Browsing by Author "Cook, Philip J"

This dissertation encompasses three essays which examine the development of obesity in black and white girls and its responses to interventions.

The first chapter asks the question, how does obesity develop in girls? Using the National Growth and Health Study (NGHS), a longitudinal study of 2400 girls from age 9 to age 18, this chapter aims to address gaps in knowledge about the development and persistence of obesity in girls. Analyses using multivariate regression and growth-mixture modeling describe trajectories of body mass change in children and their correlates. Results suggest that obesity in children begins early and persists in most cases--BMI at age 17 is, on average, 1.3 times BMI at age 9. However, change does occur; 0.8 percent of the sample move from being obese at age 9 to healthy weight at age 17, and 2.2 percent of the sample make the reverse journey from healthy weight to obese. Where change occurs, it is most commonly seen among those who socio-demographically were anomalies among their body mass cohort at age 9. These results emphasize the importance of early interventions as well as the need for more study into body mass mutability in population subsamples.

The second chapter investigates 1) what motivates children to pursue weight loss; and 2) what aspects of interventions may most effectively support healthy child motivations and program success. These questions are qualitatively studied among a sample of 45 obese girls aged 9 to 13 girls participating in a behavior modification intervention. In total, 106 interviews were conducted. All of the girls in the study were interested in losing weight, most commonly in order to fit in (n=11), reduce teasing (n=10), or express particular social identities (n=6). However, not all of the girls were able to translate this desire to lose weight into a healthy and effective lifestyle change motivation. Several factors were associated with adopting healthy motivation and behavior, including familial involvement, self-regulation skills, non-social weight desires, realistic weight loss goals, and clear messages about body ideals. Other program protocols also supported motivation during difficult periods for those who adopted healthy motivation, including nutrition information, incentives, lack of physician judgment, and patient autonomy. Finally, two other potential program protocols were mentioned by girls in the study as useful aids. More support services, particularly during the summer, and more information on the expected course of weight loss could, these girls argued, help sustain motivation. Together, these findings suggest a role for self-regulation theory in the design of lifestyle change motivation and for more directly addressing expectations in weight loss treatment.

The third chapter investigates the relationship between self-worth and obesity among girls, again using the National Growth and Health Study. Results indicate a negative relationship between self-worth and obesity across all participants. However, this relationship only has predictive power from early body mass to later self-worth and self-worth trajectories. That is, higher body mass at age 9 predicts lower self-worth at age 17 and decreases in self-worth from age 9 to age 17. The effect is larger for Caucasians and for those in young adolescence but persists across the sample. Mechanisms for this relationship are also investigated, and some support found for stigma. Analyses using self-worth components suggest most of the self-worth effects are driven by social concerns, while mediational analyses suggest social body image pressures explain the relationship between global self-worth and body mass. Overall, the findings suggest a complex interrelation between self-worth and body mass in girls, meriting further investigation as well as a more nuanced discussion in the public realm.

This dissertation consists of two original empirical studies on the determinants of teenage childbearing in the United States. The first study examines the impact of educational attainment on teenage childbearing, using school entry laws as an instrument for education and a highly detailed North Carolina administrative dataset that links birth certificate data to school administrative records. I show that being born after the school entry cutoff date affects educational success in offsetting ways, with a negative impact on years of education but positive impact on test scores. Using an IV regression strategy to distinguish the impacts of years of education and test scores, I show that both educational measures have negative impacts on teenage childbearing.

The second study examines potential causes of the decline in the U.S. teenage birth rate between 1991 and 2010. Using age-period-cohort models with Vital Statistics birth data and Census population counts, I show that the decline was driven by period changes in the early 1990s but by cohort changes between the mid-1990s and mid-2000s. I also use a difference-in-differences model to investigate the extent to which social policies in the 1970s-1980s can explain these cohort changes. The evidence suggests that while legalization of abortion for adult women and unilateral divorce laws had a significant impact on teenage birth rates in the 1990s-2000s, abortion legalization is unlikely to be a major explanation for the observed decline.

Population aging is a global phenomenon occurring both in developed and less developed countries. While families are still playing an important role in providing support for elderly people, governments are also expanding their public old-age support programs in many societies. Public pensions are one of the major policy tools geared to social protection of the elderly. However, little is known about how the programs affect elders particularly in terms of their subjective well-being. Such effectiveness depends in part on the extent to which public pension income displaces or `crowds out' family elder support. Using the introduction of the Basic Old-Age Pension (BOAP), a non-contributory old-age pension in Korea, this dissertation examines the relationship among public support, family support, and life satisfaction of the elderly.

As an introductory chapter, chapter 1, "The continuing importance of children in relieving elder poverty: evidence from Korea," describes the actual financial status of elderly Koreans and the amount of financial support they receive from children. Analysis of the 2006 Korean Longitudinal Study of Ageing shows that almost 70 per cent of Koreans aged 65 or more years received financial transfers from children and that the transfers accounted for about a quarter of the average elder's income. While over 60 per cent of elders would be poor without private transfers, children's transfers substantially mitigate elder poverty, filling about one quarter of the poverty gap. Furthermore, children's transfers to low-income parents tend to be proportionally larger, so elder income inequality is reduced by the transfers. Over 40 per cent of elders lived with a child and co-residence helps reduce elder poverty.

Using the introduction of BOAP, chapter 2, "Does money buy happiness?: Evidence from a new government pension in Korea," assesses how the program affected elders' life satisfaction. Notably, this study adds valuable evidence to the literature of whether money buys happiness, a question of great interest but notoriously difficult to answer given the difficulties associated with isolating income as a causal factor. To make the causal inference, this chapter utilizes a difference-in-difference research design and analyzes longitudinal data from the Korean Retirement and Income Study (KReIS). Results show that BOAP did raise elders' life satisfaction: annual benefits of 1,000 kW, approximately 1,000 U.S. dollars, raised elders' life satisfaction by 0.16-0.22 of one standard deviation and the effect was statistically significant.

Chapter 3, "Public support crowds out family support: Evidence from a new government pension in Korea," investigates how public financial provision affects family support. In particular, the present study provides a novel estimate of crowd-out by BOAP by using a combined measure of financial support and in-kind support received from all adult children regardless of their co-residence status with elderly parents. This paper also examines the impact on co-residence and is the first quasi-experimental study on the crowd-out question using data from an Asian nation. Results from difference-in-difference analyses of the KReIS data show that every $1 from the pension led to a 30-cent drop in children's support, netting a 70-cent increase in elders' income. The impact on the likelihood of elders' co-residing with children was positive but not statistically significant.

By showing that Korean children still play a crucial role in providing financial old-age security, chapter 1 demonstrates how important it is for the Korean government to design old-age policies that preserve the incentives for private assistance. The second chapter suggests that, at least in the context of modern-day Korea, pensions do buy happiness, or at least satisfaction. This finding suggests that researchers and policymakers need to pay further attention to public pensions as a tool to intervene people's subjective well-being. Finally, chapter 3 confirms that crowd-out of family support does occur in Korea and that increases in income, more so than other factors, have a positive impact on elders' life satisfaction found in chapter 2. These findings may generalize to other rapidly changing societies with a strong family elder-support tradition and emerging public elder-support system.