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S A Strathdee

Publications and source records attributed to S A Strathdee.

At least 73 records · Page 4Linked to original sources
PubMed1997

Modelling the impact of HIV disease on mortality in gay and bisexual men.

OBJECTIVE: To assess how HIV infection and AIDS (HIV/AIDS) impacts on mortality rates for gay and bisexual men. METHODS: Vital statistics data were obtained for a large Canadian urban centre from 1987 to 1992. Three scenarios were utilized with assumed proportions of gay and bisexual men of 3%, 6% and 9% among the male population age 20 years. For each scenario, non-HIV deaths were distributed according to the assumed proportion of the total population (3%, 6% or 9%) but 95% of HIV deaths were distributed to gay and bisexual men as this is the proportion of AIDS cases in gay and bisexual men in this centre. The main outcome measures of interest were age-specific patterns of death, life expectancy and life expectancy lost due to HIV/AIDS at exact age 20 years, and the probability of living from age 20 to 65 years. RESULTS: Estimates of the mid-period gay and bisexual population ranged from 5406 to 16,219 for the three scenarios, and total deaths in these men from 953 to 1703. Age-specific mortality was significantly higher for gay and bisexual men than all men aged 30-44. Life expectancy at age 20 for gay and bisexual men ranged from 34.0 years to 46.3 years for the 3% and 9% scenarios respectively. These were all lower than the 54.3 year life expectancy at age 20 for all men. The probability of living from age 20 to 65 years for gay and bisexual men ranged from 32% for the 3% scenario, to 59% for the 9% scenario. These figures were considerably lower than for all men where the probability of living from 20 to 65 was 78%. CONCLUSION: In a major Canadian centre, life expectancy at age 20 years for gay and bisexual men is 8 to 20 years less than for all men. If the same pattern of mortality were to continue, we estimate that nearly half of gay and bisexual men currently aged 20 years will not reach their 65th birthday. Under even the most liberal assumptions, gay and bisexual men in this urban centre are now experiencing a life expectancy similar to that experienced by all men in Canada in the year 1871.

Adult↗
PubMed1997

Needle exchange is not enough: lessons from the Vancouver injecting drug use study.

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.

Adolescent↗
PubMed1997

Determinants of HIV seroconversion in injection drug users during a period of rising prevalence in Vancouver.

To identify determinants of HIV seroconversion among injection drug users (IDUs) during a period of rising prevalence, a case-control investigation was conducted. Cases were IDUs with a new positive test after 1 January 1994, and a negative test within the prior 18 months. Controls required 2 negative tests during the same period. Subjects completed a questionnaire on demographic, psychosocial, and behavioural factors. Eighty-nine cases and 192 controls were similar with respect to gender, age, ethnicity and inter-test interval. Multivariate analyses of events during the inter-test interval showed borrowing syringes (adj. OR = 2.96; P < 0.006), unstable housing (adj. OR = 2.01; P = 0.03) and injecting > or = 4 times daily (adj. OR = 1.71; P = 0.06) to be independently associated with seroconversion. Protective associations were demonstrated for sex with opposite gender (adj. OR = 0.36; P = 0.001) and tetrahydrocannabinol use (adj. OR = 0.41; P = 0.001). There is a need to evaluate programmes dealing with addiction, housing and the social underpinnings of risk behaviours in this population.

Adult↗
PubMed1997

Social determinants predict needle-sharing behaviour among injection drug users in Vancouver, Canada.

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.

Adult↗
PubMed1996

Lack of consistency between five definitions of nonprogression in cohorts of HIV-infected seroconverters.

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.

CD4-Positive T-Lymphocytes↗
PubMed1996

A decade of research on the natural history of HIV infection: Part 1. Markers.

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.

AIDS-Related Opportunistic Infections↗
PubMed1996

A decade of research on the natural history of HIV infection: Part 2. Cofactors.

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.

Comorbidity↗
PubMed1996

HIV/AIDS mortality in Canada: evidence of gender, regional and local area differentials.

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.

Acquired Immunodeficiency Syndrome↗
PubMed1996

The epidemiology of HIV-associated Kaposi's sarcoma: the unraveling mystery.

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.

AIDS-Related Opportunistic Infections↗
PubMed1996

Summary of track C: epidemiology and public health.

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.

Female↗
PubMed1995

Motivations for service volunteer involvement at Casey House AIDS Hospice.

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.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Access to health care and geographic mobility of HIV/AIDS patients.

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.

Adult↗
PubMed1995

Quantitative measures of human immunodeficiency virus-specific antibodies predict progression to AIDS.

Studies examining specific antibodies directed against antigenic components of human immunodeficiency virus (HIV), as potential markers of progression to AIDS, have reported inconsistent results. We used reflectance densitometry and survival analysis to determine whether single quantitative measures of HIV-specific antibodies predicted progression to AIDS in a prospective cohort of 159 HIV-infected homosexual men. Lowered baseline levels of p24 antibody and p24/gp41 antibody ratio were independent predictors of progression to AIDS and retained statistical significance after simultaneously controlling for CD4:CD8 ratio, age, use of zidovudine, and clinical symptoms. Quantitative measures of p24 antibody and p24/gp41 antibody ratio warrant further study with regards to their clinical application as markers of HIV disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Is the human immunodeficiency virus-related Kaposi's sarcoma epidemic coming to an end? Insights from the Tricontinental Seroconverter Study.

A decline in the proportion of Kaposi's sarcoma among AIDS cases since the 1980s has been attributed to changes in sexual behavior among homosexual men and a decreasing exposure to a hypothesized Kaposi's sarcoma cofactor. Recent studies have shown that the incidence rate of Kaposi's sarcoma has remained relatively stable, which seems to argue against the hypothesis of a declining exposure to the putative cofactor. To examine this paradox, we evaluated the incidence of Kaposi's sarcoma, using Cox proportional hazard analyses, and performed a simulation to compare incidences of different AIDS outcomes among 407 homosexual men with documented dates of seroconversion. Our data show that men who seroconverted early in the epidemic did not progress faster to Kaposi's sarcoma than men who seroconverted more recently. A lower incidence rate of Kaposi's sarcoma would be expected among the latter group if exposure to the hypothesized cofactor is decreasing over time. The percentage of Kaposi's sarcoma among incident AIDS cases decreased over the years following seroconversion, but not over calendar time. This study demonstrates that the decline in the proportion of Kaposi's sarcoma among AIDS cases should not be interpreted as a decline in the incidence of Kaposi's sarcoma and that there is no evidence that a hypothesized Kaposi's sarcoma cofactor is declining over calendar time.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Use of pooling and outpatient laboratory specimens in an anonymous seroprevalence survey of HIV infection in British Columbia, Canada.

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.

AIDS Serodiagnosis↗
PubMed1995

Rectal gonorrhoea as an independent risk factor for HIV infection in a cohort of homosexual men.

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.

Adult↗