Child blood tests for Vitamin D levels rise significantly without need

21 Jun 2023

Doctors are ordering unnecessary, costly and invasive blood tests for children to detect Vitamin D deficiency when it would be better to give them supplements as needed, according to a study by The University of Queensland and Macquarie University.

The findings show that 61,809 blood tests for Vitamin D levels were conducted on 46,960 young children and adolescents who presented to Victorian GPs in 2018, which is 30 times greater than in 2003, without any increase in Vitamin D deficiency detected.

Co-lead author Professor Yvonne Zurynski, from Macquarie University’s Australian Institute of Health Innovation, said even when a deficiency was detected, only four percent of children were followed up within three months to check if their Vitamin D levels had improved.

“All this testing seems counterintuitive and is symptomatic of low-value care,” Professor Zurynski said.

“These findings add to previous research by international experts who recommend that testing for Vitamin D deficiency without symptoms is unnecessary.

“However, this advice doesn’t appear to have taken root in general practice in Australia.”

Professor Craig Munns, Director of the UQ Child Health Research Centre and Paediatrician at Queensland Children’s Hospital, said local GPs need more education on the latest evidence-based global guidelines, so that prevention, rather than testing, is their first choice and patients get best-practice care.

“Children with Vitamin D deficiency can have serious clinical complications," Professor Munns said.

“It's a spectrum — you can go from being completely asymptomatic, to having vague aches and pains or nutritional rickets, to having hypocalcemia (very low calcium) and then a seizure. Thankfully, the severe end of the spectrum is very rare,” he said.

“From a clinical perspective, children with bones affected by rickets may be reluctant to walk because they have sore legs or tire easily. They may have skeletal deformities, such as thickening of the ankles, wrists and knees, bowed legs, soft skull bones and rarely, bending of the spine.

“There are about 4.9 cases of rickets per 100,000 children in Australia, compared with 2.9 cases per 100,000 children in Canada and 7.5 cases per 100,000 children in the UK.

"If we provided Vitamin D supplements to all babies for the first 12 months of life, then we would eradicate it, just the same as we’ve done with spina bifida by giving folate to pregnant women. It’s within our reach.”

Professor Munns was the lead author of a study by 33 global experts in 2016 who created the Global Consensus Recommendations on Prevention and Management of Nutritional Rickets.

Many countries have adopted these guidelines, including the US, Canada, UK and Europe, and food products in these countries are also fortified with Vitamin D.

Australia has yet to adopt these recommendations nationally — although some local government health authorities have taken them up.

Professor Munns and Professor Zurynski are among a group of experts who are advocating to have the recommendations adopted in Australia.

This study was published in the British Medical Journal’s Archive of Disease in Childhood.