Pregnant women who don’t get enough sunshine are more likely to have children with dyslexia, autism or ADHD, a major study suggests.
Researchers found 21 per cent of children conceived during the winter months of February, March and April had a learning disability.
In comparison, the figure was just 16.5 per cent for youngsters conceived in June and July.
The findings come from a major investigation using NASA satellite data and records of more than 400,000 youngsters living in Scotland.
Experts believe a lack of sunlight in pregnancy, which means lower levels of vitamin D, could be to blame.
Researchers found 21 per cent of children conceived during the winter months of February, March and April had a learning disability. In comparison, the figure was just 16.5 per cent for youngsters conceived in June and July
Glasgow University’s Professor Jill Pell, lead author of the study, said: ‘Learning disabilities can have profound lifelong effects on the affected child and their family.
‘The importance of our study is that it suggests a possible way to prevent learning disabilities in some children.
‘Women who are pregnant or trying to conceive are already recommended to take vitamin D supplements because it is important for the development of the baby’s brain.’
Professor Pell added: ‘Clinical trials are needed to confirm whether taking vitamin D supplements during pregnancy could reduce the risk.’
The researchers found 20 per cent of babies conceived in January and May and 19 per cent of those conceived in December had learning difficulties.
This was higher than the Scottish average of 18.8 per cent, according to the results published in the journal Scientific Reports.
Experts believe a lack of sunlight in pregnancy, which means lower levels of vitamin D, could be to blame
THE SIGNS AND SYMPTOMS OF AUTISM
According to the Centers for Disease Control and Prevention, people with autism have trouble with social, emotional and communication skills that usually develop before the age of three and last throughout a person’s life.
Specific signs of autism include:
- Reactions to smell, taste, look, feel or sound are unusual
- Difficulty adapting to changes in routine
- Unable to repeat or echo what is said to them
- Difficulty expressing desires using words or motions
- Unable to discuss their own feelings or other people’s
- Difficulty with acts of affection like hugging
- Prefer to be alone and avoid eye contact
- Difficulty relating to other people
- Unable to point at objects or look at objects when others point to them
Scots obtain most of their vitamin D from sunlight exposure from around April to September, mostly between 11am and 3pm.
But the level of ultraviolet B (UVB) rays reaching the Earth can also be affected by weather such as clouds.
This means many Scots are unlikely to receive sufficient vitamin D from sunlight.
All Scots are advised by the NHS to take a daily vitamin D supplement, particularly during the winter months.
Those at greater risk of vitamin D deficiency are advised to take a vitamin D supplement year-round. Vitamin is also added to some foods.
They include all babies and children from birth to four years except those who are fully bottle-fed, and pregnant and breastfeeding women.
The Department of Health and Social Care advises women in the UK to ‘consider taking’ a vitamin D supplement while pregnant.
Previous studies have already shown that the prevalence of autism is higher in populations that are further from the equator than those that are closest to it.
The new study adds more weight to the theory that sunlight and vitamin D play a role, as well as other factors, such as family history, in the development of intellectual disabilities. Vitamin D is considered crucial for a baby’s development, meaning low levels in early pregnancy could affect their brain.
The results show a ‘statistically significant’ relationship between lower UVB exposure over the whole of pregnancy and the risk of learning disabilities.
The academics also found a slightly stronger relationship with low UVB exposure in the first trimester, suggesting that early pregnancy may be the most vulnerable to the effects of insufficient UVB.
A Scottish Government spokesman said: ‘Everyone should consider taking a daily vitamin D supplement, particularly pregnant and breastfeeding women.’
Dr Claire Hastie, who conducted the analysis, said: ‘We really hope the study does not worry pregnant women.
‘We hope this is just useful information so people know it would be a good idea to get supplements, especially in a high latitude country like Scotland.’
The Times reports that Dr Hastie added: ‘The risk is still tiny of your child having special educational needs.’
WHO SHOULD TAKE VITAMIN D SUPPLEMENTS?
The Department of Health recommends that certain groups of people should take daily vitamin D supplements to make sure they get enough:
- all babies from birth to one year old (including breastfed babies and formula-fed babies who have less than 500ml a day of infant formula)
- all children aged one to four years old
- people who aren’t often exposed to the sun (for example, people who are frail or housebound, or are in an institution such as a care home, or if they usually wear clothes that cover up most of their skin when outdoors)
For the rest of the population, everyone over the age of five (including pregnant and breastfeeding women) is advised to consider taking a daily supplement containing 10 micrograms (μg) of vitamin D.
But the majority of people aged five and above will probably get enough vitamin D from sunlight in the summer (late March/early April to the end of September).
Source: NHS Choices