Lead researcher Patria Hume said neither the AUT or British study was set up to determine causation.
"The cross-sectional study design does not allow researchers to state any cause and effect relationship," she said.
"High loads to joints may result in joint tissue damage which theoretically could progress to osteoarthritis. However, there is no cause and effect evidence for sport leading to osteoarthritis to date.
Longitudinal studies taking into account the multiple factors that might influence arthritis - diet, access to medical treatment, load intensity and volume - have not been conducted."
While the cautionary note will be welcomed, the study comes at a time when the spotlight is being shone brightly on the collateral damage of rugby and other contact sports.
There has been a renewed plea from academics to ban tackling and scrums in schools, though the calls were rejected as "extreme" and "alarmist" by World Rugby.
Allyson Pollock and Graham Kirkwood from the Institute of Health at Newcastle University said governments have a duty to "ensure the safety of children" and argued that removing collision is likely to "reduce and mitigate the risk of injury".
John 'JJ' Williams, who recently shared his CTE-symptoms diagnosis with the Herald, said he would hate to see tackling removed from rugby at school level and didn't think it was realistic.
"You can't take tackling out of rugby," he said. "It's bloody ridiculous."
Chronic Traumatic Encephalopathy has also re-emerged in the news over the past week when it was announced that Aaron Hernandez, the former NFL star serving a life sentence for murder before he hanged himself in his cell aged 27, was suffering from severe CTE.
Reports of the injuries enveloping many English rugby premiership clubs pockmarked the British papers over the weekend, adding to the sense that the sport is nearing a health and safety crisis, and this latest study could serve to fan the flames.
There was a silver lining, however, with former rugby players less likely to develop diabetes.
