A major Australian study has found a link between asthma in children and bone fractures, but it affects boys more than girls.

One in seven children have asthma, which restricts breathing and can be deadly if it is not managed.

The University of Melbourne study of more than 16,000 Victorian School students is the largest of its kind.

Sharon Brennan-Olsen is a senior research fellow from the University of Melbourne.

"What we found was that severity of asthma was associated with radiologically confirmed fracture in children — more likely boys than girls," Dr Brennan-Olsen said.

Why boys?

According to the research findings, there is approximately 30 per cent increased odds of a fracture in boys with asthma compared to girls with asthma.

"Boys are more likely to fracture due to not only different lifestyle behaviours, but also entering puberty at a later date," Dr Brennan-Olsen said.

"In children, bone development occurs up until around the age of 20, meaning that if boys are maturing later, their bone development is much less mature.

"Increased fracture rates actually relate to the bone mineralisation lagging in bone growth," Dr Brennan-Olsen explained.

Medications not to blame

The good news is the increase in bone breakages was not found to be related to the cortico-steroids in preventative and reliever puffers used to treat asthma.

So the advice is: keep up the medication and physical exercise for bone strength.

Is this a good excuse for boys with asthma to have extra ice-cream and more cream on their dessert?

"That's a parent call," Dr Brennan-Olsen cautioned light-heartedly, "but I'd say yes."