THE IMPACTS OF PUBLIC POLICIES ON HEALTH-RELATED OUTCOMES

This dissertation consists of three chapters that study how public policies affect health-related outcomes in China. The first two papers examine the impacts of the country’s Critical Illness Insurance program on health-related outcomes. The third paper studies the effects of maternal education on children’s early childhood health outcomes and cognitive skills. The first chapter evaluates the impact of a recent social health insurance benefits expansion program on middle-aged and elderly individuals. In 2012, China launched a Critical Illness Insurance (CII) program, which aimed to reduce out-of-pocket costs for individuals covered by the government’s health insurance programs. This chapter utilizes the staggered timing of CII adoption across cities to estimate the impact of CII on medical costs and health services for middle-aged and elderly individuals. For rural insured people, I find that CII had a negligible impact on the likelihood of using inpatient care but decreased out-of-pocket inpatient costs by 45% for those who did receive inpatient care. The reductions are largest for individuals over 60 years old, those who live in poor households, and enrollees with chronic illnesses. I do not find evidence of similar effects on urban insured residents’ inpatient and outpatient expenditures or utilization, which is expected since the urban insured are less affected by the CII program, given the higher pre-existing benefits in the urban insurance program. The second chapter examines the impact of CII on health outcomes, health service utilization, and risky health behaviors. I explore the staggered timing of CII adoption across the cities and utilize generalized difference-in-differences and event-study models to provide the first estimates of CII’s health and behavioral impacts. Using a nationally representative longitudinal dataset, I show that CII has little effect on self-reported health, probability of getting diagnosed with any disease, inpatient care use, smoking and drinking behaviors, and BMI. These results suggest that the income effect from CII reducing out-of-pocket inpatient costs for middle-aged and elderly adults, as documented in the first chapter, has little improvement on health and no discernible impact on risky health behaviors. The third chapter studies how maternal education affects children’s early childhood health outcomes and cognitive skills. I take advantage of the college expansion in China, which creates credible exogenous variation in access to colleges that improves educational attainment. Utilizing the difference in the number of colleges across provinces and cohorts, I employ an instrumental variable approach to examine how maternal education improves children’s outcomes. The results show that maternal education reduces the probability of infant low birth weight and improves children’s early cognitive skills development for mothers of rural origins. In contrast, little impact is found for mothers who grew up in urban areas. I investigate several mechanisms which could explain the outcomes and find that maternal education is strongly associated with assortative marriage and rural-urban migration

Perturbed gut microbiome and fecal and serum metabolomes are associated with chronic kidney disease severity

Abstract Background Chronic kidney disease (CKD) is a severe public health problem associated with a disordered gut microbiome. However, the functional alterations of microbiota and their cross talk with metabolism pathways based on disease severity remain unclear. Results We performed metagenomics and untargeted metabolomics in a cohort of 68 patients with CKD of differing severities and 20 healthy controls to characterize the complex interplay between the gut microbiome and fecal and serum metabolites during CKD progression. We identified 26 microbial species that significantly changed in patients with CKD; 18 species changed as the disease progressed, and eight species changed only in a specific CKD group. These distinct changes in gut microbiota were accompanied by functional alterations in arginine and proline, arachidonic acid, and glutathione metabolism and ubiquinone and other terpenoid-quinone biosynthesis pathways during CKD progression. Further metabolomic analyses revealed that the distributions of toxic and pro-oxidant metabolites from these four essential metabolic pathways varied in the feces and serum as CKD progressed. Furthermore, we observed a complex co-occurrence between CKD severity-related bacteria and the characterized metabolites from the four essential metabolic pathways. Notably, Ruminococcus bromii, fecal hydroquinone, and serum creatinine were identified as the main contributors to the integrated network, indicating their key roles in CKD progression. Moreover, a noninvasive model including R. bromii and fecal hydroquinone, L-cystine, and 12-keto-tetrahydro-LTB4 levels classified the CKD severity (area under the curve [AUC]: > 0.9) and had better performance than the serum creatinine level for mild CKD (AUC: 0.972 vs. 0.896). Conclusions Perturbed CKD severity-related gut microbiota may contribute to unbalanced toxic and pro-oxidant metabolism in the gut and host, accelerating CKD progression, which may be an early diagnostic and therapeutic target for CKD. Video Abstrac

Design and Comparative Study of O3/P2 Hybrid Structures for Room Temperature Sodium-Ion Batteries

Rechargeable sodium-ion batteries have drawn increasing attention as candidates for the post lithium-ion batteries in large-scale energy storage systems. Layered oxides are the most promising cathode materials and their pure phases (e.g., P2, O3) have been widely investigated. Here we report a series of cathode materials with O3/P2 hybrid phase for sodium-ion batteries, which possesses advantages of both P2 and O3 structures. The designed material, Na_0.78Ni_0.2Fe_0.38Mn_0.42O₂, can deliver a capacity of 86 mAh g^–1 with great rate capability and cycling performance. 66% capacity is still maintained when the current rate reaches as high as 10C, and the capacity retention is 90% after 1500 cycles. Moreover, <i>in situ</i> XRD was performed to examine the structure change during electrochemical testing in different voltage ranges, and the results demonstrate 4 V as the optimized upper voltage limit, with which smaller polarization, better structural stability, and better cycling performance are achieved. The results obtained here provide new insights in designing cathode materials with optimal structure and improved performance for sodium-ion batteries