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Objective: To compare characteristics of first-time needle exchange participants who enrolled at a mobile van-based exchange site versus a fixed pharmacy-based exchange site, in an area where both types of needle exchange programs were available., Methods: Demographic and drug use data were collected on needle exchange program participants on enrollment. Participants were included if they were first-time participants at the Baltimore needle exchange program between December 1997 and March 1999, and if their first visit was at either one van-based site or at one of two pharmacy-based sites. Descriptive statistics and inferences were based on the type of needle exchange into which participants enrolled., Results: Among 286 first-time participants, 92% were African American, 28% were women, 11% were currently employed, 55% completed high school, and the median age was 40 years. In multivariate analyses, van-based enrollment was more common among frequent injectors (odds ratio [OR] = 2.0), but less common among African American participants (OR = 0.21)., Conclusions: Our data suggest that different venues for needle exchange program settings attract different types of drug injecting participants. This suggests that offering different venue types to reach participants with differing drug use patterns will be important to optimize risk reduction strategies.

Objective: To compare demographic characteristics, sexual practices, unprotected receptive and insertive anal intercourse, substance use and rates of HIV-1 seroconversion between two prospective cohorts of HIV-negative men who have sex with men., Design: Comparative analysis of two independent cohorts., Methods: Between May 1995 and April 1996, 235 HIV-negative Vanguard Project (VP) participants were enrolled and between January and December 1985, 263 HIV-negative participants in the Vancouver Lymphadenopathy AIDS Study (VLAS) completed a follow-up visit. The VP participants were compared with VLAS participants with respect to self-reported demographic variables, sexual behaviors, unprotected sex, substance use and rates of HIV-1 seroconversion during follow-up., Results: In comparison with the VLAS participants the VP participants were younger (median age, 26 versus 34 years; P< 0.001), more likely to be non-Caucasian (75 versus 97%; P< 0.001), and were less likely to have attended university/college (35 versus 46%; P = 0.014). The VP participants reported a higher mean number of male sex partners in the previous year (15 versus 12; P= 0.026) and a higher mean number of regular partners (1.7 versus 0.6; P < 0.001). The VP participants were more likely to report engaging in receptive (92 versus 60%; P< 0.001) and insertive (90 versus 69%; P < 0.001) anal intercourse with regular partners and receptive anal intercourse with casual partners (62 versus 38%; P< 0.001). The VLAS participants were more likely to report never using condoms during insertive and receptive anal intercourse with both regular and casual partners. The VP participants were less likely to report using nitrite inhalants (34 versus 43%; P= 0.033), but more likely to report the use of cocaine (30 versus 8%; P< 0.001), LSD (21 versus 3%; P < 0.001), amphetamine (11 versus 1%; P< 0.001), heroin (3 versus 0%; P= 0.010) and methyldiamphetamine (17 versus 10%; P= 0.034). The VLAS participants were nine times more likely to report high-risk sexual behavior, after controlling for differences in age, ethnicity, substance use, and method of recruitment between cohort members. After adjustment for differences in demographics, sexual behaviors, and level of substance use, the risk ratio for seroconversion among VLAS participants remained significantly elevated compared with VP participants., Conclusion: These data provide evidence that men who have sex with men who were enrolled in the VP were more sexually active than their VLAS counterparts were 10 years ago as measured by self-reported numbers of regular and casual partners and frequency of anal intercourse with these partners. However, condom use appears to be significantly higher among VP participants, which has contributed to a lower rate of HIV-1 infection.

Background: Young gay and bisexual men may perceive that the consequences of HIV infection have dramatically improved with the availability of highly active antiretroviral therapy. We therefore sought to identify trends in HIV infection rates and associated risk behaviours among young gay and bisexual men in Vancouver., Methods: Prospective cohort study involving gay and bisexual men aged 18-30 years who had not previously tested HIV positive. Subjects were recruited through physicians, clinics and community outreach in Vancouver. Annually participants were tested for HIV antibodies and asked to complete a self-administered questionnaire pertaining to sociodemographic characteristics, sexual behaviours and substance use. Prevalence of HIV infection and risk behaviours were determined for eligible participants who completed a baseline questionnaire and HIV testing as of May 1998. The primary outcome was the proportion of men who reported having protected sex during the year before enrollment and who reported any episode of unprotected sex by the time of the first follow-up visit., Results: A total of 681 men completed a baseline questionnaire and HIV testing as of May 1998. The median duration between baseline and the first follow-up visit was 14 months. The median age was 25 years. Most of the subjects were white and of high socioeconomic status. The majority (549 [80.6%]) reported having sex only with men; 81 (11.9%) reported bisexual activity. Of the 503 men who had one or more regular male partners, 245 (48.7%) reported at least one episode of unprotected anal sex in the year before enrollment; the corresponding number among the 537 who had one or more casual male partners was 140 (26.1%). The prevalence and incidence of HIV seropositivity were 1.8% (95% confidence interval [CI] 0.8%-2.8%) and 1.7 per 100 person-years [95% CI 0.7-2.7], respectively. Fifty-two (26.5%) of the 196 and 55 (29.7%) of the 185 men with regular partners who reported having practiced protected insertive and receptive anal sex in the year before the baseline visit reported engaging in these activities without a condom at the follow-up visit; the corresponding numbers among the 232 and 242 men with causal partners who had practiced protected insertive and receptive anal sex before the baseline visit were 43 (15.5%) and 26 (9.4%) respectively at follow-up., Interpretation: The incidence of HIV infection is unacceptably high among this cohort of young gay and bisexual men. Preliminary results suggest a disturbing trend toward increasing levels of unprotected anal intercourse.

Objective: The aim of this study was to describe the relationship between sociodemographic characteristics and human immunodeficiency (HIV) status of a cohort of injection drug users (IDUs) on their self-reported health service utilization., Design: Interviewer-administered questionnaire., Methods: IDUs who had injected illicit drugs within the previous month were recruited through street outreach. They underwent serology for HIV-1 and questionnaires on demographics, drug using behaviors, housing status, and health service utilization (hospitalization overnight and emergency department visits) in the previous 6 months. Logistic regression analysis was used to identify independent associations with the use of health services., Results: Of 1,103 cohort participants, 65% were male, 63% were white, and 23% were HIV positive. Cocaine was the most frequently injected drug used. Almost half (47%) had used health services in the previous 6 months. The following variables were associated independently with health service utilization (adjusted odds ratio; 95% confidence interval): unstable housing, defined as living primarily in a hotel, boarding room, or transition house or on the street in the past 6 months (1.44; 1.11-1.86); female gender (1.45; 1.11-1.89); HIV-positive status (1.43; 1.06-1.92); injection of cocaine (1.50; 1.12-2.02); and primary care I physician visit in past 6 months (1.91; 1.39-2.64)., Conclusion: IDUs with unstable housing were more likely to report emergency department and hospital use, which may be a reflection of their disorganized lifestyle or poorer health status. Further studies are required to assess the effect on the health status and health care use of IDUs of interventions that increase the availability of safe, affordable housing.

Objectives: This study examined the frequency of transmission of drug resistant HIV in the population of injecting drug users (IDU) in Vancouver, Canada during a period of particularly high virus transmission., Design: All subjects enrolled in the Vancouver Injection Drug Users Study who seroconverted from HIV negative to positive status (n = 61) between December 1996 and February 1998 were eligible for analysis. The first seropositive sample from 57 individuals with plasma samples available was analyzed for resistance to antiretroviral agents by population based sequencing of the HIV protease and reverse transcriptase genes., Methods: Plasma viral RNA was extracted and the viral reverse transcriptase and protease regions were amplified by nested reverse transcription-PCR. The presence of mutations associated with antiretroviral drug resistance was assessed by automated sequence analysis., Results: Protease and reverse transcriptase sequences were successfully obtained from the 57 recent seroconverters. No cases of transmission of variants associated with significant resistance to protease inhibitors or nucleoside and non-nucleosides reverse transcriptase inhibitors were detected., Conclusion: The frequency of transmission of drug resistant HIV amongst these recently infected IDU is extremely low, with no protease or reverse transcriptase inhibitor resistant strains detected soon after seroconversion. The data provide no rationale for withholding treatment from this already marginalized population.

Objective: To enhance HIV surveillance within a non-nominal provincial testing system., Methods: Confirmatory HIV tests from a provincial laboratory were analyzed during 1995 and 1996. Enhancements included elimination of repeat positive tests for the same individual using automated matching of non-nominal identifiers and nurse call-back of health care providers, completion of missing information through call-back and connection of providers with resources for patient care., Results: Forty-seven percent of 2,683 reactive HIV tests were identified as duplicates for the same individual, meaning that 1,401 people tested positive for the first time. From laboratory test data to enhanced unduplicated data after call-back, the proportion of tests for which risk and ethnic information was unknown dropped from 37% to 11% and from 64% to 18% respectively (p < 0.0001)., Conclusions: Enhanced non-nominal surveillance for HIV is a practical means of marrying the needs of public health for epidemiological information and the rights of patients to privacy.

Objective: An association between needle exchange attendance and higher HIV prevalence rates among injecting drug users (IDU) in Vancouver has been interpreted by some to suggest that needle exchange programmes (NEP) may exacerbate HIV spread. We investigated this observed association to determine whether needle exchange was causally associated with the spread of HIV., Design and Method: Prospective cohort study of 694 IDU recruited in the downtown eastside of Vancouver. Subjects were HIV-negative at the time of recruitment and had injected illicit drugs within the previous month., Results: Of 694 subjects, the 15-month cumulative HIV incidence was significantly elevated in frequent NEP attendees (11.8+/-1.7 versus 6.2+/-1.5%; log-rank P = 0.012). Frequent attendees (one or more visits per week) were younger and were more likely to report: unstable housing and hotel living, the downtown eastside as their primary injecting site, frequent cocaine injection, sex trade involvement, injecting in 'shooting galleries', and incarceration within the previous 6 months. The Cox regression model predicted 48 seroconversions among frequent attendees; 47 were observed. Although significant proportions of subjects reported obtaining needles, swabs, water and bleach from the NEP, only five (0.7%) reported meeting new friends or people there. When asked where subjects had met their new sharing partners, only one out of 498 respondents cited the needle exchange. Paired analysis of risk variables at baseline and the first follow-up visit did not reveal any increase in risk behaviours among frequent attendees, regardless of whether they had initiated drug injection after establishment of the NEP., Conclusions: We found no evidence that this NEP is causally associated with HIV transmission. The observed association should not be cited as evidence that NEP may promote the spread of HIV. By attracting higher risk users, NEP may furnish a valuable opportunity to provide additional preventive/support services to these difficult-to-reach individuals.

Data from a cohort of young HIV-negative gay and bisexual men were analyzed to identify determinants of sexual risk-taking at baseline. Gay/bisexual men aged between 18 and 30 completed a self-administered questionnaire including demographics, depression, social support, substance use, and consensual versus nonconsensual sex. Risk-takers were defined as those who had unprotected anal sex with casual male sex partners in the previous year; non-risk-takers were defined as those who reported consistent condom use during anal sex with all male partners in the previous year. Logistic regression was used to identify independent predictors of sexual risk-taking. Of 439 men studied, risk-takers had less education, a higher depression score, less social support, and were more likely to report nonconsensual sex and recreational drug use relative to non-risk-takers. Independent predictors of sexual risk-taking were low education, nitrite use, low social support (adjusted odds ratio [AOR]=1.65; 95% CI, 1.04-2.59), and nonconsensual sex experienced as a youth or adult (AOR=1.85; 95% CI, 1.15-2.96). Young gay/bisexual men reporting nonconsensual sex, low social support, or nitrite use were significantly more likely to have recently had unprotected anal sex with casual partners. HIV prevention programs aimed at young gay/bisexual men should include sexual abuse counselling and foster community norms supporting safer sex practices.

Context: In British Columbia, human immunodeficiency virus (HIV)-infected persons eligible for antiretroviral therapy may receive it free but the extent to which HIV-infected injection drug users access it is unknown., Objective: To identify patient and physician characteristics associated with antiretroviral therapy utilization in HIV-infected injection drug users., Design: Prospective cohort study with record linkage between survey data and data from a provincial HIV/AIDS (acquired immunodeficiency syndrome) drug treatment program., Setting: British Columbia, where antiretroviral therapies are offered free to all persons with HIV infection with CD4 cell counts less than 0.50 x 10(9)/L (500/microL) and/or HIV-1 RNA levels higher than 5000 copies/mL., Subjects: A total of 177 HIV-infected injection drug users eligible for antiretroviral therapy, recruited through the prospective cohort study since May 1996., Main Outcome Measures: Patient use of antiretroviral drugs through the provincial drug treatment program and physician experience treating HIV infection., Results: After a median of 11 months after first eligibility, only 71 (40%) of 177 patients had received any antiretroviral drugs, primarily double combinations (47/71 [66%]). Both patient and physician characteristics were associated with use of antiretroviral drugs. After adjusting for CD4 cell count and HIV-1 RNA level at eligibility, odds of not receiving antiretrovirals were increased more than 2-fold for females (odds ratio [OR], 2.53; 95% confidence interval [CI], 1.08-5.93) and 3-fold for those not currently enrolled in drug or alcohol treatment programs (OR, 3.49; 95% CI, 1.45-8.40). Younger drug users were less likely to receive therapy (OR, 0.47/10-y increase; 95% CI, 0.28-0.80). Those with physicians having the least experience treating persons with HIV infection were more than 5 times less likely to receive therapy (OR, 5.55; 95% CI, 2.49-12.37)., Conclusions: Despite free antiretroviral therapy, many HIV-infected injection drug users are not receiving it. Public health efforts should target younger and female drug users, and physicians with less experience treating HIV infection.

Objective: To investigate the significance of the time from seroconversion to AIDS (incubation time) and other covariates for survival from AIDS to death., Methods: In survival analysis, survival from AIDS to death was compared for different categories of length of incubation time adjusted and unadjusted for other covariates, and significant predictors for survival from AIDS to death were investigated., Results: Survival after AIDS was not affected by the incubation time in univariate as well as in multivariate analyses. Predictive factors for progression from AIDS to death were age at seroconversion, type of AIDS diagnosis, and CD4 cell count at AIDS. The relative hazard for age at seroconversion increased 1.38-fold over 10 years. Men with a CD4 cell count at AIDS of <130 x 10(6)/l had a twofold higher risk in progression to death than men with higher CD4 cell counts. Persons diagnosed with lymphoma had a sixfold higher risk of progression to death than persons with Kaposi's sarcoma or opportunistic infections., Conclusions: The incubation time as well as other factors before AIDS did not affect survival after AIDS. Survival from AIDS to death can be predicted by data obtained at the time of AIDS diagnosis, such as type of diagnosis, age and CD4 cell count. AIDS seems to be a significant point in progression to death, and not just a floating point between infection and death affected by prior factors for persons who did not receive effective therapy and did not have long incubation times.

The objective of this study was to identify factors associated with frequent needle exchange program (NEP) attendance by injection drug users (IDUs) in Vancouver, Canada. Data were examined from a case control study of recent HIV infection. IDUs with documented HIV seroconversion after January 1, 1994 (n = 89) and seronegative controls with two documented HIV-negative test results in the same period (n = 192) were asked about demographic and social information, drug injection and sexual behavior, and NEP attendance. Logistic regression was used to examine the effect of multiple variables on NEP attendance while adjusting for HIV status and other potential confounders. Frequent (> 1 time/week) versus nonfrequent (< or = 1 time/week) NEP attenders did not differ with respect to gender, age, ethnicity, education, or HIV serostatus. For men, multivariate analysis showed that frequent cocaine injection was the only variable independently associated with NEP attendance (adjusted odds ratio [AOR] = 3.9; 95% confidence interval [CI] = 1.8-8.3); for women, independently associated variables were frequency of any drug injection (AOR = 5.5; 95% CI = 1.7-17), shooting gallery attendance (AOR = 11.5; 95% CI = 2.2-66), and having a nonlegal source of income (AOR = 3.4; 95% CI = 1.0-12). Borrowing used needles was associated with frequent NEP attendance in the univariate analysis. The NEP in Vancouver attracts IDUs who are frequent injectors (especially men using cocaine) and who have high-risk behaviors or an unstable lifestyle. This finding reinforces the role of NEPs as potential focal points for intervention in this hard-to-reach population.

Despite the fact that needle exchange was introduced in Vancouver as early as 1988, needle sharing remains common. An analysis was conducted to identify determinants of borrowing used needles among subjects participating in a case-control study. IDUs had a documented HIV seroconversion after 1 January, 1994 (n = 89), or repeatedly tested HIV-seronegative after this date (n = 192). Interviewer-administered questionnaires focused on drug use, sexual behaviours, source of needles and depression. Subjects were asked if they had "ever been forced to have sex" as a child, youth or adult. Logistic regression identified determinants of borrowing needles. After controlling for HIV serostatus, factors independently associated with borrowing were injecting > 4 times/day, polydrug use, and ever experiencing non-consensual sex (AOR = 3.4, 95% CI: 1.8, 6.5). Depression was associated with borrowing, although not independently so. Homosexual activity was independently associated with borrowing among males, whereas living with a sexual partner was an independent predictor for females. Access or barriers to clean needle use were not associated with borrowing. Social determinants, particularly a history of sexual abuse, are among the most significant predictors of needle borrowing among Vancouver's IDUs. Early identification of these factors should be a component of HIV prevention programmes.

A cohort of 79 homosexual men with documented dates of human immunodeficiency virus type 1 (HIV-1) seroconversion and baseline CD4 cell counts of > or = 500/microL were followed for up to 11.5 years. HIV-1 RNA was measured from stored sera obtained a median of 7 months after the estimated seroconversion date. AIDS progression and mortality among the men were studied, stratified by median baseline levels of HIV-1 RNA. AIDS progression rates at 11.5 years were 69% and 34%, respectively, among those with higher versus lower than median baseline virus loads (> or = 3040 copies/mL; P = .002), and mortality rates were 61% and 27%, respectively (P = .003). Survival curves continued to diverge throughout the 11.5 years, suggesting that the future clinical course of HIV-1 infection may already be determined at the earliest phases of disease. Initiation of definitive treatment very early in HIV-1 infection may be essential.

Objective: To describe prevalence and incidence of HIV-1, hepatitis C virus (HCV) and risk behaviours in a prospective cohort of injecting drugs users (IDU)., Setting: Vancouver, which introduced a needle exchange programme (NEP) in 1988, and currently exchanges over 2 million needles per year., Design: IDU who had injected illicit drugs within the previous month were recruited through street outreach. At baseline and semi-annually, subjects underwent serology for HIV-1 and HCV, and questionnaires on demographics, behaviours and NEP attendance were completed. Logistic regression analysis was used to identify determinants of HIV prevalence., Results: Of 1006 IDU, 65% were men, and either white (65%) or Native (27%). Prevalence rates of HIV-1 and HCV were 23 and 88%, respectively. The majority (92%) had attended Vancouver's NEP, which was the most important syringe source for 78%. Identical proportions of known HIV-positive and HIV-negative IDU reported lending used syringes (40%). Of HIV-negative IDU, 39% borrowed used needles within the previous 6 months. Relative to HIV-negative IDU, HIV-positive IDU were more likely to frequently inject cocaine (72 versus 62%; P < 0.001). Independent predictors of HIV-positive serostatus were low education, unstable housing, commercial sex, borrowing needles, being an established IDU, injecting with others, and frequent NEP attendance. Based on 24 seroconversions among 257 follow-up visits, estimated HIV incidence was 18.6 per 100 person-years (95% confidence interval, 11.1-26.0)., Conclusions: Despite having the largest NEP in North America, Vancouver has been experiencing an ongoing HIV epidemic. Whereas NEP are crucial for sterile syringe provision, they should be considered one component of a comprehensive programme including counselling, support and education.

To characterize the associations of age, immunosuppression, and AIDS outcomes, we evaluated serial measures of CD4+ lymphocytes from 376 homosexual men with documented dates of HIV-1 seroconversion registered in the Tricontinental Seroconverter Study. Using regression models and adjusting for variation within individuals, we found no association between age and the number of CD4+ lymphocytes at seroconversion or with CD4+ lymphocyte decline after seroconversion. Men who developed opportunistic infections had fewer CD4+ lymphocytes at the time of diagnosis compared with men who developed AIDS-defining Kaposi's sarcoma. Older age was significantly associated with higher numbers of CD4+ lymphocytes in individuals diagnosed with AIDS-defining Kaposi's sarcoma but was not significant for individuals with opportunistic infections. Because older age shortens the latency period of Kaposi's sarcoma and does not affect the CD4+ lymphocyte loss, it results in higher CD4+ lymphocytes at the time of diagnosis. These findings suggest distinct biologic mechanisms for various AIDS manifestations, which is important for clinical decision making and health care planning.

Purpose: To study HIV-associated risk behaviours among young offenders., Methods: Juveniles aged 12 to 19 years entering correctional facilities in British Columbia volunteered in an unlinked anonymous study. Logistic regression was used to identify factors associated with high-risk sexual behaviours and injection drug use (IDU)., Results: Despite low HIV prevalence (0.25%), patterns of risk behaviour were evident. IDU and homosexual/bisexual activity were equally prevalent among youth aged 12 to 15 and 16 to 19 years. For both age groups, IDU and female gender were significant predictors of sex for trade and sex with another drug user. Natives aged 12 to 15 years were five times more likely to inject drugs than non-Natives. However, predictors of IDU differed for older vs. younger youth., Conclusions: Patterns of high-risk activity begin early and selective pressures may differ for younger vs. older young offenders. Youth in detention provide a window of opportunity for enhanced HIV/AIDS education.

Aim: To review Track C on epidemiology and public health., Descriptive Epidemiology: Recent trends in the descriptive epidemiology are reported, for example, the rapid spread of HIV in certain Asian countries and the more precise insights in the spread thanks to subtyping of HIV-1 (and HIV-2)., Transmission: There is now ample evidence that sexually transmitted diseases enhance the rate of transmission. Viral load in the plasma of the mother is highly predictive for perinatal transmission., Progression: Natural history studies have shown that true non-progressors are probably rare. Preliminary evidence indicates that the progression rate to AIDS and death does not differ by HIV-1 subtype. Some genetic factors are associated with the rate of disease progression and a few with susceptibility to HIV infection., Interventions and Prevention: Needle-exchange programmes as an intervention measure for injecting drug users were hotly debated and so were HIV (home) testing and counselling. Successes in prevention were reported from Thailand and Uganda, and also from small scale programmes.

Objective: To identify appropriate criteria for characterizing HIV-infected nonprogressors., Design: Five definitions were compared as follows: (1) last CD4 count > 500 x 10(6)/l; (2) two most recent CD4 counts > 500 x 10(6)/l; (3) calculated CD4 count based on linear regression > 500 x 10(6)/l; (4) CD4 slope > or = 0 with no antiretroviral use; (5) all CD4 counts > 500 x 10(6)/l, decline in CD4 slope < 5 cells per year, no antiretroviral use., Participants: Five prospective cohorts of homosexual men with documented dates of HIV-1 seroconversion., Main Outcome Measures: Proportions of nonprogressors were calculated 7, 8, 9 and 10 years following seroconversion (n = 285). Definitions were evaluated with respect to consistency over time and across sites. Subjects lacking CD4 counts within 3 years preceding end of follow-up were excluded., Results: Across sites, proportions of nonprogressors ranged from 1% (definition 5) to 17.5% (definition 1) 10 years after seroconversion. Definitions based on absolute CD4 counts (definitions 1-3) had higher proportions and were less consistent than those based on stable slopes (definitions 4 and 5). For each definition, proportions decreased as follow-up increased, but were most stable for definition 4 (3%). Site differences decreased as follow-up increased, but remained nearly threefold for definitions 1-3. None of the definitions classified the same subjects as nonprogressors at any timepoint., Conclusions: Observations regarding nonprogression are highly dependent on the definition and the duration of follow-up. Our findings highlight methodological challenges which will need to be overcome in natural history studies of nonprogression.

Objective: To assess the impact of HIV infection and AIDS on mortality patterns in Canada with specific reference to gender and regional differentials and to other leading causes of death., Design: Descriptive, population-based study., Setting: Canada., Patients: All persons for whom HIV/AIDS [ninth revision of the International Classification of Diseases (ICD-9) 042-044] was recorded as the underlying cause of death as reported to Statistics Canada between 1987 and 1992. For comparative purposes data was obtained on five other leading underlying causes of death including coronary heart disease (ICD-9 410-414), motor vehicle accidents (ICD-9 E810-E819), and suicides (ICD-9 E950-E959) in men and women, lung cancer (ICD-9 162) in men and breast cancer (ICD-9 174) in women. Population figures were obtained from Statistics Canada estimates., Main Outcome Measures: Age and cause-specific mortality rates, standardized mortality ratios (SMR), potential years of life lost (PYLL) before age 65 years, and life expectancy lost due to a select underlying cause of death., Results: Over the period 1 January 1987 to 31 December 1992, 5546 deaths attributed to HIV/AIDS (5229 in men and 317 in women) were recorded in Canada. SMR for men were significantly higher than the national average in the cities of Vancouver, Toronto and Montreal, whereas those for women were significantly greater only in Montreal. Deaths from HIV/AIDS accounted for 3.6% of PYLL in men and 0.4% of PYLL in women. In 1992, HIV/AIDS was the third leading cause of male PYLL surpassing lung cancer. In the cities of Montreal, Toronto, and Vancouver HIV/AIDS was the leading cause of PYLL and was responsible for significant decrease in life expectancy at birth in men over the study period., Conclusions: HIV/AIDS has had considerable impact on mortality within Canada, principally among men and particularly in the cities of Toronto, Vancouver and Montreal.

Within the context of HIV disease, a marker may be described as a consequence of disease that varies over time but does not necessarily predict future disease course. To date, the most powerful marker of HIV disease progression is the CD4 cell count. Other immunologic markers include neopterin, beta 2-microglobulin, and total and HIV-specific immunoglobulin levels. Further research, which focuses on cell-mediated factors such as interleukins, tumour necrosis factor, natural killer cell activity and apoptosis, is required. Measures of viral burden, such as p24 antigenemia and proviral DNA or RNA, may also offer additional prognostic information. As methods involving quantitative polymerase chain reaction become more refined, it is hoped that they may soon be applied to the clinical setting. Clinical markers of interest include the appearance of minor opportunistic infections and the occurrence of acute retroviral syndrome, which may indicate a faster disease course. Although population-based studies have identified a number of HIV disease markers, further research is required to generalize these findings to the individual level.

Cofactors of HIV disease may be considered risk modifiers that are causally related to future disease course. The search for potential cofactors, of viral, host or environmental origin, may provide avenues for altering the natural history of HIV infection. Potential viral cofactors include viral strains, such as syncytium-inducing and nonsyncytium-inducing variants, and strains that are resistant to specific antiretroviral therapies. Although there is strong evidence that sexually transmitted diseases that lead to genital ulcers or abrasions are important cofactors of HIV transmission, their role as cofactors in HIV disease progression is less clear. Further study of agents such as human herpesviruses 6 and 8 and hepatitis C may shed light on the role of other infectious agents in progressive HIV disease. Far less research has been conducted on behavioural, genetic and sociodemographic factors that may influence HIV disease progression rates. Since current anti-HIV therapies do not offer a cure, but only a means of prolonging life, the identification of possible cofactors is critical.

Unraveling the mysteries associated with the etiology of KS is of tremendous public health significance. Whereas the introduction of prophylaxis has led to a decreased incidence of Pneumocystis carinii pneumonia, the incidence of KS has remained relatively stable and treatment of the HIV-infected KS patient remains a challenge. The last year has brought forth significant breakthroughs in KS research. Although KSHV has only recently been described, rapid progress is being made in understanding the role of this virus in the pathophysiology of the various forms of KS. It is too early to conclude whether KSHV is the elusive 'KS cofactor' or if all forms of KS share a common etiology, but it appears to be the single most plausible agent to be identified to date. Since all cancers are multifactorial in origin, it is likely that other host, environmental and possibly other viral cofactors could influence the risk of developing KS. The search for such cofactors must continue. Even if KSHV plays a central role, the exact mechanisms by which HIV and KSHV may interact to induce KS lesions, the tendency for KS to occur among homosexual men relative to other HIV transmission groups, and the reasons for the aggressive course of this neoplasm in HIV-infected persons remain to be determined. If a causal association can be established, KSHV could provide a model for the understanding of virus-induced neoplasia, like its cousin EBV. Although important questions regarding the specificity and temporality of KSHV and KS remain unanswered, the development and application of a sensitive serodiagnostic tool in longitudinal studies will be a crucial next step.

Objective: To determine the patterns and determinants of mobility in persons with HIV infection or AIDS on a population basis., Design: Descriptive cross-sectional population health study., Target Population: 650 full members (i.e., HIV-positive) of the Vancouver Persons with AIDS Society who were residents of British Columbia and who allow the society to include unsolicited material with their monthly newsletter., Main Outcome Measures: Migration history, access to HIV-related care at diagnosis, current and pre-HIV sociodemographic characteristics, and current health status., Results: Two hundred and fifty-two persons living with HIV/AIDS participated in the study. At the time of the survey, the majority of subjects were male (94 percent), aged between 30 and 54 years (87 percent), and able to carry out daily activities without assistance (84 percent). The median time since the known date of HIV infection was 6 years. Access to care at diagnosis was associated in this population with being diagnosed in the largest metropolitan area in the province (OR = 2.14; 95 percent CI: 1.18, 3.87), a pre-HIV income of $30,000 or more per annum (OR = 0.49; 95 percent CI: 0.27, 0.89), a known date of diagnosis prior to 1990 (78 percent versus 64 percent; p = 0.019), and living in the same residence from the date of known HIV diagnosis to the date of the survey (63 percent versus 51 percent; p = 0.024)., Conclusion: Although no definitive causal association can be provided by this cross-sectional analysis, our results clearly highlight several ways in which the need for treatment and care potentially affect where persons with HIV/AIDS choose to live.

Objective: To conduct an anonymous HIV seroprevalence survey to establish a baseline estimate of HIV seroprevalence in a general population; to evaluate serum pooling and alternative testing strategies as cost-saving measures., Design: Prospective anonymous HIV seroprevalence study using outpatient laboratory specimens., Setting: Two large non-hospital-associated outpatient chemistry testing laboratories in the major population centers in British Columbia, Canada. PATIENTS AND SERA: Leftover sera received for chemistry screen testing in outpatient laboratories were provided to the study after chemistry testing was completed. Those from patients aged < 15 and > or = 55 years were excluded., Methods: Patient identifiers were erased from samples. Sera were pooled 10:1 and tested by viral lysate enzyme-linked immunosorbent assay (ELISA). Sera from HIV-positive pools were tested individually. All individual HIV-positive specimens were retested for verification of positivity using a recombinant protein ELISA., Main Outcome Measures: HIV seroprevalence rates were stratified by sex, age group, and geographic area; and costs of pooling and alternative algorithm strategy were compared with those of conventional methods., Results: A total of 80,238 sera were collected from 66,658 individuals (53% women, 47% men). Of these, 276 men (88.3 per 10,000) and 24 women (6.8 per 10,000) were HIV-seropositive. The highest rates were in those aged 30-34 years, for both men and women. Using pooling and non-Western blot verification saved US$2.07 per specimen, or 80% of the cost for conventional testing., Conclusions: The anonymous outpatient laboratory setting is practicable to obtain a reasonable estimate of HIV seroprevalence rates in a general population. Such studies can be made cost-effective by pooling sera and using alternative confirmatory strategies.

Objective: To determine whether certain sexually transmitted diseases are independent risk factors for HIV transmission in a cohort of homosexual men., Methods: Eligible cases were identified as those who had seroconverted between November 1982 and November 1990. Two persistently HIV-seronegative control participants were randomly selected for each case from all participants who remained seronegative in November 1990. For cases, risk factor data were taken from an index visit which was defined as the first seropositive visit, while for controls these data were obtained from a matched visit which occurred within two months of the index visit for the corresponding case. Mantel-Haenszel methods and logistic regression were used to compare differences in risk factors for seroconversion between cases and controls., Results: A total of 125 cases and 250 controls were eligible for this study. Cases were significantly more likely to have had reported any gonorrhoea (17% versus 6%; OR = 2.94; 95% CI: 1.51-5.73) or syphilis (7% versus 2%; OR = 3.78; 95% CI: 1.33-10.79) than controls during the seroconversion period. Multivariate logistic regression revealed rectal gonorrhoea to be independently associated with risk of seroconversion (odds ratio = 3.18; p = 0.044), whereas urethral gonorrhoea (p = 0.479) and pharyngeal gonorrhoea (p = 0.434) were not after inclusion of rectal gonorrhoea. In addition, the following variables were also shown to exert an independent effect on seroconversion: frequency of anal intercourse, use of illicit drugs, number of male sexual partners, and lack of a post-secondary education., Conclusions: In this observational study, rectal gonorrhoea was found to be associated with HIV seroconversion after adjustment for a number of HIV risk factors. We cannot rule out that rectal gonorrhoea was not directly associated with HIV infection but rather with other residual lifestyle factors not fully adjusted for in the analysis. However, the relationship with gonococcal involvement of a specific anatomic site lends support to a biological association between gonorrhoea and HIV infection, rather than to alternative non-biologic explanations. Our findings are consistent with previous studies reporting an association between HIV infection and non-ulcerative sexually transmitted diseases. Such a direct association might be explained by postulating that gonorrhoea results in inflamed rectal mucosa and compromised epithelial integrity, thereby predisposing an individual to subsequent HIV infection.

Despite the fact that volunteers are an integral component of an AIDS hospice program, there are few studies describing the motivations they may have in choosing to become involved in an AIDS hospice such as Casey House Hospice in Toronto, Ontario, Canada. This study made use of existing mechanisms to track Casey House service volunteers. Volunteers completed questionnaires at the time of application, and at three months and one year following their orientation. Volunteers were asked to describe why they wished to volunteer at the hospice, what their expectations were, and what motivated them to remain involved as a volunteer. This study revealed that Casey House volunteers are motivated by a general desire to contribute, as well as a desire for interaction and personal growth, and to experience the Casey House model of care. However, many volunteers do not enter the program with predetermined expectations, and their motivations for involvement may not be consciously recognized. Major factors relating to their continued involvement are the support and sense of value they receive from staff and residents, as well as the intensity of their experiences. Since this report is part of an ongoing, prospective study of AIDS hospice volunteers, there will be an opportunity to examine some of these issues in more detail at a later date.

Objective: To characterize the associations of age and progression rates to AIDS-defining neoplasms and opportunistic infections (OI) in HIV-infected homosexual men., Methods: Data from 407 homosexual men with documented dates of HIV seroconversion participating in cohort studies from four geographic locations were merged. Kaplan-Meier and Cox proportional hazards analyses were conducted with respect to the association of age with time from seroconversion to the first AIDS-defining neoplasm and OI., Results: Among the 407 participants, 139 (34%) were diagnosed with AIDS; 45 (11%) with neoplasms and 90 (22%) with OI. Older age at seroconversion was significantly associated with faster progression to neoplasms, but not to OI. For each 10-year increase in age the risk for neoplasms increased 1.65-fold [95% confidence interval (CI), 1.12-2.43], after adjustment for clinical treatments. For OI this risk estimate was 0.98 (95% CI, 0.72-1.34)., Conclusions: Increasing age is associated with faster progression to AIDS-defining neoplasms, but not with progression to OI. This has not been previously reported and may explain conflicting results in other studies among homosexual men that considered AIDS as a single entity. Our findings suggest that age and AIDS manifestations should be considered, particularly in the context of natural history studies, clinical trials and mathematical modelling.

Objective: To describe the changing spectrum of AIDS index diseases in Canada over a 10-year period from 1981 to 1991., Design: A descriptive, population-based study., Setting: Canada., Patients: All cases of AIDS in Canada reported by the Division of HIV/AIDS Epidemiology of the Department of National Health and Welfare., Main Outcome Measures: Age-standardized rates of initial AIDS manifestations (1987 Centers for Disease Control and Prevention case definition), by year of diagnosis among adults in Canada., Results: A total of 6641 adult AIDS cases were examined. The rate of Pneumocystis carinii pneumonia (PCP) peaked in 1989 with a rate of 3.18 per 100,000, declining to 2.74 per 100,000 in 1991 (P = 0.894). Similarly, the rate of Kaposi's sarcoma (KS) stabilized during this interval from 1.06 per 100,000 in 1987 to 1.14 per 100,000 in 1991 (P = 0.189). In contrast, the rates of all other AIDS-defining illnesses increased from 1.48 per 100,000 in 1987 to 3.43 per 100,000 in 1991 (P = 0.001). For these other AIDS index diseases, significant rate increases were observed for esophageal candidiasis, cytomegalovirus (CMV) diseases, wasting syndrome, toxoplasmosis, and Mycobacterium avium complex (MAC) disease., Conclusions: Our study shows a leveling and decline in incidence of KS and PCP, respectively, and a concomitant increase of other diagnoses, especially esophageal candidiasis, CMV, wasting syndrome, toxoplasmosis, and MAC disease in Canada. These findings highlight the importance of developing specific strategies to prevent emerging AIDS index diseases and serve as a cautionary note to practicing clinicians, indicating the relative widening of the spectrum of HIV index diseases.