People who regularly consume at least one sugary soft drink a day, no matter the size of their waist, could be at increased risk of cancer, according to a new study.

Researchers from Cancer Council Victoria and University of Melbourne studied more than 35,000 Australians who developed 3,283 cases of obesity-related cancers.

Published on Thursday, the study found a positive association between soft drink consumption and cancer risk, independent of obesity, after statistically adjusting for waist circumference.

The authors say the results justify the need to minimise the intake of sugar-sweetened soft drinks.

“Initially our hypothesis was that drinking soft drinks would cause obesity which would then cause an association with obesity-related cancers but we found that there was more beyond the effect of obesity,” said the lead researcher, Assoc Prof Allison Hodge of Cancer Council Victoria’s epidemiology and intelligence division.

“These particular cancers are commonly associated with obesity, however, our research found this risk existed for all participants, no matter their size.”

According to the research, which was conducted through the Melbourne Collaborative Cohort Study, the more sugary soft drinks participants drank the higher their risk of cancer.

This was not the case for those who drank diet soft drinks, suggesting sugar could be the key, said Hodge, adding that the “surprising” findings warranted further research.

“We definitely would like to see these findings confirmed in other studies and then also to understand something about the mechanism and whether sugar could be a driver of this association,” she said.

Cancer Council Victoria’s chief executive, Todd Harper, said this new research provided another reason for Australians to switch to water.

“Sugary drinks, including soft drinks, are already known to be a cause of obesity, which greatly increases the risk of 13 types of cancer,” Harper said. “And cancer is just one of many chronic health conditions associated with sugary drink consumption, including increased risk of type 2 diabetes, heart disease, and tooth decay.”