Exposure Reconstruction for the TCDD-Exposed NIOSH Cohort Using a Concentration- and Age-Dependent Model of Elimination

Recent studies demonstrating a concentration dependence of elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suggest that previous estimates of exposure for occupationally exposed cohorts may have underestimated actual exposure, resulting in a potential overestimate of the carcinogenic potency of TCDD in humans based on the mortality data for these cohorts. Using a database on U.S. chemical manufacturing workers potentially exposed to TCDD compiled by the National Institute for Occupational Safety and Health (NIOSH), we evaluated the impact of using a concentration- and age-dependent elimination model (CADM) (Aylward et al., 2005) on estimates of serum lipid area under the curve (AUC) for the NIOSH cohort. These data were used previously by Steenland et al. (2001) in combination with a first-order elimination model with an 8.7-year half-life to estimate cumulative serum lipid concentration (equivalent to AUC) for these workers for use in cancer dose-response assessment. Serum lipid TCDD measurements taken in 1988 for a subset of the cohort were combined with the NIOSH job exposure matrix and work histories to estimate dose rates per unit of exposure score. We evaluated the effect of choices in regression model (regression on untransformed vs. ln-transformed data and inclusion of a nonzero regression intercept) as well as the impact of choices of elimination models and parameters on estimated AUCs for the cohort. Central estimates for dose rate parameters derived from the serum-sampled subcohort were applied with the elimination models to time-specific exposure scores for the entire cohort to generate AUC estimates for all cohort members. Use of the CADM resulted in improved model fits to the serum sampling data compared to the first-order models. Dose rates varied by a factor of 50 among different combinations of elimination model, parameter sets, and regression models. Use of a CADM results in increases of up to five-fold in AUC estimates for the more highly exposed members of the cohort compared to estimates obtained using the first-order model with 8.7-year half-life. This degree of variation in the AUC estimates for this cohort would affect substantially the cancer potency estimates derived from the mortality data from this cohort. Such variability and uncertainty in the reconstructed serum lipid AUC estimates for this cohort, depending on elimination model, parameter set, and regression model, have not been described previously and are critical components in evaluating the dose-response data from the occupationally exposed populations.     

Professional Perspectives on Decision Making about the Long-term Care of Older People

With the increasing pressure on social and health care resources,professionals have to be more explicit in their decision makingregarding the long-term care of older people. This groundedtheory study used 19 focus groups and nine semi-structured interviews(99 staff in total) to explore professional perspectives onthis decision making. Focus group participants and intervieweescomprised care managers, social workers, consultant geriatricians,general medical practitioners, community nurses, home care managers,occupational therapists and hospital discharge support staff.The emerging themes spanned context, clients, families and services.Decisions were often prompted by a crisis, hindering professionalsseeking to make a measured assessment. Fear of burglary andassault, and the willingness and availability of family to helpwere major factors in decisions about living at home. Serviceavailability in terms of public funding for community care,the availability of home care workers and workload pressureson primary care services influenced decision ‘thresholds’regarding admission to institutional care. Assessment toolsdesigned to assist decision making about the long-term careof older people need to take into account the critical aspectsof individual fears and motivation, family support and the availabilityof publicly funded services as well as functional and medicalneeds.     

Pathways between education and health: a causal modelling approach

Summary.  The association of poor education and poor health has been consistently observed in many studies and in various countries. Thus far, studies examining the mechanisms underlying this association have looked at only a limited set of potential pathways. This study simultaneously examines six distinctive pathways, which have been hypothesized to link education and health and found support from previous studies. A causal analysis of education and health was performed using structural equation models. Data were used from six phases of the National Child Development Study, which is based on following up an initial sample of 17416 children who were born in 1958. The association between education and health appears to be explained by a combination of mechanisms: adolescent health and adult health behaviours for men and women, adult social class among men and parental social class among women. We conclude that improvements in population educational attainment may not automatically lead to improvements in population health, and that health policies for improving health and reducing health inequalities need to target specific causal pathways.     

Sektion Jugendsoziologie Tätigkeitsbericht 2004

Ohne Zusammenfassung     

Happiness has traitlike and statelike properties: A reply to Veenhoven

Veenhoven (1994) contrasted hypotheses of whether happiness is a trait or state, concluding that it is a state variable. This article critiques the conceptual foundation of Veenhoven's paper, and examines technical deficiencies in his review of evidence. Based on previous findings and new analyses, we conclude that happiness has both traitlike and statelike properties, but that individual differences in happiness endure despite its situational reactivity, and explain greater variance than situational effects.     

Predicting Participation in Environmental Treaties: A World-System Analysis*

Which countries tend to sign international environmental treaties and why? This study tests the ability of quantitative cross-national political and economic analysis to predict participation in international environmental agreements over the period 1963–1987. Cross-sectional ordinary least squares regressions suggest that poor, highly indebted countries that are dependent on very few trading partners and that have repres-sive regimes are far more likely to be nonsignatories. The results suggest strategies for increasing the likelihood that nations will ratify hture environmental treaties.     

Exploring structure-effectiveness relationships in nonprofit arts organizations

The authors examined nineteen nonprofit performing arts organizations, investigating the distribution of influence among organizational members, the grouping of volunteers and staff in organizational structures, and the effectiveness of the organizations. The organizations' effectiveness was assessed using multiple performance indicators. The analysis revealed five groupings or configurations of influence, which correlated to the organizations exhibiting the highest and lowest levels of organizational effectiveness. The authors conclude that a variety of structures are associated with good performance but structural dysfunctions are associated with organizational failure, and that members' commitment to an organization's structure is an important element of success.     

On the derivation of a full life table from mortality data recorded in five-year age groups

Mortality data are often gathered using 5-year age groups rather than individual years of life. Furthermore, it is common practice to use a large open-ended interval (such as 85 and over) for mortality data at the older ages. These limitations of the data pose problems for the actuary or demographer who wishes to compile a full and accurate life table using individual years of life. The author devises formulae which handle these problems. He also devises methods for handling mortality during the 1st year of life and for dealing with other technical problems which arise in the compilation of the full life table from grouped data.     

Monitoring the education gap in Thailand: trends and differentials in lower and upper secondary schooling

"Using 1980 census and 1987 survey data on birth cohorts to examine recent primary and secondary school enrollment trends [in Thailand], this study reports that primary enrollment is nearly universal but secondary enrollment is much less prevalent. The study assesses several factors thought to influence enrollment and finds that urban residence, parents' completion of primary school, the mother's positive attitude toward education, and the family's being comfortable economically to be associated with children's enrollment in secondary school. It also indicates that, for moderately well-off families, proximity to schools has a major influence on secondary school attendance. For the wealthiest families, however, distance is not a hindrance to attendance, and for the poorest families, having a school nearby is not sufficient to ensure attendance."     

Africa's expanding population: old problems,new policies

Sub-Saharan Africa faces an historic challenge: to achieve economic and social progress while experiencing extraordinary population growth. With an estimated 1989 population of 512 million, the 42 countries of sub-Saharan Africa have the highest birth and death rates of any major world region. While death rates have fallen since the 1960s, persistently high birth rates yield annual growth rates above 3% in many countries. The United Nations projects that the region's population will increase 2.7 times by 2025--to 1.4 billion. Throughout the region, population has outstripped economic growth since the mid-1970s. In addition, many African countries are experiencing an epidemic of AIDS (Acquired Immunodeficiency Syndrome). The extent and demographic impact of the epidemic still are unknown, but disturbing social and political effects are already being felt. The region's population growth will slow only when African couples begin to have fewer children. The average number of children per woman ranges from 6 to 8 for most countries. The Africans' preference for large families is deeply rooted in the culture and fed by the perceived economic benefits they receive from their children. Economic stagnation during the 1980s prompted many national governments to recognize that rapid population growth was hindering their socioeconomic development. The political climate has shifted away from pronatalist or laissez-faire attitudes toward official policies to slow population growth. The policy formation process--detailed here for 4 countries (Zambia, Nigeria, Zaire, and Liberia)--is ponderous and beset with political and bureaucratic pitfalls, However, policy shifts in more and more countries combined with evidence of increased contraceptive use and fertility downturns in a few countries give some hope that the region's extraordinary population growth may have peaked and will start a descent. Whatever the case, the decade of the 1990s will be crucial for the future of sub-Saharan Africa.