Obtaining cancer risk factor prevalence estimates in small areas: combining data from two surveys

Summary.  Cancer surveillance research requires accurate estimates of risk factors at the small area level. These risk factors are often obtained from surveys such as the National Health Interview Survey (NHIS) or the Behavioral Risk Factors Surveillance System (BRFSS). The NHIS is a nationally representative, face-to-face survey with a high response rate; however, it cannot produce state or substate estimates of risk factor prevalence because the sample sizes are too small and small area identifiers are unavailable to the public. The BRFSS is a state level telephone survey that excludes non-telephone households and has a lower response rate, but it does provide reasonable sample sizes in all states and many counties and has publicly available small area identifiers (counties). We propose a novel extension of dual-frame estimation using propensity scores that allows the complementary strengths of each survey to compensate for the weakness of the other. We apply this method to obtain 1999–2000 county level estimates of adult male smoking prevalence and mammogram usage rates among females who were 40 years old and older. We consider evidence that these NHIS-adjusted estimates reduce the effects of selection bias and non-telephone coverage in the BRFSS. Data from the Current Population Survey Tobacco Use Supplement are also used to evaluate the performance of this approach. A hybrid estimator that selects one of the two estimators on the basis of the mean-square error is also considered.     

Issues Related to Time Averaging of Exposure in Modeling Risks Associated with Intermittent Exposures to Lead

Typical exposures to lead often involve a mix of long-term exposures to relatively constant exposure levels (e.g., residential yard soil and indoor dust) and highly intermittent exposures at other locations (e.g., seasonal recreational visits to a park). These types of exposures can be expected to result in blood lead concentrations that vary on a temporal scale with the intermittent exposure pattern. Prediction of short-term (or seasonal) blood lead concentrations arising from highly variable intermittent exposures requires a model that can reliably simulate lead exposures and biokinetics on a temporal scale that matches that of the exposure events of interest. If exposure model averaging times (EMATs) of the model exceed the shortest exposure duration that characterizes the intermittent exposure, uncertainties will be introduced into risk estimates because the exposure concentration used as input to the model must be time averaged to account for the intermittent nature of the exposure. We have used simulation as a means of determining the potential magnitude of these uncertainties. Simulations using models having various EMATs have allowed exploration of the strengths and weaknesses of various approaches to time averaging of exposures and impact on risk estimates associated with intermittent exposures to lead in soil. The International Commission of Radiological Protection (ICRP) model of lead pharmacokinetics in humans simulates lead intakes that can vary in intensity over time spans as small as one day, allowing for the simulation of intermittent exposures to lead as a series of discrete daily exposure events. The ICRP model was used to compare the outcomes (blood lead concentration) of various time-averaging adjustments for approximating the time-averaged intake of lead associated with various intermittent exposure patterns. Results of these analyses suggest that standard approaches to time averaging (e.g., U.S. EPA) that estimate the long-term daily exposure concentration can, in some cases, result in substantial underprediction of short-term variations in blood lead concentrations when used in models that operate with EMATs exceeding the shortest exposure duration that characterizes the intermittent exposure. Alternative time-averaging approaches recommended for use in lead risk assessment more reliably predict short-term periodic (e.g., seasonal) elevations in blood lead concentration that might result from intermittent exposures. In general, risk estimates will be improved by simulation on shorter time scales that more closely approximate the actual temporal dynamics of the exposure.     

Mentors for adolescents in foster care

Significant numbers of adolescents in foster placement plan to live independently following discharge. Mentoring is increasingly being used as a support service to assist older foster youths to make the transition to adult living. A survey of 29 child welfare programs indicate that a variety of mentoring models are in use. The main models are transitional Life Skills Mentors, Cultural-Empowerment Mentors, and Corporate-Business Mentors. Mentoring connects foster wards with a cross-section of community citizens who provide a bridge to higher education and employment, and serve as a resource for transitional problem-solving. Information is needed on the impacts of mentor-mentee matches and efforts to sustain mentor-mentee relationships.Based on a paper presented at the Second National Child Welfare Conference, Division of Child Welfare Research, Arlington, Virginia, 1994. The research is supported by Research Grant #90CW1026 entitled Mentors as Resources for Preparing Foster Youths for Independent Living, from the Department of Health and Human Services, Administration for Children and Families, Washington, D.C.the Principal Investigator, Foster Youth Project and Adolescent Mentor Project.     

SOCIAL STRESS AND MENTAL HEALTH IN THE SOUTHERN BLACK BELT

Black Belt counties in the southeastern United States are among the very poorest of all. Much of the economic, political, and social landscape of the region still echoes the problems of its antebellum past. Black white relations in the region are still characterized by antagonisms at all levels of social life. In this study, I examine the impact of social and material conditions of the Black Belt on mental health. I use data from a sample of Black and White workers in North Carolina, a state that re ects many of the racial dynamics found across the Southeast. Findings show that racial patterns in psychological distress are associated with the strength of political and economic elites in the Black Belt who have historically maintained power through racial subjugation. In conclusion, I discuss the theoretical implications of the findings.