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  • Researchers analysed data from more than 2,700 people in Alberta with syphilis
  • 42% of people with infectious syphilis reported past use of stimulants
  • The researchers called for integration of sexual health and harm reduction programs

Over the past decade, Canada has been undergoing a marked surge in cases of syphilis, a sexually transmitted infection. The populations that have been affected are gay, bisexual and other men who have sex with men (gbMSM); heterosexual men and women; and infants born to parents who have syphilis.

Syphilis can cause complex multistage disease if left untreated. Initial symptoms of syphilis can be minor—usually a small, painless lesion. If this lesion occurs inside the anus, genitals, mouth or throat, it can go unnoticed.

The germs (called treponemes) that cause syphilis can quickly spread within the body and enter the eyes and ears. In some cases, treponemes can enter the brain, bones, heart, cardiovascular system, liver and/or kidneys. If left untreated, syphilis can eventually cause serious complications in adults and in the fetus of the infected person.

In most cases, syphilis can be easily diagnosed with a simple blood test. The vast majority of people with syphilis can recover after a single course of treatment. As with other conditions, the earlier syphilis is diagnosed and treated, the better the outcome. People can become re-infected with syphilis after treatment, so some sexually active people may require regular, sometimes frequent, testing.

A study in Alberta

In reviewing data collected over the past decade, a team of researchers in Alberta suggest that there has been an increased use of stimulants, particularly methamphetamine (meth). The researchers found an overlap between syphilis and the use of stimulants in many people.

As part of a study, the same team of researchers in that province collected and analysed extensive health-related information from people who were diagnosed with syphilis in 2018 and 2019.

The researchers found that among people with syphilis in the study, gbMSM were less likely to have ever used stimulants (24%) compared to women (44%) or men who have sex with women (46%). Statistical analysis of the data found that stimulant use was associated with the following factors:


  • injecting drugs
  • history of being incarcerated
  • having multiple sex partners

Other key findings included the following:

  • Women were likely to be co-infected with gonorrhea.
  • Men who have sex with women were more likely to identify as Indigenous compared to men who had sex with men.

A large proportion of participants in the study reported injecting stimulants at some point in the past. As a result, the researchers called for the “integration of sexual health services into programs for people who use substances and those in corrections custody.”

Study details

During the study, nurses interviewed participants to help uncover risk factors for syphilis. As part of the interview, people were asked about the use of non-prescribed drugs and how such drugs were put into their body.

The average profile of the 2,761 participants upon diagnosis with syphilis was as follows:

  • age – 31 years
  • male – 59%; female – 41% (a very small number of people did not identify as male or female but the researchers did not provide additional details)
  • major ethno-racial groups: Indigenous – 41%; White – 31%; Metis – 10%
  • 27% were incarcerated at some point in the past
  • 21% disclosed injecting drugs
  • 18% had a partner who injected drugs
  • 8% were sex workers
  • 5% sought services from sex workers
  • sexually transmitted infections (STIs): chlamydia co-infection – 20%; gonorrhea co-infection – 16%; HIV co-infection – 6%


Nearly 42% of participants in the study reported use of stimulants in the past. The researchers compared people who used stimulants with those who did not use stimulants within each of the three sub-populations studied.



Researchers found that gbMSM who reported stimulant use were more likely to:

  • be under the age of 25
  • inject drugs
  • have a sexual partner who injected drugs
  • obtain services from a sex worker
  • have been imprisoned

Men who have sex with women (MSW)

Within this sub-group, men who used stimulants were more likely to:

  • either be under the age of 25 or between 35 to 39 years
  • inject drugs
  • have a history of incarceration
  • have more than one sexual partner


Women who used stimulants were more likely to:

  • inject drugs
  • have a history of incarceration
  • have four or more sexual partners
  • be co-infected with gonorrhea and syphilis

In the United States

The Alberta team reviewed reports from the U.S. and found that rates of both syphilis and stimulant use appeared to have risen over the past decade. Furthermore, they stated, “mirroring trends seen within the U.S., most people with syphilis infections and stimulant use were heterosexual individuals in our study.”

A shift in the use of stimulants

The researchers stated that, in the past in the U.S. and Canada, gbMSM comprised “a significant proportion” of people using stimulants, particularly through the sexualized use of drugs (chemsex). However, in both the U.S. and Canada, “stimulant use now predominates among heterosexual persons.”

More infants with syphilis

The researchers also stated: “Alberta has seen an unprecedented number of [infants with syphilis], which rose by a staggering 200% between 2018 and 2019.” They added that “ongoing stimulant use around the time of conception and into pregnancy poses additional risks to the developing fetus.”

To begin to address the issue of infants with syphilis, the researchers stated that “adequate provision of contraception, barrier protection and education, along with creating pathways to identify and treat substance use disorders, are therefore paramount among sexually active individuals of reproductive age.”

A legacy of hurtful policies

In reflecting upon the situation of Indigenous people in Canada, the researchers noted the following:

“Racial disparities in terms of stimulant use were also present in our study. Although those identifying as First Nations and Métis comprise only 6.5% and 2.9% of Alberta’s population, they accounted for 41.2% and 10.3% of the total infectious syphilis cases during the study period. Moreover, we observed how MSW who reported First Nations ethnicity were more likely to use stimulants when compared with other persons reporting White ethnicity. First Nations people are disproportionately affected by STIs. The historical legacy of colonialism has led to structural and systemic health inequities for First Nations peoples of Canada. These include, but are not limited to, lower income, food insecurity, and lack of stable housing along with overrepresentation in corrections, domestic violence, sexual abuse, and substance use. These deep and systemic differences are undoubtedly contributing to our findings, which are a known symptom of these disparities.”

Different levels of governments (municipal, provincial and federal) need to continue to work with Indigenous communities to address the issues raised by the researchers. Until these structural issues are dealt with, many Indigenous people will continue to suffer disproportionally from poor health and well-being.

Helping people who use drugs

The researchers noted that “people who use drugs are more likely to report stigma and mistrust of the health care system. This, along with unstable housing, poverty, incarceration, and other social factors, may contribute to decreased health care utilization and reluctance to identify and locate sex partners. Persons experiencing homelessness also have high levels of substance use disorders, mental illness, and HIV risk. Addressing these [intersecting] factors will require an integrated approach to addressing social factors such as housing instability, mental illness, addiction, and sexual health.”

For the future

The present study is an important landmark—it links any previous use of stimulants to an increased risk for syphilis in the province of Alberta. Similar studies exploring connections between syphilis and risk behaviours are needed across Canada to help identify points for potential intervention to help reduce the burden of syphilis and other STIs. The researchers call for future studies “to better characterize the optimal care model for integrating substance use disorders and STI care and the contribution of social determinants of health.”

—Sean R. Hosein


SyphilisGovernment of Canada

Responding to Syphilis in CanadaGovernment of Canada

Congenital syphilisNational Collaborating Centre for Infectious Diseases

SyphilisGovernment of Quebec

Syphilis outbreakAlberta Health Services

SyphilisBritish Columbia Centre for Disease Control

Global Health Sector StrategiesWorld Health Organization

Alberta study finds high rates of sexually transmitted infections among people in prisonCATIE News

Study finds some people with HIV are at greater risk for STIsCATIE News

A syphilis awareness and education campaign for men makes some progress in B.C. – CATIE News


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