Rickets sees resurgence with 20 cases in four months

The condition causes deformed bone growth in growing children, and in the worst cases, seizures - leading to death. Photo: 123RF

Rickets, a disease often thought of as being a thing of the past, has seen an alarming resurgence across the country.

The condition causes deformed bone growth and in the worst cases, seizures - leading to death.

Ben Wheeler, professor at the University of Otago's Department of Women and Children's Health, said last time there was a significant rise in rickets in Aotearoa - about a decade ago - there were 60 cases in three years.

This time, there had been 20 cases in just four months.

Rickets was most frequently caused by a deficiency of vitamin D, Wheeler said.

"We make it from ... generally the sun ... UVB radiation from the sun then creates the active form of vitamin D. We can also get it from our diet, but vitamin D is unique in that it's the only vitamin where we where we don't have to take it from our diet and we can make it ourselves," he said.

In adults a lack of vitamin D caused a lack mineral in their bones, but in children this deficiency was more harmful, he said.

Professor Ben Wheeler. Photo: Supplied / Ben Wheeler

"In growing children, because they're growing so fast and they need so much mineral, it damages the growth plate and the growth plate in the bone then leads to the bending, and the softening, and those sort of signs that we think about when we think of rickets."

Vitamin D was also key in the absorption of calcium, which meant that a lack of vitamin D could also lead to low levels of calcium in the body.

"Rickets, then, because of the low levels of calcium, can eventually affect nerve and muscle function.

"In the most extreme cases we see seizures and sometimes we also see damage to the muscle of the heart.

"What we think of as an historical disease is definitely here with us, and and it's doing those things to New Zealand children, you know, as we speak," he said.

Children with darker skin were more at risk of being affected by the "more serious end of rickets", Wheeler said.

"The groups we see the highest rates are the people who are New Zealanders of South Asian backgrounds or African or Middle Eastern backgrounds generally."

The simple cure was to supplement vitamin D which would allow babies at risk to avoid rickets entirely.

A 2019 study published in the New Zealand Medical Journal by Massey University researchers found that a third of tested children did not meet recommended levels of vitamin D.

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