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Biomedical subjects

S Shiboski

Publications and source records attributed to S Shiboski.

At least 19 recordsLinked to original sources
PubMed2001

Risks for incident human papillomavirus infection and low-grade squamous intraepithelial lesion development in young females.

CONTEXT: Low-grade squamous intraepithelial lesions (LSILs) have been described as a benign cytological consequence of active human papillomavirus (HPV) replication. Several studies have reported that certain behavioral and biological risks exist for LSIL, suggesting that HPV alone is not sufficient for the development of LSIL. However, because most of these studies have been cross-sectional, it is not known whether behavioral and biological risks are simply risks for HPV infection itself. OBJECTIVE: To prospectively examine risks of incident HPV infection in HPV-negative females and of incident LSIL development in females with HPV infection. DESIGN: Prospective cohort study conducted between 1990-2000, with a median follow-up of 50 months. SETTING AND PARTICIPANTS: Females aged 13 to 21 years who attended 2 family planning clinics in the San Francisco bay area; 496 had prevalent HPV infection and 105 were HPV-negative. MAIN OUTCOME MEASURE: Incident development of HPV infection and LSIL, analyzed by various demographic, behavioral, and clinical risk factors. RESULTS: Fifty-four incident HPV infections occurred in the 105 females who were HPV-negative at study entry (median duration of follow-up for those who remained HPV-negative was 26 months). Multivariable analysis showed that risks of HPV included sexual behavior (relative hazard [RH], 10.10; 95% confidence interval [CI], 3.24-31.50 per new partner per month), history of herpes simplex virus (RH, 3.54; 95% CI, 1.37-9.10), and history of vulvar warts (RH, 2.73; 95% CI, 1.27-5.87). Current use of oral contraceptives had a significantly protective effect (RH, 0.49; 95% CI, 0.28-0.86). Among the 496 individuals who were HPV-positive at baseline or in follow-up, there were 109 incident cases of LSIL during the follow-up interval, with a median follow-up time of 60 months for those who never developed LSIL. Human papillomavirus infection was the most significant risk factor for development of LSIL. The multivariable model showed the following risks for LSIL: HPV infection for less than 1 year (RH, 7.40; 95% CI, 4.74-11.57); HPV infection for 1 to 2 years (RH, 10.27; 95% CI, 5.64-18.69); HPV infection for 2 to 3 years (RH, 6.11; 95% CI, 1.86-20.06); and daily cigarette smoking (RH, 1.67; 95% CI, 1.12-2.48). CONCLUSION: Our results indicate distinct risks for HPV and LSIL. In addition, most women with HPV infection in our study did not develop LSIL within a median follow-up period of 60 months. These findings underscore the hypothesis that certain biological risks thought to be associated with LSIL are, in fact, risks for acquisition of HPV. Cigarette smoking was a risk specific to LSIL, supporting the role of tobacco in neoplastic development.

Adolescent↗
PubMed2000

Effect of intravaginal practices on the vaginal and cervical mucosa of Zimbabwean women.

OBJECTIVES: Lesions on the vaginal and cervical mucosa may facilitate transmission of HIV and other sexually transmitted diseases (STDs). We evaluated the relationship between intravaginal practices and the presence of colposcopic lesions in Zimbabwean women. METHODS: Users and nonusers of intravaginal practices were seen at enrollment, and at 1 and 6 months. Interviewing, counseling, and pelvic and colposcopic examinations were performed at each study visit. Specimens were collected at enrollment and 6 months. RESULTS: Colposcopic lesions were found at least once in 83% of the participants (n = 162), and in 66% of all exams (n = 430). Most lesions were classified as related to infection with human Papillomavirus (HPV) (58%) or another pathogen (20%), but 11% of lesions could have been caused by intravaginal practices (signal lesions). Intravaginal practices were not associated with an increased incidence in signal lesions (95 and 124 lesions per 100 person-years of follow-up for users and nonusers respectively; p = .290), nor with the presence of signal lesions in multivariate baseline (odds ratio [OR], 1.32; 95% confidence interval [CI], 0.37-4.72; p = .666) and six month transition models (OR, 1.67; 95% CI, 0.59-4.70; p = .333). CONCLUSIONS: No associations between intravaginal practices and colposcopic lesions were found in this study. However, the potential effect of intravaginal practices on the cervical and vaginal mucosa, and on subsequent HIV and STD transmission, warrants further study. The usefulness of colposcopy as a research tool in areas with high prevalences of HIV and HPV is questioned.

Adolescent↗
PubMed2000

Intravaginal practices, vaginal flora disturbances, and acquisition of sexually transmitted diseases in Zimbabwean women.

One hundred sixty-nine Zimbabwean women were studied to determine whether the use of intravaginal practices (cleaning with the fingers, wiping the vagina, and inserting traditional substances) are associated with disturbances of vaginal flora and acquisition of sexually transmitted diseases (STDs). Subjects were interviewed and received counseling and a pelvic examination at enrollment, 1 month, and 6 months, and vaginal specimens were collected at enrollment and at 6 months. Users were more likely than nonusers to have vaginal flora disturbances but were not more likely to acquire an STD (relative risk [RR], 2.15; P=.188). Certain vaginal flora disturbances were associated with increased STD incidence and HIV prevalence. The absence of lactobacilli from the vaginal flora was associated with being positive for human immunodeficiency virus in baseline (odds ratio [OR], 0.24; P=.001) and 6-month transition multivariate models (OR, 0.39; P=.025). The presence of clue cells at baseline was associated with a higher incidence of STDs (RR, 1. 94; P=.025).

Adult↗
PubMed2000

Is audio computer-assisted self-interviewing a feasible method of surveying in Zimbabwe?

BACKGROUND: Research into reproductive health is dependent on participants accurately reporting sensitive behaviours. We examined whether audio computer-assisted self-interviewing (ACASI), which increased sensitive behaviour reporting in the US, is a feasible method of surveying in developing countries. METHODS: Zimbabwean women in three educational groups were surveyed about demographics and family planning using interviewer and ACASI modes. An exit survey was administered to elicit information about the participants' opinions and experiences using ACASI. RESULTS: The majority of women (86%) preferred ACASI to interviewer mode. The reasons mentioned were always related to increased confidentiality and privacy. Ability to use ACASI and user preferences varied with educational level. More women with primary school or less education (53%) reported problems with computer use than women in the higher educational groups (10-12%). The percentage of women having perfect response concordance between ACASI and interviewer modes increased significantly with education (64%, 81%, and 84% respectively; P(trend) < 0.001). CONCLUSIONS: Use of ACASI may be more feasible in Zimbabwe and other developing countries than was originally thought, but ACASI programs should continue to be improved and tested in various countries and population groups.

Adult↗
PubMed1999

The significance of squamous metaplasia in the development of low grade squamous intraepithelial lesions in young women.

BACKGROUND: The purpose of this study was to examine, prospectively, the presence and extent of cervical epithelial immaturity as well as the rate of squamous metaplastic activity as a risk for the development of low grade squamous intraepithelial lesions (LSIL). METHODS: The study was a nested case-control design that used subjects from an ongoing cohort study of human papillomavirus infection. Fifty-four sexually active young women who developed LSIL were matched for age and number of visits with 54 women who had never developed LSIL. The percent of cervical immaturity was interpreted from colpophotography using a computer-generated pixel count of delineated immature and total cervical areas. Activity of squamous metaplasia was interpreted as the percent change in the area of immaturity over a defined time period. Conditional logistic regression analysis examined risks for the development of LSIL. RESULTS: Baseline area of biologic immaturity was not a predictor of LSIL. However, women with the a high degree of metaplastic activity near the SIL event were more likely to develop LSIL (odds ratio = 3.01 [95% confidence interval, 1.3, 6.8] for every 10% unit change in area of immaturity). CONCLUSIONS: A rapid rate of metaplastic change within the transformation zone, rather than the initial area of biologic immaturity, is a significant risk factor for the development of LSIL.

Adult↗
PubMed1999

The Marks Asthma Quality of Life Questionnaire: further validation and examination of responsiveness to change.

We performed analyses to examine the structure, validity, and responsiveness to change of the Marks Asthma Quality of Life Questionnaire (AQLQ), originally validated in Australia in a self-administered format, among 539 U.S. subjects with asthma. Subjects were interviewed twice by telephone over an 18-month period. Based on factor analyses, the subscale structure of the AQLQ was modified slightly to eliminate item overlap among subscale scores. Cross-sectionally, total AQLQ scores were significantly correlated in expected directions with baseline asthma severity scores (r = 0.58), SF-36 physical (r = -0.66) and mental (r = -0.40) health status scores, and pulmonary function (FEV1% predicted, r = -0.14). Longitudinally, changes in AQLQ total and subscale scores were significantly (P<0.01) associated with changes in asthma severity and both physical and mental status. The AQLQ, administered by telephone, appears to be useful for assessing changes in the impact of adult asthma.

Adult↗
PubMed1999

Risk factors for abnormal anal cytology in young heterosexual women.

Although anal cancers are up to four times more common in women than men, little is known about the natural history of anal human papillomavirus (HPV) infections and HPV-related anal lesions in women. This study reports on the prevalence of and risks for anal cytological abnormalities over a 1-year period in a cohort of young women participating in a study of the natural history of cervical HPV infection. In addition to their regularly scheduled sexual behavior interviews and cervical testing, consenting women received anal HPV DNA and cytological testing. Anal cytology smears were obtained from 410 women whose mean age was 22.5 +/- 2.5 years at the onset of the study. Sixteen women (3.9%) were found to have abnormal anal cytology: 4 women had low-grade squamous intraepithelial lesions (SILs) or condyloma; and 12 women had atypical cells of undetermined significance. Factors found to be significantly associated with abnormal anal cytology were a history of anal sex [odds ratio (OR), 6.90; 95% confidence interval (CI), 1.7-47.2], a history of cervical SILs (OR, 4.13; 95% CI, 1.3-14.9), and a current anal HPV infection (OR, 12.28; 95% CI, 3.9-43.5). The strong association between anal intercourse and the development of HPV-induced SILs supports the role of sexual transmission of HPV in anal SILs. Young women who had engaged in anal intercourse or had a history of cervical SILs were found to be at highest risk.

Adolescent↗
PubMed1998

The natural history of human papillomavirus infection as measured by repeated DNA testing in adolescent and young women.

OBJECTIVES: The objectives of this study were to describe the early natural history of human papillomavirus (HPV) infection by examining a cohort of young women positive for an HPV test and to define within this cohort (1) the probability of HPV regression, (2) the risk of having a squamous intraepithelial lesion, and (3) factors that were associated with HPV regression. STUDY DESIGN: The study was a cohort analytic design. An inception cohort of 618 women positive for HPV participated. HPV testing, cytologic evaluation, and colposcopic evaluation were performed at 4-month intervals. HPV testing was characterized for two groups: low risk (five types rarely associated with cancers) and high risk (nine types most commonly associated with cancers). RESULTS: Estimates provided by Kaplan-Meier curves showed that approximately 70% of women were found to have HPV regression by 24 months. Women with low-risk HPV type infections were more likely to show HPV regression than were women with high-risk HPV type infections (log rank test p = 0.002). The relative risk for the development of high-grade squamous intraepithelial lesion (HSIL) was 14.1 (95% confidence interval: 2.3, 84.5) for women with at least three positive tests for high-risk HPV preceding the development of the HSIL compared with that for women with negative tests for high-risk HPV. However, 88% of women with persistent positive HPV tests have not had HSIL to date. No factors associated with high-risk HPV type regression were identified except for a negative association with an incident history of vulvar condyloma (relative risk = 0.5 [95% confidence interval: 0.3 to 0.8]). CONCLUSION: Most young women with a positive HPV test will become negative within a 24-month period. Persistent positive tests with oncogenic HPV types represented a significant risk for the development of HSIL. However, we found that most young women with persistent positive HPV tests did not have cytologically perceptible HSIL over a 2-year period. Factors thought to be associated with the development of HSIL were found not to be important in HPV regression.

Adolescent↗
PubMed1996

Population- and individual-based approaches to the design and analysis of epidemiologic studies of sexually transmitted disease transmission.

Epidemiologic studies of sexually transmitted disease (STD) transmission present a number of unique challenges in design and analysis. These arise both from the social nature of STD transmission and from inherent difficulties in collecting accurate and informative data on exposure and infection. Risk of acquiring an STD depends on both individual-level factors and the behavior and infectiousness of others. Consequently, study designs and analysis methods developed for studying chronic disease risk in individuals or groups may not apply directly. Simple models of STD transmission were used to investigate these issues, focusing on how the interplay between individual- and population-level factors influences design and interpretation of epidemiologic studies, with particular attention to interpretation of common measures of association and to common sources of bias in epidemiologic data. Existing methods for investigating risk factors can be modified such that these issues may be addressed directly.

Bias↗
PubMed1996

Predictors of repeat cesarean delivery after trial of labor: do any exist?

BACKGROUND: We evaluated the predictive value of risk factors for repeat cesarean delivery identified in retrospective studies. STUDY DESIGN: We identified 175 consecutive patients who underwent trial of labor (TOL) and compared detailed admission, intrapartum, and postpartum characteristics of those who required repeat cesarean delivery with those who had vaginal births. We calculated relative risks, positive predictive values, and sensitivities for potentially predictive admission characteristics. We also performed multiple logistic regression and classification analyses. RESULTS: Ninety-five percent of eligible patients underwent a TOL, and 85 percent of them delivered vaginally. Patients who had labor induced and patients with high fetal station on admission were significantly more likely to require repeat cesarean section (relative risk [RR]=2.9 and 2.1; 95 percent confidence interval [CI]=1.5 to 5.3, 1.1 to 4.2, respectively), but even these patients had high rates of vaginal birth (67 percent and 75 percent, respectively). A subgroup of patients who underwent labor induction and had large fetuses (estimated weight 3,800 g or more) had a 75 percent risk of cesarean delivery (RR=2.5, 95 percent CI=0.9 to 7.5). Multivariate models using different combinations of admission characteristics could not correctly identify which patients would require repeat cesarean delivery. CONCLUSIONS: Admission characteristics with statistically significant risk ratios have low predictive values because of the extremely low rate of repeat cesarean delivery in this population. A larger series is needed to study TOL outcomes in patients with large fetuses who are being induced. We conclude that until risk factors with high predictive value for repeat cesarean delivery are identified, all eligible patients should be encouraged to undergo a TOL.

Adult↗
PubMed1995

Socioeconomic differences in sexually transmitted disease rates among black and white adolescents, San Francisco, 1990 to 1992.

This paper examines the effect of socioeconomic position on the differences in the 3-year rates (1990 to 1992) of reported cases of gonorrhea and chlamydia between Black and White adolescents, aged 12 to 20 years, residing in San Francisco. The crude relative risks for Blacks were 23.4 (95% confidence interval [CI] = 20.4, 27.8) for gonorrhea and 9.3 (95% CI = 8.3, 10.3) for chlamydia. Adjusting for poverty and occupational status, the relative risks were 28.7 (95% CI = 22.5, 36.1) for gonorrhea and 8.9 (95% CI = 7.4, 10.6) for chlamydia. This study demonstrates that factors other than poverty and occupational status account for the racial/ethnic differences in the rates of gonorrhea and chlamydia among adolescents in San Francisco.

Adolescent↗
PubMed1994

Changes in AIDS survival time in two San Francisco cohorts of homosexual men, 1983 to 1993.

BACKGROUND: During the first decade since the recognition of the acquired immunodeficiency syndrome (AIDS), new therapies have been introduced and the frequency of clinical manifestations has changed. The impact of these changes on AIDS survival, however, has not been well characterized. DESIGN: A prospective cohort study of the outcomes of human immunodeficiency virus (HIV) infection. SETTING: Homosexual and bisexual men residing in San Francisco, Calif, recruited in 1983 and 1984 for two prospective studies and followed up for more than 9 years with clinical examinations. PARTICIPANTS: A total of 761 HIV-positive homosexual and bisexual men. MAIN OUTCOME MEASURES: Survival time from a CD4 lymphocyte count at 0.20 x 10(9)/L (200/microL) and from a clinical AIDS diagnosis to death. RESULTS: Median survival time from a CD4 lymphocyte count at 0.20 x 10(9)/L increased from 28.4 months in the October 1983 to November 1986 period to 40.1 months in the November 1986 to November 1988 period and is estimated at 38.1 months in the November 1988 to February 1993 period. Patients diagnosed with Pneumocystis carinii pneumonia (PCP) accounted for most of this increase with a gain in median survival time of 9.7 months (P = .0009), compared with a nonsignificant decline in the survival time of those patients without a PCP diagnosis. Multivariate analysis showed that rate of CD4 lymphocyte loss (P < .001) and receipt of both PCP prophylaxis and antiretroviral therapy (P = .04) were significantly associated with longer survival time, whereas antiretroviral therapy alone was not (P = .81). Time to death from a clinical AIDS diagnosis was 14.7 months in the 1983 to 1986 period, 19.1 months in the 1986 to 1988 period, and an estimated 15.7 months in the 1988 to 1993 period. CONCLUSIONS: Survival time from a CD4 lymphocyte count at 0.20 x 10(9)/L has improved significantly by about 1 year; yet survival time using the 1987 AIDS case definition has shown small improvement. The largest increase in survival time from a CD4 lymphocyte count at 0.20 x 10(9)/L was in patients diagnosed with PCP, suggesting that PCP prophylaxis and treatment were more important factors in longer survival time than antiretroviral therapy.

AIDS-Related Opportunistic Infections↗
PubMed1994

Progressive immunodeficiency due to infection with human immunodeficiency virus does not lead to waning immunity to measles in a cohort of homosexual men.

The relationship between progressive immunodeficiency related to infection with human immunodeficiency virus (HIV) and waning immunity to measles was investigated in this retrospective cohort study. Titers of serum antibodies to measles virus were measured by enzyme immunoassay of stored sera from a cohort of homosexual men who were studied at San Francisco General Hospital. Subjects underwent a baseline and follow-up measure of measles antibodies. High levels of antibodies to measles virus were maintained in the HIV-positive and negative groups. One (2%) of the 50 HIV-negative controls was seronegative for the measles virus, and no controls evidenced seroreversal (decline in antibody to a level at which protection is not provided) during the study. Two (1.4%) of the 145 HIV-positive subjects were measles-seronegative, and two others evidenced seroreversal. Analysis with Spearman's rank correlation revealed no relationship between changes in the CD4 cell count and measles antibody level. Thus we conclude that waning measles immunity is not greatly accelerated in HIV-infected adults despite progressive HIV-related immunodeficiency.

Adult↗
PubMed1994

Time from HIV seroconversion to oral candidiasis or hairy leukoplakia among homosexual and bisexual men enrolled in three prospective cohorts.

OBJECTIVES: We evaluated time from HIV seroconversion to diagnosis of two common oral lesions associated with HIV infection and disease progression. DESIGN: Oral examinations were performed on homosexual and bisexual men enrolled in prospective cohorts. SETTING: Homosexual and bisexual men were followed in three epidemiologic cohort studies in San Francisco, California, USA. PARTICIPANTS: Data were evaluated from 80 men with well-defined dates of HIV seroconversion from 1984 through 1991. MAIN OUTCOME MEASURES: We determined the cumulative incidence of oral candidiasis and hairy leukoplakia after HIV seroconversion. RESULTS: Four per cent of men developed oral candidiasis within 1 year after HIV seroconversion, 8% within 2, 15% within 3, 18% within 4, and 26% within 5 years. Nine per cent developed hairy leukoplakia within 1 year, 16% within 2, 25% within 3, 35% within 4, and 42% within 5 years. The median CD4+ count was 391 x 10(6)/l when oral candidiasis was first reported and 468 x 10(6)/l when hairy leukoplakia was first reported. CONCLUSIONS: Oral candidiasis or hairy leukoplakia appeared in a significant proportion of HIV-infected homosexual and bisexual men. These lesions occurred relatively soon after HIV seroconversion, typically before AIDS. Evaluation of HIV-infected individuals for these lesions has many potential clinical and research benefits, including the possible use of oral lesions as primary end-points in clinical trials.

AIDS-Related Opportunistic Infections↗
PubMed1994

Risk factors for anal human papillomavirus infection and anal cytologic abnormalities in HIV-positive and HIV-negative homosexual men.

Men with advanced human immunodeficiency virus (HIV) disease have a high prevalence of anal human papillomavirus (HPV) infection and potentially precancerous anal disease. To characterize prevalence of and risk factors for anal HPV infection and anal cytologic abnormalities, 37 HIV-positive and 28 HIV-negative participants in the San Francisco General Hospital Cohort Study were studied. A questionnaire was administered, followed by an anal examination consisting of two consecutive anal swabs for cytology and HPV DNA hybridization, and anoscopy with biopsy of visible lesions. Ten of 28 (36%) HIV-negative men and 19 of 37 (51%) HIV-positive men had anal HPV infection (p = 0.32). Risk factors for anal HPV infection included HIV positivity with a CD4 count < 200/mm3 (p = 0.03) and a history of smoking (p = 0.03). Abnormal anal cytology was found in 2 of 26 (8%) HIV-negative men and 10 of 36 (28%) HIV-positive men with cytology adequate for interpretation (p = 0.09). Risk factors for abnormal anal cytology included HIV positivity with a CD4 count < 200/mm3 (p = 0.006) and current smoking (p = 0.03). We conclude that the risk of development of anal disease and HPV infection was highest among HIV-positive men with a CD4 count of < 200/mm3, and that smoking may play a role in the pathogenesis of anal disease.

Adult↗
PubMed1993

Use of T lymphocyte subset analysis in the case definition for AIDS.

Infection with HIV-1 and < 200 CD4+ lymphocytes/mm3 has been proposed as an AIDS-defining condition. We have evaluated the effects of using this and other T-cell subset measurements, in the diagnosis of AIDS in two cohorts of homosexual/bisexual men in San Francisco. Among 762 HIV-1 infected men, 200 CD4+ lymphocytes/mm3 corresponded to 13 percent CD4+ lymphocytes and a CD4+/CD8+ ratio of 0.23. If these AIDS-defining criteria had been implemented in mid-1991, the number of living AIDS cases would have increased by 106 (212%), 133 (266%), and 136 (272%), respectively. When these criteria were first met, either before or in the absence of a clinical AIDS diagnosis, about half of the subjects were asymptomatic and the median clinically AIDS-free interval was approximately 2 years. Using two consecutive tests or pair-wise combinations of criteria reduced the number of cases identified by testing error or transient biological variation, but the number of living AIDS cases would still be increased more than twofold. Finally, any AIDS case definition using a specific T-cell subset value will be compromised by the inherent variability in these measurements and the substantial overlap in the results for those with and without clinical manifestations of HIV infection.

Acquired Immunodeficiency Syndrome↗