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Biomedical subjects

R M Anderson

Publications and source records attributed to R M Anderson.

At least 415 records · Page 23Linked to original sources
PubMedDate not supplied

Incubation period of AIDS in patients infected via blood transfusion.

Temporal trends in the prevalence of HIV (human immunodeficiency virus) infection are uncertain because of the reluctance of most governments to embark on large-scale programmes of serological surveillance. In the absence of such data, attempts have been made to relate the number of reported cases of AIDS (acquired immune deficiency syndrome) in a defined population to the proportion of that population infected with the virus as a specified time point. One crucial determinant of this relationship is the probability distribution of the incubation period of the disease, with the period defined as the time interval from infection to diagnosis. Recent statistical analysis suggests a mean incubation period of 4.5 years with wide confidence limits, whereas a more heuristic study reports a mean of 15 years. Here we report on a new analysis which reveals age-related differences in the mean (and median) incubation period: 1.97 (1.90) years for children (0-4 yrs old at infection), 8.23 (7.97) years for adults (5-59 yrs old), 5.50 (5.44) years for elderly patients (60 yrs and older).

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Contact tracing and the estimation of sexual mixing patterns: the epidemiology of gonococcal infections.

BACKGROUND AND OBJECTIVES: The concept of a core group of individuals who change sexual partners frequently has played an important role in the study of the epidemiology of sexually transmitted diseases (STDs). It is widely believed that the core group is important in the persistence of infection and that it provides a sensible target for control interventions. GOAL OF THIS STUDY AND STUDY DESIGN: Simple mathematical models are used to assess the significance of sexual mixing between core and noncore groups. Published data from contact tracing studies, which base the definition of the core group on gonorrhea incidence by area of residence, are used to derive estimates of the degree of mixing within and between groups. RESULTS: Analyses reveal patterns of high mixing within core groups in the urban study sites, which suggests that within-group transmission ensures the persistence of gonococcal infection in the community as a whole. CONCLUSIONS: An extension of the analysis of contact tracing data to facilitate the development of mathematical models of STD transmission is detailed.

Contact Tracing↗
PubMedDate not supplied

Sexual mixing patterns of patients attending sexually transmitted diseases clinics.

BACKGROUND: Theorectical studies have highlighted the importance of patterns of choice of sex partner in the transmission and persistence of sexually transmitted diseases (STDs). GOAL: To describe reported patterns of sexual mixing according to numbers of sex partners in STD clinics. STUDY DESIGN: Patients attending public health clinics in Seattle, Washington were interviewed about their own and their partners' behaviors. RESULTS: Throughout, patterns of sexual mixing were weakly assortative. Across activity groups, many respondents believed their partners had no other sexual contacts. Those with three or more partners frequently perceived their partners to have three or more partners as well. CONCLUSIONS: Assortatively mixing persons of high sexual activity makes the persistence of STDs within a population likely (i.e., they act as a "core group"). Additionally, because mixing is not highly assortative (like with like), a steady trickle of infection from members of the core group will pass to other segments of the population.

Adolescent↗
PubMedDate not supplied

Human immunodeficiency virus transmission and the role of other sexually transmitted diseases. Measures of association and study design.

BACKGROUND: Studies have reported that infection with certain sexually transmitted diseases (STD), such as chancroid, gonorrhea, and genital herpes, enhances the probability of human immunodeficiency virus (HIV) transmission by sexual contact with an infected partner. Epidemiologic studies vary in design from longitudinal to cross-sectional, with varying periods of follow-up or retrospective history of exposure to STD. The major difficulty in assessing the results of past work centers on the validity and precision of widely used measures of association, such as relative risk (RR) and odds ratio (OR), in situations in which common behavior (e.g., different facets of sexual behavior) underpins the acquisition of both the STD cofactor and HIV. GOAL: To evaluate the quality of the cumulative incidence ratio (CIR), the hazard rate ratio (HRR), and the prevalence ratio (PR) as measures of association to estimate and test the increase in HIV transmission probabilities caused by the STD. STUDY DESIGN: The study is based on a proportional hazard stochastic model of concomitant HIV and STD cofactor transmission. Analysis was performed using Monte-Carlo simulation. RESULTS: Estimates of the HIV-STD association by the CIR, HRR, and PR, adjusted and nonadjusted for sexual activity, are shown to have poor validity and great variability. The adjusted CIR, HRR, and PR tend to underestimate the strength of the true association (specified in the model) in both longitudinal and cross-sectional designs. In the absence an HIV-STD association, the PR tends to overestimate the magnitude, whereas the CIR and HRR may either underestimate or overestimate it in longitudinal studies. These results have direct consequences on the reliability of the test of association showing both a lack of specificity (empirical type I error) and sensitivity (empirical power). Some reasons contributing to the bias in the estimates of the measures of association are the presence of confounding variables, namely the frequency of change of sex partner and the mixing pattern between sexual activity classes, as well as the adopted definition of exposure to the STD cofactor and the prevalence of both HIV and the STD cofactor. CONCLUSIONS: The precision of estimates and reliability of the test of HIV-STD association could be improved through longitudinal studies using more careful definition and measurement of exposure to the STD cofactor and larger sample sizes permitting finer stratification of sexual behavior and a sufficient number of persons per stratum.

Bias↗
PubMedDate not supplied

Effects of anticonvulsant drug therapy on bone mineral density in a pediatric population.

Twenty epileptic outpatients, aged 5-20 years and taking either phenobarbital or phenytoin for anticonvulsant therapy, were evaluated for femoral neck area bone mineral content and bone mineral density using dual photon absorptiometry. Duration of treatment averaged 51.4 months (range, 9-124 months). A group of 20 normal children who were matched for age, sex, and race served as controls. There were no statistically significant differences between the femoral neck area bone mineral densities of the epileptic patients as compared to the controls. There were also no correlations between duration of anticonvulsant therapy and bone mineral density, nor any differences in bone mineral density values when comparing epileptic patients taking phenobarbital with those patients taking phenytoin.

Adolescent↗
PubMedDate not supplied

Assessing the cultural relevance of an education program for urban African Americans with diabetes.

PURPOSE: This study was conducted to assess the cultural relevance of an education program for urban African Americans with diabetes. METHODS: A set of 12 videotape vignettes were developed for use in diabetes education for urban African Americans with diabetes. Focus groups and questionnaires were used to determine if patients and diabetes educators would find the materials stimulating, culturally appropriate, and useful. RESULTS: The videotape and discussion guide were perceived as valuable by both healthcare professionals and patients. CONCLUSIONS: This education program could be a valuable resource for diabetes educators who want to provide culturally sensitive and relevant diabetes education for urban African Americans with diabetes.

Black or African American↗
PubMedDate not supplied

Compliance and adherence are dysfunctional concepts in diabetes care.

Recognizing that adherence and compliance are dysfunctional concepts is not a passing fad or the latest trend in behavioral approaches to diabetes care and education. Shifting from the acute-care/compliance-focused paradigm to an empowerment/collaborative approach requires a new vision of diabetes education and a new definition and enactment of the roles of educators and patients. Our practice is always an expression of our vision; therefore, if our vision is transformed, our practice will most likely change to reflect our vision. Eliminating the concepts of adherence and compliance makes it possible for our patients to discover and actualize their personal responsibility for their diabetes self-management. Also, it helps us to practice diabetes education as win-win collaboration among equals.

Choice Behavior↗
PubMedDate not supplied

Words and meaning: a cautionary tale for diabetes educators.

The authors developed a Diabetes Attitude Survey (DAS) to measure the attitudes of health care professionals toward diabetes. After examining the results of an initial survey using the DAS, the authors felt that it would be useful to know something about the attitudes of patients regarding these same diabetes-related issues. The DAS was reworded to eliminate technical terms and to make it appropriate for patients with diabetes. To assess the impact of these wording changes, both versions of the DAS were sent to a sample of physicians, nurses, and dietitians. The wording changes produced changes in scores on the majority of the items that had been modified. The paper discusses some of the reasons for the changed scores and the impact of modifying the wording of assessment and evaluation instruments.

Attitude of Health Personnel↗
PubMedDate not supplied

Empowerment: an idea whose time has come in diabetes education.

We have learned much in the past 10 years about how to help patients to acquire diabetes-related knowledge and skills and how to use strategies to help patients change behaviors. However, the application of knowledge and techniques should be guided by a relevant, coherent, educational philosophy. Empowerment offers a practical conceptual framework for diabetes patient education. Empowering patients provides them with the knowledge, skills, and responsibility to effect change and has the potential to promote overall health and maximize the use of available resources. It is an idea whose time has come for diabetes education.

Diabetes Mellitus↗
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The attitudes of nurses, dietitians, and physicians toward diabetes.

This paper describes the attitudes of physicians, nurses, and dietitians toward diabetes. The study involves 1,608 diabetes attitude surveys that were completed by both diabetes specialists and nonspecialists. The study found that overall the attitudes of diabetes specialists were consistently more positive than those of nonspecialists. Also, the study found that the diabetes-related attitudes of nurses and dietitians were consistently more positive than the attitudes of physicians. The respondents were most positive in their support of the need for special training to treat diabetes, the team approach to diabetes care, and the relationship between glycemic control and the subsequent development of complications. The support for patient autonomy in the treatment of diabetes and for the seriousness of non-insulin-dependent diabetes mellitus (NIDDM) was less strong although still favorable.

Attitude of Health Personnel↗
PubMedDate not supplied

An assessment of computer use, knowledge, and attitudes of diabetes educators.

A questionnaire to survey attitudes, use, and knowledge of computers was sent to 816 randomly selected members of AADE to determine the degree to which currently available computer resources are used in diabetes education and to investigate the need for future computing resources designed to support diabetes education. Analysis of the data showed that even diabetes educators who use computers infrequently have a generally favorable attitude toward them. Highest use of computers is in noneducational applications, mostly for word processing and record keeping. Most respondents believe that computers have yet to make a major contribution to the teaching and learning process in diabetes education, and few felt adequately prepared for creative use or development of computer applications. Increasing the role of computers in support of patient education will require encouragement and demonstrations of computer efficacy from health care institutions and professional organizations.

Adult↗
PubMedDate not supplied

Perceived effectiveness, cost, and availability of patient education methods and materials.

To determine the efficacy of and need for patient education methods and media, a needs assessment was sent to 816 members of the American Association of Diabetes Educators. Respondents (n = 325, 40%) included 62% RNs, 36% RDs, 1% other; 62% CDEs. Their mean number of years experience in diabetes education was 8.5, and 99% routinely provided patient education. Respondents indicated that videotapes and slide tapes were the most educationally effective media and books and audiotapes were the least effective. Booklets and videotapes were the most cost-effective and computer-assisted instruction the least effective. While respondents perceived one-to-one counseling, skills training, and diabetes content sessions to be the three most educationally effective methods, support groups and large and small discussion groups were seen as the three most cost-effective educational methods. Among nine potential barriers to quality patient education listed, educators rated lack of third-party reimbursement as a major barrier most frequently and national availability of quality education materials as a barrier least frequently.

Computer-Assisted Instruction↗