Sun exposure during pregnancy reduces the risk of multiple sclerosis. Children conceived in winter had a 30% higher risk of multiple sclerosis later in life compared to those conceived in summer, in an Australian study published in the British Medical Journal.
Low levels of vitamin D has long been associated with risk of multiple sclerosis. The disease is also more common in countries far from the equator.
Judith Staples of the Australian National University and colleagues analyzed birth records of 1524 people with the disease, born between 1920 and 1950. They were more likely to be born in summer (November and December in Australia), which means that their first quarter was during the winter months (from April to June). Conversely, they were less likely to be born in May and June (first quarter in summer).
Vitamin D may be particularly important in the development of the nervous, immune and supplements of vitamin D could be considered during pregnancy, the researchers conclude.