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Journal Club: Risk factors for syphilis infection in MSM: a case-control study in Lille, France

Article reviewed

Karen Champenois, Anthony Cousien, Bakhao Ndiaye, et al. Risk factors for syphilis infection in men who have sex with men:  results of a case-control study in Lille, France. Sex Transm Infect 2013 89: 128-132.

Purpose of study

Since the early 2000s, there has been a surprising resurgence of infectious syphilis cases in North America and Western Europe. These cases have been concentrated mainly in urban areas and affect men who have sex with men (MSM). An estimated 40-50% of MSM infected with syphilis are co-infected with HIV. Although syphilis can be treated fairly easily, it and other ulcerative STIs may increase the risk of transmission and acquisition of HIV by two to three times.  This study aimed to assess risk factors for syphilis infection to better understand the increasing rates.


This was a case-control study conducted in Lille, France (population 1 million people) from April 2008-2010. Eligible participants were MSM, over the age of 18, with a diagnosis of early syphilis (<1 year) based on clinical and serological evaluation. For each case, two controls were selected and matched for age and HIV status.  A control was a male not infected with syphilis at enrolment and with no history of syphilis infection.  A total of 53 cases and 90 controls were enrolled.Data was collected using two standardized questionnaires. The first was completed by the practitioner and included clinical and serological data on syphilis, HIV and other STIs (histories and co-infections). The second was completed by participants and included socio-demographic characteristics, venues frequented for meeting sex partners, and sexual behaviour during the 6 months prior to enrollment.

Key findings

The major risk factors identified in this study were:

  • unprotected receptive oral sex
  • use of anal sex toys

These are sexual practices that have been shown to have a low risk of HIV transmission.  However, these practices still pose a significant risk for transmitting other STIs. Other factors that were identified included: use of poppers, erectile dysfunction drugs and use of the internet to meet sex partners. These factors were not directly associated with syphilis acquisition but were associated with high-risk sexual behavior overall.

Implications for practice

This study identified the need for more education and promotion addressing routes of transmission of not only HIV, but also of syphilis.

For further information

Pubmed link: http://www.ncbi.nlm.nih.gov/pubmed/22679099


Dr. Richard Lester, Medical Head, STI/HIV Control, Clinical Prevention Services, BCCDC
Avril Spencer, Clinical Nurse Educator, STI/HIV Control, Clinical Prevention Services, BCCDC