The Cedar Project: exploring determinants of psychological distress among young Indigenous people who use drugs in three Canadian cities.

BACKGROUND: Mental health and wellbeing, including addressing impacts of historical trauma and substance use among young people, has been identified as a key priority by Indigenous communities and leaders across Canada and globally. Yet, research to understand mental health among young Indigenous people who have used drugs is limited. AIMS: To examine longitudinal risk and strengths-based factors associated with psychological distress among young Indigenous people who use drugs. METHOD: The Cedar Project is an ongoing cohort study involving young Indigenous people who use drugs in Vancouver, Prince George, and Chase, British Columbia, Canada. This study included participants who completed the Symptom Checklist-90-Revised, returned for follow-up between 2010 and 2012, and completed the Childhood Trauma Questionnaire. Adjusted linear mixed-effects models estimated effects of study variables on changes in area T-scores of psychological distress. RESULTS: Of 202 eligible participants, 53% were women and the mean age was 28 years. Among men, childhood maltreatment (emotional abuse, physical abuse, sexual abuse, physical neglect), any drug use, blackouts from drinking, and sex work were associated with increased distress. Among women, childhood maltreatment (emotional abuse, physical abuse, physical neglect), blackouts from drinking, and sexual assault were associated with increased distress, while having attempted to quit using drugs was associated with reduced distress. Marginal associations were observed between speaking their traditional language and living by traditional culture with lower distress among men. CONCLUSION: Culturally safe mental wellness interventions are urgently needed to address childhood trauma and harmful coping strategies that exacerbate distress among young Indigenous people who use drugs.

HIV and ethnicity in Canada: is the HIV risk-taking behaviour of young foreign-born MSM similar to Canadian born MSM?

There is a dearth of information on the HIV risk-taking behaviour of foreign-born men who have sex with men (MSM) in Canada. This study focused on identifying sexual risk behaviour among MSM who immigrated to Canada and compared them to MSM who were born in Canada. Baseline data from the Omega Cohort in Montreal and the Vanguard Project in Vancouver were combined to form four ethnicity/race analytical categories (n = 1,148): White born in Canada (WBIC), White born outside of Canada, non-White born in Canada (NBIC) and non-White born outside of Canada (NBOC). Psychological, demographic and sexual behaviour characteristics of the groups were similar except: NBOC were more likely to be unemployed, less likely to be tattooed, had fewer bisexual experiences and less likely worried of insufficient funds. WBOC were more likely to report unprotected sex with seropositives and more likely to have had unprotected sex while travelling. NBIC were more likely to have ever sold sex and to have had body piercing. WBOC are at high risk of acquiring as well as transmitting HIV. It is important to consider place of birth in addition to ethnicity when developing programmes to prevent the transmission of HIV.

Inadequacies in antiretroviral therapy use among Aboriginal and other Canadian populations.

We undertook this study to provide a profile of Aboriginal people initiating antiretroviral therapy and their response to treatment. Aboriginal peoples were identified through self-report. Baseline socio-demographics and risk factors were compared between Aboriginal and non-Aboriginal participants as were baseline factors associated with two consecutive plasma viral load measures below 500 copies/ml using contingency table analysis. Multivariate survival analysis of the prognostic factors associated with time to two consecutive plasma viral load measures below 500 copies/ml among eligible participants was undertaken to characterize response to antiretroviral therapy. There were 892 participants with available data for this analysis, of those 146 (16%) self-identified as Aboriginal. Aboriginal participants were more likely to be female (p < or = 0.001), have lower baseline plasma viral loads (p = 0.010), be co-infected with HCV (p < 0.001), live in unstable housing (p < or = 0.001), and report an income of >10K CDN (p < or = 0.001) per annum. Aboriginal people were less likely to report men who have sex with men (p < or = 0.001) and more likely to report injection drug use (p < or = 0.001) as a risk factor for HIV infection. Aboriginal participants were more likely to receive double versus triple combination antiretroviral therapy (p = 0.002), be less adherent in the first year on therapy (p = 0.001) and to have a physician less experienced with treating HIV (p < or = 0.001). When these factors were controlled for, Aboriginal people treated with triple combination therapy were as likely to respond and suppress their viral load below 500 copies. In the era of HAART, our results indicate that Aboriginal people living with HIV/AIDS were less likely to receive optimal therapy. However, when Aboriginals did receive triple drug therapy they suppressed just as well as non-Aboriginals.

Drastic elevations in mortality among female injection drug users in a Canadian setting.

The health and social conditions of women living in Vancouver's Downtown Eastside has recently been the focus of substantial international attention. Since few studies have examined rates and correlates of death among addicted women in Canada, we have characterized patterns of mortality among female injection drug users (IDUs) in Vancouver. The Vancouver Injection Drug Users Study (VIDUS) is a prospective open cohort study of IDUs. The analyses presented here, were restricted to women enrolled between May 1996 and May 2002 and who were aged 14 years or older. We estimated cumulative mortality rates using Kaplan-Meier methods and Cox regression was used to calculate univariate and adjusted relative hazards. Between May 1996 and May 2002, 520 female IDUs have been recruited from the Vancouver area among whom 68 died during the study period. Elevated rates of mortality were observed among those who reported, baseline sex-trade involvement, those with HIV-infection at baseline, and those who lived in unstable housing at baseline (all log-rank: p<0.05). In adjusted analyses, HIV infection (RH = 3.09 [95% CI: 1.86-5.11]; p<0.001), unstable housing (RH = 1.74 [95% CI: 1.10-2.86]; p=0.029) and sex-trade involvement (RH = 1.82 [95% CI: 0.95-3.45]; p=0.071) were associated with the time to death. When the number of observed deaths was compared to the number of expected deaths based on the general female population of British Columbia using indirect standardization, the rate of death among female IDUs was elevated by a factor of 47.3 (95% CI: 36.1-58.5). In Vancouver, female IDUs have rates of mortality almost 50 times that of the province's female population. Our findings are consistent with a growing number of reports from other settings internationally, and demonstrate the need for an appropriate evidence-based strategy to address the health and social needs of addicted women.

Quality of life, depression and fatigue among persons co-infected with HIV and hepatitis C: outcomes from a population-based cohort.

The objective of the study was to describe the additional burden generated by hepatitis C (HCV) infection among HIV-infected individuals as measured by self-reported quality of life, depression and fatigue. The provincial HIV/AIDS Drug Treatment Program (DTP) distributes all antiretroviral medication in the province of British Columbia. Eligibility for accessing antiretrovirals is based on published guidelines commensurate with the International AIDS Society. Each participant is asked to complete a self-administered mailed questionnaire that includes patient sociodemographic information, quality of life measures (Medical Outcomes Study-Short Form (MOS-SF), mental health issues (Centre for Epidemiological Studies Depression scale (CESD) and fatigue information. HIV-HCV co-infected individuals were compared to HIV mono-infected individuals using parametric and nonparametric methods. Multivariate logistic regression was used to examine the impact of hepatitis C on quality of life, depression and fatigue, after controlling for sociodemographics and HIV-specific clinical characteristics. Of the 4,134 individuals who were sent a HIV/AIDS DTP survey in 1999, 2000 or 2001, 484 participants both returned one and had an HCV-antibody test result on file. Of the 484 participants eligible for this analysis, 105 (22%) were HCV-positive. In comparison to the 379 (78%) patients testing negative for HCV, a larger proportion of co-infected patients were female (18% versus 3%, p<0.001), aboriginal (20% versus 3%, p<0.001), had ever injected drugs (79% versus 5%, p<0.001), were unemployed (91% versus 49%, p<0.001) and lived in unstable housing (19% versus 1%, p<0.001) at the time they completed the survey. Co-infected patients reported more symptoms consistent with depression, increased fatigue and poorer quality of life. However, using multivariate modeling, it was determined that the impact of HCV on quality of life, depression and fatigue was better explained by the sociodemographic factors related to poverty and injection drug use, than by HCV itself. In conclusion, individuals co-infected with HIV and HCV represent a patient population with significant physical and mental health challenges. Although these patients experience poorer quality of life, increased depression and fatigue, this experience appears to be primarily related to socio-economic issues rather than HCV infection.

Factors associated with sex trade involvement among male participants in a prospective study of injection drug users.

OBJECTIVES: While much research to date has examined female sex trade work, little has been done to evaluate factors associated with male sex trade involvement or to assess their health service needs. This is particularly true for male sex trade workers who are also injection drug users (IDUs). Therefore, the present analyses were undertaken to evaluate factors associated with sex trade work in a prospective cohort study of male IDUs. METHODS: We identified factors associated with sex trade involvement among male participants enrolled in the Vancouver Injection Drug Users Study (VIDUS). Since serial measures for each individual were available at semiannual intervals, variables potentially associated with sex trade involvement were evaluated with adjusted odds ratios (AOR) and 95% confidence intervals (CI) computed using generalised estimating equations (GEE). RESULTS: Between 1996 and 2003, 995 male IDUs were enrolled into the VIDUS cohort among whom 108 (11%) reported being involved in the sex trade at enrolment and 102 (10%) individuals initiated sex trade involvement during the follow up period. In multivariate analyses, factors independently associated with sex trade involvement included HIV positive serostatus (AOR: 1.77 (95% CI: 1.44 to 2.17)), daily cocaine injection (AOR: 1.37 (95% CI: 1.11 to 1.70)), daily crack smoking (AOR: 1.36 (95% CI: 1.07 to 1.72)), borrowing syringes (AOR: 1.73 (95% CI: 1.32 to 2.25)), and inconsistent use of condoms with casual sexual partners (AOR 0.66, CI 0.53 to 0.82). We also found that male sex trade workers were more likely to report having sought but been unable to access substance abuse treatment (AOR: 1.28 (95% CI: 0.98 to 1.67); p=0.076). CONCLUSIONS: Males involved in the sex trade in this setting have higher levels of HIV infection and engage in risky injection behaviours at an elevated rate. Since these behaviours have major implications for HIV acquisition and public health, prevention efforts and targeted provision of addiction treatment to this population should be expanded.

Surviving the sex trade: a comparison of HIV risk behaviours among street-involved women in two Canadian cities who inject drugs.

In Canada, very little is known about the factors and processes that cause drug-related harm among female intravenous drug users (IDUs). Women who inject drugs and participate in the survival sex trade are considered to be at increased risk for sexual and drug-related harms, including HIV infection. Between September 1999 and September 2000, women participating in the VIDUS cohort in Vancouver and the St. Luc Cohort in Montreal completed interviewer-administered questionnaires. Analyses were conducted to compare the demographic characteristics, sexual risk behaviours, risky injection practices and drug use patterns among women who self-identified as participating in the sex trade with those who did not identify as participating in the sex trade. Logistic regression was used to identify factors independently associated with exchanging sex for money or drugs. HIV prevalence at the study visit (September 1999-2000) was 29% for sex trade workers and 29.2% for non-sex trade workers. While patterns of sexual risk were similar, the risky injection practice and drug use patterns between sex trade workers and non-sex trade workers were markedly different. Logistic regression analysis of cross-sectional data revealed that independent behaviours associated with the sex trade included: greater than once per day use of heroin (adjusted OR 2.7), smokeable crack cocaine (adjusted OR = 3.3) and borrowing used syringes (adjusted OR = 2.0). Creative, client-driven interventions are urgently needed for women who trade sex for money or for drugs.

The impact of needle-exchange programs on the spread of HIV among injection drug users: a simulation study.

OBJECTIVE: To determine the impact of the implementation of a needle-exchange program (NEP) on the spread of human immunodeficiency virus (HIV) in an injection drug user (IDU) community. We conducted a Monte Carlo simulation study of a theoretical population of 10000 IDUs. The population was followed monthly from 1984 to 2000. HIV was assumed to be transmitted only by needle sharing. The NEP was introduced in 1989 and evaluated over a period of 11 years. The impacts of the proportion of the population attending the NEP, the risk level of IDUs attending the NEP, the reduction in needle-sharing frequency, and the number of new needle-sharing partners acquired at the NEP on prevalence and incidence of HIV were determined. Increasing the proportion of the population who always attend the NEP and eliminating needle-sharing incidents among IDUs who always attended the NEP were the most effective ways of reducing the spread of HIV. Attracting high-risk users instead of lower risk users to the NEP also reduced the spread of HIV, but to a lesser extent. NEPs are effective at reducing the spread of HIV; even under the worst case scenario of low risk users more likely to attend the NEP, one additional partner per month as a result of attending the NEP, and poor NEP attendance, the estimated prevalence was still less than that from the scenario without an NEP. Under our model, NEPs were shown to reduce the spread of HIV significantly. Efforts should be focused on getting as many IDUs as possible to become regular NEP attenders and stop sharing needles rather than partially reducing the frequency of sharing by a larger number of IDUs.

High pregnancy rates and reproductive health indicators among female injection-drug users in Vancouver, Canada.

OBJECTIVE: To determine the incidence of pregnancy among active injection-drug users and to identify factors associated with becoming pregnant. METHODS: The Vancouver Injection Drug User Study (VIDUS) is a prospective cohort study that began in 1996. Women who had completed a baseline and at least one follow-up questionnaire between June 1996 and January 2002 were included in the study. Parametric and non-parametric methods were used to compare characteristics of women who reported pregnancy over the study period with those who did not over the same time period. RESULTS: A total of 104 women reported a primary pregnancy over the study period. The incidence of pregnancy over the follow-up period was 6.46 (95% confidence interval (CI) 5.24-7.87) per 100 person-years. The average age of women who reported pregnancy was younger than that of women who did not report pregnancy (27 vs. 32 years, p < 0.001). Women of Aboriginal ethnicity were more likely to report pregnancy (odds ratio 1.6, 95% CI 1.0-2.5). Comparison of drug use showed no significant differences in pregnancy rate with respect to the use of heroin, cocaine or crack (p > 0.05). In examining sexual behavior, women who reported having had a regular partner in the previous 6 months were three times more likely to have reported pregnancy. Despite the fact that 67% of women in this study reported using some form of contraception, the use of reliable birth control was low. Only 5% of women in our study reported the use of hormonal contraceptives. CONCLUSION: There were a high number of pregnancies among high-risk women in this cohort. This corresponded with very low uptake of reliable contraception. Innovative strategies to provide reproductive health services to at-risk women who are injecting drugs is a public health priority.

Risky sexual behaviours among injection drugs users with high HIV prevalence: implications for STD control.

Injection drug use is inextricably linked to commercial sex work and the transmission of sexually transmitted disease (STD). In many communities prevention efforts have been stalled owing to the marginal existence of this community. This study describes the sexual activities, condom use, reported STDs, and commercial sex work in a large cohort of injection drug users. Seventy two per cent of male and 92% of female subjects in the cohort were sexually active. Among female subjects, 57% reported more than 100 lifetime partners. Condoms were generally not used with regular partners, used about half the time with casual partners, and used about 80% of the time with paying partners. Female sex workers were more likely to have unstable housing and to report incarceration in the previous six months. Reducing the transmission of STDs and HIV in drug using communities is a public health priority. While existing prevention programmes should be strengthened, innovative approaches to STD surveillance, diagnosis, and prevention are needed.

Industry-sponsored clinical research: a double-edged sword.

Drug development has accelerated exponentially since the 1950s. It is difficult to estimate the relative contributions or rates of success of industry sponsored as opposed to government supported research in any field. However, it is clear that much of the therapeutic innovation of recent decades has emerged from biotechnology and pharmaceutical industry sponsored efforts. This sponsorship is leading to new stresses in the relationship between academic institutions and industry.

Impact of HIV infection on mortality in a cohort of injection drug users.

The prevalence of HIV has been rising among injection drug users (IDUs) and AIDS is now an important cause of death among that population. We tracked mortality and recorded detailed causes of death in the Vancouver Injection Drug Users Study (VIDUS). This is an open cohort of over 1,400 active IDUs that began in May 1996. At enrollment and at semiannual follow-up visits, a trained interviewer administers a detailed semistructured questionnaire. Mortality was recorded during follow-up and detailed causes of death were collected from coroner's reports, hospital records, and the provincial (British Columbia) registry. Causes of death were obtained on 125 participants. Overall, the leading cause of death was overdose accounting for 25% of deaths among HIV-positive participants and 42% among HIV-negative participants. Of the 65 deaths among HIV-positive individuals, 22 (34%) were HIV related. Mortality was associated with older age (adjusted hazards ratio [AHR], 1.03 per year), HIV positivity (AHR, 2.67), injection cocaine use (AHR, 2.23) and methadone treatment (AHR, 0.47). The high rate of HIV in this population has added significantly to the burden of illness and death in this marginalized population.

Risk factors associated with HIV infection among young gay and bisexual men in Canada.

OBJECTIVE: To assess risk factors associated with HIV prevalence and incidence among gay and bisexual men in two prospective Canadian cohorts. METHODS: The Vanguard Project and the Omega Cohort are prospective cohort studies of gay and bisexual men ongoing in Vancouver and Montreal, respectively. For this analysis, baseline sociodemographic characteristics, sexual behavior, and substance use data from these two cohorts were combined. Assessment of risk factors for HIV seroprevalence and seroconversion were carried out using univariate and multivariate analysis. RESULTS: This analysis was based on 1373 gay and bisexual men aged 16 to 30 years. Men who were HIV-seropositive at baseline (n = 48) were more likely to report living in unstable housing, to have had less than a high school education, and to have been unemployed than those who were HIV-negative (n = 1325). HIV-positive men were also more likely to report having engaged in sexual risk behavior, including having had consensual sex at a younger age, having had at least 6 partners during the previous year, ever having been involved in the sex trade, and having engaged in unprotected receptive anal intercourse. With respect to substance use, HIV-positive men were more likely to report the use of crack, cocaine, heroin, and marijuana and to use injection drugs. Similarly, men who seroconverted during the course of the studies (n = 26) were more likely to report having less than a high school education and having lived in unstable housing at baseline. Compared with HIV-negative men, men who seroconverted were more likely to report ever having been involved in the sex trade and engaging in unprotected receptive anal intercourse. Reports of cocaine use and injection drug use were also significantly higher for men who seroconverted compared with HIV-negative men. CONCLUSIONS: Our data indicate that HIV-positive gay and bisexual men are more likely to be living in unstable conditions and to report more risky sexual and substance use behaviors than HIV-negative men.

Incidence of hepatitis C virus infection among injection drug users during an outbreak of HIV infection.

BACKGROUND: Beginning in 1994, Vancouver experienced an explosive outbreak of HIV infection among injection drug users (IDUs). The objectives of this study were to measure the prevalence and incidence of hepatitis C virus (HCV) infection in this context and to examine factors associated with HCV seroconversion among IDUs. METHODS: IDUs recruited through a study site and street outreach completed interviewer-administered questionnaires covering subjects' characteristics, behaviour, health status and service utilization and underwent serologic testing for HIV and HCV at baseline and semiannually thereafter. A Cox proportional hazards model was used to identify independent correlates of HCV seroconversion. RESULTS: As of Nov. 30, 1999, 1345 subjects had been recruited into the study cohort. The prevalence of anti-HCV antibodies was 81.6% (95% confidence interval [CI] 79.6% to 83.6%) at enrollment. Sixty-two HCV seroconversions occurred among 155 IDUs who were initially HCV negative and who returned for follow-up, for an overall incidence density rate of 29.1 per 100 person-years (95% CI 22.3 to 37.3). The HCV incidence remained above 16 per 100 person-years over 3 years of observation (December 1996 to November 1999), whereas HIV incidence declined from more than 19 to less than 5 per 100 person-years. Independent correlates of HCV seroconversion included female sex, cocaine use, injecting at least daily and frequent attendance at a needle exchange program. INTERPRETATION: Because of high transmissibility of HCV among those injecting frequently and using cocaine, the harm reduction initiatives deployed in Vancouver during the study period proved insufficient to eliminate hepatitis C transmission in this population.

Longitudinal patterns of sexual behavior and condom use in a cohort of HIV-negative gay and bisexual men in Vancouver, British Columbia, Canada, 1995-2000.

OBJECTIVE: To characterize longitudinal patterns of sexual behavior in a cohort of young gay and bisexual men and determine their reasons for not using condoms. METHODS: Prospective data from a cohort of young gay and bisexual men aged 18 to 30 years were studied. Study participants had completed a baseline questionnaire and HIV test between May 1995 and April 1996 and four annual follow-up questionnaires. RESULTS: A total of 130 HIV-negative Vanguard participants met the eligibility criteria for this analysis. The median age at baseline was 26 years (range, 24-28). Most were white (79%), had completed high school (85%), were currently employed (82%), lived in stable housing (95%), and reported annual incomes of > or =$10,000 (82%). (All dollar amounts are given in Canadian dollars.) Consistently over the 5-year study period, > 70% of study subjects reported having > or =1 regular male sexual partners in the previous year. During each of the five successive 1-year periods, between 34% and 40% of respondents reported having had unprotected receptive anal intercourse with regular partners. Slightly fewer individuals (between 29%-39%) reported having had unprotected insertive anal intercourse with regular partners. Between 13% and 25% of participants reported having had insertive unprotected anal intercourse with casual sexual partners; and between 9% and 18% reported having had unprotected receptive anal intercourse with casual sexual partners. Reasons for engaging in unprotected anal intercourse varied depending on type of sexual partnership. CONCLUSION: High-risk sexual behaviors remained fairly consistent over a 5-year period in this study. This suggests that it is critically important to understand the motivations for unprotected sex when designing and implementing programs aimed at reducing HIV risk among young gay and bisexual men.

Unsafe injection practices in a cohort of injection drug users in Vancouver: could safer injecting rooms help?

BACKGROUND: In several European countries safer injecting rooms have reduced the public disorder and health-related problems of injection drug use. We explored factors associated with needle-sharing practices that could potentially be alleviated by the availability of safer injecting rooms in Canada. METHODS: The Vancouver Injection Drug User Study is a prospective cohort study of injection drug users (IDUs) that began in 1996. The analyses reported here were restricted to the 776 participants who reported actively injecting drugs in the 6 months before the most recent follow-up visit, during the period January 1999 to October 2000. Needle sharing was defined as either borrowing or lending a used needle in the 6-month period before the interview. RESULTS: Overall, 214 (27.6%) of the participants reported sharing needles during the 6 months before follow-up; 106 (13.7%) injected drugs in public, and 581 (74.9%) reported injecting alone at least once. Variables independently associated with needle sharing in a multivariate analysis included difficulty getting sterile needles (adjusted odds ratio [OR] 2.7, 95% confidence interval [CI] 1.8-4.1), requiring help to inject drugs (adjusted OR 2.0, 95% CI 1.4-2.8), needle reuse (adjusted OR 1.8, 95% CI 1.3-2.6), frequent cocaine injection (adjusted OR 1.6, 95% CI 1.1-2.3) and frequent heroin injection (adjusted OR 1.5, 95% CI 1.04-2.1). Conversely, HIV-positive participants were less likely to share needles (adjusted OR 0.5, 95% CI 0.4-0.8), although 20.2% of the HIV-positive IDUs still reported sharing needles. INTERPRETATION: Despite the availability of a large needle-exchange program and targeted law enforcement efforts in Vancouver, needle sharing remains an alarmingly common practice in our cohort. We identified a number of risk behaviours--difficulty getting sterile needles, needle sharing and reuse, injection of drugs in public and injecting alone (one of the main contributing causes of overdose)--that may be alleviated by the establishment of supervised safer injecting rooms.

Hospital utilization and costs in a cohort of injection drug users.

BACKGROUND: Many injection drug users (IDUs) seek care at emergency departments and some require hospital admission because of late presentation in the course of their illness. We determined the predictors of frequent emergency department visits and hospital admissions among community-based IDUs and estimated the incremental hospital utilization costs incurred by IDUs with early HIV infection relative to costs incurred by HIV-negative IDUs. METHODS: The Vancouver Injection Drug User Study (VIDUS) is a prospective cohort study involving IDUs that began in 1996. Our analyses were restricted to the 598 participants who gave informed consent for our study. We used the participants' responses to the baseline VIDUS questionnaire and, from medical records at St. Paul's Hospital, Vancouver, we collected detailed information about the frequency of emergency department visits, hospital admissions and the primary diagnosis for all visits or hospital stays between May 1, 1996, and Aug. 31, 1999. The incremental difference in hospital utilization costs by HIV status was estimated, based on 105 admissions in a subgroup of 64 participants. RESULTS: A total of 440 (73.6%) of the 598 IDUs made 2763 visits to the emergency department at St. Paul's Hospital during the study period. Of these 440, 265 (160.2%) made frequent visits (3 or more). The following factors were associated with frequent use: HIV-positive status (seroprevalent: adjusted odds ratio [OR] 1.7, 95% confidence interval [CI] 1.2-2.6; seroconverted during study period: adjusted OR 3.0, 95% CI 1.6-5.7); more than 4 injections daily (adjusted OR 1.5, 95% CI 1.1-2.1); cocaine use more frequent than use of other drugs (adjusted OR 2.0, 95% CI 1.2-3.6); and unstable housing (adjusted OR 1.5, 95% CI 1.1-2.2). During the study period 210 of the participants were admitted to hospital 495 times; 118 (56.2%) of them were admitted frequently (2 or more admissions). The 2 most common reasons for admission were pneumonia (132 admissions among 79 patients) and soft-tissue infections (cellulitis and skin abscess) (90 admissions among 59 patients). The following factors were independently associated with frequent hospital admissions: HIV-positive status (seroprevalent: adjusted OR 5.4, 95% CI 3.4-8.6; seroconverted during study period: adjusted OR 2.9, 95% CI 1.4-6.0); and female sex (adjusted OR 1.8, 95% CI 1.1-3.1). The incremental hospital utilization costs incurred by HIV-positive IDUs relative to the costs incurred by HIV-negative IDUs were $1752 per year. INTERPRETATION: Hospital utilization was significantly higher among community-based IDUs with early HIV disease than among those who were HIV negative. Much of the hospital use was related to complications of injection drug use and may be reduced with the establishment of programs that integrate harm reduction strategies with primary care and addiction treatment.

A computer model to simulate family history of breast/ovarian cancer in BRCA1 mutation carriers.

The BRCA1 gene and its relationship to family history of breast/ovarian cancer are difficult to study in a population because of practical and ethical issues. The paucity of information on BRCA1 in the general population was a major theme in a recent review of genetic testing in Canada. We develop a simulation model to mimic genetic inheritance and cancer incidence in the family of someone with a germline BRCA1 mutation. Given someone's age and family structure, our model simulates his or her family history in three steps: (1) determine which family members have the mutation, (2) determine the ages of family members and (3) determine which family members have breast/ovarian cancer. Each step involves random variation. Some parameters in our model are estimated using local (British Columbia, Canada) population data. The breast/ovarian cancer risk associated with BRCA1 mutations is estimated using values published in the literature. An example is provided to illustrate the model's application. The model incorporates results from genetics, demography and epidemiology, but requires several additional assumptions. Research to address these assumptions is recommended.

Sex trade involvement and rates of human immunodeficiency virus positivity among young gay and bisexual men.

BACKGROUND: Susceptibility to human immunodeficiency virus (HIV) infection is of particular concern for marginalized populations. The objective of this study was to determine risk factors associated with sex trade work among young gay and bisexual men. Further, we aimed to compare HIV prevalence and incidence among men involved and not involved in sex trade work. METHODS: The study is based upon data obtained from a prospective cohort study of young gay and bisexual men. Participants had completed a baseline questionnaire which elicited information on demographic information, sexual behaviours, and substance use. Sex trade involvement was defined as the exchange of money, drugs, goods, clothing, shelter or protection for sex within the one year prior to enrollment. Contingency table and multivariate logistic regression analyses were used to identify risk factors associated with involvement in the sex trade. RESULTS: Of the 761 eligible participants, 126 (16%) reported involvement in sex trade work. Multivariate logistic regression analysis revealed regular alcohol use (Odds Ratio [OR] = 3.6, 95% CI : 1.8-7.2), aboriginal ethnicity (OR = 3.7, 95% CI : 1.6-8.7), unemployment (OR = 3.9, 95% CI : 2.1-7.3), history of residence in a psychiatric ward (OR = 4.2, 95% CI : 1.8-9.8), bisexual activity (OR = 7.0, 95% CI : 3.5-14.1) and the use of crack (OR = 7.4, 95% CI : 3.0-18.7) to be independently associated with sex trade work. Sex trade workers had a significantly higher HIV prevalence at baseline compared with non-sex trade workers (7.3% versus 1.1%, P < 0.001). As well, HIV incidence was found to be significantly higher for sex trade workers compared with non-sex trade workers (4.7% versus 0.9%, P = 0.011). CONCLUSION: Our study reveals that for male sex trade workers in this setting increased vulnerability to HIV infection is related to unfavourable living conditions, substance use and sexual risk behaviour.