April babies at far greater risk of MS

THE risk of developing multiple sclerosis leaps among children born in the month of April, experts say.

And those born in northerly areas are most likely to suffer from the neurological condition.

A study by Oxford University looked at more than 21,000 cases of MS – with special emphasis on Scotland – dating back before the Second World War.

It found that there was a 24 per cent difference in the prevalence of MS across the year, with spring babies facing the highest risk.

The report, led by Dr Jacqueline Palace of the Nuffield Department of Clinical Neurosciences in Oxford, said: ‘There was increased risk of disease in the peak month April – compared with the trough month November.

‘Perhaps there is still a role for birth date in understanding the risk for certain human diseases.’

The study, co-authored by Professor John Zajicek of St Andrews University, studied a total of 21,138 cases of MS – the biggest study sample ever used for research into the neurological condition.

The report says: ‘The largest seasonal effects on birth patterns have been observed in the United Kingdom, particularly in Scotland.’

It explains that vitamin D levels, which are reduced by absence of sunlight, are ‘a potential culprit’ for cases of MS.

But other factors that come with typically colder weather may also increase the risk of developing the condition: ‘Infectious exposures to the mother vary by season. Influenza increases in the winter months.

‘Diet as well as activity level may also change by season, even in pregnant women.’

MS progressively affects the brain and spinal cord, causing problems with vision, movement, sensation and balance.

Around the world, roughly 2.3million people have the condition, which disproportionately affects women by a ratio of 2:1.

Some 107,000 people in the UK have MS, and the number grows by about 2.4 per cent every year as people who have the condition are starting to live longer.

Scotland has a much higher rate of MS than either England or Wales; about 209 of every 100,000 people have the condition, compared with 164 in England and 138 per 100,000 in Wales. Across the country, more than 400 people are diagnosed every year.

The condition is most common in Orkney, where one in every 170 women are sufferers.

The study, which has been published in JAMA Neurology, said: ‘Comparison of the peak month of risk, April, with the lowest month of risk, November, demonstrated a 24 per cent increase in the risk for MS in the most contemporary birth cohort evaluated.’

Recent American research suggested that 55 illnesses may be linked to the season of a person’s birth, among them MS and childhood-onset type 1 diabetes.

The study concluded: ‘The cause of multiple sclerosis remains elusive, but environmental factors are thought to be important.

‘Seasonal differences in population birth rates are present across time and regions in the United Kingdom, with both factors contributing to the monthly distribution of births in the general population.

‘Environmental influences may be acting before the disease is clinically evident. Further interrogation of this may give clues as to the cause of MS.’

Dr David Schley, from charity The MS Society, said: ‘More than 100,000 people live with multiple sclerosis in the UK, and we know that it’s likely to be caused by a combination of genetic and environmental factors.

‘This is an informative study because of its scale, but it doesn’t show why birth month plays a role. We would like to see more research into how vitamin D levels, both during pregnancy and after birth, could influence the risk of MS.’

‘A potential culprit’