New research suggests the number of sexual assault survivors to visit Ontario hospitals is significantly higher than previously thought.

The study, published Thursday in the American Journal of Public Health, examined five databases used for medical documentation in Canada and found there have been 52,780 cases of sexual assault survivors treated in Ontario hospitals between 2002 and 2016, amounting to about 3,500 cases each year.

Two of the databases use an internationally recognized code for identifying the reason for a patient’s hospital visit known as the Classification of Diseases. The code “Y05: sexual assault by bodily force” is typically only used for the most extreme cases, leading to underreporting of other instances of sexual violence.

The researchers expanded the definition of sexual assault to include several additional codes, including “Z04.4: examination and observation following alleged rape and seduction” and “Z61.4: problems related to alleged sexual abuse of child by person within primary support group.”

By adding the additional codes, the researchers found another 40,000 cases of sexual assault which had been previously missed.

“There’s a large problem with underreporting with sexual violence and there can be ambiguity, whether a provider or coder believes a sexual assault happened or not,” Katherine Muldoon, a senior research associate at The Ottawa Hospital and the lead researcher on the study, told in a recent phone interview.

“My goal in the future would be anybody looking at these types of patterns would think about trying to capture sexual assault using a broad definition, instead of one that is very narrow and would exclude most people.”

The study found that approximately 90 per cent of the cases involved female victims, but that there were 7,094 incidents involving males, primarily under the age of 10.

“We do know sexual assault is more common among females, but often what happens is males don’t even get included in the research or in our reports,” Muldoon said.

Among the females, most of the victims were aged 15-19 (11,829 cases), while the study also found 696 cases of sexual violence among women over the age of 60.

The report also found 1,428 people had experienced two sexual assaults within the same year and found that sexual violence was most common in Ontario’s poorest neighbourhoods (17,607 cases).

Muldoon said these numbers represent just a fraction of the overall incidents of sexual violence in the province as many cases do not make it to a doctor’s office or emergency room and thus would not be found in the data sets.

“We have this sample that is very different than the entire population experiencing sexual violence,” she said. “That is a very important part to remember.”

Because the research period ended in 2016, Muldoon said in the future she will be able to examine how the #MeToo movement -- which began in October 2017 -- changed the number of victims of sexual violence coming forward to medical professionals and how differently these cases are being reported.

“With this study, we have the information to now have our follow-up be looking at pre and post-#MeToo and how that type of a large social movement impacts our health care systems, how we provide care and who comes in for care,” she said.

Muldoon said she expects to see a spike in reported cases of sexual assault post-#MeToo, which should be easy to notice as the number of reported cases remained relatively flat from 2002-2016.

Two of the databases contain nationwide information, meaning the research can also be expanded across the country.

“It is absolutely something I would like to do and we’re plotting next steps on how to collaborate,” Muldoon said. “I’m hoping that the attention that we can get from this large number that we captured can influence national reporting.”

The research was conducted in partnership with The Ottawa Hospital, the University of Ottawa and ICES, “a non-profit research institute that uses population-based health information to produce knowledge on a broad range of health care issues.”

If you or a loved one are impacted by sexual violence, you can find a sexual assault centre near you here.