The increasing number of kids who prefer to stay indoors and play games on their iPads while the sun is beaming down outside might cause a problem in the near future: Vitamin D deficiency.

A new research project from the Department of Exercise, Nutrition and Sport (DENS) at the University of Copenhagen has revealed that an alarming number of children had a lack of vitamin D in their blood during the summer.

“Over a third of the children we tested had a vitamin D level in their bloodstream that was under the recommended amount,” Christian Mølgaard, a professor at DENS and co-author of the research, told Videnskab.dk.

READ MORE: Too little Vitamin D can kill you, say Danish researchers

No need to panic
Despite the dire-sounding results, which have been published in the British Journal of Nutrition, Mølgaard wasn’t overly concerned.

“We know that vitamin D levels in the blood fall to about half during the winter months, when the sun doesn’t shine very much,” said Mølgaard.

“The vast majority of the kids were healthy and led a normal life. As long as they don’t show signs of deficiency diseases, I don’t think there is any reason to be worried.”

Significant vitamin D deficiency can lead to weakened bones and rickets, and research has also shown that vitamin D deficiency can also be connected to a number of other diseases, such as diabetes, asthma and psychological illnesses.

The research project measured the vitamin D content in the blood of almost 800 Danish school children aged 8-11 during the summer period.

Vitamin D is generated in the skin when it is exposed to sunlight, but it can also be obtained through certain food products, such as fish.