Prevalence and predictors of urethral chlamydia and gonorrhea infection in male inmates in an Ontario correctional facility.
Kouyoumdjian, Fiona G. ; Main, Cheryl ; Calzavara, Liviana M. 等
Around the world, effective control of the bacterial sexually
transmitted infections (STIs) chlamydia and gonorrhea remains elusive,
despite the fact that they are easy to prevent, test for and treat. In
Canada, reported rates have increased in the past decade. (1,2) A
potential control strategy is to identify populations at high risk of
infection and tailor primary and secondary prevention programs for these
groups, a method that has been shown to be both effective and
cost-effective. (3)
One such high-risk population is people who are incarcerated.
Studies of HIV in Canada4 and of chlamydia and gonorrhea in the UK5 and
US (6-8) consistently show that STIs are more common in incarcerated
persons, indicating a prevalence of chlamydia ranging from 2.8% to 13%
and a prevalence of gonorrhea ranging from 0.1% to 2.6% in males.
Reported rates likely underestimate the true prevalence of these
STIs, in particular in incarcerated men, due to barriers to testing,
including high rates of asymptomatic infection, (9) a lack of routine
screening (7) in men in the community and in correctional facilities,
and poor access to health care. (10) Nonetheless, reported rates serve
as a proxy for population-based rates, which are not available for
Canada, and the reported rates of chlamydia and gonorrhea in Canada are
relatively high for the incarcerated population. In males and females in
Canadian federal penitentiaries in 2002, chlamydia was reported for
0.32% and gonorrhea for 0.12% of the population, respectively. (10) In
the general population of Canadian males in 2008, the reported rate of
infection was 168.7 per 100,000 (0.17%) for chlamydia and 42.9 per
100,000 (0.04%) for gonorrhea, (1,2) with higher rates in the age groups
20-24 and 25-29 for both diseases: for chlamydia, 884.2 per 100,000
(0.9%) and 538.7 per 100,000 (0.5%), respectively; and for gonorrhea,
165.4 per 100,000 (0.2%) and 122.5 per 100,000 (0.1%), respectively. The
reported overall and age-specific rates were similar but consistently
lower for males in the jurisdiction in which the study took place as
compared with the rates for Canada; (11,12) the overall prevalence was
163.9 per 100,000 (0.16%) for chlamydia and 25.8 per 100,000 (0.02%) for
gonorrhea, and the highest age-specific rates for the two diseases,
respectively, were for 20 to 24 year olds at 804.5 per 100,000 (0.8%)
and 109.7 per 100,000 (0.11%).
Given the relatively high rates of infection in incarcerated males,
screening programs may function as an effective secondary prevention
measure for inmates and for their sexual contacts, and also potentially
lead to primary prevention at the level of the population. However,
relatively little research has been done on this subject. The value of
routine screening has been demonstrated by a study in San Francisco
which found that greater density of testing in jails was associated with
a decrease in chlamydia rates in females attending neighbourhood medical
clinics. (13) Also, cost-effectiveness analyses of screening
incarcerated males and providing notification services to partners have
shown that screening programs may be cost-saving, (14,15) depending on
the prevalence of the STIs.
Screening may be more cost-effective if it is targeted based on
risk factors. Within the population of incarcerated males, several
potential risk factors for these STIs have been investigated, including
age, race, charge at the time of arrest, recent drug use, the presence
of symptoms, prevalence of the STIs in the jurisdiction of residence of
the inmate, the number of sexual partners, the recency of sexual
encounter, previous STI, and condom use. (6-8) Younger age (for those
older than 15 years), having a greater number of sexual partners, and
having symptoms have been associated with infection, (6-8) though a lack
of consistency in the inclusion and definition of these variables across
studies precludes a clear understanding of the independent contribution
of each of these factors to risk.
There are no studies in the published literature that
systematically determine the prevalence in Canada of these STIs in
incarcerated males. For this reason and given the potential population
health value of primary and secondary prevention programs, the
objectives of this study were to define the prevalence of urethral
chlamydia and gonorrhea infection in adult male inmates on admission to
an Ontario correctional facility, and to explore predictors of
infection.
METHODS
The study was conducted in a correctional facility in southern
Ontario, which receives approximately 5% of the total population of
people who are arrested in Ontario each year. Between June and December
2009, a study nurse attended the correctional facility on approximately
every third day to recruit participants. Initially, the jail nursing
staff invited all inmates to participate at the time of admission, and
the study nurse followed up to determine eligibility and obtain consent.
However, due to low recruitment with this method, the protocol was
modified in July 2009 such that inmates were invited to participate
directly by the study nurse in the days subsequent to admission. Under
this modified protocol, a list of inmates who had been admitted since
the study nurse's previous visit and who were still in the facility
(i.e., had not been discharged or transferred in the interim) was
generated. All those on this list were approached regarding
participation, with the exception of those who were deemed to present a
risk to the study nurse as determined by the jail staff. For inmates who
were at court at the time the study nurse was present, the study nurse
attempted follow-up at each subsequent visit until 14 days after
admission. Inmates were eligible to participate if they were at least 18
years old and understood English well enough to consent. Participation
in the study was voluntary. The nurse obtained written consent for
participation, and then orally conducted a survey of risk factors. The
nurse then obtained a first-void urine specimen for gonorrhea and
chlamydia testing. Testing was conducted using the Becton Dickinson
ProbeTec Amplified DNA Assay (Franklin Lakes, New Jersey), according to
the manufacturer's instructions. Results were reported to
participants either while they were incarcerated or in the community
subsequent to their release. Treatment was offered to those who tested
positive and any positive tests were reported to the local public health
unit for follow-up including contact tracing. Enrollment continued until
there were 500 participants. This sample size was calculated a priori to
allow detection with 95% confidence of a prevalence of chlamydia of 5%
+/- 2% or 2%
A descriptive analysis was conducted of the survey data. For
participants who submitted a urine sample, the prevalence and 95%
confidence intervals were calculated using the exact method. For
participants who had been sexually active in the past year and who had
provided a urine sample, bivariate odds ratios and 95% confidence
intervals were calculated to look at the association between each
variable and infection with chlamydia or gonorrhea. Using this same
population, a multivariable logistic regression model was developed
which included all putative risk factors, and a final model was
determined by comparing nested models and selecting the model that best
fit the data.
Approval was obtained for the study from the Research Ethics Boards
at McMaster University and the University of Toronto, as well as from
the Ontario Ministry of Community Safety and Correctional Services.
RESULTS
Only 15 men were recruited in June and July 2009 prior to the
modification of the recruitment protocol. Subsequent to the
modification, 241 men were released or transferred before being
contacted to participate and 131 were ineligible to participate because
of psychiatric or other illness, inability to speak English, or
potential safety risk to the nurse. Of the 921 who were eligible to
participate and were contacted by the study nurse, 485 (52.7%) agreed to
participate. All 500 participants completed the survey and 488 (97.6%)
provided a urine sample for testing. The sexual risk behaviour and drug
use characteristics of the 12 men who refused to provide a urine sample
were similar to those of the 488 men who provided a urine sample (data
not shown).
The mean age of the 500 participants was 33.6 years and the median
age was 30.5 years, with a standard deviation of 11.8 and a range of 18
to 90 years. The majority (61.6%) of participants were single, 19% were
in common-law relationships, 7.2% were married, 6.4% were separated, and
5% were divorced.
The majority of the men (78%; 390/500) had had intercourse in the
past 3 months, and 90.4% (452/500) had had intercourse in the past 12
months. As shown in Table 1, most of those who had been sexually active
within the past year had had multiple partners and had not used condoms.
A variable was generated for risky sexual behaviour, defined as having
more than one partner and not always using condoms, and more than 80% of
sexually active men had engaged in such risky behaviours. A minority of
sexually active participants reported commercial sex involvement,
defined as having given or taken money, drugs, shelter or food in
exchange for sex. About three quarters of men had had sex while drunk or
high in both the past 3 and 12 months.
When asked about drug use in the previous 12 months, 56.6%
(283/500) reported any recreational drug use. Of the 500 participants,
37.6% (188) had used cocaine, 35.2% (176) had used opioids other than
heroin, 29% (145) had used crack, 7.4% (37) had used heroin, and 6% (30)
had used crystal meth.
Regarding STI history, 13% (65/500) reported having ever been
diagnosed with chlamydia, and 6.4% (32/500) with gonorrhea. Twelve point
six percent (12.6%) reported having been infected with hepatitis C
(63/500), 5.8% (29/500) with genital warts, and 1.4% (7/500) with
genital herpes. One percent or less of participants reported a history
of infection with hepatitis B (5/500), HIV (2/500), trichomonas (2/500),
or syphilis (1/500).
As shown in Table 2, of the 488 participants who provided a urine
sample, 2.9% tested positive for chlamydia (95% CI 1.6-4.8) and 0.6%
tested positive for gonorrhea (95% CI 0.1-1.8), with 3.5% testing
positive for either of these infections (95% CI 2.0-5.5). No
participants were co-infected with chlamydia and gonorrhea. The rate of
infection for each of these STIs was highest for participants who were
younger than 30 years old, with rates of chlamydia of 4.7% (95% CI
2.4-8.3), of gonorrhea of 1.3% (95% CI 0.3-3.7), and of either infection
of 6.0% (95% CI 3.3-9.9).
In the logistic regression, it was not possible to look at the odds
ratios for involvement in commercial sex, for having had male partners
or male and female partners in the past year, or for a self-reported
history of gonorrhea, HIV/AIDS, syphilis, genital warts, trichomonas, or
hepatitis B, since there were no cases of gonorrhea or chlamydia in
those inmates who reported these potential risk factors. As shown in
Table 3, younger age and use of cocaine were each associated with
infection in bivariate but not multivariable logistic regression, but
these associations were not statistically significant at p<0.05. Use
of opioids other than heroin was significantly associated with infection
in the bivariate model. Any drug use was positively associated with
infection in the bivariate and full multivariable models, though was not
statistically significant. Risky sexual behaviour, defined as having
more than one partner and not always using condoms, was associated with
lower odds of infection compared with those who always used condoms or
had only one partner in both bivariate and multivariable analyses,
though this was not significant. The best fit model for the data
included only younger age as a predictor of infection.
DISCUSSION
This is the first published study to systematically investigate the
prevalence of chlamydia and gonorrhea in a Canadian correctional
facility. The study reveals very high rates of these STIs in male
inmates on admission to a correctional facility in Ontario, in
particular for younger males. The study also indicates high levels of
risky sexual behaviours and drug use in this population.
The high prevalence of gonorrhea and chlamydia and the
identification of younger age as a potential risk factor are consistent
with studies of incarcerated men internationally. (5-8) In fact, the STI
rates in this study are on the low end of the range found in studies in
the US and UK, which may reflect differences in the general epidemics
across these regions. Regarding the risk factors explored in the study,
it is unclear why risky sexual behaviour would be associated with a
decreased risk of infection; this relationship may be spurious, may
reflect residual negative confounding, or could reflect that some males
are able to appropriately identify specific situations where they would
be at particularly high risk of STIs and use condoms in these
circumstances. The associations between recent drug use and infection
are of interest, as drug use may be associated with risky sexual
behaviours that were not adequately accounted for in the study.
A limitation of the study is that not all newly admitted inmates
were included, for the following four reasons: recruitment occurred only
approximately every third day; some inmates were not available for
interview prior to release because of scheduled appointments at court;
some inmates were ineligible to participate; and since participation was
voluntary, some inmates refused to participate. It is not clear whether
a more comprehensive inclusion protocol would affect the rate of these
STIs. However, the age distribution of all admitted inmates during the
period was not significantly different from the age distribution of
those who were included in the study (data not shown), which supports
the supposition that these results are internally generalizable. Also of
note, this study was conducted in a single correctional facility in
Ontario, and the results may not accurately reflect the rates of STIs in
male inmates in facilities across Ontario and Canada. However, given
that the population at this correctional facility represents a large
proportion of the inmates admitted in Ontario and that the study results
are consistent with findings of international studies, the true rates
across correctional facilities are likely to be high in comparison with
the rates in males in the general population. Finally, it would be
valuable to compare the STI rates found in this study to
population-based rates from active screening programs instead of
reported rates, however, these data are not available due to the lack of
population-based studies of these STIs in Canada.
This study begins to address the substantial gap in information
regarding these bacterial STIs in people in correctional facilities in
Canada, and may significantly impact policy and practice regarding
testing and treatment. Further research is needed to ensure the
generalizability of these findings, as well as to determine the
cost-effectiveness of screening in this population. Given the high
prevalence of chlamydia in particular in males aged 18 to 19 years,
research should also be done to determine the prevalence of these STIs
in juvenile detention centres. However, the extremely high rates of
gonorrhea and chlamydia detected in the study also indicate the need for
prompt action. Given the sizeable population of persons incarcerated
annually in Canada as well as the network of sexual contacts who could
be offered testing and treatment, a screening program could
significantly contribute to population-level control of chlamydia and
gonorrhea in Canada.
Acknowledgements: We thank the staff at the correctional facility
for their cooperation with the conduct of the study, and Guy LeBlanc and
Jeffrey Pernica for their review and thoughtful comments on earlier
versions of the manuscript.
Conflict of Interest: None to declare.
Received: August 30, 2010
Accepted: November 22, 2010
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Fiona G. Kouyoumdjian, MD, MPH, CCFP, [1] Cheryl Main, MD, FRCPC,
[2] Liviana M. Calzavara, MA, PhD, [1] Lori Kiefer, MD, MHSc, FRCPC
[1,3]
[1.] Dalla Lana School of Public Health, University of Toronto,
Toronto, ON
[2.] Hamilton General Hospital and McMaster University, Hamilton,
ON
[3.] Ontario Ministry of Community Safety and Correctional
Services, Toronto, ON
Correspondence: Dr. Fiona Kouyoumdjian, Dalla Lana School of Public
Health, University of Toronto, 155 College Street, Toronto, ON M5T 3M7,
E-mail:
[email protected]
Funding: This study was funded by a Resident Research Grant from
Physicians' Services Incorporated Foundation.
Table 1. Sexual Behaviours Reported by Sexually Active Men
Past 3 Months, *
Risk Behaviour N=390
Number of partners,
mean (SD), range 1.97 (5.3), 1-100
Frequency of condom use Always 12.8%
Usually 11.5%
Occasionally 9.0%
Never 66.2%
Risky sexual behaviour Yes 83.6%
([dagger]) No 16.2%
Use of condom during last Yes --
intercourse No --
Gender of sexual partner Female only --
Male only --
Male and female --
Involvement in commercial Yes 2.8%
sex No 93.4%
Sex while drunk or high Yes 74.1%
No 24.6%
Past 12 Months, *
Risk Behaviour N=452
Number of partners,
mean (SD), range 3.32 (8), 1-110
Frequency of condom use Always 13.7%
Usually 12.0%
Occasionally 17.5%
Never 56.2%
Risky sexual behaviour Yes 84.1%
([dagger]) No 15.5%
Use of condom during last Yes 22.6%
intercourse No 77.4%
Gender of sexual partner Female only 98.7%
Male only 0.2%
Male and female 0.7%
Involvement in commercial Yes 3.1%
sex No 87.4%
Sex while drunk or high Yes 78.5%
No 20.1%
* Of those sexually active during the specified period.
([dagger]) Defined as having more than one partner and not
always using condoms.
Table 2. Prevalence of STIs, Overall and by Age Category (Years), N=488
Overall, % 18-19, % 20-24, %
(95% CI) (95% CI) (95% CI)
Chlamydia 2.9 16 3.7
(1.6-4.8) (4.5-36) (1.0-9.3)
Gonorrhea 0.6 0 1.9
(0.1-1.8) (0-13.7) (0.2-6.6)
Either STI 3.5 16 5.6
(2.0-5.5) (4.5-36) (2.1-11.8)
25-29, % 30-39, % [greater than
(95% CI) (95% CI) or equal to] 40,
% (95% CI)
Chlamydia 3 1.8 0.7
(0.6-8.5) (0.2-6.2) (0-3.8)
Gonorrhea 1 0 0
(0-5.4) (0-3.2) (0-2.5)
Either STI 4.0 1.8 0.7
(1.1-9.9) (0.2-6.2) (0-3.8)
Table 3. Logistic Regression of Infection With Chlamydia or
Gonorrhea *
Variable Bivariate Models
Age (years) [greater than 1
or equal to] 40
30-39 2.56 (0.23-28.58)
25-29 5.92 (0.65-53.75)
20-24 8.44 (1-71.15)#
18-19 27.05 (2.88-253.74)#
Sex while drunk or high No 1
in past 12 months Yes 3.92 (0.51-30.08)
Risky sexual behaviour No 1
Yes 0.42 (0.14-1.24)
Marital status Common-law 1
Married 1.55 (0.14-17.74)
Single 2.13 (0.47-9.68)
Separated 3.46 (0.46-25.78)
Drug use in past Any drug 1.75 (0.61-5.07)
12 months Heroin 0.78 (0.10-6.03)
Other opioids 2.69 (1.01-7.20)#
Cocaine use 2.44 (0.91-6.54)
Crack use 0.51 (0.14-1.79)
Crystal meth 0.99 (0.13-7.71)
History of previous STIs Any STI 0.66 (0.21-2.09)
Chlamydia 0.91 (0.20-4.08)
Genital herpes 5.19 (0.57-47.02)
Hepatitis C 1.01 (0.23-4.57)
Multivariable Model
Containing All
Variable Variables
Age (years) [greater than 1
or equal to] 40
30-39 1.74 (0.14-20.99)
25-29 5.42 (0.53-54.99)
20-24 6.99 (0.68-71.57)
18-19 22.32 (1.70-292.81)#
Sex while drunk or high No 1
in past 12 months Yes 2.88 (0.34-24.78)
Risky sexual behaviour No 1
Yes 0.50 (0.14-1.8)
Marital status Common-law 1
Married 5.02 (0.28-89.32)
Single 2.88 (0.35-23.8)
Separated 10.39 (0.79-136.46)
Drug use in past Any drug 2.99 (0.78-11.48)
12 months Heroin --
Other opioids --
Cocaine use --
Crack use --
Crystal meth --
History of previous STIs Any STI 1.16 (0.33-4.10)
Chlamydia --
Genital herpes --
Hepatitis C --
* Bold indicates statistical significance at p<0.05.
Note: Statistical significance at p<0.05 indicated with #.
