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Biomedical subjects

N S Padian

Publications and source records attributed to N S Padian.

At least 19 recordsLinked to original sources

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

Epidemiologic evidence for time variation in HIV infectivity.

Data from three epidemiologic studies of heterosexual transmission of HIV among monogamous couples are used to assess evidence for time variation in HIV infectivity, possibly related to varying levels of infectiousness following infection in the primary infected partner. Analyses are based on statistical techniques that account for the inherent incompleteness of exposure information from such studies, and that allow direct assessment of the hypotheses that infectivity varies with time since infection and across partnerships. Data include findings from 302 couples from the California Partners' Study and 51 and 31 couples, respectively, from two U.S. Center for Disease Control and Prevention (CDC)-sponsored studies of infection in partners of transfusion recipients. Results indicate weak evidence for higher infectivity following infection of the primary partner, decreasing to relatively lower levels from 2 to 10 years after. Although these findings are consistent with biologic observations of time variation in viral levels, other explanations of the observed pattern (e.g., heterogeneity of infectivity) are equally plausible, pointing out some inherent limitations of data from such studies.

Adult

Risk factors for plasma cell endometritis among women with cervical Neisseria gonorrhoeae, cervical Chlamydia trachomatis, or bacterial vaginosis.

OBJECTIVE: We sought to determine potential risk factors for upper genital tract inflammation in women with cervical Neisseria gonorrhoeae, Chlamydia trachomatis, or bacterial vaginosis. STUDY DESIGN: In a case-controlled study we compared 111 women with cervical Neisseria gonorrhoeae, Chlamydia trachomatis, or bacterial vaginosis (the study group) with 24 women who had negative tests for each of these infections (the control group). We evaluated potential risk factors for upper genital tract inflammation by use of bivariate and then logistic regression analysis. RESULTS: We found plasma cell endometritis in 53 of 111 women in the study group and 3 of 24 controls (odds ratio = 6.4, 95% confidence interval 1.7 to 35.0). On logistic regression, the study group women who were in the proliferative phase had increased likelihood of plasma cell endometritis (odds ratio = 4.5, 95% confidence interval 1.6 to 12.4). CONCLUSION: The proliferative phase of the menstrual cycle seems to be the primary risk factor for ascending infection by organisms associated with pelvic inflammatory disease. This may be due to a hormonal effect or to the loss of the cervical barrier during menstruation.

Adolescent

Managing HIV among serodiscordant heterosexual couples: serostatus, stigma and sex.

A qualitative study was conducted with 28 men and women in HIV-serodiscordant couples to explore the management of HIV in their relationship. Content analysis of the interviews revealed the role of serostatus and stigma in shaping partners' experience of HIV, sex and risk. Partners' differing serostatus often created feelings of alienation within the relationship. Compounding this interpersonal dynamic, the HIV service community was experienced as segregating because they were not funded or prepared to work with seronegative partners. Thus many, particularly seronegative women, felt invisible both within and outside of the relationship. Yet, the uninfected partners shared the burden of a stigmatizing illness because of the serodiscordant relationship. Stigma hindered communication about HIV and sex, disclosure to others and access to services. Many experienced HIV as a loss of their sexuality. Seronegative partners spoke about 'keeping sex alive' and often had to push to continue having sex. Couples used multiple strategies to manage HIV, including developing strict behavioural guidelines, connecting with other couples, accessing scientific information and becoming educators and activists. These altruistic activities, which also included participation in research, helped to transcend external and internalized stigma. Implications for developing interventions for HIV-serodiscordant couples are discussed.

Adult

Genetic and immunological host factors associated with susceptibility to HIV-1 infection.

The probability of HIV transmission depends on the interplay of many different factors related to infectiousness of the HIV-infected partner, susceptibility of the HIV-uninfected partner, and biological characteristics of HIV strains. Here, we review recent studies of host immunological and genetic factors which may affect susceptibility to HIV-1 infection. These factors are summarized in Table 1. We propose how to explore biological correlates of susceptibility to HIV-1 infection in epidemiological studies, discuss the strengths and limitations of this research, and address the implications for public health.

Disease Susceptibility

Heterosexual transmission of human immunodeficiency virus (HIV) in northern California: results from a ten-year study.

To examine rates of and risk factors for heterosexual transmission of human immunodeficiency virus (HIV), the authors conducted a prospective study of infected individuals and their heterosexual partners who have been recruited since 1985. Participants were recruited from health care providers, research studies, and health departments throughout Northern California, and they were interviewed and examined at various study clinic sites. A total of 82 infected women and their male partners and 360 infected men and their female partners were enrolled. Over 90% of the couples were monogamous for the year prior to entry into the study; < 3% had a current sexually transmitted disease (STD). The median age of participants was 34 years, and the majority were white. Over 3,000 couple-months of data were available for the follow-up study. Overall, 68 (19%) of the 360 female partners of HIV-infected men (95% confidence interval (CI) 15.0-23.3%) and two (2.4%) of the 82 male partners of HIV-infected women (95% CI 0.3-8.5%) were infected. History of sexually transmitted diseases was most strongly associated with transmission. Male-to-female transmission was approximately eight-times more efficient than female-to-male transmission and male-to-female per contact infectivity was estimated to be 0.0009 (95% CI 0.0005-0.001). Over time, the authors observed increased condom use (p < 0.001) and no new infections. Infectivity for HIV through heterosexual transmission is low, and STDs may be the most important cofactor for transmission. Significant behavior change over time in serodiscordant couples was observed.

Adolescent

Human immunodeficiency virus testing for patient-based and population-based diagnosis.

Laboratory testing for human immunodeficiency virus (HIV) has been introduced for individual patient-based diagnosis as well as high-risk and low-risk population-based screening. The choice of test, confirmatory algorithm, and interpretative criteria used depend on the clinical setting. In the context of general population-based testing, factors affecting test performance will have to be considered carefully in the development of testing policy.

Algorithms

Attributable risk of exposures associated with sexually transmitted disease.

Attributable risk combines information on the prevalence of an exposure with a measure of the associated increment in risk, providing an estimate of the proportion of incident or prevalent disease that might be avoided by eliminating the exposure. Thus, attributable risk identifies exposures most productively targeted by public health interventions. Attributable risk can be defined as the ratio of average excess risk to average risk. As with other measures of association between exposure and disease computed from observational data, adjustment must be made for confounding factors. Estimates of attributable risk are highly variable. Nonetheless, attributable risk retains its usefulness as an approximate measure of the public health significance of exposures associated with acquisition of sexually transmitted disease, provided it is estimated and interpreted cautiously.

Female

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

Risk factors for postcoital bleeding among women with or at risk for infection with human immunodeficiency virus.

Risk factors for postcoital bleeding were examined in 475 women who were enrolled in a study of heterosexual transmission of human immunodeficiency virus (HIV). In bivariate analyses, history of sexually transmitted diseases (STDs; P = .03), HIV infection (P = .008), and dyspareunia or pain during intercourse (P = .0001) were significant risk factors. In multivariate analysis, the two latter factors remained significant (for HIV, odds ratio [OR] = 2.1, P = .02, 95% confidence interval [CI] = 1.1-4.0; for dyspareunia, OR = 3.5, P < .001, 95% CI = 1.8-6.6), as did the interaction term of STD history and heavy smoking (OR = 2.4, P = .02, 95% CI = 1.2-5.0). Pain during intercourse was the strongest predictor of postcoital bleeding but may be part of the same phenomenon. Similarly, because this study relied on cross-sectional data, the direction of the causal pathway linking HIV to postcoital bleeding cannot be established. However, these data suggest that smoking, a modifiable risk factor, may increase risk of postcoital bleeding and contribute to susceptibility for HIV and other STDs.

Adult

Targeted HIV-prevention programs.

An effective program to prevent HIV infection must have both universal and targeted components. The universal component includes reducing HIV-related discrimination, removing commercial restrictions on the materials necessary for safer behavior, and providing information about the risk of HIV. The targeted component involves focusing the limited resources for intensive programs of behavioral change on situations in which the risk of HIV transmission is highest. Such a strategy would follow the dictum "Warn widely and spend wisely."

Communicable Disease Control

Pelvic inflammatory disease. A brief overview.

Most pelvic inflammatory disease (PID) is caused by the ascent of sexually transmitted disease pathogens from the endocervix. In fact, PID remains the most common serious complication of infection from sexually transmitted bacterial pathogens. PID also may be caused by normal vaginal micro-organisms (such as those associated with bacterial vaginosis) that have overgrown in the vagina. PID has been linked to the occurrence of long-term sequelae, most commonly and most importantly infertility and ectopic pregnancy. In many patients PID may remain undiagnosed and asymptomatic, and may not become evident until such long-term consequences become manifest. We briefly review the epidemiology of PID including case definitions, the prevalence of the problem, and causal pathways and associated risk factors. Risk factors for both PID and its sequelae are discussed in relation to the mechanism of ascent of associated etiologic agents from the lower to the upper genital tract.

Female

Risk factors for hepatitis C virus seropositivity in heterosexual couples.

OBJECTIVES: To determine the risk of heterosexual transmission of hepatitis C virus (HCV) and to identify other risk factors for HCV seropositivity in heterosexual couples. DESIGN: Retrospective cross-sectional study comparing HCV-seropositive and HCV-seronegative heterosexual men and women. SETTING: Couples recruited from the community and screened for participation in a study of the heterosexual transmission of human immunodeficiency virus. PARTICIPANTS: A total of 340 subjects, 170 men and 170 women in sexual partnerships, aged 18 through 61 years. MAIN OUTCOME MEASURE: Seropositivity for HCV antibodies. RESULTS: Overall, 31 (18%) of the 170 women and 56 (33%) of the 170 men were positive by a four-antigen HCV immunoblot. Injection drug use and hemophilia were strongly associated with HCV seropositivity. Sixty-four percent of injection drug users were positive (odds ratio [OR], 27.0; 95% confidence interval [CI], 13.4 to 56.1; P < .0001), as were all four hemophiliacs in the study. History of blood transfusion was significantly associated with HCV seropositivity (OR, 2.7; 95% CI, 1.1 to 7.0; P = .02). Positivity for HCV was not associated with measures of sexual behavior within couples or with numbers of other sexual partners, history of sexually transmitted diseases, or human immunodeficiency virus seropositivity. However, two of the 31 women without parenteral risk but with a long-term HCV-positive male partner were HCV seropositive compared with none of 81 women with an HCV-negative male partner (P = .07). CONCLUSIONS: These results provide little evidence of HCV sexual transmission but are consistent with infrequent sexual transmission. They corroborate the importance of injection drug use and transfusion of blood or blood products in transmitting HCV and underscore the importance of ascertaining parenteral exposures when examining sexual transmission of HCV.

Adult

Prevention of heterosexual transmission of human immunodeficiency virus through couple counseling.

In the absence of an effective vaccine, behavior change remains the most effective means to prevent the spread of HIV. We examined behavior change over time and rates of HIV seroconversion in a cohort of HIV individuals and their heterosexual partners recruited since 1985. Participants were recruited from various HIV counseling and testing sources throughout California and were usually interviewed and tested in their own homes. Couple counseling and risk assessments were conducted at average intervals of six months. Data from 144 couples who were discordant for HIV serostatus are reported. Of the index cases, 78% were men. Most male index cases were bisexuals, and most female index cases were infected through heterosexual intercourse with a previous sexual partner. The mean duration of the relationship for the couple at intake was 5.6 years. Both condom use and sexual abstinence increased over time (p < 0.001 for both), and most behavior change occurred between intake and first follow-up visit. We observed no seroconversion after 193 couple-years of follow-up. Couple counseling in combination with social support appears to be an effective means to promote and sustain behavior change among HIV-infected individuals and their heterosexual partners.

Adolescent