system development, this study provides a potential biological explanation for the widely observed 'month of birth' effect in MS. Higher levels of autoreactive T-cells, which have the ability to turn on the body, could explain why babies born in May are at a higher risk of developing MS," said co-author Dr. Sreeram Ramagopalan, lecturer in neuroscience at Barts and The London School of Medicine and Dentistry at Queen Mary.

"The correlation with vitamin D suggests this could be the driver of this effect. There is a need for long-term studies to assess the effect of vitamin D supplementation in pregnant women and the subsequent impact on immune system development and risk of MS and other autoimmune diseases."

The research letter was published in the journal JAMA Neurology.