The rapid increase in human longevity has raised important questions about what implications this development may have for the variability of age at death. Earlier studies have reported evidence of a historical trend towards mortality compression. However, the period life table model, commonly used to address mortality compression, produces a compressed picture of mortality as a built-in feature of the model. To overcome this limitation, we base our study on an examination of the durations of exposure, in years of age, of birth cohorts and period life tables to selected short ranges of the death rate observed at old age. Overall, old-age mortality has been decompressing, cohort-wise, since the 1960s. This process may further indicate good prospects for ever-decreasing mortality. In the future, deaths may not be concentrated within a narrow age interval, but will instead become more dispersed, though at ever later ages on average.

Two vital American social institutions, education and health care, are intimately related. The individual-level relationship between education and health is tenuous, changing over time, throughout the life course, and across generations. Previous research in this area does not separate the mediating effects of age, period, and cohort or assess the unique effects of various levels of educational attainment on health. Using longitudinal data from the Panel Study of Income Dynamics, this dissertation untangles these factors to find that education has become a more important predictor of health now than twenty years ago, education benefits health across the life course, and college education is necessary for good health in recent generations whereas high school education was a more important predictor of health in earlier generations. From a theoretical standpoint, this study illustrates the need for a more prominent theory to explain the changing nature of the education and health relationship. Methodologically, results suggest that longitudinal analysis is a superior technique to cross-sectional analysis, as the effects of education on health are suppressed in cross-sectional analyses. From a policy standpoint, findings indicate that one viable solution to decreasing health disparities is improved access to education, rather than improved access to physicians, which is the dominant solution in today’s society.

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For many years, nationwide, approximately one third of American high school students have not been graduating from high school. The dropout rate is one of the reasons cited for the implementation of the No Child Left Behind legislation, which highlighted the severity of the dropout problem and the imposing priorities and standards placed on school districts. Mississippi leads the nation in the rate of students who drop out of high school. The purpose of this study was to examine the factors that contribute to the dropout epidemic in secondary schools in the Jackson (Mississippi) Public School District where annually a high percentage of students, particularly African Americans, fail to graduate with their Grade 9 cohorts. This study used a descriptive and causal-comparative research design to identify the contributing factors to secondary school dropouts among 80 students enrolled in the Career Academic Placement (CAP) program in the Jackson Public School District. The Jackson Public Schools Dropout (JPSD) Questionnaire was utilized for the study. Differences in the students’ responses were examined using a Mann-Whitney U and Kruskal-Wallis analysis of variance (ANOVA). Findings in this study indicated that the number one factor that led students to decide to drop out of school was feeling that they were behind, or failing course work. This affected about 55% of the students, causing them to leave school early. Additional results revealed 15% of the respondents who dropped out were Grade 9 students, and approximately 15% of the respondents who dropped out were Grade 12 students. Approximately 42.5% of the students comprised 10th graders and 27.5% were 11th graders.

Yes / Understanding what influences changes over time in caregiver well-being is important for the development of effective support. This study explores differences in trajectories of caregiver stress and positive aspects of caregiving (PAC). Methods Caregivers of community-dwelling individuals with mild-to-moderate dementia at baseline from the IDEAL cohort were interviewed at baseline (n = 1,203), 12 months (n = 917), and 24 months (n = 699). Growth mixture models identified multiple growth trajectories of caregiver stress and PAC in the caregiver population. Associations between study measures and trajectory classes were examined using multinomial logistic regression and mixed-effects models. Results Mean stress scores increased over time. A 4-class solution was identified: a “high” stable class (8.3%) with high levels of stress, a “middle” class (46.1%) with slightly increasing levels of stress, a “low” class (39.5%) with initial low levels of stress which slightly increased over time, and a small “increasing” class (6.1%) where stress level started low but increased at a steeper rate. Mean PAC scores remained stable over time. A 5-class solution was identified: 3 stable classes (“high,” 15.2%; “middle,” 67.6%; “low” 9.3%), a small “increasing” (3.4%) class, and 1 “decreasing” class (4.5%). For stable classes, positive ratings on study measures tended to be associated with lower stress or higher PAC trajectories and vice versa. Those with “increasing” stress also had worsening trajectories of several study measures including depression, relationship quality, competence, and ability to cope. Discussion The findings highlight the importance of identifying caregivers at risk of increased stress and declining PAC and offering them targeted support.

From a theoretical point of view, competition for the educational resources at the family and the population levels may change as the demographic transition advances. Although family size started to decline in the mid-1960s in México, the reduction in the size of the cohorts that compete for educational resources has recently occurred and it is an ongoing process in most municipalities of the country. Therefore, the main goal of this study was to examine the relationship between teenagers’ education and the demographic transition in México. The study explored if the teenagers’ school enrollment, age-grade delay at school and lower-secondary school attainment were linked to the teenagers’ number of siblings, as well as their cohort size in the municipality of residence in 2000. The 10% sample of the Mexican Housing and Population Census of 2000 was used as the main source of information. The study employed multivariate logistic regression models to accomplish its goals. Interactions between number of siblings and cohort size were tested. Also, interactions between these indicators and the teenagers’ gender and socioeconomic status were assessed respectively. The results indicated that contextual factors explained the initial negative association between teenagers’ education and cohort size, since this association disappeared or became small and positive after the addition of covariates. The Mexican educational system seems to have had the capacity of absorbing the demands in school coverage of the growing teenage population. The study revealed, however, that there was a large and negative association between teenagers’ education and number of siblings. Moreover, the study showed that the odds of the educational outcomes generally experienced larger changes by each additional sibling in the places where the demographic transition is more advanced, as well as among females and among the teenagers with high socioeconomic status. These results suggest that the educational disadvantages associated with multiple siblings may become more pronounced in the future and within certain contexts, as the demographic transition continues and big families become a smaller proportion of Mexican families. / text

Background: Recently, some US cohorts have shown a moderate association between red and processed meat consumption and mortality supporting the results of previous studies among vegetarians. The aim of this study was to examine the association of red meat, processed meat, and poultry consumption with the risk of early death in the European Prospective Investigation into Cancer and Nutrition (EPIC). Methods: Included in the analysis were 448,568 men and women without prevalent cancer, stroke, or myocardial infarction, and with complete information on diet, smoking, physical activity and body mass index, who were between 35 and 69 years old at baseline. Cox proportional hazards regression was used to examine the association of meat consumption with all-cause and cause-specific mortality. Results: As of June 2009, 26,344 deaths were observed. After multivariate adjustment, a high consumption of red meat was related to higher all-cause mortality (hazard ratio (HR) = 1.14, 95% confidence interval (CI) 1.01 to 1.28, 160+ versus 10 to 19.9 g/day), and the association was stronger for processed meat (HR = 1.44, 95% CI 1.24 to 1.66, 160+ versus 10 to 19.9 g/day). After correction for measurement error, higher all-cause mortality remained significant only for processed meat (HR = 1.18, 95% CI 1.11 to 1.25, per 50 g/d). We estimated that 3.3% (95% CI 1.5% to 5.0%) of deaths could be prevented if all participants had a processed meat consumption of less than 20 g/day. Significant associations with processed meat intake were observed for cardiovascular diseases, cancer, and 'other causes of death'. The consumption of poultry was not related to all-cause mortality. Conclusions: The results of our analysis support a moderate positive association between processed meat consumption and mortality, in particular due to cardiovascular diseases, but also to cancer.

A growing body of literature has elaborated the life-course and cohort patterns in the relationships between social factors and depression in Western societies. Nonetheless, far less research has focused on whether inequalities in social status have caused the inequality in misery over the life course in Eastern societies such as Taiwan, which is a collectivist society that has undergone tremendous social change. This research examines the life-course depression trajectories, with taking cohort variations into consideration, and assesses the multidimensional effects of education on depression in a network perspective. This study is based on the nationally representative samples from the repeated cross-sectional Taiwan Social Change Survey and from the longitudinal Survey of Health and Living Status of the Middle Aged and Elderly in Taiwan. Results reveal a U-shaped aging trajectory in depression: depression declines in early adulthood, bottoms out in middle age, and then rises again in late life. This trajectory is the composite outcome established by factors associated with historical trends in education, differential survivals, life stages, health decline, and maturity. Moreover, the direction of the trajectory depends on education. For the well-educated Taiwanese, depression decreases from early adulthood to middle life and maintains relatively stable in old age. For the less educated, depression increases steeply over the life course. Taken together, the education-based disparity increases with age and the pattern even strengthens across more recent cohorts, consistent with respectively the cumulative advantage theory and the rising importance theory. Although late-life convergence is found in cross-sectional analyses, aging vector analyses with FIML estimation and Gompertz survival analysis suggest that selective mortality is the plausible reason. Meanwhile, education is not the only root cause of psychological well-being in Taiwan. Social relationships factors--such as children’s education, co-residence, social support, and familial negative interaction--also demonstrate substantial influence on depression, but mediate educational effects slightly. However, in the aging vector analyses, education is the resource that consistently displays negative coefficients with respect to the slope of depression. Consistent with the resource substitution theory, educational effects are greater for those in disadvantageous statuses. Therefore, increased education is the most specific resource that suppresses the progression of depression over the life course and under difficult times. / text

This thesis presents a series of longitudinal studies of HIV-outcomes in Australia and the Asia-Pacific region since highly active antiretroviral therapy (HAART) became available. The primary source of data is the Australian HIV Observational Database (AHOD). AHOD is an observational cohort of more than 2000 patients with HIV recruited via hospitals, sexual health centres and general medical practices specialising in HIV medicine. Chapter five of this thesis addresses whether there were any differences in antiretroviral therapy use and virological response that might explain the different trends in new HIV diagnosis rates between state jurisdictions in Australia in recent years. Analysis of data from cohort studies of primary and chronic HIV infection, gay community surveys and national prescription data suggest that, for the most part, antiretroviral therapy use and virological response were similar in each jurisdiction during the first decade of HAART. Chapter six describes the prevalence of, and risk factors for, an incomplete immune response despite sustained viral suppression in patients on HAART in AHOD. The clinical relevance of this phenomenon is also explored in terms of AIDS and death during follow-up. Of those with sustained viral suppression, one third of patients did not achieve immune recovery greater than 350 cells/??l in the 12-24 months after starting their first or second HAART regimen, and this was associated with a lower CD4 cell count at baseline. Chapter seven describes cause-specific mortality in patients with HIV in the Asia-Pacific region. Immunodeficiency was associated with non-AIDS and AIDS mortality, and the risk of non-AIDS mortality increased with age. Less conclusive was the relationship between country-income level and risk of death from AIDS or non-AIDS causes because of the relatively high proportion of unknown causes of death in low-income settings. Chapter eight presents hospitalisation rates, risk factors and associated diagnoses in patients with HIV in Australia. Older, sicker individuals, as indicated by markers of advanced immunodeficiency or frequency of hospitalisation, were at greater risk of hospitalisation and death in the AHOD cohort. Despite effective antiretroviral therapy, patients with HIV are currently hospitalised at higher rates than people of similar age in the general population.

Thesis (Ph.D.) - Carleton University, 2005. / Includes bibliographical references (p. 128-139). Also available in electronic format on the Internet.