Reducing Conservatism in Risk Estimation for Mixtures of Carcinogens

The excess cancer risk that might result from exposure to a mixture of chemical carcinogens usually must be estimated using data from experiments conducted with individual chemicals. In estimating such risk, it is commonly assumed that the total risk due to the mixture is the sum of the risks of the individual components, provided that the risks associated with individual chemicals at levels present in the mixture are low. This assumption, while itself not necessarily conservative, has led to the conservative practice of summing individual upper-bound risk estimates in order to obtain an upper bound on the total excess cancer risk for a mixture. Less conservative procedures are described here and are illustrated for the case of a mixture of four carcinogens.     

Mortality Risks Induced by Economic Expenditures

Existing evidence shows that lower incomes are associated with higher mortality risks. This paper examines the implications for fatalities when the relationship is interpreted as an induced relationship, meaning that lower incomes will on average lead to higher mortality risks. A model is developed for estimating the number of fatalities possibly induced by economic expenditures. This model accounts for different allocations of the expenditures on family units with varying income levels. Illustrative calculations provide insights about the possible significance of fatalities induced by economic expenditures. These results suggest that some expensive regulations and programs intended to save lives may actually lead to increased fatalities. Important caveats to reduce the likelihood of misinterpreting or misusing the results are included.     

Fitting the Two-Stage Clonal Expansion Model Based on Exact Hazard to the ED01 Data Using SAS NLIN

The two-stage clonal expansion model is a popular model for carcinogenesis data. One common form of this model is based on the approximate hazard function. In certain situations, this formulation is not appropriate, and the exact hazard should be applied. However, the difficulty of implementing the model based on the exact hazard has deterred many from using it. This paper presents a program implementing the exact hazard model for piecewise constant dosing using SAS, a package that is readily available to most that are interested in this type of analysis. Also, an analysis of the ED₀₁ data is presented using this program, and comparisons are made to an earlier analysis based on the approximate hazard. By allowing for an independent background tumor mechanism, an excellent fit to the bladder tumor incidence data was obtained.     

The College Mental Health Center: A Report After Ten Years

Abstract

The College Center is a unique mental health facility providing care for thousands of students from many colleges in the Greater Boston area. The authors report on data collected during the 1975–76, 1976–77 school years regarding patient variables such as: gender, year in school, academic major, presenting problem, and others. The center's handling of these patients is reported in terms of diagnoses, treatment recommendations, and numbers of visits. Several commonly held staff assumptions and hypotheses are tested, and from the data available in this study, are not generally confirmed. The impressions, however, of a more recent decrease in antisocial acting out behavior and drug abuse (other than alcohol) and an increase in patients presenting with more classical neurotic and adjustment symptoms are confirmed.     

Medicine and Social Work: An Exploration in Interprofessionalism,Edited by Helen Rehr. Neal Watson Academic Publications,New York, 1974. $3.95 Paper

This article presents the results of focus groups conducted with participants following the completion of a Child Welfare Practice Certificate Program. Concept mapping was used as the guiding research method for the data collection and analysis. Social work students and child welfare workers generated statements during the focus group session that were then sorted into conceptual piles. Participants then rated the statements as to their importance and practicality and their interest in learning about them. Results revealed that the concept Reporting, Assessment, and Case Planning in the Real World was rated highest in all three categories. Recommendations are provided regarding infusing a child welfare curriculum into social work programs, and the authors discuss how concept mapping can be used in evaluation research.     

Evaluation of school‐based AIDS education curricula in San Francisco

Students in 3 middle (n=385) and 3 high schools (n=254) in the San Francisco Unified School District participated in the evaluation of an AIDS education curriculum. Classes within‐schools were designated as either intervention classes or nonintervention classes. Students in intervention classes received 3 class periods of AIDS instruction with a newly developed curriculum. Students in nonintervention classes did not receive any special AIDS instruction. All students completed a pretest and posttest AIDS knowledge and attitude survey. The results indicated that AIDS instruction classes demonstrated a significant knowledge‐advantage, as well as change in attitudes (e.g., reflecting greater tolerance for attending class with students who may have AIDS or HIV infection).