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Blood-Borne
Infections and Persons With Mental Illness: Gender Differences
in Hepatitis C Infection and Risks Among Persons With Severe
Mental Illness
Marian I.
Butterfield, M.D., M.P.H., Hayden B. Bosworth, Ph.D., Keith G.
Meador, M.D., M.P.H., Karen M. Stechuchak, M.S., Susan M. Essock,
Ph.D., Fred C. Osher, M.D., Lisa A. Goodman, Ph.D., Jeffrey W.
Swanson, Ph.D., Lori A. Bastian, M.D., Ronnie D. Horner, Ph.D.
and the Five-Site Health and Risk Study Research Committee
http://www.psychservices.psychiatryonline.org/cgi/content/full/54/6/848
Abstract
OBJECTIVES: The authors assessed gender
differences in hepatitis C infection and associated
risk behaviors among persons with severe mental
illness. METHODS: The sample consisted of 777
patients (251 women and 526 men) from four sites.
RESULTS: Across sites, the rate of hepatitis
C infection among men was nearly twice that among
women. Clear differences were noted in hepatitis C
risk behaviors. Men had higher rates of lifetime drug-related
risk behaviors: needle use (23.1 percent compared with
12.5 percent), needle sharing (17.6 percent compared
with 7.7 percent), and crack cocaine use (45.2
percent compared with 30.8 percent). Women had
significantly higher rates of lifetime sexual risk
behaviors: unprotected sex in exchange for drugs (17.8 percent
compared with 11.2 percent), unprotected sex in exchange
for money or gifts (30.6 percent compared with 17
percent), unprotected vaginal sex (94 percent
compared with 89.7 percent), and anal sex (33.7
percent compared with 22.6 percent). Gender appeared
to modify some sex risks. Unprotected sex in exchange for drugs
increased the risk of hepatitis C seropositivity for both
men and women. In the multivariate model, gender was
not significantly associated with hepatitis C
seropositivity after adjustment for other risk
factors. CONCLUSIONS: Gender differences in the
lifetime rates of drug risks explain the higher rates of
hepatitis C infection among men with severe mental
illness.
Introduction
In the United States, the rates of hepatitis C infection differ
by gender: 2.5 percent for men compared with 1.2 percent
for women (1).
Among persons with severe mental illness, hepatitis C
rates are higher and also differ by gender: 19.6 percent for
men and 9.8 percent for women (2).
The gender differences in infection rates among
persons with severe mental illness may reflect
differences in patterns of risk behaviors or in the
risk associated with a given behavior. However, few studies
have examined gender differences in risk behaviors for
hepatitis C infection, and none have examined these
issues among persons with severe mental illness.
Understanding
gender differences in risks and rates of hepatitis C
infection among persons with severe mental illness may help
clarify the role of sexual transmission. A study of HIV
risks among persons with severe mental illness found
female gender to be predictive of high-risk sexual
behaviors (3).
The literature suggests that the hepatitis C virus
may be spread sexually but less efficiently than HIV
or hepatitis B. Although reports are mixed, estimates
of sexual transmission of hepatitis C range from zero
in some cohorts to 23 percent in high-risk cohorts (4,5,6,7).
In one study, the rate of hepatitis C transmission
from infected persons to their spouses (non-injection drug
users) was 6 percent (8).
Another study reported evidence of sexual
transmission of hepatitis C among women with or at risk of HIV
infection (9).
A third study did not find evidence of sexual
transmission of hepatitis C (5).
In a large
multisite study of infectious diseases among persons
with severe mental illness, we investigated gender differences
in the constellation of risk behaviors associated with
hepatitis C infection and sought to answer three
questions. First, does the prevalence of hepatitis C
risk behaviors differ by gender? Second, does gender
influence the risk of hepatitis C associated with a
given behavior? Finally, do gender differences in hepatitis
C risk behaviors account for the differences in hepatitis
C infection rates between men and women?
Methods
We performed a secondary analysis of data from a large multisite
investigation of risk behaviors and sexually transmitted
diseases among women and men with severe mental
illness, described in the other articles in this
special section of this issue of Psychiatric
Services (10).
We recruited 969 participants from five sites between
June 1997 and December 1998. We excluded 192
participants at one site (Duke) who did not test positive
for hepatitis C, which left a sample of 777. A detailed
description of the sampling and data collection
methods is provided elsewhere (2).
We used the
AIDS Risk Inventory (ARI) (11)
to assess risk behaviors that may be associated with
hepatitis C infection. We assessed comorbid substance
use disorders with the Dartmouth Assessment of
Lifestyle Instrument (DALI), a sensitive and reliable measure
for substance use disorders among persons with severe
mental illness (12).
We tested for serum antibodies to hepatitis C with
the Abbott enzyme immunoassay kit (2).
The primary
outcome variable was hepatitis C serostatus. The
primary independent variable was gender. The other key variables
were lifetime risk behaviors, including drug risks, such
as injection drug use and needle sharing, and sex
risks, such as unprotected sex in exchange for money
or drugs.
We stratified
analyses by site because of the variability in
demographic characteristics, recruitment, and sampling
strategies. We assessed associations between gender
and demographic variables with the
Cochran-Mantel-Haenszel, Wilcoxon-Mann-Whitney, and
Cochran-Armitage trend tests, depending on the distribution
of the demographic variable. We assessed the bivariate
relationships between risk and hepatitis C
serostatus, risk and gender, and risk and hepatitis C
serostatus for each gender. Common odds ratios (ORs)
for each specified bivariate association were tested
for homogeneity by the Zelen test for homogeneity of odds ratio
(13).
If the test for homogeneous ratio was not rejected, a
common OR was calculated by the exact inference method using
StatXact software (14).
If the test for homogeneous odds ratio was rejected,
an OR for each site was calculated and tested for
significance within each site. Analyses used the SAS version
6.12 and the StatXact packages.
After assessing
bivariate relationships, we performed a multiple
logistic regression analysis, adjusting for site. Variables
in the model were selected on the basis of their relative
importance in the domains of drug- and sex-related
risk behaviors and their relevance to research
questions. We used casewise deletion to handle
missing data in all statistical tests.
Results
Patient characteristics
Characteristics of the 251 women and 526 men who participated
in the study, stratified by gender (not adjusted for
site), are summarized in
Table 1.
Compared with the men, the women had higher rates of
ever being married and of having at least one child.
The men had higher rates of institutionalization,
residence in supervised settings, and homelessness than the
women. Approximately two-thirds of the participants had
schizophrenia-spectrum disorders. A higher percentage
of women had schizoaffective disorder or mood
disorders, and a higher percentage of men had a
comorbid substance use disorder. Gender differences were noted
in education and number of sexual partners in the previous
six months—women tended to have more education and
more sexual partners. These gender differences in
demographic characteristics were statistically
significant after we controlled for site (p<.05).
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Table
1. Characteristics of persons with severe mental illness
who participated in a study of gender differences in
hepatitis C infection

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Prevalence of hepatitis C and risk behaviors
The nonadjusted prevalence of hepatitis C and selected hepatitis
C risks stratified by gender and the common ORs for gender
and these risks are shown in
Table 2,
with men as the reference group. At each of the five
sites, the rate of hepatitis C infection was higher
for men, ranging from 7.9 percent to 35.5 percent,
compared with 4.9 percent to 16.9 percent for women. Men had
significantly higher rates of lifetime drug risks than did
women: needle use, needle sharing, or crack cocaine
use. Women were significantly less likely than men to
have ever used injection drugs, shared needles, or
smoked crack.
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Table
2. Hepatitis C infection and risk behaviors among
persons with severe mental illness in a study of gender
differences in hepatitis C infection

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Women had significantly higher rates of lifetime sex-related
risk behaviors than did men: unprotected vaginal sex, anal
sex, unprotected sex in exchange for drugs, and
unprotected sex in exchange for money or gifts. More
than 90 percent of both men and women had unprotected
sex during their life, and 44 percent had unprotected
sex within the previous six months. Women were
significantly more likely than men to have lifetime unprotected
vaginal and anal sex. Women were also more likely than men
to have had sex in exchange for drugs or for money or
gifts during their lifetime. Similar gender-based
trends in sex-related risk for the six months before
the risk interview were also noted.
Gender as a
modifier of risks
Table 3
presents the lifetime risks and common ORs for hepatitis
C seropositivity, controlled for site and stratified by
gender. The drug-related risk behaviors, including
lifetime injection drug use, sharing needles, and
smoking crack, were associated with hepatitis C
seropositivity for both men and women. Among the
unprotected lifetime sex-related risks, anal sex for women
(but not men) and oral sex for men (but not women) were
associated with a significant increase in the odds of
hepatitis C seropositivity. Unprotected sex in
exchange for drugs was associated with a higher risk
of hepatitis C seropositivity for both men and women.
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Table
3. Odds of hepatitis C infection by risk behaviors,
stratified by gender, among persons with severe mental
illness, controlling for site

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To further understand hepatitis C risks, we reviewed specific
risks among the study participants who were infected with
the hepatitis C virus (98 men and 24 women). Of this
group, 31 participants (25 percent) did not report
any lifetime needle use: 22 (71 percent) were men,
and nine (29 percent) were women. Among the hepatitis
C-positive men, 17 reported other drug risks that
could explain the hepatitis C infection, and four reported three
or more high-risk sex behaviors. Among the hepatitis
C-positive women, seven reported other drug-related
risks, and four reported three or more high-risk sex
behaviors.
Multivariate
analysis
The results of our multiple logistic regression analysis of
risk factors related to hepatitis C are presented in
Table 4.
After we adjusted for other important factors, gender was
not significantly associated with hepatitis C
seropositivity, although the OR was higher for men
than for women. Site, age, and needle sharing were
all significantly related to hepatitis C infection.
The OR for site ranged from 3.36 for the Department of Veterans
Affairs (VA) site in North Carolina to 9.70 for the
Connecticut site. (New Hampshire was treated as the
reference group.) This analysis showed that both
needle use and older age were associated with an
increased odds of hepatitis C infection and is discussed
more extensively in the article by Osher and colleagues (15)
in this issue of Psychiatric Services.
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Table
4. Multiple logistic regression model for hepatitis C
infection among persons with severe mental illnessa
a
N=739 observations; -2 log likelihood=438.28; Wald 2=136.72,
df=7, p<.001; C=.85

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Discussion and conclusions
This is the first study to examine gender differences in
behavioral risks and the relationship of these
differences to the very high rates of hepatitis C
reported for men and women with severe mental illness
(2).
In addition to the twofold rates of hepatitis C among
men compared with women, we also found significant gender
differences in patterns of hepatitis C risk behavior.
Women had significantly more sexual risk behaviors
than did men, whereas men had significantly more
drug-related risk behaviors than did women. Overall,
our data show striking gender differences in patterns
and types of risk behaviors. Our data suggest that
gender may modify some of the sexual risks, but the high risk
of hepatitis C associated with drug use behaviors appear
similar for men and women.
Male gender did
not contribute independently to the risk of hepatitis
C infection, whereas site, age, and needle sharing
were significantly related to hepatitis C serostatus. The higher
rates of hepatitis C among men can be explained primarily
by lifetime exposure to injection drug
use—specifically, needle sharing. The gender
differences in drug risks that we observed have been
reported for other populations. The findings of
higher lifetime rates of illicit drug use and substance use
disorders among men than among women are consistent across
studies (16,17,18,19,20,21).
Our analysis confirms the importance of drug-related
risks, particularly needle sharing, as a component of
risk for hepatitis C for both genders. Osher and colleagues
(15)
provide a focused analysis of the importance and complexity
of drug risks in hepatitis C transmission. The
site-specific effect we observed differs from that
observed by Osher and colleagues in part because of
differences in the inclusion criteria.
We also
observed significant gender differences in sexual risk
behaviors. Compared with men, women had significantly more
lifetime unprotected sex risks, including vaginal
sex, anal sex, sex in exchange for drugs, and sex in
exchange for money or gifts. These sexual risks do
not appear to play a major role in hepatitis C
transmission. However, given that there were only 24 hepatitis
C-positive women in the sample, we were unable to model
risks separately by gender. When we examined the
specific risks in hepatitis C-positive participants
who did not use needles, the suggestion of a
cumulative role for multiple sexual risk factors
emerged. Our results are consistent with other reports of gender
differences in the rates of HIV sexual risks (3).
For example, one study of injection drug users noted
that women had higher sexual risks than did men and
that they engaged in behaviors that protected their
partners more often than themselves (22).
Because of the
high baseline rates of sex-related risk behaviors and
gender differences in patterns of risk, we were able to
evaluate the relationship of sex risks to hepatitis C
serostatus and compare these risks between men and
women. In the bivariate analysis, several sexual
risks were significantly associated with hepatitis C
serostatus. These associations suggest that gender
may modify several of these sexual risks. However, in
the logistic regression model, sexual risk behaviors did not
contribute independently to the risk of hepatitis C
infection. Our results are consistent with those of a
study that evaluated patients at a sexually
transmitted diseases clinic (5).
The authors of that study concluded that sexual risks
do not play a major role in hepatitis C transmission,
although that sample was primarily male.
The results of
other studies support a more prominent role of sexual
transmission of hepatitis C among women (9,23,24,25,26,27).
One study found evidence for sexual transmission of
hepatitis C among HIV-infected or at-risk women in
Chicago (9).
In that study, injection drug use was the strongest
predictor of hepatitis C infection among women, as it
was in ours, but sexual risks—history of gonorrhea or
sex with an injection-drug-using partner—were also
independently associated with hepatitis C infection. Another
study of injection drug use among men found that 10
percent of the men's women partners
(non-injection-drug users) were infected with the
hepatitis C virus, suggesting that sexual
transmission of hepatitis C from infected men to their female
partners may occur and that women partners of men who
inject drugs are at risk (24).
Blood-to-blood
contact is important for hepatitis C transmission,
and there appears to be convergent evidence for sexual
transmission. It has been theorized that
menstruation, anal sex, and concurrent sexually
transmitted diseases are all hepatitis C risk factors
for women (25,26).
This theory is especially salient for women with
severe mental illness, who have high rates of sexual risk
behaviors. Although sex was not the prominent mode of
hepatitis C transmission in our study sample, the
high rates of sexual risks that we observed among
women with severe mental illness are of concern.
Gender appears to modify the risk conveyed by some
sexual risk behaviors. For example, for women but not men,
lifetime unprotected anal sex did convey a risk of
hepatitis C transmission in the stratified bivariate
analysis. This gender difference may be related to
which partner is receptive during anal sex. However,
we did not query to obtain this information. Sexual
risk behaviors are also associated with a high risk of
HIV, hepatitis B, and other sexually transmitted diseases.
Centers for Disease Control and Prevention guidelines
on hepatitis C risk reduction recommend condom use to
persons at risk of sexually transmitted diseases (27).
Our study had
several limitations. Whereas injection drug use was
the single most important risk factor predicting hepatitis
C seropositivity, the actual role of high-risk sex
behaviors could not be ascertained in our
cross-sectional study. Furthermore, there were
sampling differences across sites, although we controlled
for these differences in our analysis. Given the
cross-sectional study design, we were able to draw
correlational inferences only. Respondents may resist
disclosing socially stigmatized high-risk behaviors
in a personal interview. To address this possibility,
our research group is currently assessing the validity
of computer-assisted risk interviews among persons with
severe mental illness.
Our study
raises several important clinical issues for mental
health care providers. First, men and women with severe mental
illness have a high risk of hepatitis C. Because
significant gender differences in hepatitis C risk
behaviors exist, different assessment and education
strategies for men and women that target the highest
domains of risk may be warranted. Thus provider
interventions can be informed by knowledge of hepatitis C risks
and gender differences in patterns of risk.
Hepatitis C
issues for women and their partners have been reviewed
elsewhere (28),
and several points are especially relevant to women
with severe mental illness. Our risk data suggest that
spending more time educating women about sexual risk
reduction may be indicated—for example, role-playing
to minimize sexual risks. Other clinical issues for
women with severe mental illness who are infected
with the hepatitis C virus include the risks of
vertical transmission (4 percent to 18 percent) and
breastfeeding (probably low risk) (29,30).
The rate of depression is twice as high among women
and is a relative contraindication to hepatitis C
treatment with alpha interferon. Although there have
been case reports of treating hepatitis C-infected persons
with a history of depression, more treatment studies need
to be done (31).
Adequate
clinical time is warranted for assessing drug and alcohol
risks among men with severe mental illness. Given the
compelling data on risk of lifetime injection drug
use and the high rates of this risk behavior among
men with severe mental illness, it is also important
that mental health clinicians understand and assess
these risks. Further, alcohol dependence—also common
among men with severe mental illness—is known to
promote the progression of hepatitis C-related liver disease.
Although both depression and alcohol abuse are relative
contraindications to hepatitis C retroviral treatment
with alpha interferon, the research in this area is
minimal. A final point is that many men and women
with severe mental illness take multiple medications,
some of which are hepatically metabolized. The clinical
implications of this for hepatitis C-infected
persons—liver function and progression of liver
disease—need to be evaluated.
Footnotes
Dr. Butterfield, Dr. Bosworth, Dr. Meador, Ms. Stechuchak, Dr.
Bastian, and Dr. Horner are affiliated with the Health
Services Research and Development Service (152),
Department of Veterans Affairs (VA) Medical Center,
508 Fulton Street, Durham, North Carolina 27705
(e-mail,
mimi@acpub.duke.edu ). Dr. Essock is with the department of psychiatry of Mount
Sinai School of Medicine in New York City and the
Bronx VA Medical Center. Dr. Osher is with the
department of psychiatry of the University of Maryland
School of Medicine in Baltimore. Dr. Goodman is with the
department of counseling, developmental, and
educational psychology at Boston College. Dr. Swanson
is with the department of psychiatry of Duke
University Medical Center in Durham. This article is
part of a special section on blood-borne infections among
persons with severe mental illness.
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