Featured Articles Summer 2013

the information societyPregnancy as a Risk Factor for Ambulatory Limitation in Later Life
Abigail R. A. Aiken, Jacqueline L. Angel, and Toni P. Miles
American Journal of Public Health 102(12): 2330-2335, 2013
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Abstract: We investigated the relationship between the number of times a woman has been pregnant and walking difficulty in later life. With data from the Hispanic Established Populations for Epidemiologic Studies of the Elderly, a representative population-based cohort of Mexican Americans aged 65 years and older residing in 5 Southwestern states, we measured walking difficulty using 2 items from the performance-oriented mobility assessments: the timed walk and seated chair rise. We observed significantly higher rates of ambulatory limitation among women with 6 or more pregnancies than among women with 4 or fewer pregnancies: 44.9% and 27.0%, respectively, were unable to perform or performed poorly in the seated chair rise and timed walk. Ordinal logistic regression models show that gravidity predicts level of performance in both mobility tasks and that higher gravidity is associated with worse performance, even after adjustment for both age and chronic disease. Gravidity is a risk factor for ambulatory limitation in old age. A life course approach to reproduction in public health research and practice is warranted.

New Geographies of Water and Climate Change in Peru: Coupled Natural and Social Transformations in the Santa River Watershed

Jeffrey Bury, Bryan G. Mark, Mark Carey, Kenneth R. Young, Jeffrey M. McKenzie, Michel Baraer, Adam French, and Molly H. Polk
Annals of the Association of American Geographers 103(2): 363-374, 2013
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Abstract: Projections of future water shortages in the world's glaciated mountain ranges have grown increasingly dire. Although water modeling research has begun to examine changing environmental parameters, the inclusion of social scenarios has been very limited. Yet human water use and demand are vital for long-term adaptation, risk reduction, and resource allocation. Concerns about future water supplies are particularly pronounced on Peru's arid Pacific slope, where upstream glacier recession has been accompanied by rapid and water-intensive economic development. Models predict water shortages decades into the future, but conflicts have already arisen in Peru's Santa River watershed due to either real or perceived shortages. Modeled thresholds do not align well with historical realities and therefore suggest that a broader analysis of the combined natural and social drivers of change is needed to more effectively understand the hydrologic transformation taking place across the watershed. This article situates these new geographies of water and climate change in Peru within current global change research discussions to demonstrate how future coupled research models can inform broader scale questions of hydrologic change and water security across watersheds and regions. We provide a coupled historical analysis of glacier recession in the Cordillera Blanca, declining Santa River discharge, and alpine wetland contraction. We also examine various water withdrawal mechanisms, including smallholder agriculture, mining, potable water use, hydroelectric power generation, and coastal irrigation. We argue that both ecological change and societal forces will play vital roles in shaping the future of water resources and water governance in the region.

Temporary Help Work: Multiple Job-Holding and Compensating Differentials

Sarah Hamersma, Carolyn J. Heinrich, and Peter Mueser
Industrial Relations, 2013
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Abstract: Temporary Help Services (THS) employment has been growing in size, particularly among disadvantaged workers, and in importance in balancing cyclical fluctuations in labor demand. Does THS employment provide some benefits to disadvantaged workers, or divert them from better jobs? We investigate whether THS jobs pay a compensating differential, as would be expected for relatively undesirable jobs. We also address multiple job-holding, exploring whether workers get 'stuck' in THS jobs. We find lower quarterly earnings at THS jobs relative to others, but a $1 per hour wage premium. We reconcile these findings by examining hours worked at THS and traditional jobs. Tables, Figures, Appendixes, References.

American Education ResearchThe Efficacy of Private Sector Providers in Improving Public Educational Outcomes

Carolyn J. Heinrich and Hiren Nisar
American Educational Research Journal, 2013
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Abstract: School districts required under No Child Left Behind (NCLB) to provide supplemental educational services (SES) to students in schools that are not making adequate yearly progress rely heavily on the private sector to offer choice in services. If the market does not drive out ineffective providers, students may not gain through SES participation. We estimate SES provider effects on students’ math and reading achievement in an urban school district that accounts for a significant share of participating students. We expect this research to inform education policy on the viability of policy interventions employing a private market model to improve public sector outcomes, including the reauthorization of Title I and district tutoring interventions under NCLB and after federal waivers from NCLB.

DemographyProvider and patient influences on the formation of socioeconomic health behavior disparities among pregnant women
Elaine Hernandez
Social Science & Medicine 82: 35-42, 2013
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Abstract: Socially advantaged individuals are better positioned to benefit from advances in biomedicine, which frequently results in the emergence of social inequalities in health. I use survey and in-depth interviews with pregnant women and their health care providers from four Midwestern clinics in the United States, conducted in 2009 and 2010. I compare socioeconomic differences in intake of two new prenatal supplements: Vitamin D and omega-3 fatty acid. Although socioeconomic differences in omega-3 fatty acid supplementation emerged, there were no differences in the use of vitamin D. I argue that providers may have contributed to the prevention of a health disparity in vitamin D supplementation by implementing an aggressive uniform protocol. These results suggest that providers not only serve as a conduit for the dissemination of new biomedical information, the strength and uniformity of their recommendations have the potential to prevent or exacerbate socioeconomic differences in health behaviors.

Obesity and Mortality Risk over the Life Course

Ryan K. Masters, Daniel A. Powers, and Bruce Link
American Journal of Epidemiology 177(2):431-442, 2013
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Abstract: In this study, we analyzed age variation in the association between obesity status and US adult mortality risk. Previous studies have found that the association between obesity and mortality risk weakens with age. We argue that existing results were derived from biased estimates of the obesity-mortality relationship because models failed to account for confounding influences from respondents' ages at survey and/or cohort membership. We employed a series of Cox regression models in data from 19 cross-sectional, nationally representative waves of the US National Health Interview Survey (1986–2004), linked to the National Death Index through 2006, to examine age patterns in the obesity-mortality association between ages 25 and 100 years. Findings suggest that survey-based estimates of age patterns in the obesity-mortality relationship are significantly confounded by disparate cohort mortality and age-related survey selection bias. When these factors are accounted for in Cox survival models, the obesity-mortality relationship is estimated to grow stronger with age.

Demography Is the Sky Falling? Grade Inflation and the Signaling Power of Grades
Evangeleen Pattison, Eric Grodsky, and Chandra Muller
Educational Researcher, 2013
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Abstract: Grades are the fundamental currency of our educational system; they signal academic achievement and noncognitive skills to parents, employers, postsecondary gatekeepers, and students themselves. Grade inflation compromises the signaling value of grades and undermines their capacity to achieve the functions for which they are intended. We challenge the “increases in grade point average” definition of grade inflation and argue that grade inflation must be understood in terms of the signaling power of grades. Analyzing data from four nationally representative samples, we find that in the decades following 1972: (a) grades have risen at high schools and dropped at 4-year colleges, in general, and selective 4-year institutions, in particular; and (b) the signaling power of grades has attenuated little, if at all.

DemographyParadox Revisited: A Further Investigation of Racial/Ethnic Differences in Infant Mortality by Maternal Age
Daniel A. Powers
Demography 50(2):495-520, 2013
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Abstract: I reexamine the epidemiological paradox of lower overall infant mortality rates in the Mexican-origin population relative to U.S.-born non-Hispanic whites using the 1995-2002 U.S. NCHS linked cohort birth-infant death files. A comparison of infant mortality rates among U.S.-born non-Hispanic white and Mexican-origin mothers by maternal age reveals an infant survival advantage at younger maternal ages when compared with non-Hispanic whites, which is consistent with the Hispanic infant mortality paradox. However, this is accompanied by higher infant mortality at older ages for Mexican-origin women, which is consistent with the weathering framework. These patterns vary by nativity of the mother and do not change when rates are adjusted for risk factors. The relative infant survival disadvantage among Mexican-origin infants born to older mothers may be attributed to differences in the socioeconomic attributes of U.S.-born non-Hispanic white and Mexican-origin women.

DemographyMarital Processes around Depression: A Gendered Perspective
Mieke Thomeer, Tetyana Pudrovska, and Debra Umberson
Society and Mental Health, 2013
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Abstract: Despite extensive evidence of the importance of marriage and marital processes for mental health, little is known about the interpersonal processes around depression within marriage and the extent to which these processes are gendered. We use a mixed-methods approach to explore the importance of gender in shaping processes around depression within marriage. We approach this in two ways: First, using quantitative longitudinal analysis of 2,601 couples from the Health and Retirement Study (HRS), we address whether depressive symptoms in one spouse shape the other spouse’s depressive symptoms and whether men or women are more influential in this process. We find that a wife’s depressive symptoms influence her husband’s future depressive symptoms, but a husband’s depressive symptoms do not influence his wife’s future symptoms. Second, we conduct a qualitative analysis of in-depth interviews with 29 couples wherein one or both spouses experienced depression to provide additional insight into how gender impacts depression and reactions to depression within marriage. Our study points to the importance of cultural scripts of masculinity and femininity in shaping depression and emotional processes within marriage and highlights the importance of applying a gendered couple-level approach to better understand the mental health effects of marital processes.

DemographyHow Job Characteristics Affect International Migration:The Role of Informality in Mexico
Andres Villarreal and Sarah Blanchard
Demography 50(2):751-775, 2013
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Abstract: Despite the importance given to employment opportunities as a primary motive for migration, previous studies have paid insufficient attention to the kinds of jobs that are more likely to retain workers in their countries of origin. We use information from a panel survey of Mexican adults to examine how job characteristics affect the risk of international migration. The sampling strategy and overall size of the survey allow us to analyze the effect of employment characteristics on migration from urban areas, which have much greater labor market diversity, and to separate our analysis by gender. We also distinguish migrants according to whether they migrate for work or for other reasons. We find informality to be a significant predictor of international migration. Even after controlling for individual factors including workers’ wages, as well as various household- and community-level predictors, we find that workers employed in the informal sector have significantly higher odds of migrating than their counterparts in the formal sector. The pervasive nature of informality in many developing countries from which a high proportion of international migrants originate may therefore create a constant supply of workers who are predisposed to migrate. Our findings thus have important implications for a proper understanding of the effects of economic development on migration.

Cover image for Vol. 21 Issue S1Extending the History of Child Obesity in the United States:The Fels Longitudinal Study, Birth Years 1930 to 1993

Paul T. von Hippel and Ramzi W. Nahhas
Obesity, 2013
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Abstract: Objective: Little is known about the prevalence of child obesity in the U.S. before the first national survey in 1963. There is disagreement about whether the obesity epidemic is entirely a recent phenomenon or a continuation of longstanding trends. Methods: We analyze the BMIs of 1,116 children who participated in the Fels Longitudinal Study near Dayton, Ohio. Children were born between 1930 and 1993 and measured between 3 and 18 years of age. Results: Between the birth cohorts of 1930 and 1993, the prevalence of obesity rose from 0% to 14% among boys and from 2% to 12% among girls. The prevalence of overweight rose from 10% to 28% among boys and from 9% to 21% among girls. The mean BMI Z-score rose from +0.25 to +0.72 among boys and from -0.11 to +0.26 among girls. Among boys, all these increases began after birth year 1970. Among girls, obesity began to rise after birth year 1970, but overweight and BMI Z-scores were already rising as early as the 1930s and 1940s. Conclusions: Most of the results suggest that the child obesity epidemic was recent and sudden. The recency of the epidemic offers some hope that it may be reversed.

Child DevelopmentSample Size Limits for Estimating Upper Level Mediation Models Using Multilevel SEM
Xin Lia and S. Natasha Beretvas
Structural Equation Modeling: A Multidisciplinary Journal 20(2): 241-264, 2013
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Abstract: This simulation study investigated use of the multilevel structural equation model (MLSEM) for handling measurement error in both mediator and outcome variables (M and Y) in an upper level multilevel mediation model. Mediation and outcome variable indicators were generated with measurement error. Parameter and standard error bias, confidence interval coverage, and power to detect the ab mediated effect using Empirical-M confidence interval estimates were assessed for the correct MLSEM versus a conventional multilevel model (MM) that used composite scores for M and Y. The following conditions were manipulated: level 1 and 2 sample sizes, intraclass correlation, degree of measurement error in M, and the true value of ab. The MLSEM more accurately recovered the ab effect's value, but serious convergence issues were encountered with MLSEM estimates based on fewer than 80 clusters. More power for detecting a nonzero ab was found for MM than for MLSEM estimates.

Child DevelopmentAn Implicit Theories of Personality Intervention Reduces Adolescent Aggression in Response to Victimization and Exclusion
David S. Yeager, Adriana S. Miu, Joseph Powers, and Carol S. Dweck
Child Develpment, 2013
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Past research has shown that hostile schemas and adverse experiences predict the hostile attributional bias.This research proposes that seemingly nonhostile beliefs (implicit theories about the malleability of personality) may also play a role in shaping it. Study 1 meta-analytically summarized 11 original tests of this hypothesis (N = 1,659), and showed that among diverse adolescents aged 13–16 a fixed or entity theory about personality traits predicted greater hostile attributional biases, which mediated an effect on aggressive desires. Study 2 experimentally changed adolescents’ implicit theories toward a malleable or incremental view and showed a reduction in hostile intent attributions. Study 3 delivered an incremental theory intervention that reduced hostile intent attributions and aggressive desires over an 8-month period.

Child DevelopmentMarital Status, Self-Rated Health, and Mortality: Overestimation of Health or Diminishing Protection of Marriage?
Hui Zheng and Patricia A. Thomas
Journal of Health and Social Behavior 54(1): 128-143, 2013
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Abstract: This study challenges two well-established associations in medical sociology: the beneficial effect of marriage on health and the predictive power of self-rated health on mortality. Using The National Health Interview Survey 1986-2004 with 1986-2006 mortality follow-up (789,096 respondents with 24,095 deaths) and Cox Proportional Hazards Models, we find the protective effect of marriage against mortality decreases with deteriorating health so that the married and unmarried in poor health are at similar risk for death. We also find the power of self-rated health to predict mortality is higher for the married than for any unmarried group. By using ordered logistic regression models, we find thresholds shift such that, compared to the unmarried, the married may not report poorer health until developing more severe health problems. These findings suggest the married tend to overestimate their health status. These two phenomena (diminishing protection and overestimation) contribute to but do not completely explain each other