University of South Australia researchers have discovered that young children experiencing growing pains had significantly greater body weight than children for whom no pain was reported.
While little has been known about the profile of children affected by growing pains, it is a common childhood condition that results in frequent visits to health professionals, according to researcher Dr Angela Evans from UniSA's School of Health Science.
"It's a much bigger problem than first thought, with our study indicating about one child in every three is affected," Dr Evans said.
"Children who are otherwise healthy can be described as having growing pains when they experience recurrent leg pain and aches in both legs. It is important to note that these pains occur in the muscle groups, not in the joints, which differentiates them from more serious conditions.
"Growing pains typically start late in the day, particularly at night, and seem more likely to occur after increased activity. The level of distress varies from complaints by some children to distress and crying by others, depending on the intensity of the pain. In terms of frequency, it seems to occur in spates. It may occur four times in a week and then not at all for a month, making it difficult to monitor," Dr Evans said.
Researchers conducted the large study involving a random sample of children aged 4 to 6 years from primary schools and childcare centres across South Australia's metropolitan and rural regions.
"Children in this age group are purported to be the most affected by growing pains but have been the least studied," Dr Evans said.
"This is the first time that research has focused specifically on young children."
Parents completed specially developed questionnaires on the prevalence of growing pains in their children, and researchers conducted height, weight and other measures that included assessing the foot posture of the children.
"Our results indicate that as many as 36.9 per cent of young children are affected by growing pains to the point that some are seeing a health professional or taking pain medication, so the community impact of this condition is clear.
"The measurements revealed no significant difference in height between children with and without growing pains, and parents reported similar activity levels in children from both groups.
"But the finding that children with growing pains have significantly greater body weight (about five per cent heavier) requires further exploration given the concerns of childhood obesity. In particular, the areas of activity and anthropometry (size and proportions of children's bodies) warrant further investigation," Dr Evans said.
A family history of growing pains was reported in about 70 per cent of the children affected, most commonly a parent or sibling.
The researchers found that variations in foot posture, such as flat feet, made no difference to the children's experience of growing pains.
Parents associated increased activity and sport with half of the pain symptoms reported, rapid growth was seen as the cause of 35.9 per cent of pain, and flat feet, 7.3 per cent of leg pain.
"Pain relief techniques used by parents include rubbing their child's legs, administering paracetamol and applying hot water bottles, all of which lesson pain in the short term but do not address the underlying cause of growing pains. Unfortunately, the one intervention, which has been shown to be scientifically supported (muscle stretching), is not generally used by parents, nor advised by health care professionals," Dr Evans said.
In a recent European study using implanted micro-transducers within the tibiae (lower leg bone) of three lambs, investigators found that some 90 per cent of bone elongation occurred when the lambs were lying down and that almost no growth occurred during weight bearing. From this observation, the researchers propose that similar growth patterns may occur in children, which could support the concept of night time growth and even a relationship to growing pains.
Research that leads to the cause of growing pain will help children and their parents to better manage the condition and reduce the number of visits to health professionals, according to Dr Evans, whose PhD research was supervised by Associate Professor Sheila Scutter from the Division of Health Sciences.