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Purpose: The purposes of this study were: (a) to identify human immunodeficiency virus (HIV) prevalence in Toronto street youth through paired blood and saliva specimens; (b) to identify the HIV risk and prevention behaviors of street involved youth; and (c) to identify demographic or other factors that may contribute to the risk of street youth becoming infected with HIV/acquired immunodeficiency syndrome (AIDS) in the future. Methods: This was a cross-sectional convenience study of street-involved youth aged 14–25 years. The youth participated in interviews to identify HIV-related knowledge and personal risk and preventive behaviors. Following interviews, they were asked to provide a saliva sample, blood spot, or both. They could refuse one or both samples without jeopardizing their involvement or receiving an honorarium. Two males were the only participants who declined to provide a sample. Results: Fifteen of 695 (2.2%) youth tested positive for HIV infection. All were male, ranging in age from 18 to 25 years. Same and opposite sex, intravenous (IV) drug use, prostitution, and incarceration were risk factors associated with positive HIV test results. The rate of HIV infection was seven times greater for the group 20 years of age and older (20–25) compared to the younger group aged 14–9 years. The proportion testing positive for HIV from small cities, towns, and rural communities in Ontario was 40%; yet, they represented 21% of the study population. Most (57%) youth had been on their own for no more than 3 years and had moved frequently. Nearly two thirds (60%) had stayed in hostels or homeless shelters in the previous 6 months. Conclusion: Street youth in Canada are at high risk of HIV infection with their risk increasing with age. Unprotected (same and opposite) sex, IV drug use, prostitution and incarceration were linked to their HIV infections. The high level of mobility identified by street youth challenges governments, communities, and public health officials to develop appropriate prevention strategies and to carefully monitor the spread of HIV infection in this vulnerable population.

Objective: Since both the incidence of lung cancer and the proportion of the population over age 65 are increasing rapidly in North America, we undertook a retrospective review of elderly patients with small cell lung cancer (SCLC) in an attempt to assess the effect of age on treatment decisions, response, survival, and toxicity. Design: Retrospective chart view. Setting: Oncology Unit of a university-affiliated teaching hospital. Patients: There were 123 patients age >70 years treated from 1976–88. Chemotherapy consisted of either cyclophosphamide, doxorubicin, and vincristine, or etoposide and cisplatin. Results: There were 74 patients aged 70–74, 35 aged 75–80, and 14 aged 80 years or older. No significant differences existed between the groups in sex, stage, performance status, or presence of co-morbid disease. Median survivals for patients with limited and extensive disease were 11.9 and 5.2 months, respectively (P =

Cirrhosis mortality death rates in Ontario for ages 20 and over declined from a high of 9.3 per 100,000 in 1911 to a low of 5.6 per 100,000 in 1919 (p less than 0.001) and after a 17-year period of relative stability, rose steadily to a high of 19.7 per 100,000 in 1975 (p less than 0.0001) and then declined to 13.3 per 100,000 in 1986 (p less than 0.001). Rates were consistently higher for men than for women and the male to female ratio of the rates increased from a low of 1.3 in 1933 to a high of 2.5 in 1986. The rate of increase in the rates for both men and women, and the rate of decline after the mid 1970s was most noted in the younger ages. Differences in trend could not be related to changes in disease classification, method of recording deaths, changes in diagnostic habits such as introduction of needle liver biopsy or to method of standardizing the rates. There was a positive and significant correlation between per capita alcohol consumption and rates of cirrhosis in Ontario from 1932 to 1975. However, while cirrhosis rates declined markedly from 1976 to 1986, alcohol consumption remained stable from 1976 to 1980 and declined only slightly from 1981 to 1986. A possible explanation for lack of correlation between alcohol consumption and the cirrhosis rates from 1976 to 1986 could be that the balance of force favoured recovery i.e. those people who already had cirrhosis who decreased (or stopped) their consumption of alcohol, did not die. Correlations with lagged alcohol consumption could not explain all the changes in the cirrhosis rates. Although cirrhosis rates consistently increased with increasing age from 35 to 85, our results showed that succeeding generations were developing cirrhosis at successively younger ages after the age of 35. Possible explanations for this cohort effect are increased survival from infectious diseases in infancy and childhood, increase in hepatitis B infection, excessive drinking habits being established at younger ages or a change in the pathogenesis of the disease.

In a cohort of 249 male sexual contacts of men with acquired immunodeficiency syndrome (AIDS) or an AIDS-related condition in Toronto, Ontario, Canada, 143 cohort members were seropositive on enrollment and 16 seroconverted between initial recruitment in July 1984 to July 1985 and December 1988. Data on age, smoking and drinking status, recreational drug use, and history of sexually transmitted diseases and other diseases were obtained from interviews at induction and during follow-up on the cohort members every 3 months. Cox relative risk regression models, in which time was calculated from estimated date of human immunodeficiency virus (HIV) infection for seroprevalent cohort members and from 90 days prior to the first positive test for seroconverters, examined the potential effect of use of a variety of recreational drugs and the occurrence of selected infections on the risk of development of AIDS. Thirty-five cohort members developed AIDS while under study. No significant association with risk of progression to AIDS was noted for use of various recreational drugs (singly or in combination), history of specific infections, age at enrollment, or smoking and drinking status at enrollment. Only estimated duration of HIV infection appeared to be associated with increasing risk of development of AIDS.

The Toronto Sexual Contact Study comprises a cohort of 249 male sexual contacts of men with HIV disease which has been followed every 3 months for almost 5 years. On enrolment 143 were seropositive and 16 seroconverted during the follow-up period. By 31 December 1989,41 of the 159 seropositive cohort members had developed AIDS. Using Cox relative risk regression models, we investigated the association of a number of laboratory and clinical variables and progression to AIDS. Fixed covariate models examined laboratory variables from the enrolment visit of cohort members, with time calculated from this date. In models assessing time dependent covariates, time was calculated from the estimated date of HIV infection. In the univariate models of either fixed or time dependent covariates, many variables were significantly associated with risk of progression to AIDS (T4 cell count, T4/T8 ratio, blastogenic responses to phytohemagglutinin, concanavalin A, and pokeweed mitogen, serum IgA, appearance of p24 antigen, and the development of oral hairy leukoplakia, thrush, or herpes zoster). Appearance of persistent generalized lymphadenopathy was not associated with increased risk of progression. In the multivariate model which evaluated fixed laboratory covariates, T4/T8 ratio, IgA level, and PHA response at enrolment were significantly associated with elevated risk. In order to evaluate the impact of the serial observations of immune function variables, these variables were lagged one year in a model with other time dependent covariates; the following point estimates of relative risk of progression to AIDS were observed: for a unit decline in T4/T8 ratio, RR=60.8 ( p p = 0.07); for a 100 μg/l increase in IgA, RR=1.33, ( p = 0.02); for the development of oral hairy leukoplakia, thrush, or herpes zoster, RR=2.69, ( p = 0.02); and treatment with zidovudine, RR=0.06, ( p = 0.01).

In a cohort of 249 male sexual contacts of men with AIDS or an AIDS-related condition (ARC), 143 cohort members were seropositive on enrollment and 16 seroconverted during follow-up. A logistic Weibull mixture model was used to estimate the probability of progression to AIDS after HIV infection when infection was assumed to occur during the period of sexual contact with the primary case. Forty cohort members developed AIDS while under study. It appears that at least 50% of men with HIV disease will progress to AIDS and that the best estimate of this probability lies anywhere in the interval 70% to 100%.

For some time, there has been interest in quantifying the risks of progressing to Aids from infection with the human immunodeficiency virus (HIV) associated with changes in the immunological markers. Until recently, little attention has been paid to the considerable variability of these markers and the corresponding effect on estimates of relative risk. We estimate the risks of progression to Aids associated with immunological markers among a group of homosexual men infected with HIV who have been followed at quarterly intervals for 5 years. Errors in measurement in the markers are shown to bias these estimates. Smoothing techniques are compared for their effectiveness in reducing the amount of variation in the markers and the subsequent bias in the coefficients

• Eight hundred volunteers from health care and emergency fields participated in a randomized double-blind clinical trial of a new experimental mammalian cell—derived recombinant DNA hepatitis B vaccine (Betagen) compared with a licensed plasmaderived vaccine (Heptavax-B). Vaccine injections (20 μg) were administered intramuscularly at 0, 1, and 6 months, and sera were tested at 0,1, 2, 3,6, 7, and 12 months for hepatitis B surface antigen, antibody to hepatitis B surface antigen, and antibody to hepatitis B core antigen. Data from 745 vaccinees (93.1%), analyzed at the 7th month of follow-up, showed no significant difference in the seroconversion rates for Betagen (94.4%) vs Heptavax-B (97.3%), but the geometric mean titer of antibody was significantly higher for Heptavax-B (11 833 mlU/L) than for Betagen (4628 mlU/mL). The antibody response of Betagen was significantly and independently related to age and sex, while that of Heptavax-B was related to age only. Reported side effects from both vaccines were minor and mild, with approximately one fourth of all vaccinees reporting at least one side effect. Vaccinees, who had a protective level of antibody at the 7th month, were tested for antibodies at the 12th month. Of those in the Betagenvaccinated group and those in the Heptavax-B-vaccinated group, 99.0% and 100%, respectively, were still protected. There was a proportionately larger decline in the geometric mean titers of antibody to hepatitis B surface antigen for Heptavax-B than for Betagen. (Arch Intern Med. 1990;150:1195-1200)

The degree of clinical agreement amongst different physicians on the presence or absence of generalized lymphadenopathy was assessed in 32 randomly selected participants from a prospective study of male sexual contacts of men with AIDS or an AIDS-related condition (ARC). Three physicians completed the same standard examination that was developed for the main project and conducted the examination of the anatomic regions in the same order on each person, at approximately the same time, and in random order. One physician (Doctor A) was the physician responsible for conducting examinations on the main cohort from which these participants were selected. Intra-observer agreement was assessed by comparing Doctor A's examinations on these participants with those he had recently conducted within a one and a half month period in the main study. Acceptable levels of intra-observer agreement (kappa = 0.72) and interobserver agreement (kappa = 0.66) were demonstrated for the presence or absence of generalized lymphadenopathy for Doctor A and Doctor B, a physician who periodically replaced Doctor A in the main project. Agreement between Doctors A, B, and C, was less satisfactory (kappa of 0.45 and 0.39, respectively). Doctor C was the least experienced with the standardized examination. However, during the progress of this study, agreement between the three doctors improved (kappa values for the latter 16 participants ranged from 0.60 to 0.86) suggesting that experience with the criteria and the standardization of the examination may enhance agreement.(ABSTRACT TRUNCATED AT 250 WORDS)

As part of a prospective study in Toronto, Canada of male sexual contacts of men with either acquired immunodeficiency syndrome (AIDS) or an AIDS-related condition (primary cases), separate interviews were conducted in 1984-1985 with primary cases and their corresponding sexual contacts. Seventy-five primary cases and their corresponding sexual contacts were asked details concerning the sexual activities involved in their sexual encounters. Spearman correlation coefficients were calculated for the responses regarding frequency of various sexual activities between the primary case and his corresponding contact. Comparison of responses revealed good to excellent correlations for the majority of the sexual activities. Regression analysis of responses (dependent variable = contact's response; independent variable = primary's response) revealed the tendency for primary cases to report greater numbers of various activities than sexual contacts, as illustrated by regression coefficients that were consistently less than unity. Agreement between primary responses and sexual contact responses appeared to be affected by the time lapsed from the last sexual encounter with the contact and the date of the primary case's interview. No effect on agreement was observed when primary case diagnosis and the total number of other sexual partners of primary cases were considered. The authors conclude that such data can be captured with sufficient reliability and validity for use in epidemiologic investigations to assess the risk of acquisition of human immunodeficiency virus for the more common forms of sexual activity. However, some caution may be necessary in interpreting the results for some activities (anal digit insertion, anilingus) since agreement is less satisfactory for these activities.

Soon after the Acquired Immunodeficiency Syndrome (AIDS) was initially described, the epidemiology of the syndrome suggested that a blood-borne, sexually transmitted agent was an important factor in the development of the syndrome. The identification and isolation of the human immunodeficiency virus (HIV) as the etiologic agent of AIDS, followed by the development of sensitive and specific assays for the detection of antibodies to its viral proteins, facilitated the study of specific forms of transmission of the virus as well as the natural history of HIV infections. In this paper, the current evidence is reviewed regarding the modes of sexual transmission of HIV in homosexuals and heterosexuals. Several well designed studies support the efficient transmission of HIV via receptive and insertive anal intercourse and by vaginal intercourse. There is no current evidence, despite detailed study, to suggest that kissing, oral-genital, or oral-anal sexual contact provides an efficient means of viral transmission. Activities which promote or result in anorectal or vaginal mucosal injury appear to facilitate infection with this virus.

We are currently witnessing a global epidemic of a group of diseases which are known as AIDS and which have in common an underlying profound impairment of the host immune system. The causative agent,human immunodeficiency virus (HIV), has been identified and testing for antibodies to this virus has demonstrated its spread into many populations around the world. HIV is now known to give rise to a wide clinical spectrum including asymptomatic infection, progressive central nervous system infection, and the fatal immune deficiency termed AIDS. The proportion of HIV-infected persons who will eventually develop AIDS cannot be known with precision at this time although it is likely to be at least 40% and could be as high as 100%. AIDS and HIV have been reported in over half of the countries in the world including the USSR and China. The global distribution follows 3 epidemiologic patterns: that of the developed countries where the virus has primarily affected homosexual/bisexual men and intravenous drug users; that of Central Africa and parts of the Caribbean where it is essentially a heterosexually transmitted disease; and that of Asia and most of Central and South America where the disease is still rare. Although HIV has been recovered from peripheral blood, semen, saliva, tears, alveolar fluid, cerebrospinal fluid, brain tissue, and cervical and vaginal secretions, there is much data to indicate that its modes of spread are limited to sexual, parenteral (i.e. contaminated needles), iatrogenic (i.e. blood and blood products, transplantation, etc.), and perinatal (i.e. mother to offspring). There is now substantial evidence to indicate that casual contact, that is the type of non-sexual personal contact that might occur in the household, school setting, or workplace, does not give rise to HIV transmission. Similarly, transmission of HIV by insect vectors, e.g. mosquitoes, has also been effectively ruled out.

The relationship between liver cirrhosis death rates and certain nutritional factors was studied in 38 countries where mortality statistics were considered to be reliable. A partial correlation analysis showed that several food commodity consumption factors were independently and negatively (p less than 0.01) associated with liver cirrhosis death rates after adjustment for alcohol consumption. These factors were total calories, protein, fat, calcium, vitamin A and vitamin B2. The significant association of protein, vitamin A, vitamin B2 and calcium with the cirrhosis death rates is of importance since they were not intercorrelated with alcohol consumption. Further results showed that animal protein was more significantly related to cirrhosis death rates than vegetable protein. However, in view of certain limitations of this study, the findings do not necessarily reflect causal relationships but rather support the consideration by scientists that protein and vitamin deficiency may have certain effects on liver cirrhosis.

The relationships between the prevalence of hepatitis B surface antigen (HBsAg), mean annual per capita alcohol consumption and primary liver cancer (PLC) death rates were explored in 30 countries. HBsAg prevalence was associated, significantly, with the logarithm of the primary liver cancer death rate (simple correlation coefficient = 0.44, p less than 0.05). This significant association increased following adjustment for a country's mean annual per capita alcohol consumption (partial correlation coefficient = 0.53, p less than 0.01). A logarithmic linear relationship was also found between per capita alcohol consumption and the primary liver cancer death rate after adjustment for the country's prevalence of HBsAg (partial correlation coefficient = 0.38, p less than 0.05). Results from both correlation and regression analyses showed that prevalence of HBsAg was more significantly associated with PLC death rates than was alcohol consumption. However, these two variables were independently related to the PLC death rate in a stepwise multiple regression model. We could not demonstrate an interaction between the two variables. These findings are consistent with the prevailing view that chronic hepatitis B infection is the major factor in the most common form of primary liver cell cancer, hepatocellular carcinoma. In addition, they support the notion that alcohol consumption contributes significantly and independently, although probably to a lesser extent than hepatitis B, to deaths from that disease.

A total of 246 healthy male sexual contacts of men with either acquired immunodeficiency syndrome (AIDS) or an AIDS-related condition were recruited into a prospective study in Toronto, Canada between July 1984 and July 1985. At induction, data were collected on the sexual relationship between the contact and his primary case, sexual activities with other men, history of sexually transmitted diseases and other diseases, and use of recreational drugs. At recruitment, 144 sexual contacts had antibodies to human immunodeficiency virus (HIV); 102 of the contacts were seronegative at induction and at three months following recruitment. No association between HIV seropositivity and total number of sexual partners could be demonstrated. In univariate and multivariate analyses, receptive and insertive anal intercourse with the primary cases, and activities which either indicated or potentially caused anorectal mucosal injury (rectal douching, perianal bleeding, receipt of objects in ano, and receptive fisting) were strongly associated with HIV seropositivity. In the final multiple logistic regression model, two significant interaction effects were observed: the interaction between receptive anal intercourse and insertive anal intercourse and that between receptive anal intercourse and the anorectal mucosal injury index. These two interaction terms had negative regression coefficients which suggested that change in one sexual activity would not decrementally reduce risk of HIV infection without a comparable modification in the other activity. No association could be demonstrated between oral-genital and oral-anal sexual contact and odds ratios for these sexual activities declined to levels below 1.0 when adjusted for frequency of receptive anal intercourse.