Testing for HIV infection: ethical considerations revisited.
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Acquired Immunodeficiency Syndrome↗
Biomedical subjects
R A Coates
Publications and source records attributed to R A Coates.
Assessment of generalized lymphadenopathy in AIDS research: the degree of clinical agreement.
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)
AIDS-Related Complex↗
Relationship between hepatitis B surface antigen prevalence, per capita alcohol consumption and primary liver cancer death rate in 30 countries.
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.
Alcohol Drinking↗
Relationship between liver cirrhosis death rate and nutritional factors in 38 countries.
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.
Alcohol Drinking↗
Validity of sexual histories in a prospective study of male sexual contacts of men with AIDS or an AIDS-related condition.
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.
AIDS-Related Complex↗
Risk factors for HIV infection in male sexual contacts of men with AIDS or an AIDS-related condition.
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.
3,4-Methylenedioxyamphetamine↗
A method for estimating "persons" versus "cases" from hospital morbidity data in the absence of unique personal identifiers.
The authors present a method for estimating the number of persons (as opposed to the number of admissions) admitted to hospital for a defined time period for specific diagnoses when unique personal identifiers are not available. A simple computer algorithm (algorithm 1), employing a family-based scrambled health insurance number in conjunction with diagnosis, sex, and age was used to estimate the rates of readmission to hospital specific diagnoses. A proportion of the hospital morbidity records used in the study did not contain a health insurance number; therefore, estimated readmission ratios for specific diagnoses, calculated from admissions with health insurance numbers, were applied to all admissions for those diagnoses to obtain the estimates of total persons admitted to hospital in the given time period. The validity of the methodology was tested for selected diagnoses for a specific year by 1) comparing estimates of persons obtained by applying algorithm 1 with manual counts of persons obtained through examination of printed lists of all Ontario admissions to hospital for the specific diagnoses, and 2) comparing actual counts of persons admitted to a specific hospital with computer estimates of persons admitted to that hospital. The conclusions drawn were that the method, using algorithm 1, is a valid one for obtaining estimates of the number of persons admitted to hospital in a given year with a specific diagnosis and that the information derived is potentially useful for conducting epidemiologic studies. Readmission ratios were also estimated through the use of a second algorithm (algorithm 2) which was not dependent on a scrambled health insurance number. Sensitivity and specificity of these ratios were found to be low when compared with ratios estimated by algorithm 1.
Algorithms↗
The relationship between 2-5A synthetase levels and persistent lymphadenopathy in homosexual men with antibodies to HTLV-III.
This study compared clinical and laboratory parameters in 37 individuals with serologic evidence of exposure to human T-cell lymphotropic virus type 3 (HTLV-III) and generalized lymphadenopathy. Basal levels of the interferon-induced enzyme, 2-5A synthetase were also measured and compared with the clinical parameters. A significant linear relationship (p less than .05) was demonstrated between the logarithm of the basal synthetase level and both the number and size of palpable nodes in the posterior cervical triangles of the men studied. No other lymph node chains demonstrated such a relationship. In addition, men with more than 3 palpable nodes (the median number) in the posterior triangles had lower mean levels of lymphocytes, reduced mean mitogen responses to PWM, PHA, and ConA, elevated mean levels of IgG, IgA, and IgM, and were more frequently anergic on skin testing. These findings suggest the need for further longitudinal study of the possibility that extent of lymphadenopathy and level of 2-5A synthetase might serve as useful parameters to monitor disease activity.
2',5'-Oligoadenylate Synthetase↗
Hepatitis B markers and risk factors for hepatitis B in liver biopsy patients.
As part of a study of all patients undergoing liver biopsy in 6 Toronto teaching hospitals from February 1, 1981 to January 31, 1982, participants had hepatitis B marker (HBV) studies and were interviewed concerning, among other things, potential hepatitis B exposure risk factors. All analyses were conducted by sex. Of 376 males, and 342 females participating in the study, complete data were available on 243 (65%) males and 230 (67%) females. Information was obtained on country of birth, race, previous exposure to hepatitis, previous blood transfusions, sexual preference, use of intravenous drugs, occupation, tattooing, and ear piercing. Thirty-five percent of males and 17 percent of females had at least one HBV marker present. Males with at least one HBV marker, compared to males with no HBV markers were more frequently oriental (p less than 0.001), homosexual (p less than 0.05), or born in a country with a higher level of HBV endemicity than in Canada (p less than 0.001). Females with at least one HBV marker, compared to females with no HBV markers were more frequently oriental (p less than 0.001), employed in a health occupation (p less than 0.05), or born in a country with a higher level of HBV endemicity than in Canada (p less than 0.0001). For each sex, multiple logistic regression analysis was conducted to adjust for potential confounding by significant variables detected in univariate analyses.(ABSTRACT TRUNCATED AT 250 WORDS)
Age Factors↗
Risk of fatty infiltration or cirrhosis of the liver in relation to ethanol consumption: a case-control study.
A case-control study was conducted to investigate the risk of either fatty infiltration of the liver or cirrhosis, in males and females, in relation to varying levels of ethanol consumption. Male and female cases of fatty infiltration of the liver (47 males and 43 females) and male and female cases of cirrhosis (85 males and 66 females) were identified during 1981-1982 as part of a liver biopsy study in 6 teaching hospitals in Toronto. All cases were confirmed by biopsy. Male and female controls (394 males and 225 females) were obtained from 7 different local industries during the same period as part of a study for the early detection of liver disease. Cases and controls were interviewed by a nurse practitioner using a standard questionnaire designed to elicit data on daily and cumulative alcohol consumption. In both males and females, a dose-response effect between increasing levels of both daily and cumulative alcohol consumption and increasing risk of either fatty liver or cirrhosis was demonstrated and was independent of effects of age and duration of consumption. In males, risk for fatty liver was 1.37 (95% CL = 0.47, 4.0) for those consuming 40-59 g absolute alcohol/day compared to males consuming less than 40 g/day, rising to 50 (95% CL = 15.0, 170.7) for males consuming 80 or more g/day. In females, risk for fatty liver appeared at lower levels and was 2.82 (95% CL = 1.02, 7.82) for females consuming 20-59 g/day compared to females consuming less than 20 g/day, rising to 8.53 (95% CL = 2.12, 34.31) for females consuming 60 or more g/day.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Alcohol consumption and blood pressure: analysis of data from the Canada Health Survey.
Recent epidemiologic studies report a significant association between alcohol consumption and elevations in both systolic (SBP) and diastolic (DBP) blood pressures. To test this hypothesis, we conducted a multivariate analysis of physical examination and other data on 721 men and 697 women aged 20 or more collected during the Canada Health Survey in 1978-1979. SBP and DBP were considered as separate dependent variables in multiple regression models with the following independent variables: age, alcohol consumption (measured as a 7-day recall history and as an average frequency of consumption), serum cholesterol, plasma glucose, physical activity, Quetelet index, parental history of hypertension, cigarette consumption, income, education, and exogenous hormonal use in women. In both weighted and unweighted multiple regression analyses, we could not demonstrate for either sex, a significant association between alcohol consumption (as recorded and following quadratic and logarithmic transformations) and either SBP or DBP. For both sexes, only age and Quetelet index were highly significantly (P less than 0.0001) and consistently associated with both SBP and DBP. No other independent variables were consistently associated, for either sex, with SBP and DBP. Further, the dose-response patterns noted by other investigators suggesting either a positive and linear relationship or a curvilinear relationship were not found in either our univariate or multivariate analyses. Rather, the alcohol-blood pressure curves showed no consistent patterns of any kind in either sex. These findings do not support recent claims that alcohol consumption is a determinant of elevations in either SBP or DBP.
Adult↗
Elevated levels of interferon-induced 2'-5' oligoadenylate synthetase in generalized persistent lymphadenopathy and the acquired immunodeficiency syndrome.
The levels of the 2'-5' oligoadenylate enzyme synthetase in extracts of peripheral blood mononuclear cells from individuals with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC) were measured and compared with synthetase levels in peripheral blood mononuclear cells (PBMs) from healthy heterosexual and homosexual controls. The mean basal synthetase level in heterosexual and homosexual controls was 14 +/- 13 and 12 +/- 9 pmol per hr/10(5) PBMs, respectively. Thirteen individuals with AIDS had a mean basal level of 129 +/- 75 pmol. Serial levels were persistently elevated in six of these individuals over a one- to 10-month period. Twelve of the 13 individuals had antibodies to human T cell lymphotrophic virus-III/lymphadenopathy-associated virus (HTLV-III/LAV). Thirty-three individuals with ARC had a mean basal synthetase level of 68 +/- 84 pmol. Thirty-two of the 33 had antibodies to HTLV-III/LAV. Eleven (33%) have had consistently normal synthetase levels (less than 2 SD above the mean for the homosexual controls, i.e., 30 pmol) over a three- to nine-month follow-up period. Fourteen (42%) had persistently elevated levels over the same period; four (29%) of these developed AIDS during the follow-up period. Eight have had fluctuating levels but have remained clinically well. These studies suggest that persistently elevated synthetase levels in individuals with ARC and antibodies to HTLV-III/LAV indicate progressive virus-induced disease activity. Elevated synthetase levels may be an important prognostic indicator of increased risk of progression to AIDS.
2',5'-Oligoadenylate Synthetase↗
Cost without benefit? The introduction of hepatitis B vaccine in Canada.
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Adolescent↗
Hepatitis B vaccine requirements in at-risk hospital personnel: a survey of hospitals in Metropolitan Toronto.
Approximately 50 000 individuals are employed in various hospital-based occupations in Metropolitan Toronto. To determine the proportion of this population that might be considered as first-priority recipients of the new hepatitis B vaccine, a questionnaire was sent to the executive directors of 45 hospitals in this region. The questionnaire requested data on the numbers of full- and part-time employees whose frequency of contact with blood and blood-related equipment was the greatest. The response rate was 89%. Of the 9545 individuals identified as being at risk of exposure to hepatitis B, 5443 (57%) were nonphysicians and 4102 (43%) were physicians. A highly significant (p less than 0.001) positive and linear relation was found between the numbers of personnel at highest risk of exposure and the total number of hospital personnel and type of hospital. Therefore, the potential exists for developing and validating a simple bivariate model that could predict the initial vaccine requirements for hospital-based personnel in Ontario and other provinces.
Hepatitis B↗
Needle sharing behaviour among injection drug users (IDUs) in treatment in Montreal and Toronto, 1988-1989.
Injection drug users (IDUs) entering treatment programs in Montreal and Toronto were recruited for a study of drug using behaviour and risk of HIV infection. Only those who had injected within 6 months of entering their treatment program were eligible for participation. 183 subjects were recruited in Montreal and 167 in Toronto between November, 1988 and October, 1989. Each participant completed a standardized interviewer-administered questionnaire which focussed on, among other things, drug history and needle sharing behaviour. Approximately three-quarters of respondents in both cities reported sharing needles and syringes within the 6-month period prior to their entry into treatment. Our analysis, which focussed on variables associated with needle sharing revealed that having a sexual partner who injected, trouble obtaining sterile needles and syringes and cocaine injection were significantly and independently associated with needle sharing in a logistic regression model which also controlled for city of recruitment.
AIDS Serodiagnosis↗
The knowledge, attitudes and concerns of hospital staff about AIDS.
Staff from 3 Toronto hospitals were surveyed for knowledge, attitudes and concerns about AIDS. 70% of the 1,366 respondents had direct clinical experience with persons with AIDS. Data were analyzed according to hospital setting and professional group: physicians, nurses, technologists and supervisory staff. No setting difference was observed and although statistically significant differences (at the .001 level) were observed between professional groups, these differences are small and have little practical importance. In general, subjects answered 68% of the knowledge questions correctly. All attitudes and concerns were inversely associated to knowledge (Pearson r range was -.31 to -.20). Multivariate analysis demonstrated that knowledge and concern about contagion are important mediating variables (multiple r = .40) for other attitudes and concerns.
Acquired Immunodeficiency Syndrome↗
Sexual behaviour changes in a cohort of male sexual contacts of men with HIV disease: a three-year overview.
We describe the sexual behaviour reported by 240 seronegative and seropositive homosexual men over a 3-year period. Sexual partners of men with HIV disease were recruited into a prospective study between July 1984 and July 1985 and were monitored every 3 months thereafter. Data on sexual activities were collected through interviewer-administered questionnaires. The cohort experienced a reduction in both the number of sexual partners and the volume of sexual activity. Reductions in the number of partners were early and dramatic. Changes in sexual activities were gradual and consistent in trend. The greatest reduction occurred in high risk activities (receptive and insertive anal intercourse). After 3 years of follow-up, only 10% of the men continue to be exposed to semen through unprotected receptive anal intercourse and 18% through unprotected receptive oral-genital sex. The proportion of men engaging in oral-genital contact and masturbation remained stable over the 3 years. Once informed of their serostatus, both seropositive and seronegative men reduced their high risk behaviour. The decline in rates of STDs and seroconversion confirmed that this cohort had indeed reduced their high risk behaviour.
Cohort Studies↗
Sample sizes for needles in a haystack: the case of HIV seroprevalence surveys.
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HIV Seroprevalence↗